Global warming debate

[jordanfan20]

At school I am constantly called stupid, or an idiot because of my global warming skepticism.
I do not try to get into debates, but kids who think the have a good understanding of global warming try to anchor me to debate them. Although I try to avoid debate I do eventually get in them, and most of the times it results in them using ad hominem, and straw men arguments or they quote Al Gores movie, (Which for the most part is a weak portrayal of anything)

So I came here to ask if any of you guys could give me a hand in finding some material I could print out to show them if they try to make the same arguments, so here are the common arguments they have made.

1. There is a global consensus that man made global warming will cause a catastrophe if not stopped.

2. One kid says that, if ice land melts the whole world will flood. (I don't buy this since I'm pretty sure Iceland wont melt for 1000s of years, and if he is referring to glaciers sliding, this has been refuted, but it would be a great help if someone could link me to this.

3. Everyone who is a skeptic has been paid by Exon mobile.

4. The polar caps are melting, therefore man made global warming is happening and will lead to the major problems.

5. The mere .5 increase in temperature is enough to cause catastrophe.



These are their best arguments, the rest are just calling people stupid and what not.


Thanks guys.

[Skyhunter]

Why are you skeptical of global warming?

[jordanfan20]

When the first hokey stick graph was debunked, I began to take an interest in global warming. I read different arguments surrounding many of the graphs and models used to predict temperatures. When I saw them I was shocked by how inaccurate they were and their inability to even predict temperature as of now. I was also amazed at the overwhelming number of scientists signatures confirming global warming that had no connection to climate studies what so ever.

As the years seemed to go by Al Gores movie appeared so incorrect I began to wander why so many people took it literally, and like other things I realized that many people only believed it because they thought all people believed it except the crazy skeptics.

I do not deny global warming or man made global warming I merely believe that global warming is not going to cause enormous catastrophe.

[Skyhunter]

1. There is a global consensus that man made global warming will cause a catastrophe if not stopped.

Here is the latest report from MIT

http://globalchange.mit.edu/files/document/MITJPSPGC_Rpt180.pdf

2. One kid says that, if ice land melts the whole world will flood. (I don't buy this since I'm pretty sure Iceland wont melt for 1000s of years, and if he is referring to glaciers sliding, this has been refuted, but it would be a great help if someone could link me to this.


I think you mean Greenland not Iceland. Glaciers are losing mass. Here is a Google Earth of sea level change.

<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/kgCYhU5ISwI&hl=en&fs=1&"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/kgCYhU5ISwI&hl=en&fs=1&" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>

3. Everyone who is a skeptic has been paid by Exon mobile.

I assume you are not

4. The polar caps are melting, therefore man made global warming is happening and will lead to the major problems.


Melting ice is a good indicator of warming temperatures.

5. The mere .5 increase in temperature is enough to cause catastrophe.

The global temperature has already risen ~.6C and this change in climate is causing stress on ecosystems.

[jordanfan20]

The Mit Document is interesting and I'd like to do some more research on it.

but to what you were saying before

3. Yes I haven't been paid by Exon mobile, but what I meant was the prominent speculators.

4. I realize that things melting is the result in rising temperatures, however this video doesn't explain how this is not a natural process but instead a man made process. If you view temperatures of the last thousand years there are times when the earth is warm and times when the earth is cold.

5. I don't disagree that .6 increase causes stress on an ecosystem but, I am not aware that it could cause the catastrophes described by many. How do you explain why the models predicted changes above 4 degrees when co2 was doubled, yet our changes have been merely .6 degrees.

[Xnn]

http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-ts.pdf

The above link is a technical summary of current scientific understanding regarding global warming. It is clear that average surface temperature have warmed, especially since 1950 and especially in the arctic.

The thing about global warming is that the rate of warming is so gradual that it is barely noticeable. Even over a 20 year period, it amounts to such a small amount (0.3C or 0.5F) that it is less than the typical temperature changes we experience every day.

Wether it is a catastrophe depends on if and where one is living. Canada and Russia actually stand to benefit, while places like Florida and Holland will eventually lose land to flooding. However, this is over hundreds of years or so and most all of us will be long dead before then.

[Skyhunter]

Exxon did fund a lot of think tanks and bloggers, but they don't anymore.

The current episode of global warming is due to the enhanced radiative forcing brought on by the rise in greenhouse gases, promarily CO2, from human activities, primarily the combustion of fossil fuels.

The physics behind AGW, especially CO2 are well understood. The climate sensitivity is estimated at 2C - 4.5C for a doubling of CO2.

Here is a good thread on this forum that you might find helpful.

http://www.physicsforums.com/showthread.php?t=307685

[Xnn]

How do you explain why the models predicted changes above 4 degrees when co2 was doubled, yet our changes have been merely .6 degrees.


CO2 levels have not doubled. They have risen from about 285ppm to 386ppm.
That equates to 0.44 of a doubling (=LOG((386/285),2)-1).
Climate sensitivity over the long term to CO2 doubling is more likely about 3C/doubling.
So, we expect about 1.3C of warmth from the rise in CO2.

However, there has been a increase in cloudiness over the last century from sulfate aerosals
that has resulted in about 0.5C of cooling.

The total temperature increase from 1850-1899 to 2001-2005 is 0.76°C ± 0.19°C.

[D H]

[QUOTE]1. There is a global consensus that man made global warming will cause a catastrophe if not stopped.
No. There is a consensus that the world has warmed in the last 400 years. That this is caused by man? That consensus is losing steam. That this will cause a catastrophe? No consensus.

That global warming might cause problems for humanity, whether caused by humans or not is a different question. Life is very resilient. It has endured far worse than this global warming. Modern society is a rather fragile compared to life as a whole. What global warming will do to us is a very important question.

2. One kid says that, if ice land melts the whole world will flood. (I don't buy this since I'm pretty sure Iceland wont melt for 1000s of years, and if he is referring to glaciers sliding, this has been refuted, but it would be a great help if someone could link me to this.
That the whole world will flood in the sense of the movie Waterworld is a ridiculous notion. That flooding will affect coastal areas world wide is a realistic notion. It has happened many times in the past, without human help, and it will certainly happen in the far far future, with or without human help. The key issue is how much flooding, and when, is the current global warming going to cause.

BTW, Iceland is not an issue. Greenland is an issue. Antarctica is a very big issue.

3. Everyone who is a skeptic has been paid by Exon mobile.
Assuming for the sake of argument that this is true, so what? Does the fact that a researcher is financed by Exxon-Mobil inherently mean they are lying? This is a logical fallacy called poisoning the well.

More importantly, this assertion is not true. There are plenty of reasoned skeptics who do not work for or consult for "Big Oil", or "Big Anything" for that matter.

4. The polar caps are melting, therefore man made global warming is happening and will lead to the major problems.
That the polar caps are melting is not proof per se that man made global warming is happening. Think of it this way: The polar caps melted a whole lot more 10,000 years ago than they are melting right now. That the polar caps are melting is a sign that the warming that began 10,000 or so years ago is continuing. Is man-made global warming exacerbating this warming? Different issue.

Ice coverage in the Antarctic is currently on the increase. It is the northern ice cap that was getting smaller every year.

5. The mere .5 increase in temperature is enough to cause catastrophe.
Bogus. First off, what catastrophe are your friends talking about? Ask them to be specific. Secondly, the Earth has been a lot warmer than 0.5 degrees warmer than it is now. A 0.5 degree warming is not a catastrophe. A 0.5 degree increase might even be beneficial. Real harm to humanity will require more than a 0.5 degree increase.

Real harm to nature will require even more warming than a paltry 0.5 temperature increase. That said, that there are nearly 7 billion people on the Earth has already done a lot of harm to nature. We have changed the face of the planet. Focusing on the maybe/maybe not global warming problem has, in my opinion, directed attention away from a real problem.

[chriscolose]

I smell lots of straw man.

[mheslep]

CO2 levels have not doubled. They have risen from about 285ppm to 386ppm...depending on when one starts counting of course. It's been down to 180ppm several times in the last million years.

[Skyhunter]

No. There is a consensus that the world has warmed in the last 400 years. That this is caused by man? That consensus is losing steam. That this will cause a catastrophe? No consensus.

Perhaps the consensus is losing steam at Wattsupwiththat, but in the scientific community, especially the climate science community, the evidence supporting AGW is growing.

http://www.thescientificworld.com/headeradmin/upload/2007.03.91.pdf

That global warming might cause problems for humanity, whether caused by humans or not is a different question. Life is very resilient. It has endured far worse than this global warming. Modern society is a rather fragile compared to life as a whole. What global warming will do to us is a very important question.

Life is resilient true. But it takes millions of years after a major extinction event before it rebounds.

Assuming for the sake of argument that this is true, so what? Does the fact that a researcher is financed by Exxon-Mobil inherently mean they are lying? This is a logical fallacy called poisoning the well.


Actually a more accurate characterization would be a red herring fallacy known as an appeal to motive.
(http://en.wikipedia.org/wiki/Appeal_to_motive)
That the polar caps are melting is not proof per se that man made global warming is happening. Think of it this way: The polar caps melted a whole lot more 10,000 years ago than they are melting right now. That the polar caps are melting is a sign that the warming that began 10,000 or so years ago is continuing. Is man-made global warming exacerbating this warming? Different issue.


The warming that began at the beginning of the Holocene peaked about 7000 - 8000 years ago and the Earth has been cooling until the recent Anthropocene epoch.

http://upload.wikimedia.org/wikipedia/commons/c/ca/Holocene_Temperature_Variations.png

The Arctic, until recently had been cooling for at least the last 2000 years.

http://www.physicsforums.com/showthread.php?t=335800

http://www.physicsforums.com/attachment.php?attachmentid=20509&stc=1&d=1252598357

Ice coverage in the Antarctic is currently on the increase. It is the northern ice cap that was getting smaller every year.


Sea ice extent has increased slightly in the Antarctic, but overall ice mass on the continent is decreasing. The Arctic sea ice extent has recovered slightly since the 2007 minimum, but thicker perennial ice is still in decline.

[Skyhunter]

depending on when one starts counting of course. It's been down to 180ppm several times in the last million years.

And those doublings resulted in more than 3C, but were associated with changes in insolation and albedo flip.

http://www.daviesand.com/Choices/Precautionary_Planning/New_Data/IceCores1.gif

[mheslep]

And those doublings resulted in more than 3C, but were associated with changes in insolation and albedo flip....I'm not sure what you mean here when you say 'resulted in...' followed by 'but were associated with...'

[Andre]

Maybe -from seeing all symtoms in this thread- that global warming is much more interesting as a socialogical case than as climatological case. Of course it's also a splendid example of the prevailance of fallacies over science.

Meanwhile, I wonder what the evidence is, that the difference between the current average temperature and any average temperature from the past, is mainly caused by the increase of concentrations of radiative gasses gasses in the atmosphere.

[Vals509]

I feel that whether global warming is true or not, there is still a necessity for us to change our lifestyles. Lets face it, everyone knows that coal and oil are not unlimited and when these resources do run out, we are in a lot of trouble.
It is because of this that we must see that the concept of global warming is like a signal that our current life is not practical and should be changed before its too late. Even if more coal and oil is found, we need to see the wider implications such as petrodictatorship and general public health in particulalry polluted places like beijing.
This is why we should not underestimate the power of global warming true or not.

[Skyhunter]

I'm not sure what you mean here when you say 'resulted in...' followed by 'but were associated with...'

What I was saying is that a doubling resulted in more than 3C rise in temperature, closer to 8C. Not all of that rise however was from CO2.

[Skyhunter]

Meanwhile, I wonder what the evidence is, that the difference between the current average temperature and any average temperature from the past, is mainly caused by the increase of concentrations of radiative gasses gasses in the atmosphere.

Of course you do.

Of course it's also a splendid example of the prevailance of fallacies over science.

[Andre]

Then why don't you tell it finally?

[Skyhunter]

Then why don't you tell it finally?

John Tyndall already did. Modern physics has confirmed it. You simply refuse to believe it in your quest for a black swan.

[Andre]

so how did he proof it and what has modern science confirmed?

I still don't see that there is positive proof for the difference between the current average temperature and any average temperature from the past, to be caused mainly by the increase of concentrations of radiative gasses gasses in the atmosphere.

[z0rn dawg]

I feel that whether global warming is true or not, there is still a necessity for us to change our lifestyles. Lets face it, everyone knows that coal and oil are not unlimited and when these resources do run out, we are in a lot of trouble.
It is because of this that we must see that the concept of global warming is like a signal that our current life is not practical and should be changed before its too late. Even if more coal and oil is found, we need to see the wider implications such as petrodictatorship and general public health in particulalry polluted places like beijing.
This is why we should not underestimate the power of global warming true or not.

New estimates have been coming out that show there's more oil than once thought. We're developing the technologies to actually get this oil. OPEC can just say there's xxxx oil left when there's actually yyyy oil left. There's an interview with an OPEC representative on YouTube that I'm trying to find.

Here's my questions about global warming:
1. What's the proof that anthropogenic release of CO2 is causing global warming? Is it just association as causation? Graphs that I've seen show that temperature rises before CO2, which leads me to believe that something besides CO2 initially causes global warming. And according to the IPCC's 2001 report, over 97% of CO2 in the atmosphere is natural and not from man.
2. What are Al Gore's qualifications? Or any politician really? Al Gore has a degree in political science IIRC. He's not an expert in natural science, so why is he considered an authority? Plus he got sued for fraud. And his "documentary" had at least 11 falacies according to the UK. His "documentary" was filled with lies. I've heard many politicians talk about global warming/climate change. Most of them talk out of their rear ends.
3. Why doesn't the IPCC (or Al Gore) cite water vapor as a greenhouse gas? I'm pretty sure it is and there's a lot of it. Something like 95% of all greenhouse gas is water vapor. That's not to say that 95% of the greenhouse effect is attributed to water vapor, but if you take water vapor out of the equation, CO2 looks like a huge problem.

[Xnn]

3. Why doesn't the IPCC (or Al Gore) cite water vapor as a greenhouse gas? I'm pretty sure it is and there's a lot of it. Something like 95% of all greenhouse gas is water vapor. That's not to say that 95% of the greenhouse effect is attributed to water vapor, but if you take water vapor out of the equation, CO2 looks like a huge problem.

I'm not going to bother discussing Al Gore's qualifications for obvious reasons.

Anyhow, earth is covered with water and the amount of water vapor is a function of other factors. So, it'd be silly to cite water vapor as a climate driver; similar to wondering about Al Gore.

The amount of water vapor in the atmosphere is primarily a function of CO2 and CH4 levels.
Without CO2 or CH4, there'd be almost no water vapor in the atmosphere.

[Andre]

The amount of water vapor in the atmosphere is primarily a function of CO2 and CH4 levels.
Without CO2 or CH4, there'd be almost no water vapor in the atmosphere.

So how about an empirical test?

Take a chamber with water on the bottom and above it ,one atmosphere of inert gas and one chamber with any radiative gas, CO2 whatever.

Have both chambers heated with an insolation flux of 1367/pi , that's roughly the average solar energy at the equator. Since there was no water vapor and hence no clouds, the albedo of those chambers could be about the same as the moon, say 12% so we have about 383 w/m2left that is absorpted and that heats the chambers to a temp of 287 Kelvin. At that average temperature (14C) water can evaporate, without help of CO2, to attain a maximum of 12.1 gram/m3 (http://www.humidity-calculator.com/index.php).

So how much water vapor would both chambers contain after stabilisation? Why would the chamber without radiative gasses hold no water vapor?

And what if the CO2 less air of that hypothetical earth is getting to several gram/m3 at the equator, would that not start greenhouse effect and create positive feedback?

Also the residence time of water vapor in the atmosphere is very short, which is the reason why it is thought that it is a feedback of CO2. But water evaporates all the time and the vapor that disappears by condensation, clouds and precipitation, is simply replaced with new water vapor especially in the equator, sustaining it's own greenhouse effect, regardless of the residence time.

[mheslep]

...Anyhow, earth is covered with water and the amount of water vapor is a function of other factors. So, it'd be silly to cite water vapor as a climate driver; ....Er not really. If I understand correctly, the reason why water vapor is not germane to forcings is that near the ground water vapor completely dominates and shuts off nearly all long wave outward radiation, and thus near the ground the only outward bound thermal paths are conduction/convection. Thus near the ground more or less CO2 doesn't matter. Most of the potential for radiative change is at the higher altitudes where water vapor is not, and CO2 is.


The amount of water vapor in the atmosphere is primarily a function of CO2 and CH4 levels.
Without CO2 or CH4, there'd be almost no water vapor in the atmosphere.
That's not a useful statement. With out a great many factors there'd be no water vapor in the atmosphere, and yes w/ no greenhouse effect at all the water would nearly all be ice. Obviously solar insolation is the primary driver. I think you want something like "for human caused changes to water vapor in the atmosphere, increases to CO2 are the primary agent" - and I don't know if even that is true.

[Skyhunter]

so how did he proof it and what has modern science confirmed?

I still don't see that there is positive proof for the difference between the current average temperature and any average temperature from the past, to be caused mainly by the increase of concentrations of radiative gasses gasses in the atmosphere.

And there is nothing anyone can say to change your mind. You seem to ignore fact that certain gasses are transparent to SW radiation (incoming) and opaque to LW radiation (outgoing) by itself is proof that adding more of these gasses will result in higher temperatures at the surface. The only question is how much. Denial of the basic physics is unscientific.

[Andre]

The denial part is a strawman. Nobody is denying any basic physics. It's more that one should consider all of the applicable physics and not only the absorption of LW transmission, simply because absorption also means retransmission.

But a principle is not proof. There are many factors considered to be forcing the climate or not. How is it proved that LW absorbtion and retransmission is the most important one?

[Skyhunter]

Here's my questions about global warming:
1. What's the proof that anthropogenic release of CO2 is causing global warming? Is it just association as causation? Graphs that I've seen show that temperature rises before CO2, which leads me to believe that something besides CO2 initially causes global warming. And according to the IPCC's 2001 report, over 97% of CO2 in the atmosphere is natural and not from man.

Isotopic fractionation of the carbon atom is proof that the buildup of CO2 in the atmosphere is from anthropogenic sources, which is to be expected since humans are adding an additional 7-8 gigatons of carbon a year to the atmosphere.

If the graphs you are referring to are from the Antarctic ice cores, then yes, the initial forcing that terminates a glacial epoch is from orbital forcings. However, those are slight forcings that cannot account for the temperature differential from glacial to interglacial epochs. CO2 and CH4 are feedbacks in those cases. There are other periods in Earth's history however when CO2 leads. The current Anthropocene is one of those epochs. The present day global warming is being driven by enhanced radiative forcing due to atmosphere becoming optically thicker from GHG.

Human emissions are ~5% of the natural carbon cycle. The cycle is generally in equilibrium, humans are adding more to the positive side of the equilibrium. Natural sinks can only take up about half of these emissions, while the rest builds up in the atmosphere. Additionally, the ocean is becoming more acidic due to the higher rate of absorption.

2. What are Al Gore's qualifications? Or any politician really? Al Gore has a degree in political science IIRC. He's not an expert in natural science, so why is he considered an authority? Plus he got sued for fraud. And his "documentary" had at least 11 falacies according to the UK. His "documentary" was filled with lies. I've heard many politicians talk about global warming/climate change. Most of them talk out of their rear ends.

What are your qualifications? What orifice are you talking out of?

3. Why doesn't the IPCC (or Al Gore) cite water vapor as a greenhouse gas? I'm pretty sure it is and there's a lot of it. Something like 95% of all greenhouse gas is water vapor. That's not to say that 95% of the greenhouse effect is attributed to water vapor, but if you take water vapor out of the equation, CO2 looks like a huge problem.

The IPCC does cite water vapor as a GHG.

Water vapor accounts for ~66% of the greenhouse effect, Clouds and water vapor ~85%, and CO2 ~12%. Water vapor is not a forcing, it is a feedback since specific humidity is dependent on atmospheric temperature and a source for evaporation. The warmer the Earth is the more water vapor that is present in the atmosphere.

[Skyhunter]

The denial part is a strawman. Nobody is denying any basic physics. It's more that one should consider all of the applicable physics and not only the absorption of LW transmission, simply because absorption also means retransmission.

But a principle is not proof. There are many factors considered to be forcing the climate or not. How is it proved that LW absorbtion and retransmission is the most important one?

Andre we have been over this time and time again.

The Earth's blackbody temperature is 255K, the surface is 288K.

If GHG are not the mechanism driving the 33K temperature differential, (as every climatologist believes) then what do you propose is the mechanism?

[jordanfan20]

http://www.climateaudit.org/?p=7320


Most of this stuff is way over my head since I am only a high school student, but from what I've read Steve Mcentire does a pretty amazing job debating climatologist and presenting the side of skeptics. I'm not sure if this is the correct hyper link or not but he released a paper that was pretty incredible.

[Skyhunter]

http://www.climateaudit.org/?p=7320


Most of this stuff is way over my head since I am only a high school student, but from what I've read Steve Mcentire does a pretty amazing job debating climatologist and presenting the side of skeptics. I'm not sure if this is the correct hyper link or not but he released a paper that was pretty incredible.

McIntyre is not a climatologist, and his website is not a credible source for this forum.

For the most part he is just a nay sayer, attacking the work of others and offering very little to the scientific body of knowledge.

[Xnn]

Why would the chamber without radiative gasses hold no water vapor?


Without greenhouse gases like CO2 and CH4, water freezes into ice or snow and albedo goes up. So evaporation ceases, water vapor levels drop and it cools off.

The key is that water can exist in more than 1 state and it's albedo is much higher when it cools.

[Xnn]

If I understand correctly, the reason why water vapor is not germane to forcings is that near the ground water vapor completely dominates and shuts off nearly all long wave outward radiation, and thus near the ground the only outward bound thermal paths are conduction/convection. Thus near the ground more or less CO2 doesn't matter.

It's true that water vapor dominates at lower elevations. However, CO2 does influence temperatures at lower elevations by increasing the total height of the active atmosphere.



I think you want something like "for human caused changes to water vapor in the atmosphere, increases to CO2 are the primary agent" - and I don't know if even that is true.

A 100,000 years ago, when humans had negligible impact, the amount of water vapor in the atmosphere was still linked to the levels of CO2 and CH4. The physics of the relationship between water and greenhouse gases has not changed.

[mheslep]

It's true that water vapor dominates at lower elevations. However, CO2 does influence temperatures at lower elevations by increasing the total height of the active atmosphere.If that means that the CO2 blocked long wave in the upper atmosphere radiates/conducts back down to the lower elevations - yes.

A 100,000 years ago, when humans had negligible impact, the amount of water vapor in the atmosphere was still linked to the levels of CO2 and CH4. The physics of the relationship between water and greenhouse gases has not changed.Perhaps. I was taking issue with the use of "the atmosphere is primarily a function of ", which has now changed to a more reasonable "linked".

[Andre]

Without greenhouse gases like CO2 and CH4, water freezes into ice or snow and albedo goes up. So evaporation ceases, water vapor levels drop and it cools off.

The key is that water can exist in more than 1 state and it's albedo is much higher when it cools.

Maybe the problem is that the whole hypothetical Earth is treated as been in it's average temperature - radiation state of the black body assumption. However a large part of the Earth receives enough solar radiation all the time to have an average temperature well above freezing, generating it's own water vapor feedback effect without help of other greenhouse gasses.

[Skyhunter]

Maybe the problem is that the whole hypothetical Earth is treated as been in it's average temperature - radiation state of the black body assumption. However a large part of the Earth receives enough solar radiation all the time to have an average temperature well above freezing, generating it's own water vapor feedback effect without help of other greenhouse gasses.
Where is your evidence?

255K is -18.15C. Water freezes at 0C.

And you are proposing that water vapor is the only GHG? How do you explain the snowball earth events? Or do you deny them as well? How do you explain the glacial interglacial epochs?

The truth is that neither current climate nor paleo climate can be explained without the contribution from the known radiative forcing of the various GHG, all of them, not just the convenient ones to support your denial.


Here is the absorption spectrum.

http://www.te-software.co.nz/blog/auer_files/image001.gif

You throw out a statistical analysis that demonstrates antipersistent process in climate sensitivity as a refutation of WV and albedo feedbacks, without any explanation of a physical mechanism to support that conclusion. When the simple fact is that the primary feedback is thermal emission, and yes it is negative. Therefore Karner's paper does nothing more than prove the obvious, and says nothing about climate sensitivity in regards to absolute humidity or albedo.

And then you have the gall to insinuate that others are being unscientific.

[Skyhunter]

It's true that water vapor dominates at lower elevations. However, CO2 does influence temperatures at lower elevations by increasing the total height of the active atmosphere.


If you look at the absorption spectrum for water vapor you will notice that CO2 fills in a gap in the water vapor spectrum around 15 microns. Therefore CO2 does have an effect at lower elevations.

[Andre]

Where is your evidence?

255K is -18.15C. Water freezes at 0C.

That's again once more the average, while I have shown twice here that you cannot treath the earth for it's average. What is the black body temperature on the equator? Is that 255K too? Maybe peek here (http://www.physicsforums.com/showpost.php?p=2383978&postcount=24).

Therefore Karner's paper does nothing more than prove the obvious, and says nothing about climate sensitivity in regards to absolute humidity or albedo.

No Karner shows that the total measured output of all the series that he investigated show non-persistency. Total means for me, including all feedbacks, none excluded. And there is no need to explain what you measure. It doesn't change what you measure.

And then you have the gall to insinuate that others are being unscientific.

That's a strawman I never said that. Others may perhaps judge in which posts here the fallacies dominate the science, for instance:

And you are proposing that water vapor is the only GHG?

Strawman,

How do you explain the snowball earth events? Or do you deny them as well? How do you explain the glacial interglacial epochs?


three times red herring in a nice slippery slope construction but still totally irrelevant

[Skyhunter]

Andre,

Your water vapor feedback hypothesis and experiment in a closed chamber is plain silly. The Earth is not a test tube and the little water vapor that might ablate from the equator would be quickly dissipated and have a negligible effect on LW absorption. Any heating that occurred during the day would be quickly lost overnight.

Yes Karner did analyze the total output and found that negative feedbacks dominate according to his analysis. But as I pointed out, thermal emission is the dominant feedback, and it is negative. Therefore he simply affirmed the obvious and leaped to an illogical conclusion.

You definitely insinuated in this thread and others that those who disagree with your fringe hypothesis are resorting to fallacies over science. Then you go on to wrongly characterize my questions as fallacies.

Why do you not answer the questions?

Because you cannot. You cannot explain current climate, or paleoclimate without greenhouse gasses. Instead you declare the question a fallacy which is itself an ad hominem fallacy.

[z0rn dawg]

Isotopic fractionation of the carbon atom is proof that the buildup of CO2 in the atmosphere is from anthropogenic sources, which is to be expected since humans are adding an additional 7-8 gigatons of carbon a year to the atmosphere.Over 97% (according to the IPCC's 2001 report) of CO2 in the atmosphere is from natural sources. I'm not arguing that anthropogenic release of carbon dioxide is in the atmosphere; it just seems so insignificant that making a decision based on that may not be the best course of action.


Human emissions are ~5% of the natural carbon cycle. The cycle is generally in equilibrium, humans are adding more to the positive side of the equilibrium. Natural sinks can only take up about half of these emissions, while the rest builds up in the atmosphere. Additionally, the ocean is becoming more acidic due to the higher rate of absorption.IPCC's 2001 report stated that upwards of 98% of CO2 is absorbed, nowhere near the 50% you cited. I'd suspect it's a bit lower now, but not 48% lower.



What are your qualifications? What orifice are you talking out of?My whole point is that Al Gore isn't an expert. From what I've read (and from what he's said), I really don't think this guy should be considered an "authority" on the topic. Obviously, not everyone thinks he's an expert, but too many Americans take what he says as fact. The fact is he lied in his "documentary", was sued by 30,000 scientists, and was found guilty of fraud in the UK. He's been torn apart in Congress and all he's done IMO is spread propaganda. Even IPCC scientists think he's lying. As for me, I'm a natural science major (I can go bio, chem, or biochem...haven't officially declared yet). I've spoken to post-baccs and doctors about it. I've studied both sides of the research and made my decisions based on that. I think Gore has his own agenda, and it's dangerous what he's doing.


Water vapor accounts for ~66% of the greenhouse effect, Clouds and water vapor ~85%, and CO2 ~12%. Water vapor is not a forcing, it is a feedback since specific humidity is dependent on atmospheric temperature and a source for evaporation. The warmer the Earth is the more water vapor that is present in the atmosphere.So is carbon dioxide. As earth's temperatures rise, the solubility for gas in the ocean decreases and they release CO2 in the atmosphere. So, they both are dependent on the temperature.

From what I've read, many scientists don't believe that CO2 is the major cause of global warming.

[Skyhunter]

Over 97% (according to the IPCC's 2001 report) of CO2 in the atmosphere is from natural sources. I'm not arguing that anthropogenic release of carbon dioxide is in the atmosphere; it just seems so insignificant that making a decision based on that may not be the best course of action.

Could you provide a citation to the page where this is stated?

IPCC's 2001 report stated that upwards of 98% of CO2 is absorbed, nowhere near the 50% you cited. I'd suspect it's a bit lower now, but not 48% lower.

I said ~5% not 50.

Here is the carbon cycle.

http://worldenergyblog.com/wp-content/uploads/2009/09/carbon_cycle_NASA.jpg

My whole point is that Al Gore isn't an expert. From what I've read (and from what he's said), I really don't think this guy should be considered an "authority" on the topic. Obviously, not everyone thinks he's an expert, but too many Americans take what he says as fact. The fact is he lied in his "documentary", was sued by 30,000 scientists, and was found guilty of fraud in the UK. He's been torn apart in Congress and all he's done IMO is spread propaganda. Even IPCC scientists think he's lying. As for me, I'm a natural science major (I can go bio, chem, or biochem...haven't officially declared yet). I've spoken to post-baccs and doctors about it. I've studied both sides of the research and made my decisions based on that. I think Gore has his own agenda, and it's dangerous what he's doing.



I get your point. You don't like Al Gore or his politics. That has absolutely no bearing on his film. And BTW he was not sued by 30,000 scientists. He was threatened with a lawsuit by deniers, but that was more a publicity stunt on their part that never amounted to actual court action. He was not found guilty of fraud in the UK. His film is still being shown to students in the UK with caveats, so that students don't confuse advocacy with science.

It is against forum rules to make false assertions. If you have any evidence to prove otherwise please link it.

So is carbon dioxide. As earth's temperatures rise, the solubility for gas in the ocean decreases and they release CO2 in the atmosphere. So, they both are dependent on the temperature.

Whether CO2 is from ocean off gassing or human emissions is irrelevant to it's radiative properties in the atmosphere.

From what I've read, many scientists don't believe that CO2 is the major cause of global warming.

Then I suggest you broaden your list of literary selections.

[Andre]

This thread is going in circles and is pointless when peer reviewed articles by experts can simply be declared void here without any substantiation.

[Skyhunter]

This thread is going in circles and is pointless when peer reviewed articles by experts can simply be declared void here without any substantiation.

What are you talking about?

I agreed with Karner, antipersistency in climate sensitivity does support negative feedbacks being dominant.

I disagree with his conclusion that his analysis changes the accepted 2C - 4.5C per doubling of CO2.

Thermal emission is the dominant feedback and it is negative. The positive feedbacks are not going to overcome it.

[Xnn]

Over 97% (according to the IPCC's 2001 report) of CO2 in the atmosphere is from natural sources. I'm not arguing that anthropogenic release of carbon dioxide is in the atmosphere; it just seems so insignificant that making a decision based on that may not be the best course of action.

IPCC's 2001 report stated that upwards of 98% of CO2 is absorbed, nowhere near the 50% you cited.


I doubt these claims regarding the 2001 IPCC report are true.
Besides, the most current IPCC report is 2007.
Why reference and out of date version?

Please provide a link and reference to the page number on which it appears.

[Xnn]

If you look at the absorption spectrum for water vapor you will notice that CO2 fills in a gap in the water vapor spectrum around 15 microns. Therefore CO2 does have an effect at lower elevations.

Thanks Skyhunter;

I appreciate your post and corrections!

[mheslep]

If you look at the absorption spectrum for water vapor you will notice that CO2 fills in a gap in the water vapor spectrum around 15 microns. Therefore CO2 does have an effect at lower elevations.Good point, though I think you mean from 1 to 5 microns? Of the predicted total heat gain from CO2, I wonder how much of it is attributed to action at various elevations?

[Xnn]

This thread is going in circles and is pointless when peer reviewed articles by experts can simply be declared void here without any substantiation.

What peer reviewed articles are you referring to?

Anyhow, getting back to climate models.

Consider 2 planets covered with ice at the same distance as the earth is from the sun.
They are frozen solid.
The albedo is so great that there is not enough warmth to melt the ice.
Some ice sublimates during the day, but the water vapor in the atmosphere is very low and condenses every night.

Planet A has a atmosphere of Nitrogen and Oxygen.
Planet B has a similar atmosphere, but we are allowed to vary the level of CO2.

Which planet will be warmer?

Most people realize that earth was at one time much warmer than it is now.
It was also much colder during the ice ages.
In each extreme case, the level of CO2 was either lower or higher than it is now.

Proof positive!

[Skyhunter]

Good point, though I think you mean from 1 to 5 microns?

There is little emission at the 1-5 micron wavelength.

http://www.te-software.co.nz/blog/auer_files/image001.gif

Notice the arrow on the right. It is pointing at peak Earth emission and where water vapor drops off precipitously. You'll note that the CO2 absorption band peaks right where water vapor begins to drop. There is some overlap, but without CO2 that portion of the spectrum would not be saturated.

Of the predicted total heat gain from CO2, I wonder how much of it is attributed to action at various elevations?

That is computed by a line by line analysis of the radiation code at different pressures.

[mheslep]

There is little emission at the 1-5 micron wavelength..Yes, sorry I was clumsy there looking back and forth\ between pages.

[Vals509]

New estimates have been coming out that show there's more oil than once thought. We're developing the technologies to actually get this oil. OPEC can just say there's xxxx oil left when there's actually yyyy oil left.

Even if that is true, there is still the fact that oil is not something that is produced over a short time. In addition to this, human populations are exploding and also demand for oil is bound increase greatly. Even if there is 'yyyy' oil left, eventually it WILL GET OVER and as i have mentioned before, we will be in great trouble.

[Andre]

Which sounds absolutely logical. No problem with that all.

The problem however is if you try to coerce the world to change habits with something that is not true. Eventually, sooner or later, may it be next week or in fifty years, the truth will have its boots on.

Try to convince the world then, to change habits: "but this time it is really really true, cross my heart"; "Right that's what you say all the time".

The need to change things should be based on facts and that damage to science will be very very hard to repair.

Therefore, the sooner the straying is corrected, the better. However anybody who attempts to do so is automatically a folk devil (http://en.wikipedia.org/wiki/Folk_devil) (the deniers (http://www.amazon.com/Deniers-Renowned-Scientists-Political-Persecution/dp/0980076315)) as has been demonstrated in this thread once more.

[Skyhunter]

Andre,

You are projecting. You come into this thread (http://www.physicsforums.com/showpost.php?p=2383401&postcount=15)insulting people and declaring that there is no evidence that greenhouse gasses warm the Earth, then you offer a thought experiment (http://www.physicsforums.com/showpost.php?p=2383401&postcount=15) that is easily debunked.

Instead of defending your position you accuse others of being dishonest.

Not very scientific.

[Andre]

Well, one could not wish for better demonstration of what I'm trying to say.

Note the density of strawmans.

[Skyhunter]

So why don't you defend your argument instead of attacking others?

[z0rn dawg]

Could you provide a citation to the page where this is stated?Page 188, Figure 3.1.

I get your point. You don't like Al Gore or his politics. That has absolutely no bearing on his film. And BTW he was not sued by 30,000 scientists. He was threatened with a lawsuit by deniers, but that was more a publicity stunt on their part that never amounted to actual court action. He was not found guilty of fraud in the UK. His film is still being shown to students in the UK with caveats, so that students don't confuse advocacy with science.I'm pretty sure they sued, whether it amounted to anything I'm not sure of. It may have been a publicity stunt, but so was "An Inconvenient Truth." I was mistaken: Gore was not found guilty of fraud. The judge just found nine significant errors, proving Gore's "documentary" is not a documentary. The only thing that bothers me about the guy is that he lied to get his point accross. If he had so many scientists working with him on it, how could they make nine significant mistakes? Seems too high to be mistakes.



Then I suggest you broaden your list of literary selections.So some scientists don't believe that CO2 is causing global warming? There's no way you can just not listen to what they have to say. They're part of the scientific community. I've looked at both sides, and there does not seem to be a consensus. The media talks about man-made global warming due to CO2, but many scientists don't agree. I've read parts of the IPCC's 2001 and 2007 reports (I'm citing the 2001 report because that's what I have on hand). I'm pretty sure that's one valid, respected source that blames human activity.

[Count Iblis]

There's no way you can just not listen to what they have to say

If they don't publish what they say in peer reviewed journals, then what they say has no more value than what my grandmother has to say about this issue.

[Skyhunter]

Thanks for the citation Zorn.

I would point out however that the same figure shows the cycle in balance before the human contribution. It is not the size of the carbon cycle but the differential between emission and sequestration that is creating the problem.

Nothing wrong with being skeptical. But the errors in the documentary were not significant, besides, the film was meant to educate people to the broader public problem, not to answer open scientific questions. I don't remember all the errors found, I assume one was that you could see the clean air act in the ice cores, and another was an incomplete explanation of the correlation between carbon dioxide and temperature, leaving the insinuation that temperature would follow carbon dioxide levels, when the truth is that the temperature rise would be about 1/3 the carbon dioxide rise. Generally the film does a good job of education and was therefore approved for use in public schools with caveats.

[Bored Wombat]

When the first hokey stick graph was debunked, I began to take an interest in global warming.
I'm not sure that this is the scientific view.

Probably the most respected scientific journal in the world is Nature. (Certainly the most respected would be Science, Nature or Cell)

Their take on the National Academies review of the Hockey stick is that Academy affirms hockey-stick graph (http://www.nature.com/nature/journal/v441/n7097/full/4411032a.html). Which is approximately the reading that scientists gave the report.

It was critical of how the data was used, and there were statistical methodological errors, but these made no material difference.

Probably your view that it was "debunked" has its origins in the counterscientific blogs and opinion pieces that proliferate on the internet, rather than an unbiased scientific source.

I read different arguments surrounding many of the graphs and models used to predict temperatures. When I saw them I was shocked by how inaccurate they were and their inability to even predict temperature as of now.

Again, it seems like you are not reading scientific sources.

Current climate models hindcast global mean surface temperature within the 90% confidence interval much more than 90% of the time, so the question is actually the opposite. Why are they so accurate? (See:Why are climate models reproducing the observed global surface warming so well? (http://www.agu.org/pubs/crossref/2008/2008GL034932.shtml) - Geophys. Res. Lett., 35, L18704, doi:10.1029/2008GL034932)

I was also amazed at the overwhelming number of scientists signatures confirming global warming that had no connection to climate studies what so ever.

The closer a scientist's field is to currently publishing on climate change, the more likely they are to agree with the human influence on climate. (see: Examining the Scientific Consensus on Climate Change (http://tigger.uic.edu/~pdoran/012009_Doran_final.pdf), Eos Trans. AGU, VOLUME 90 NUMBER 3 20 JANUARY 2009)

As the years seemed to go by Al Gores movie appeared so incorrect I began to wander why so many people took it literally, and like other things I realized that many people only believed it because they thought all people believed it except the crazy skeptics.

I do not deny global warming or man made global warming I merely believe that global warming is not going to cause enormous catastrophe.

The current drop in biodiversity is attributable in part to climate change. And that is about 30% in the last 35 years. That should concern most people.

Analysis of species ranges has been pretty grim. (see: Extinction risk from climate change (http://www.gbltrends.com/doc/nature02121.pdf), Nature (2004))

Note also that adaptation is very expensive. Bhutan was the first nation to receive UN funds for the underdeveloped nations to deal with climate change. The $3.5 million was supplemented further by other international donors, but has been insufficient to drop the level of the new glacial lakes to avoid floods ... and they are only working on one of over two thousand glacial lakes in the small country. (see:Climate: When the ice melts (http://www.nature.com/news/2009/091021/full/4611042a.html), nature news.)

I am aware of desert ecological communities, and sub antarctic communities that don't exist any more because of climate change, and I think any ecologist could tell a similar story of whatever system they study. Corals are also under severe stress in many parts of the world, with large areas of bleaching (meaning the symbiote is dead). This will lower the entire productivity of the oceans. As will acidification.

The change from snow to rain in the Himalayas puts about a quarter of the worlds population under fresh water stress for most of the year. (And floods their homes and croplands for the rest of the year)

I think the science shows a lot of expensive consequences, but you have to read about them from scientific sources, because there is a lot of fossil fuel-funded nay-saying on the net. If a site is dedicated to global warming denial, it is pretty safe to not read it.

Nature reports climate change (http://www.nature.com/climate/index.html) is a good way to keep up with the science, without it becoming overly technical, and it is important to read a science based site on this subject occasionally, because the signal to noise ratio in the popular press and the blogs and forum sites is very low on this subject.

[DrClapeyron]

http://www.youtube.com/watch?v=eScDfYzMEEw&feature=related

People shouldn't be afraid of the future, especially young people such as myself. We should view the potential catastrophic consequence as a very stimulating problem to solve. Why back down and shoot ourselves in the foot?

[mheslep]

I'm not sure that this is the scientific view.

Probably the most respected scientific journal in the world is Nature. ...I think you mean prestigious, not respected, and for its peer review process of submitted papers, and not because of its news articles like the one linked here:
Their take on the National Academies review of the Hockey stick is that Academy affirms hockey-stick graph (http://www.nature.com/nature/journal/v441/n7097/full/4411032a.html). Which is approximately the reading that scientists gave the report.

Probably your view that it was "debunked" has its origins in the counterscientific blogs and opinion pieces that proliferate on the internet, rather than an unbiased scientific source.How ever one characterizes the Mann et al 1200 year temperature reconstruction, there is the observable point that it appeared right up front in the 2001 IPCC Summary for Policy Makers (http://www.grida.no/climate/ipcc_tar/wg1/005.htm) almost as an icon, with no medieval warming period, and then in the 2007 third IPCC report after the investigation it vanished from the Summary (http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-spm.pdf), was moved (http://www.ipcc.ch/graphics/ar4-wg1/jpg/fig-6-10.jpg)to the paleo section and merged in with several other reconstructions that show the medieval period as warm.

I am aware of desert ecological communities, and sub antarctic communities that don't exist any more because of climate change,Could you cite one please (obviously one in the last 30 years to be associate w/ AWG)?

The change from snow to rain in the Himalayas puts about a quarter of the worlds population under fresh water stress for most of the year. (And floods their homes and croplands for the rest of the year)Source?

I think the science shows a lot of expensive consequences, but you have to read about them from scientific sources, because there is a lot of fossil fuel-funded nay-saying on the net. If a site is dedicated to global warming denial, it is pretty safe to not read it.Science can show consequences, I don't know that estimating costs is also science, certainly not by climate scientists.

[Bored Wombat]

I think you mean prestigious, not respected, and for its peer review process of submitted papers, and not because of its news articles like the one linked here:
Nature News is still respected on the strength of the scientific basis of the organisation.

And given that most people aren't going to read the national academies report, its a good source of the scientific opinion on it.

Other news sources said the same of course:
Backing for 'hockey stick' graph (http://news.bbc.co.uk/2/hi/5109188.stm).

And the scientific blogosphere had the same analysis. The point is that the national academies report supported the hockey stick graph, and a scientist that read it could tell you that, even the reporters for Nature.

How ever one characterizes the Mann et al 1200 year temperature reconstruction, there is the observable point that it appeared right up front in the 2001 IPCC Summary for Policy Makers (http://www.grida.no/climate/ipcc_tar/wg1/005.htm) almost as an icon, with no medieval warming period, and then in the 2007 third IPCC report after the investigation it vanished from the Summary (http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-spm.pdf), was moved (http://www.ipcc.ch/graphics/ar4-wg1/jpg/fig-6-10.jpg)to the paleo section and merged in with several other reconstructions that show the medieval period as warm.

The finding of Mann et al, that the little ice age and the medieval warm period where not at the same time over the northern hemisphere is interesting, valid, and still holds now. This is why whole hemisphere reconstructions show it much more weakly than the 1990 IPPC graph from one site in central England. (still used in the denialist literature such as "swindle".)

The national academies said that it was over used, considering at the time it had not yet been reproduced.

Your argument that it "vanished from the summary", therefore it must be considered wrong doesn't follow. The IPCC reports are about the science that has been learned since the last report. The hockey stick was well reported in the 2001 IPCC report. There is no reason to put it in such a prominent place in the 2007 IPCC report.

It is true that it doesn't appear in the summary for policy makers. You are exaggerating your case when you call this the summary. It does appear in the technical summary.

Could you cite one please (obviously one in the last 30 years to be associate w/ AWG)?

I know that from conversations with ecologists, I don't know where or if they have been published. The rainy season in outback east australia has changed time of year. The ecological communities that blossom in the vastly different temperatures are different. (And not the interesting and unique ones). Freshwater communities devastated by the same effect. The rivers are out of water at the wrong time of year.

The damage to the subantarctic is from interviews with those studying it. I'll look one up if you like, but I'll submit this first, as I might not get a chance.

Source?

Common knowledge.

But the first google hit I got was this:
"Dr Claudia Sadoff of The World Bank, said in her
opening address: “The countries in the Himalayan subregion
account for 40% of the world’s population. The
rivers in the region are extreme in terms of population
density, sedimentation and variability. Each river is in
effect many rivers in one; each is an ecosystem in itself. Hence, issues related to
the Himalayan rivers are complicated. These are difficult rivers to understand,
manage and talk about. They are shared rivers, which increases complications.
There has been a lot of talk recently about how these rivers are under threat.
Glaciers are disappearing, rivers are running dry; rivers are overdrawn and
polluted. These rivers are extremely variable in terms of floods and droughts.
They are even more threatened due to climate change. The World Bank has
identified climate change hot-spots. One is over the Himalayas." - http://www.strategicforesight.com/Kathmandu%20Report.pdf

Will it do? I'm sure I could find something by the IPCC or a NGO about the consequences of climate change in the region if you want.

Science can show consequences, I don't know that estimating costs is also science, certainly not by climate scientists.
I wasn't really meaning financial costs.
But economics is a science of sorts. And an important one for deciding on climate change policy.

[mheslep]

Your argument that it "vanished from the summary", therefore it must be considered wrong doesn't follow.
I did not say that.

It is true that it doesn't appear in the summary for policy makers. You are exaggerating your case when you call this the summary. It does appear in the technical summary.Summary, as in Summary for Policy Makers.


I know that from conversations with ecologists, ...That's fine, but not appropriate for this forum.
http://www.physicsforums.com/showthread.php?t=280637

[Bored Wombat]

I did not say that.
I doubt that I misinterpreted you. If you think that the paraphrase has lost your meaning, could you point out how?

Summary, as in Summary for Policy Makers.
I can see that that's why you must mean, because of the way that it appeared in the Technical Summary. But you should still be specific when claiming something "vanished" from somewhere, and using that to imply that it has lost favour.

That's fine, but not appropriate for this forum.
It's pretty common knowledge, and not at all controversial that ecosystems are being impacted by climate change, and neither that for ecosystems with smaller geographic ranges, (being the unique in especially interesting ones) that impact is more often extinction or increased risk of extinction.

Since its not controversial, its not inappropriate.

[heldervelez]

Google for 'Joanne nova' her handbook is very helpfull.
Her 16 pages "The skeptics handbook" can help you.
quoting from her site "Volunteers have translated it into German, French, Norwegian, Finnish, Swedish, Turkish, Portuguese and Danish. (Versions in Dutch, Spanish, and possibly Italian are on the way). "

The translation to pt-br has been done by university teachears that are brasilian climatologists.
Joanne is not a scientist but, as myself and a lot of us, are tracking the inconvenient facts behind all that noise that pervades the media.
And her site has links to helpful sources.

[mheslep]

...I can see that that's why you must mean, because of the way that it appeared in the Technical Summary. But you should still be specific when claiming something "vanished" from somewhere, and using that to imply that it has lost favour....
I referred to the exact title in the first part of the sentence; in the same sentence I referenced it again. Sorry for the confusion.
How ever one characterizes the Mann et al 1200 year temperature reconstruction, there is the observable point that it appeared right up front in the 2001 IPCC Summary for Policy Makers almost as an icon, with no medieval warming period, and then in the 2007 third IPCC report after the investigation it vanished from the Summary, was moved to the paleo section and merged in with several other reconstructions that show the medieval period as warm.
And yes I'd say it is fair to say that some of the key ideas reflected in the MBH 98 hockey stick, namely that there was little or no medieval warming period, has indeed lost favour; that this is reflected by its removal from the Summary for Policy Makers and its subsequent embedding in the graph in the Paleo section with several other competing studies that show a substantial medieval warming, comparable with today's warming.

[mheslep]

On this other point, I'm referring to this specific claim: Iam aware of desert ecological communities, and sub antarctic communities that don't exist any more because of climate change

Could you cite one please (obviously one in the last 30 years to be associate w/ AWG)?

I know that from conversations with ecologists, I don't know where or if they have been published.

That's fine, but not appropriate for this forum.
http://www.physicsforums.com/showthread.php?t=280637

It's pretty common knowledge, and not at all controversial that ecosystems are being impacted by climate change, and neither that for ecosystems with smaller geographic ranges, (being the unique in especially interesting ones) that impact is more often extinction or increased risk of extinction...Perhaps I misunderstood. By 'ecological communities' that 'dont exist anymore' do you mean a species extinction? I took that to mean human communities. This another good reason for cites - in addition to the data, they avoid ambiguity.

[Xnn]

The Medieval warm period was only warm in comparison to the 17th century cold.

See Box 6.4 on page 468 to 469 in the following link.

http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter6.pdf

The evidence currently available indicates that NH mean temperatures during medieval times (950–1100) were indeed warm in a 2-kyr context and even warmer in relation to the less sparse but still limited evidence of widespread average cool conditions in the 17th century (Osborn and Briff a, 2006). However, the evidence is not sufficient to support a conclusion that hemispheric mean temperatures were as warm, or the extent of warm regions as expansive, as those in the 20th century as a whole, during any period in medieval times (Jones et al., 2001; Bradley et al., 2003a,b; Osborn and Briff a, 2006).

So, the 20th century (1900 to 1999) was warmer than the MWP.

Also, notice the following conclusions:

Centennial-resolution palaeoclimatic records provide
evidence for regional and transient pre-industrial warm
periods over the last 10 kyr, but it is unlikely that any
of these commonly cited periods were globally synchronous.
Similarly, although individual decadal-resolution
interglacial palaeoclimatic records support the existence
of regional quasi-periodic climate variability, it is unlikely
that any of these regional signals were coherent at the
global scale, or are capable of explaining the majority of
global warming of the last 100 years.


• The TAR pointed to the ‘exceptional warmth of the late
20th century, relative to the past 1,000 years’. Subsequent
evidence has strengthened this conclusion. It is very likely
that average Northern Hemisphere temperatures during
the second half of the 20th century were higher than for
any other 50-year period in the last 500 years. It is also
likely that this 50-year period was the warmest Northern
Hemisphere period in the last 1.3 kyr, and that this
warmth was more widespread than during any other 50-
year period in the last 1.3 kyr. These conclusions are most
robust for summer in extratropical land areas, and for
more recent periods because of poor early data coverage.

[mheslep]

The Medieval warm period was only warm in comparison to the 17th century cold.

See Box 6.4 on page 468 to 469 in the following link.

http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter6.pdf[my bold] Yes I've been all through it. I think you misread? Your first sentence directly contradicts the box:
The evidence currently available indicates that NH mean temperatures during medieval times (950–1100) were indeed warm in a 2-kyr context and even warmer in relation to the less sparse but still limited evidence of widespread average cool conditions in the 17th century (Osborn and Briff a, 2006).One can not draw that conclusion from MBH 98, hence its disfavour.

[Xnn]

good point mheslep; "only warm" is overstating.

However, the MWP was not as warm as the 19th century, which some people would tend to consider as a baseline.

[Bored Wombat]

Google for 'Joanne nova' her handbook is very helpfull.
It looks like a reproduction of some debunked counterscientific fossil fuel pressure group propaganda.

In what was is it "very helpful"?

Off the top of my head, a brief response to her "only four points that matter" are:

1) The greenhouse signature is missing.

No it's not. The greenhouse signature, the cooling of the stratosphere and the exaggerated warming at the poles is unambiguous, measured and real.

The "hot spot" that you are mistaking for a greenhouse signature has nothing to do with the greenhouse effect. It occurs under any warming that causes the air to hold more water vapour, and is caused by the release of the latent heat of vaporisation of that water when it condenses as rising air cools.

2) The strongest evidence was the ice cores, but newer more detailed data turned the theory inside out.

No the strongest evidence is the physics of optics, by which we understand the greenhouse effect, and therefore know that increasing the concentration of greenhouse gasses will make it warmer.

A 600 or 800 year lag in temperature change over 5000 or 6000 years is an 80% co-incidence. The fact that greenhouse feedback drives the switch from a glaciation to interglacial, set of by milankovich cycles, is perfectly in line with all previous theory. The 10 or 12 K temperature change over that time was only ever about 2 or 3 K due to the 50% increase in CO2 that occurs over that time.

The current best estimates for the effect of doubling CO2 is about 3 or 4 K.

3) Temperatures are not rising.

No they're not.

"In a blind test, the AP gave temperature data to four independent statisticians and asked them to look for trends, without telling them what the numbers represented. The experts found no true temperature declines over time." Statisticians reject global cooling (http://news.yahoo.com/s/ap/20091026/ap_on_bi_ge/us_sci_global_cooling)

4) Carbon dioxide is doing almost all the warming it can do.

No. The current best estimates for the effect of doubling CO2 is about 3 or 4 K.

And that's the top four points.

So I'm at a loss as to what help we've got from them, especially on a physics board, where people probably have some basic scientific understanding.

[Bored Wombat]

I referred to the exact title in the first part of the sentence; in the same sentence I referenced it again. Sorry for the confusion.
Well, I'm big enough to accept the apology, but I still suspect that you were trying to overstate your case. If you use an abbreviation for a term you should use it when you first use the term. But in this case it would look better for full disclosure if you explicitly mentioned that it did appear in the technical summary. Or at least that the term "summary" wasn't a good description for the summary for policy makers, especially to an audience interested in physics, who would be more familiar with the other summary.

And yes I'd say it is fair to say that some of the key ideas reflected in the MBH 98 hockey stick, namely that there was little or no medieval warming period, has indeed lost favour;
Well other northern hemisphere reconstuctions can have a slight bump around 1000 AD, but certainly not all of them.

http://www.realclimate.org/images/ipcc_6_1_large.jpg

The consensus is that it is certainly not as pronounced as might have been suspected from early, one site based studies. And the suspicion is that this would be further ameliorated if the southern hemisphere were included.

But the National Academies review found nothing wrong with Mann et al's treatment of the data at that time. It was the very recent end that they found that the statistical mistreatment resulted in Mann et al. under-reporting the expected error.

In what way do you mean "fallen out of favour"? Probably we can agree that any medieval warm period was likely at least half a degree cooler than temperatures this decade if we are talking about global mean surface temperature?

that this is reflected by its removal from the Summary for Policy Makers and its subsequent embedding in the graph in the Paleo section with several other competing studies that show a substantial medieval warming, comparable with today's warming.

Disagree. It's removal from the report was because it wasn't new, and had been covered in the 2001 report.

It speaks volumes for the respect that it is still held in that it nevertheless occurred twice in a report that is supposed to be about the findings since the previous report.

[Bored Wombat]

Perhaps I misunderstood. By 'ecological communities' that 'dont exist anymore' do you mean a species extinction? I took that to mean human communities. This another good reason for cites - in addition to the data, they avoid ambiguity.

Population extinction of many species, sometimes including total extinction.

No, I wasn't talking about human communities. I don't even know what a sub antarctic human community might mean. And we're talking about global warming, not Godzilla.

I will endeavour to cite more, but I have spoken in the last few years to ecologists looking at Australian freshwater communities, Australian desert communities, European amphibians, and Australian wetlands affected by dry land salinity, and only the last one did not speak with grief of the destruction of their studied area.

And the devastation of various sub-Antarctic communities by invasion by temperate species is now, I am told, well represented in the scientific literature. The concern seems to be now that Antarctic communities may soon fall by the same mechanism.

[Bored Wombat]

[my bold] Yes I've been all through it. I think you misread? Your first sentence directly contradicts the box:
One can not draw that conclusion from MBH 98, hence its disfavour.

Please cite a source for this claimed "disfavour".

[Andre]

One can not draw that conclusion from MBH 98Please cite a source for this claimed "disfavour".

The Wegman report (http://republicans.energycommerce.house.gov/108/home/07142006_Wegman_Report.pdf)

Overall, our committee believes that Mann’s assessments that the decade of the 1990s was the hottest decade of the millennium and that 1998 was the hottest year of the millennium cannot be supported by his analysis.

[Andre]

Population extinction of many species, sometimes including total extinction.

No, I wasn't talking about human communities. I don't even know what a sub antarctic human community might mean. And we're talking about global warming, not Godzilla.

I will endeavour to cite more, but I have spoken in the last few years to ecologists looking at Australian freshwater communities, Australian desert communities, European amphibians, and Australian wetlands affected by dry land salinity, and only the last one did not speak with grief of the destruction of their studied area.

And the devastation of various sub-Antarctic communities by invasion by temperate species is now, I am told, well represented in the scientific literature. The concern seems to be now that Antarctic communities may soon fall by the same mechanism.

Where is the peer reviewed source?

[Bored Wombat]

The Wegman report (http://republicans.energycommerce.house.gov/108/home/07142006_Wegman_Report.pdf)

The Wegman report raised some issues, and was certainly harsher than the more transparent and peer reviewed National Academies report.

It doesn't really stand for scientific opinion though. Do you have a peer reviewed source?

[Andre]

The Wegman report raised some issues, but and was certainly harsher than the more transparent and peer reviewed National Academies report.

What is your peer review resource to make that assessment?

[Bored Wombat]

Where is the peer reviewed source?

"The future problem these animals face is via displacement by alien species from lower latitudes. Such invasions are now well documented from sub-Antarctic sites." - Prospects for surviving climate change in Antarctic aquatic species (http://www.frontiersinzoology.com/content/2/1/9) , Peck, Frontiers in Zoology 2005, 2:9 doi:10.1186/1742-9994-2-9

Perhaps for example: "Warming is likely to remove
physiological barriers on lithodid crabs that currently place a
limit on the invasion of shallow waters of the high Antarctic;
a scenario that is especially likely for waters oV the Antarctic
Peninsula" - Encounter of lithodid crab Paralomis birsteini on the continental slope off Antarctica, sampled by ROV (http://epic.awi.de/Publications/Tha2008c.pdf)
Thatje et al, Polar Biol (2008) 31:1143–1148 DOI 10.1007/s00300-008-0457-5

(Antarctic marine life threatened by crab invasion (http://www.independent.co.uk/environment/nature/antarctic-marine-life-threatened-by-crab-invasion-782989.html), as the popular press put it)

Antarctic seabed ecosystems invasion threat (http://www.telegraph.co.uk/science/science-news/3325543/Antarctic-seabed-ecosystems-invasion-threat.html) is another popular press write up, this time about a presentation at the AAAS conference in 2008:
"Unique Antarctic seabed ecosystems are under threat from invasions of species taking advantage of global warming, scientists have warned.

Predatory giant crabs, sharks and other fish are poised to make a return to the rapidly warming shallow waters around the South Pole for the first time in tens of millions of years.

Their come-back will disrupt the make-up of ancient communities of unusual animals such as sea spiders, brightly-coloured brittle stars, thin-shelled muscles and giant relatives of the woodlouse called isopods."

But, again, this is hardly controversial. The fact that species range changes is contributing to the 30% biodiversity drop over the past few decades is well marked in ecology.

[Bored Wombat]

What is your peer review resource to make that assessment?

It's not controversial that the National Academies Report's peer review process was transparent and the Wegman reports wasn't.

I have provided the news at nature's article that Mann et al. was vindicated. That is also what was reported in the popular press, and it was also the response of scientists. It is you who are making the controversial claims that needs peer reviewed support.

[mheslep]

Well, I'm big enough to accept the apology, but I still suspect that you were trying to overstate your case.
Im little interested in what you suspect about me.

If you use an abbreviation for a term you should use it when you first use the term. But in this case it would look better for full disclosure if you explicitly mentioned that it did appear in the technical summary. Or at least that the term "summary" wasn't a good description for the summary for policy makers, especially to an audience interested in physics, who would be more familiar with the other summary.


Well other northern hemisphere reconstuctions can have a slight bump around 1000 AD, but certainly not all of them.

[...]

The consensus is that it is certainly not as pronounced as might have been suspected from early, one site based studies. And the suspicion is that this would be further ameliorated if the southern hemisphere were included.

But the National Academies review found nothing wrong with Mann et al's treatment of the data at that time. It was the very recent end that they found that the statistical mistreatment resulted in Mann et al. under-reporting the expected error.

In what way do you mean "fallen out of favour"? Probably we can agree that any medieval warm period was likely at least half a degree cooler than temperatures this decade if we are talking about global mean surface temperature?



Disagree. It's removal from the report was because it wasn't new, and had been covered in the 2001 report.

It speaks volumes for the respect that it is still held in that it nevertheless occurred twice in a report that is supposed to be about the findings since the previous report.
By disfavour I only refer to MBH 98/Mann99, not any broader topic in AGW, or paleo reconstruction. Perhaps I should say instead that it has been updated in 2007 w/ reconstructions considered more accurate? Anyway I see Vanesch has spoken more clearly here on the subject.
http://www.physicsforums.com/showpost.php?p=1926328&postcount=11

[mheslep]

The Wegman report (http://republicans.energycommerce.house.gov/108/home/07142006_Wegman_Report.pdf)Thanks Andre, though I think the National Academies report itself, when read in detail also does a good job of pointing out limitations.
Edit: In particular, I mean what the Academy has to say about:
...the 1990s are likely the warmest decade, and 1998 the warmest year, in at least a millennium. from

Mann, M.E and Bradley, R.S. (1999), Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties, and Limitations, in Geophysical Research Letters, Vol. 26, No. 6, p.759


...Even less confidence can be placed in the original conclusions by Mann et al. (1999) that “the 1990s are likely the warmest decade, and 1998 the warmest year, in at least a millennium” because the uncertainties inherent in temperature reconstructions for individual years and decades are larger than those for longer time periods, and because not all of the available proxies record temperature information on such short timescales.from

Surface Temperature Reconstructions for the Last 2,000 Years, Report in Brief, The National Academies, June 22, 2006

http://dels.nas.edu/dels/rpt_briefs/Surface_Temps_final.pdf

[Andre]

It's not controversial that the National Academies Report's peer review process was transparent and the Wegman reports wasn't.

I have provided the news at nature's article that Mann et al. was vindicated. That is also what was reported in the popular press, and it was also the response of scientists. It is you who are making the controversial claims that needs peer reviewed support.

Really amazing, anyway, apparantly the transcripts to the senate hearings of Oliver North seem to have disappeared; however his exact answer in testimony was recorded on numerous places, -when asked if he disputed the methodology conclusions of Wegman's report- he said:

No, we don’t. We don’t disagree with their criticism (http://www.google.nl/search?hl=nl&source=hp&q=%22No%2C+we+don%E2%80%99t.+We+don%E2%80%99t+disa gree+with+their+criticism%22&btnG=Google+zoeken&meta=&aq=f&oq=)

[Monique]

The Wegman report (http://republicans.energycommerce.house.gov/108/home/07142006_Wegman_Report.pdf) This is a link to policy makers, but not to the real science. We all know political parties are colored, that's why there's an objection to the source.

[Andre]

It would be nice if examples can be given in the Wegman report to demonstrate that the sciencific conclusion is not supported by rigid unbiased reproduceable science especially when the NAS committee agreed with that conclusion as I showed in my previous post.

[Andre]

Anyway, let's do a quick recap. So here was the hockeystick in the Third Asssesment report of the IPCC of Mann Bradley and Hughes form 1999 (MBH99) which showed a flat temperature from 1000 Bc up intil about 1850 AD with suddenly rising temperatures. McIntyre and McKitrick demonstrated that MBH had used improper statistic methodologies.

So it was asked to the NAS and to Dr Wegman (http://www.galaxy.gmu.edu/stats/faculty/wegman.html) to verify the critisism of McIntyre and McKitrick. Wegman confirmed that. The NAS with Oliver North in the chair had a more subtle approach. They had misgivings about the procedures of MBH but it would not matter because they stated that other research came to similar conclusions.

So in this thread it is now assumed that Wegman wrote something politcal (which seems to be threated here as biased/spin/fraud) while it also is assumed that the NAS endorsed MBH99. They did not. Because in the hearings of the Committee on Energy and Commerce of the House of Representatives, these were some of the statements of members of the NAS (http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=109_house_hearings&docid=f:31362.wais):

CHAIRMAN BARTON. I understand that. It looks like my time
is expired, so I want to ask one more question. Dr. North, do you
dispute the conclusions or the methodology of Dr. Wegman's report?
DR. NORTH. No, we don't. We don't disagree with their
criticism. In fact, pretty much the same thing is said in our
report. But again, just because the claims are made, doesn't
mean they are false.
CHAIRMAN BARTON. I understand that you can have the right
conclusion and that it not be--
DR. NORTH. It happens all the time in science.
CHAIRMAN BARTON. Yes, and not be substantiated by what you
purport to be the facts but have we established--we know that
Dr. Wegman has said that Dr. Mann's methodology is incorrect. Do
you agree with that? I mean, it doesn't mean Dr. Mann's
conclusions are wrong, but we can stipulate now that we have--and if
you want to ask your statistician expert from North Carolina that
Dr. Mann's methodology cannot be documented and cannot be verified
by independent review.
DR. NORTH. Do you mind if he speaks?
CHAIRMAN BARTON. Yes, if he would like to come to the
microphone.
MR. BLOOMFIELD. Thank you. Yes, Peter Bloomfield. Our
committee reviewed the methodology used by Dr. Mann and his coworkers
and we felt that some of the choices they made were inappropriate.
We had much the same misgivings about his work that was documented
at much greater length by Dr. Wegman.


Now what to say about the discussion/allegations in this thread? like:

It's not controversial that the National Academies Report's peer review process was transparent and the Wegman reports wasn't.

I have provided the news at nature's article that Mann et al. was vindicated. That is also what was reported in the popular press, and it was also the response of scientists. It is you who are making the controversial claims that needs peer reviewed support.

I leave the conclusions to the readers.

[mheslep]

This is a link to policy makers, but not to the real science. We all know political parties are colored, that's why there's an objection to the source.Edit:
The Wegman report in this link happens to be hosted on a policy maker's website.
Wegman is a scientific report, non-peer reviewed unless one counts the publicly documented statements on Wegman by the authors of the National Academies North report. On the other hand, the Nature News report post here (http://www.physicsforums.com/showpost.php?p=2419819&postcount=58) up thread on the subject is not peer reviewed material either.

[Xnn]

Of course science marches on and these past reports and reconstructions did not have the following available:

http://www.ucar.edu/news/releases/2009/arctic2k.jsp

http://www.physicsforums.com/attachment.php?attachmentid=21606&stc=1&d=1257469597

From the above perspective, it appears that the MWP (950 to 1100) was only minor warming period superimposed on a 1900 year cooling trend that was distinctly interrupted around 1900.

[Xnn]

Notice, that now we can say the following authority:

Arctic temperatures in the 1990s reached their warmest level of any decade in at least 2,000 years, new research indicates.

and it has nothing to do with tree rings or Michael Mann.

[Bored Wombat]

Im little interested in what you suspect about me.
You miss the point if you think I was discussing our personal relationship.

MBH 99 appeared in what most people here would consider the summary of the IPCC 2007 WG1 report.

By using the term "Summary" to refer to the SPM, you misrepresent the respect in which MBH is held.

By disfavour I only refer to MBH 98/Mann99, not any broader topic in AGW, or paleo reconstruction. Perhaps I should say instead that it has been updated in 2007 w/ reconstructions considered more accurate? Anyway I see Vanesch has spoken more clearly here on the subject.
http://www.physicsforums.com/showpost.php?p=1926328&postcount=11

I certainly agree that there is more data out there now, and that that increased the confidence that we have in these reconstructions. And that the more modern ones have had a many more datasets included in the analysis, and this also increases confidence in the results.

But MBH 1999 is not an outlier amongst reconstructions, and certainly the current view is nearer the MBH view than the pre-MBH view. So I don't think that it has fallen into any "disfavour".

[Bored Wombat]

...Even less confidence can be placed in the original conclusions by Mann et al. (1999) that “the 1990s are likely the warmest decade, and 1998 the warmest year, in at least a millennium” because the uncertainties inherent in temperature reconstructions for individual years and decades are larger than those for longer time periods, and because not all of the available proxies record temperature information on such short timescales.

from

* Surface Temperature Reconstructions for the Last 2,000 Years, Report in Brief, The National Academies, June 22, 2006

Less confidence than the confidence that we have that the "Northern Hemisphere was warmer during the last few decades of the 20th century than during any comparable period over the preceding millennium."

That's a fairly complete vindication of MBH, which has the average for the 20th century to be within the error bars on the temperature reconstruction for most of the time prior to about 1600.
http://upload.wikimedia.org/wikipedia/en/e/ed/Hockey_stick_chart_ipcc_large.jpg (http://en.wikipedia.org/wiki/File:Hockey_stick_chart_ipcc_large.jpg)

So, despite the phrase "even less confidence" this is exactly in line with the findings of the MBH 99 paper, for someone who has understood the error analysis in MBH 99.

[Bored Wombat]

It would be nice if examples can be given in the Wegman report to demonstrate that the sciencific conclusion is not supported by rigid unbiased reproduceable science especially when the NAS committee agreed with that conclusion as I showed in my previous post.

No the NA report found the same methodological flaws.

They, however, found that the conclusions were largely sound. Partly because the flaws did not affect the shape of the reconstruction, but only lead to an understating of the errors. And partly because those conclusions were supported by later work.

[Bored Wombat]

Edit:
The Wegman report in this link happens to be hosted on a policy maker's website.
Wegman is a scientific report, non-peer reviewed unless one counts the publicly documented statements on Wegman by the authors of the National Academies North report. On the other hand, the Nature News report post here (http://www.physicsforums.com/showpost.php?p=2419819&postcount=58) up thread on the subject is not peer reviewed material either.

The news at nature is not controversial.

It noted that the NA report found that there were methodological errors, but that these were not material, and it criticised the way the report was used.

But the claims from outside the scientific field were that the whole shape of the hockey stick was due to incorrect methodology, and this was shown not to be the case.

The Wegman report didn't focus so much on the fact that the methodological problems didn't make any material difference, and spent several pages looking at who in the field has published papers with each other ... Which I think is difficult to justify in the absence of any analysis as to what difference this makes to scientific publishing nor the peer review process.

Claiming that Mann et al is in a state of "disfavour" is controversial, because its findings have been nearly completely vindicated. So you need to provide a peer reviewed source to back that up. The Wegman report doesn't establish that "disfavour", certainly not amongst the scientific community. (About whom I assume we are talking about. Certainly there is disfavour from the aforementioned Jo Nova dot com, and other semi-professional science deniers.)

Does the IPCC 2007 report, which reproduces Mann et al 1999 twice, mention anything about its results being questionable?

[Bored Wombat]

Of course science marches on and these past reports and reconstructions did not have the following available:

http://www.ucar.edu/news/releases/2009/arctic2k.jsp

http://www.physicsforums.com/attachment.php?attachmentid=21606&stc=1&d=1257469597

From the above perspective, it appears that the MWP (950 to 1100) was only minor warming period superimposed on a 1900 year cooling trend that was distinctly interrupted around 1900.

Yes. Global warming is exaggerated at the poles, because CO2 overlaps with H2O, and there's not much atmospheric H2O concentration at the poles.

This gives more evidence that the warming is a greenhouse warming, but it is a little unfair to compare it with temperature reconstructions for the whole hemisphere, because it is stronger than the warming for the whole hemisphere.

[Xnn]

Yes. Global warming is exaggerated at the poles, because CO2 overlaps with H2O, and there's not much atmospheric H2O concentration at the poles.

This gives more evidence that the warming is a greenhouse warming, but it is a little unfair to compare it with temperature reconstructions for the whole hemisphere, because it is stronger than the warming for the whole hemisphere.

I agree. However, the reconstructions and analysis that have been done in the past did not have this new source of information available. It's not dependant on tree rings or Michael Mann. So, if a reconstruction of NH temperature history were to be constructed today, it should include this new data, which shows the MWP in an entirely differant perspective.

For example, the period 950 to 1100 was not the warmest period prior to 1900 within the Arctic and we can say that the 1990's appear to be the warmest decade for the Arctic over the last 2000.

[mheslep]

The news at nature is not controversial.Yes, it can be as it's news, but that matters not. It is not an peered reviewed source.
It noted that the NA report found that there were methodological errors, but that these were not material, and it criticised the way the report was used.The mistakes were as I detailed above (http://www.physicsforums.com/showpost.php?p=2426834&postcount=81), which state that Mann deserves little "confidence" beyond 400 years (their word, not mine). I'd appreciate it if we stick to direct quotes from the sources (Mann and NA), and not other summaries.
But the claims from outside the scientific field were that the whole shape of the hockey stick was due to incorrect methodology, and this was shown not to be the case.Not interested in claims from non scientific sources for discussion here, hopefully we can dispense with reference to those as well.Claiming that Mann et al is in a state of "disfavour" is controversial,Disfavour was a poor word choice on my part, as it smacks of a reliance on some community somewhere. I corrected it above.
because its findings have been nearly completely vindicated. There's no room for 'completely' in that sentence regarding Mann 99, given the actual source material presented in this thread.
...So you need to provide a peer reviewed source to back that up. The Wegman report doesn't establish that "disfavour", certainly not amongst the scientific community. As has been discussed in this forum, it's not useful to try and speak for the sentiment of the scientific community. Argument based on the sources is the way to go.

[mheslep]

But MBH 1999 is not an outlier amongst reconstructions, and certainly the current view is nearer the MBH view than the pre-MBH view. So I don't think that it has fallen into any "disfavour".We mean here Mann et al 1999, the millennial reconstruction covering the MWP and featured in the Summary For Policy Makers 2001, not MBH 98's 400 year reconstruction. And yes I think Mann et al 1999 deserves little "confidence" further back than 400 years as the NA report states, and yes I think there's a significant difference between what Mann et al shows around 1000AD, basically showing no MWP to my eye, and what is said in the IPCC 2007
mean temperatures during medieval times (950–1100) were indeed warm in a 2-kyr context Based on this, other reconstructions shown in IPCC 2007, and my glance at Mann et al 1999's reconstruction circa 1000AD (http://en.wikipedia.org/wiki/File:Hockey_stick_chart_ipcc_large.jpg), I qualitatively call Mann 1999 wrong about the MWP.

[mheslep]

Of course science marches on and these past reports and reconstructions did not have the following available:

http://www.ucar.edu/news/releases/2009/arctic2k.jsp

http://www.physicsforums.com/attachment.php?attachmentid=21606&stc=1&d=1257469597

From the above perspective, it appears that the MWP (950 to 1100) was only minor warming period superimposed on a 1900 year cooling trend that was distinctly interrupted around 1900.

The actual paper and abstract:

Kaufman, D.S. et al, 2009. Recent Warming Reverses Long-Term Arctic Cooling, Science 4 September 2009, Vol. 325. no. 5945, pp. 1236 - 1239. DOI: 10.1126/science.1173983


Abstract:
The temperature history of the first millennium C.E. is sparsely documented, especially in the Arctic. We present a synthesis of decadally resolved proxy temperature records from poleward of 60°N covering the past 2000 years, which indicates that a pervasive cooling in progress 2000 years ago continued through the Middle Ages and into the Little Ice Age. A 2000-year transient climate simulation with the Community Climate System Model shows the same temperature sensitivity to changes in insolation as does our proxy reconstruction, supporting the inference that this long-term trend was caused by the steady orbitally driven reduction in summer insolation. The cooling trend was reversed during the 20th century, with four of the five warmest decades of our 2000-year-long reconstruction occurring between 1950 and 2000.
http://www.sciencemag.org/cgi/content/abstract/325/5945/1236

I wonder what type of proxies are available at those latitudes. Reading to come.

[Bored Wombat]

I agree. However, the reconstructions and analysis that have been done in the past did not have this new source of information available. It's not dependant on tree rings or Michael Mann. So, if a reconstruction of NH temperature history were to be constructed today, it should include this new data, which shows the MWP in an entirely differant perspective.

For example, the period 950 to 1100 was not the warmest period prior to 1900 within the Arctic and we can say that the 1990's appear to be the warmest decade for the Arctic over the last 2000.

Good point.

[Bored Wombat]

Yes, it can be as it's news, but that matters not. It is not an peered reviewed source.

I’m not saying that news can’t be controversial; I’m saying that in this particular case isn’t controversial.

The NA report was a vindication of Mann et al. The only people saying otherwise are not only not peer reviewed, they’re on website’s whose editorial position is explicitly counterscientific.

The mistakes were as I detailed above (http://www.physicsforums.com/showpost.php?p=2426834&postcount=81), which state that Mann deserves little "confidence" beyond 400 years (their word, not mine). I'd appreciate it if we stick to direct quotes from the sources (Mann and NA), and not other summaries.

They do not state that Mann deserves little confidence.

They state that less confidence can be placed in the statement that “the 1990s are likely the warmest decade, and 1998 the warmest year, in at least a millennium” than the statement that “the Northern Hemisphere was warmer during the last few decades of the 20th century than during any comparable period over the preceding millennium.”

The previous paragraph talks more specifically about Mann et al: “The basic conclusion of Mann et al. (1998, 1999) was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes the additional large-scale surface temperature reconstructions and documentation of the spatial coherence of recent warming described above (Cook et al. 2004, Moberg et al. 2005b, Rutherford et al. 2005, D’Arrigo et al. 2006, Osborn and Briffa 2006, Wahl and Ammann in press) and also the pronounced changes in a variety of local proxy indicators described in previous chapters (e.g., Thompson et al. in press).”

As I have pointed out already, the error bars in Mann et al 1999 also show that there is not strong confidence in the conclusion that “the 1990s are likely the warmest decade, and 1998 the warmest year, in at least a millennium”. So again the NA report, is in full agreement with Mann et al on that point.

This is why those secondary sources are all explaining that the NA report backed the hockey stick graph. Now they are not peer reviewed, but neither is your own opinion that they said “that Mann deserves little "confidence" beyond 400 years”. You're misreading the report to get that, you're taking the paragraph about "confidence" isolated, out of context, and claiming it refers to Mann et al (1999) in general. In this case respected secondary sources such as news at nature can be useful, because they make it clear that your analysis is an outlier.

[Bored Wombat]

Mann et al 1999's reconstruction circa 1000AD (http://en.wikipedia.org/wiki/File:Hockey_stick_chart_ipcc_large.jpg), I qualitatively call Mann 1999 wrong about the MWP.

It agrees within the error with other reconstructions.

So it's right.

[mheslep]

Ah, finally a new page! Guys let's shrink those image posts that explode the page width?

Okay, here's the entire tail end of the NA report (http://dels.nas.edu/dels/rpt_briefs/Surface_Temps_final.pdf) without omission. I think it is helpful to post here.

[...]
o Very little confidence can be assigned to statements concerning the hemispheric mean or global mean surface temperature prior to about A.D. 900 because of sparse data coverage and because the uncertainties associated with proxy data and the methods used to analyze and combine them are larger than during more recent time periods.

The main reason that our confidence in large-scale surface temperature reconstructions
is lower before A.D. 1600 and especially before A.D. 900 is the relative scarcity of precisely
dated proxy evidence. Other factors limiting our confidence in surface temperature reconstructions include the relatively short length of the instrumental record (which is used to calibrate and validate the reconstructions); the fact that all proxies are influenced by a variety of climate variables; the possibility that the relationship between proxy data and local surface temperatures may have varied over time; the lack of agreement as to which methods are most appropriate for calibrating and validating large-scale reconstructions
and for selecting the proxy data to include; and the difficulties associated with constructing
a global or hemispheric mean temperature estimate using data from a limited number of sites and with varying chronological precision. All of these considerations introduce uncertainties that are difficult to quantify.

Despite these limitations, the committee finds that efforts to reconstruct temperature histories for broad geographic regions using multiproxy methods are an important contribution to climate research and that these large-scale surface temperature reconstructions contain meaningful climatic signals. The individual proxy series used to create these reconstructions generally exhibit strong correlations with local environmental conditions, and in most cases there is a physical, chemical, or physiological reason why the proxy reflects local temperature variations. Our confidence in the results of these reconstructions becomes stronger when multiple independent lines of evidence point to the same general result, as in the case of the Little Ice Age cooling and the 20th century warming.

The basic conclusion of Mann et al. (1998, 1999) was that the late 20th century warmth in the Northern Hemisphere was unprecedented during at least the last 1,000 years. This conclusion has subsequently been supported by an array of evidence that includes both additional large-scale surface temperature reconstructions and pronounced changes in a variety of local proxy indicators, such as melting on icecaps and the retreat of glaciers around the world, which in many cases appear to be unprecedented during at least the last 2,000 years. Not all individual proxy records indicate that the recent warmth is unprecedented, although a larger fraction of geographically diverse sites experienced exceptional warmth during the late 20th century than during any other extended period from A.D. 900 onward.

Based on the analyses presented in the original papers by Mann et al. and this newer supporting evidence, the committee finds it plausible that the Northern Hemisphere was warmer during the last few decades of the 20th century than during any comparable period over the preceding millennium. The substantial uncertainties currently present in the quantitative assessment of large scale surface temperature changes prior to about A.D. 1600 lower our confidence in this conclusion compared to the high level of confidence we place in the Little Ice Age cooling and 20th century warming. Even less confidence can be placed in the original conclusions by Mann et al. (1999) that “the 1990s are likely the warmest decade, and 1998 the warmest year, in at least a millennium” because the uncertainties inherent in temperature reconstructions for individual years and decades are larger than those for longer time periods, and because not all of the available proxies record temperature information on such short timescales.
In addition to this text, the NA report includes Figure S-1 showing other well known reconstructions in which at least two, Moberg et al and Esper et al, are showing circa 1000AD was the warmest part of their proxy reconstructions in the last 1000 years (though they may end in 1980?)

Then note the last part I bold faced. The 'less confidence' in that sentence from the NA does not refer to the wide error bars Mann et al associated with its prior to 1600AD estimates, but rather it refers to the high time resolution claims made in Mann et al's use of the terms 'decade' and 'year', i.e., because not all of the proxies record "information on such short timescales." Specifically on this point of making claims re short timescales, NA is not in agreement with Mann et al.

NA also prefers the word "plausible" over "likely" about the warmest period in a 1000 years. As an amateur, I agree.

[Bored Wombat]

In addition to this text, the NA report includes Figure S-1 showing other well known reconstructions in which at least two, Moberg et al and Esper et al, are showing circa 1000AD was the warmest part of their proxy reconstructions in the last 1000 years (though they may end in 1980?)
But less than the temperatures in the 1990s.

Then note the last part I bold faced. The 'less confidence' in that sentence from the NA does not refer to the wide error bars Mann et al associated with its prior to 1600AD estimates,
That's right.
Mann et al's error analysis is independently in agreement with the NA report on this.

but rather it refers to the high time resolution claims made in Mann et al's use of the terms 'decade' and 'year', i.e., because not all of the proxies record "information on such short timescales." Specifically on this point of making claims re short timescales, NA is not in agreement with Mann et al.

Largely it is. Mann et al says nearly exactly the same thing materially.

NA also prefers the word "plausible" over "likely" about the warmest period in a 1000 years. As an amateur, I agree.

No, they don't compare "plausible" to any other term. But if that's the basis of your claim that Mann et al. "deserves little confidence", that Mann et al used the word "likely" whereas the NA used the word "plausible", then you make too much of the language and not enough of the error analysis in Mann et al.

[Andre]

"The future problem these animals face is via displacement by alien species from lower latitudes. Such invasions are now well documented from sub-Antarctic sites." - Prospects for surviving climate change in Antarctic aquatic species (http://www.frontiersinzoology.com/content/2/1/9) , Peck, Frontiers in Zoology 2005, 2:9 doi:10.1186/1742-9994-2-9

Perhaps for example: "Warming is likely to remove
physiological barriers on lithodid crabs that currently place a
limit on the invasion of shallow waters of the high Antarctic;
a scenario that is especially likely for waters oV the Antarctic
Peninsula" - Encounter of lithodid crab Paralomis birsteini on the continental slope off Antarctica, sampled by ROV (http://epic.awi.de/Publications/Tha2008c.pdf)
Thatje et al, Polar Biol (2008) 31:1143–1148 DOI 10.1007/s00300-008-0457-5

(Antarctic marine life threatened by crab invasion (http://www.independent.co.uk/environment/nature/antarctic-marine-life-threatened-by-crab-invasion-782989.html), as the popular press put it)

Antarctic seabed ecosystems invasion threat (http://www.telegraph.co.uk/science/science-news/3325543/Antarctic-seabed-ecosystems-invasion-threat.html) is another popular press write up, this time about a presentation at the AAAS conference in 2008:
"Unique Antarctic seabed ecosystems are under threat from invasions of species taking advantage of global warming, scientists have warned.

Predatory giant crabs, sharks and other fish are poised to make a return to the rapidly warming shallow waters around the South Pole for the first time in tens of millions of years.

Their come-back will disrupt the make-up of ancient communities of unusual animals such as sea spiders, brightly-coloured brittle stars, thin-shelled muscles and giant relatives of the woodlouse called isopods."

But, again, this is hardly controversial. The fact that species range changes is contributing to the 30% biodiversity drop over the past few decades is well marked in ecology.

and the times, they are a changing:

Kathy J. Willis and Shonil A. Bhagwat, Biodiversity and Climate Change Science 6 November 2009: Vol. 326. no. 5954, pp. 806 - 807 (http://www.sciencemag.org/cgi/content/summary/326/5954/806)

Over the past decade, several models have been developed to predict the impact of climate change on biodiversity. Results from these models have suggested some alarming consequences of climate change for biodiversity, predicting, for example, that in the next century many plants and animals will go extinct (1) and there could be a large-scale dieback of tropical rainforests (2). However, caution may be required in interpreting results from these models, not least because their coarse spatial scales fail to capture topography or "microclimatic buffering" and they often do not consider the full acclimation capacity of plants and animals (3). Several recent studies indicate that taking these factors into consideration can seriously alter the model predictions (4–7).

[mheslep]

and the times, they are a changing:Interesting what happens at higher resolution. More from Willis and Bhagwat:


[...]
In one study, Randin et al. assessed the influence of spatial scale on the accuracy of bioclimatic model predictions of habitat losses for alpine plant species in the Swiss Alps (4). A coarse European-scale model (with 16 km by 16 km grid cells) predicted a loss of all suitable habitats during the 21st century, whereas a model run using local-scale data (25 m by 25 m grid cells) predicted persistence of suitable habitats for up to 100% of plant species.
[...]
Many studies have indicated that increased atmospheric CO2 affects photosynthesis rates and enhances net primary productivity—more so in tropical than in temperate regions—yet previous climate-vegetation simulations did not take this into account.

[Bored Wombat]

Interesting what happens at higher resolution. More from Willis and Bhagwat:

That is interesting.

And it helps explain why the "Extinction Risk" paper poorly modelled extinction over the end of the last glaciation.

But an isolated community with a small gene-pool is still on the road to extinction. It can be wiped out by a small land use change, or flood or fire, and has little capacity to adapt to change or disease.

So, while it improves modelling I don't think that it genuinely affects the observed facts such as: "The fact that species range changes is contributing to the 30% biodiversity drop over the past few decades is well marked in ecology."

[Bored Wombat]

and the times, they are a changing:

This is a modelling exercise, and probably a fine one in that it explains why there was so few (although nevertheless notable) extinctions at the end of the last glaciation.

However, the invasion of subantarctic systems by temperate predators is being observed, and the documentation of these events is prolific.

Times are indeed changing, because the climate is indeed changing, and the devastation of that is mostly undocumented, but not so in the subantarctic.

But it seems like you are suggesting that the implication is that your paper refutes this observed devastation. It does not.

[mheslep]

...So, while it improves modelling I don't think that it genuinely affects the observed facts such as: "The fact that species range changes is contributing to the 30% biodiversity drop over the past few decades is well marked in ecology."Eh? I don't think you mean to quote your own statement (http://www.physicsforums.com/showpost.php?p=2419819&postcount=58) as a reference for the facts ? Also, where is your reference for "observed" in that context? The only topical biodiversity reference I can find in the thread (aside from Andre's Willis and Bhagwat reference) is the Thomas et al 2004 (Nature) (http://www.gbltrends.com/doc/nature02121.pdf) paper you provided. It makes no statement about 'observing' a 30% drop. Rather Thomas estimates, as do Willis and Bhagwat.

[Bored Wombat]

Eh? I don't think you mean to quote your own statement (http://www.physicsforums.com/showpost.php?p=2419819&postcount=58) as a reference for the facts ?
Sure I did.

That was the statement that I made that I thought that you were taking issue with.

I don't think that your argument is an argument against that position.

Also, where is your reference for "observed" in that context?

Observed drop in biodiversity or Observed range changes?

For the latter I posted a few in this post (http://www.physicsforums.com/showthread.php?p=2426754#post2426754), but my point is that it is not controversial, and the reason I chose that paper is because is mentions that point: "Such invasions are now well documented from sub-Antarctic sites."

The observed drop in biodiversity is from the living planet index (http://assets.panda.org/downloads/living_planet_report_2008.pdf).

The only topical biodiversity reference I can find in the thread (aside from Andre's Willis and Bhagwat reference) is the Thomas et al 2004 (Nature) (http://www.gbltrends.com/doc/nature02121.pdf) paper you provided. It makes no statement about 'observing' a 30% drop. Rather Thomas estimates, as do Willis and Bhagwat.

The living planet index of biodiversity, as in the report linked above.

[mheslep]

Bored Wombat - above you made the statement that the following is "an observed fact"
[...]The fact that species range changes is contributing to the 30% biodiversity drop over the past few decades is well marked in ecology.I contend that statement as shown is unsupportable and requires substantial qualification to become valid. The Living Planet Report is a popular reference compiled in part by activists (WWF), which is fine though you didn't initially cite it as such, but the 30% drop shown there refers to an index of 1,686 vertebrate species, on a planet with perhaps 11 million species of which we have identified perhaps only 15% (http://www.guardian.co.uk/environment/2009/sep/29/number-of-living-species). We have not 'observed' a 30% drop in the biodiversity of this planet. We have observed, if we accept this popular source, a 30% drop in a limited collection of vertebrates over several decades. Also, from this popular source it is only fair to say that such a decrease is commonly recognized by activist groups; the science of ecology speaks through published scientific literature.

[Bored Wombat]

Bored Wombat - above you made the statement that the following is "an observed fact"
I contend that statement as shown is unsupportable and requires substantial qualification to become valid.
I contend that I have supported it with the well known and well cited living planet report.

The methods of the report appear in the scientific literature, such as:
The Living Planet Index: using species population time series to track trends in biodiversity (http://rstb.royalsocietypublishing.org/content/360/1454/289.full), (doi: 10.1098/rstb.2004.1584 Phil. Trans. R. Soc. B 28 February 2005 vol. 360 no. 1454 289-295)

And it is cited and used as a source of data for scholarly papers that appear in the scientific literature:
Monitoring Change in Vertebrate Abundance: the Living Planet Index (http://www3.interscience.wiley.com/cgi-bin/fulltext/121521774/HTMLSTART), (Conservation Biology, Volume 23, Number 2, April 2009 , pp. 317-327(11)

The Living Planet Report is a popular reference compiled in part by activists (WWF), which is fine though you didn't initially cite it as such, ...
It is research funded in part by an NGO, and published as one report by an NGO. Lots of research is funded by NGOs.

... but the 30% drop shown there refers to an index of 1,686 vertebrate species, on a planet with perhaps 11 million species of which we have identified perhaps only 15% (http://www.guardian.co.uk/environment/2009/sep/29/number-of-living-species).
I know that this is a physics and not a statistics board, but my understanding is that the size of the population (the 11 million) doesn't affect the accuracy of the estimate derived from a sample. What matters is the sample size (the 1,686), and any selection bias in the sampling.
We have not 'observed' a 30% drop in the biodiversity of this planet. We have observed, if we accept this popular source, a 30% drop in a limited collection of vertebrates over several decades.
30% over the 35 years to 2005. "Several decades" sounds like more than that.

Also, from this popular source it is only fair to say that such a decrease is commonly recognized by activist groups; the science of ecology speaks through published scientific literature.
And the living planet index appears in the published scientific literature, as per the examples above.

If you think that the scientific literature has a better accepted estimate of biodiversity, I will certainly read your citation, so please provide one.

[mheslep]

I contend that I have supported it with the well known and well cited living planet report.

The methods of the report appear in the scientific literature, such as:
The Living Planet Index: using species population time series to track trends in biodiversity (http://rstb.royalsocietypublishing.org/content/360/1454/289.full), (doi: 10.1098/rstb.2004.1584 Phil. Trans. R. Soc. B 28 February 2005 vol. 360 no. 1454 289-295)

And it is cited and used as a source of data for scholarly papers that appear in the scientific literature:
Monitoring Change in Vertebrate Abundance: the Living Planet Index (http://www3.interscience.wiley.com/cgi-bin/fulltext/121521774/HTMLSTART), (Conservation Biology, Volume 23, Number 2, April 2009 , pp. 317-327(11)Now you have, with appropriate cites, thanks.

I know that this is a physics and not a statistics board, but my understanding is that the size of the population (the 11 million) doesn't affect the accuracy of the estimate derived from a sample. What matters is the sample size (the 1,686), and any selection bias in the sampling.That's roughly correct, though the problem here is 1) the sample admits to being non-random on its face (only vertebrates), 2) it would be nearly impossible to make a non-biased sample for a global population which is mostly unknown. But this is all beside the point. The point here is that your statement about global biodiversity can only be an estimate, as you admit above (my highlight), only the sample is observed.

[Nebula815]

Isn't it impossible to really know how many species are dying on the planet? Scientists don't know how many species there are to begin with, furthermore (at least from my understanding) species die all the time and new ones are created all the time.

Also, how does one figure out exactly if a species has died? I mean you can try to count the species in a certain area, then come back again later on and count them again, but maybe some have moved to a different location...? For big animals, like whales, or gorillas or woolly mammoths, I can see it being easy to see if they're extinct, but things like insects, plants, etc...seems awfully tricky.

[Evo]

We are discovering tons of new species all of the time.

Over 350 new species including the world's smallest deer, a "flying frog" and a 100 million-year old gecko have been discovered in the Eastern Himalayas, a biological treasure trove now threatened by climate change.

The region studied covers a vast expanse of the mountain region.

A decade of research carried out by scientists for the WWF in remote mountain areas brought discoveries such as a bright green frog that uses its red and long webbed feet to glide in the air.

The WWF report, "The Eastern Himalayas -- Where Worlds Collide," details discoveries made by scientists from various organizations between 1998 and 2008 in a region reaching across Bhutan and northeast India to the far north of Myanmar as well as Nepal and southern parts of Tibet in China.

"The good news of this explosion in species discoveries is tempered by the increasing threats to the Himalayas' cultural and biological diversity," Jon Miceler, Director of WWF's Eastern Himalayas Program, said in a press statement.

http://www.cnn.com/2009/TECH/science/08/11/eco.himalayas.newspecies/index.html#cnnSTCText

A frog that eats birds and a gecko with leopard stripes are among the 163 new species discovered last year in the Greater Mekong region of southeast Asia, according to a report by the World Wildlife Fund.

The discovery of 100 new plants, 28 fish, 18 reptiles, 14 amphibians, two mammals and one bird species highlights the extent of the biodiversity in the region, said Barney Long, head of the WWF's Asian Species Conservation program.

"It's a melting pot of diverse habitats. It has some of the wettest forests on the planet, high mountains, and a diverse array of terrestrial and marine habitats, including the Mekong River," he said.

"We continue to find new species of fish, primates and mammals, and nowhere else compares to the amount of large mammals that have been discovered in the region. It shows how little we know about species in the region," he said. "From a biodiversity perspective, there are still huge amounts to discover about region."

http://www.cnn.com/2009/TECH/science/09/26/mekong.species/index.html#cnnSTCText

A rat believed to be extinct for 11 million years, a spider with a foot-long legspan, and a hot pink cyanide-producing "dragon millipede" are among the thousand newly discovered species in the largely unexplored Mekong Delta region.

The "dragon millipede" is among the 1,068 new species discovered in the Mekong Delta region.

The region, including parts of Vietnam and five other countries, is home to 1,068 species found between 1997 and 2007, according to a World Wildlife Fund report released this week.

http://www.cnn.com/2008/TECH/science/12/16/rat.mekong/index.html#cnnSTCText

The list goes on and on.

[Bored Wombat]

Now you have, with appropriate cites, thanks.
Okay.

I still think that the report itself is a respected enough piece of science, and not just those facets of it which produced scholarly papers.

That's roughly correct, though the problem here is 1) the sample admits to being non-random on its face (only vertebrates),
It's not random. But its not necessarily strongly biased.

Would invertebrates be more or less affected than vertebrates?

2) it would be nearly impossible to make a non-biased sample for a global population which is mostly unknown.
That's true if you wanted any population of any species to have an equal chance of being selected, but the living planet index makes it's estimate by tracking members of ecosystems that are assumed to be representative of those ecosystems.

It's probably not too bad.

But this is all beside the point. The point here is that your statement about global biodiversity can only be an estimate, as you admit above (my highlight), only the sample is observed.

Every measurement is an estimate.

A study is not faulty for using a sample, and for the 1 significant figure that I quoted (30%), that sample is sufficient.

[Bored Wombat]

Isn't it impossible to really know how many species are dying on the planet? Scientists don't know how many species there are to begin with, furthermore (at least from my understanding) species die all the time and new ones are created all the time.

Species do die all the time, but currently they are dying at some orders of magnitude faster than the long term average.

Most biologists say that we are in a geologically significant mass extinction.

There's not any scientific evidence for the view that new ones are created. There is certainly some evidence that new ones evolve. The rate is difficult to estimate, and speciation events depends more on the separation of populations so that they don't interbreed than with new ecological niche.

Rattus Rattus will be one species the world over, until they stop boarding cargo ships, although their behaviour and form might become more varied to allow exploitation of new food sources as human technology changes.

But speciation also depends on genetic diversity. (As does the existence of a species itself in many ways). So the population drops from land use change, pollution, over exploitation and climate change will also lower the speciation rate.

Natural speciation occurs in the long term trend only a few times per year or once every few years ... give or take an order of magnitude.

Currently extinctions are occurring approximately hourly ... give or take an order of magnitude.

So there's an imbalance.

The downside is about threefold:

Firstly, and most scientifically, humans require the biosphere for air and food. And so does everything else. There will be keystone species upon which groups of species depend on, which include species that we depend on. Because we don't know what they are, we need to maintain biodiversity.

Secondly, and least scientifically, animals are cute, and living on the world is a lesser thing for our grandchildren if they only live in a world without tigers, polar bears or coral reefs.

Thirdly and most interestingly, biodiversity is an academic resource. Each plant or animal has it's unique proteins that may be of some great medical or biotechnological value. Each one you lose is hundreds or thousands of these chemicals that are lost to science. Since this resource cannot be replaced, is should not be depleted without the greatest need.

Also, how does one figure out exactly if a species has died? I mean you can try to count the species in a certain area, then come back again later on and count them again, but maybe some have moved to a different location...?
It's not always easy, and you can get some pleasant surprises, especially with plants - whose seeds may lie dormant for years or decades.

It doesn't really matter in terms of policy which ones are the ones that are extinct though. Dropping biodiversity is a Bad Thing™, and we should try to stop it.

[Bored Wombat]

We are discovering tons of new species all of the time.

Yes.

The loss of species that are undiscovered is not a smaller loss though. If anything, it is a greater loss, because it gives science a much less opportunity to have learned from it.

And the description and naming of a species, while certainly a noble thing, is not an increase in biodiversity.

[Evo]

Yes.

The loss of species that are undiscovered is not a smaller loss though. If anything, it is a greater loss, because it gives science a much less opportunity to have learned from it.

And the description and naming of a species, while certainly a noble thing, is not an increase in biodiversity.There is no question that humans are destroying natural habitats at an alrming rate through agriculture, ranching, construction, destroying wetlands, destroying forests, killing off species that other species need to live on. But this is direct physical harm by man.

[mheslep]

...A study is not faulty for using a sample,I've not contradicted the academic papers on the LPI in this thread, I'm not qualified to do so absent other contradictory sources. The Loh et al 2005 (Phil Trans B.) authors report their data; they go to some length to point out limitations such as over representation of some types of species (birds (http://rstb.royalsocietypublishing.org/content/360/1454/289/F7.large.jpg)), thin data collection in the tropical (http://rstb.royalsocietypublishing.org/content/360/1454/289/F8.large.jpg) versus temperate areas, and over representation of threatened species (http://rstb.royalsocietypublishing.org/content/360/1454/289/F9.large.jpg).

I'm faulting the '30% biodiversity drop' and 'observation' parts of your statement in #105, for which you attempt to use the LPI to show that these are widely accepted conclusions, but which if you read the reference actually contradict your statement there about biodiversity:
The LPI indicates that populations of wild species of vertebrates have declined overall from 1970 to 2000. The extent to which this is a reflection of trends in global biodiversity as a whole has not been determined.
[...]
There are also a number of weaknesses with the LPI as a global biodiversity index. These weaknesses all relate to the representativeness of the population data.

I contend a fair summary of these papers can go little further than to say something like "The Living Planet Index, a weighted index of vertebrate population data, has shown a ~30% decline from 1970 to 2000" without distorting the paper.

[mheslep]

There is no question that humans are destroying natural habitats at an alrming rate through agriculture, ranching, construction, destroying wetlands, destroying forests, killing off species that other species need to live on. But this is direct physical harm by man.Right, and especially given the study referenced in this thread indicating that climate influences on species loss are overblown, it seems to me we'd get far more for our money in terms of preserving species by, e.g., buying up large areas of rain forest in Brazil and protecting them, rather than rushing out to paper over the all coal plants with solar panels in 5-10 years and forswearing air travel.

[Nebula815]

How can biologists think we are in a mass extinction if we don't know how many species there are on the Earth in the first place though? As said, we are discovering new ones all the time. Is there a documented list of thousands of species dying off every ten years or so...?

There is no question that humans are destroying natural habitats at an alrming rate through agriculture, ranching, construction, destroying wetlands, destroying forests, killing off species that other species need to live on. But this is direct physical harm by man.

Some of this I would say is the result of a lack of economic development in certain countries though. For example, I believe we have more trees per capita in the United States today than we did 150 years ago, because of modern farming techniques, which allow us to grow far more food utilizing far less land. This has allowed many areas that used to be farmland to grow back into forest.

Or in Third World countries, a lot of unnecessary destruction of plants and rainforest occurs because the people need the trees for energy (burn the wood).

That said, economic development if unchecked (lack of proper regulations and rules) will certainly destroy nature too (a big coal plant without proper exhaust filtration and a chemical plant dumping waste into a river are certainly highly destructive!).

One should also remember that different species mess things up for other species too, for example trees could technically be viewed as a big weed, one that sprouted up and cut off the sunlight and sucked all the water out of the ground, making it impossible for smaller plants to survive.

What we call "nature" is in many ways a constant battle of different species battling for dominance and survival. Nature is not a happy balance that humans came along and messed up.

[Mk]

There is no question that humans are destroying natural habitats at an alrming rate through agriculture, ranching, construction, destroying wetlands, destroying forests, killing off species that other species need to live on. But this is direct physical harm by man.

Wow Evo, you sound like a direct convert from the way you praised one of my posts in General Discussion a few years ago. What happened?

Assuming for the sake of argument that this is true, so what? Does the fact that a researcher is financed by Exxon-Mobil inherently mean they are lying? This is a logical fallacy called poisoning the well.
Actually a more accurate characterization would be a red herring fallacy known as an appeal to motive....

The warming that began at the beginning of the Holocene peaked about 7000 - 8000 years ago and the Earth has been cooling until the recent Anthropocene epoch.
Now that's poisoning the well (http://en.wikipedia.org/wiki/Poisoning_the_well). :smile:

Species do die all the time, but currently they are dying at some orders of magnitude faster than the long term average.
Bored Wombat, I'd like to know where it is you get your long-term data from. I can't quite imagine biologists empirically collecting meaningful biodiversity data thousands of years back. I am also unaware of the reliability of proxy data in the case of counting species over time.

[Evo]

Wow Evo, you sound like a direct convert from the way you praised one of my posts in General Discussion a few years ago. What happened?That was an awesome post if I'm not mistaken, it was the one about humans, when they try to fix things, screw things up even worse.

Am I right? I don't think I've changed from that opinion. Do you have the link to that post? If it's the one I'm thinking of, it should be bronzed.

[Nebula815]

That was an awesome post if I'm not mistaken, it was the one about humans, when they try to fix things, screw things up even worse.

I have read about that with regards to nature, just shows how little we humans understand about the mechanics of the wilderness.

[Bored Wombat]

I'm faulting the '30% biodiversity drop' and 'observation' parts of your statement in #105, for which you attempt to use the LPI to show that these are widely accepted conclusions, but which if you read the reference actually contradict your statement there about biodiversity:


I contend a fair summary of these papers can go little further than to say something like "The Living Planet Index, a weighted index of vertebrate population data, has shown a ~30% decline from 1970 to 2000" without distorting the paper.

Okay. I accept the about 30% drop, and that it could be much more or much less.

The order of magnitude is the worrying thing.

And climate change is a significant player in this - particularly well documented is the invasion of sub Antarctic ecosystems by temperate species.

But certainly invasion of mountain amphibians by fungi is also noted. There are bat populations that have also been devastated by fungi too.

[Bored Wombat]

There is no question that humans are destroying natural habitats at an alrming rate through agriculture, ranching, construction, destroying wetlands, destroying forests, killing off species that other species need to live on. But this is direct physical harm by man.
There is also no question that climate change, overexploitation and pollution are killing of species.

This is also direct physical harm by man.

[Bored Wombat]

Right, and especially given the study referenced in this thread indicating that climate influences on species loss are overblown,...
Which study is that?
I've been reading this thread, and I didn't notice that study.

Because I'm aware of a lot of biodiversity loss in this part of the world that is due to climate change more than other factors.

So I'd like to learn that this is overblown, and that these ecosystems have not been destroyed.

[Bored Wombat]

Bored Wombat, I'd like to know where it is you get your long-term data from. I can't quite imagine biologists empirically collecting meaningful biodiversity data thousands of years back. I am also unaware of the reliability of proxy data in the case of counting species over time.

There are lots of estimates of biodiversity based on the fossil record. Speciation is hard to judge from the record, and so estimates vary about an order of magnitude.

What do you find hard to believe, and why?

[mheslep]

Which study is that?
I've been reading this thread, and I didn't notice that study.

Because I'm aware of a lot of biodiversity loss in this part of the world that is due to climate change more than other factors.

So I'd like to learn that this is overblown,
Andre referenced the paper and you commented on it:
http://www.sciencemag.org/cgi/content/summary/326/5954/806.
Kathy J. Willis and Shonil A. Bhagwat, Biodiversity and Climate Change Science 6 November 2009: Vol. 326. no. 5954, pp. 806 - 807
There have also been news summaries and paper excerpts were posted in thread.
...and that these ecosystems have not been destroyed.Strawman. Nobody said that ecosystems have not taken a hit, in fact just the contrary has been stated by several posters concerning habitat loss through farming, development, etc. My comment, based on the paper, was climate influences on species loss are overblown. To head off any more strawmen, this does not mean that climate has no impact, or that we can't point to some isolated examples of climate influence on species loss. The paper attacks some of the existing, published, global estimates of species loss due to climate change, and shows why they're likely inaccurate.

[Bored Wombat]

Andre referenced the paper and you commented on it:
http://www.sciencemag.org/cgi/content/summary/326/5954/806.
Kathy J. Willis and Shonil A. Bhagwat, Biodiversity and Climate Change Science 6 November 2009: Vol. 326. no. 5954, pp. 806 - 807
There were news summaries and excerpts were posted.

Ah you mean that one paper looking at species ranges to predict drops in biodiversity produced an overestimate.

I thought you were saying that the observed drop in biodiversity that is attributed to climate change was overblown.

Strawman. Nobody said that ecosystems have not taken a hit, in fact just the contrary has been stated by several posters concerning habitat loss through farming, development, etc. My comment, based on the paper, was climate influences on species loss are overblown.

Then I would say that you've overstated the significance of the paper. The climate influences on species loss are not "overblown". A particular prediction, (that was already suspected to be high by applying it to biodiversity over the end of the last glaciation), was an overestimate, because there are niches smaller than the resolution of the other study in which a species will often survive.

But our understanding of climate influences on species loss is built up of ecological studies involving species and ecosystem loss, not that particular prediction of species loss in the coming decades.

Also, not a strawman. I was talking about ecosystems destroyed by climate change, not by land use change. Notably the subantarctic communities.

[Evo]

There are lots of estimates of biodiversity based on the fossil record. Speciation is hard to judge from the record, and so estimates vary about an order of magnitude.

What do you find hard to believe, and why?What on earth do fossil records have to do with the current gloabl warming debate? Unless you want to show that so called "global warming" has virtually no effect on species if you look at the fossil record and previous mass extinctions.

[Bored Wombat]

What on earth do fossil records have to do with the current gloabl warming debate?
Well they provide an estimate of historical biodiversity, and therefore a guide as to what rate of drop in biodiversity can be maintained.

Did I misunderstand MK's comment?

It seemed to me (s)he was questioning the long term average extinction and speication rates by wondering about my "long term data".

What do you think they were referring to?

Unless you want to show that so called "global warming" has virtually no effect on species if you look at the fossil record and previous mass extinctions.

Warm periods are periods of high extinction and high speciation (of course current climate change is very fast, which greatly exacerbates the problem), in the fossil record, and previous mass extinctions all occur at times of climatic upheaval.

What do you mean by 'so called "global warming" has virtually no effect on species if you look at the fossil record'. Surely the opposite is the case?

[mheslep]

Ah you mean that one paper looking at species ranges to predict drops in biodiversity produced an overestimate.No that is not what I mean, that is not what Willis and Bhagwa say.
Edit: If and until the paper becomes more generally available, a news summary:
Experts say that fears surrounding climate change are overblown (http://www.timesonline.co.uk/tol/news/science/article6905082.ece)
“The evidence of climate change-driven extinctions have really been overplayed,” said Professor Kathy Willis, a long-term ecologist at the University of Oxford and lead author of the article

I thought you were saying that the observed drop in biodiversity that is attributed to climate change was overblownNo, I said ... what I said.
Then I would say that you're wrong. The climate influences on species loss are not "overblown". A particular prediction, (that was already suspected to be high by applying it to biodiversity over the end of the last glaciation), was an overestimate, because there are niches smaller than the resolution of the other study in which a species will often survive.
But our understanding of climate influences on species loss is built up of ecological studies involving species and ecosystem loss, not that particular prediction of species loss in the coming decades.These kind of unsupported opinions belong over in the General Discussion, or Politics forums, not here.
Also, not a strawman. I was talking about ecosystems destroyed by climate change, not by land use change. Notably the subantarctic communities.You replied to my post with
[...]So I'd like to learn that this is overblown, and that these ecosystems have not been destroyed. attributing to me the claim that 'ecosystems have not been destroyed.' I did not say any such thing.

[Bored Wombat]

No that is not what I mean, that is not what Willis and Bhagwa say.
Edit: If and until the paper becomes more generally available, a news summary:
Experts say that fears surrounding climate change are overblown (http://www.timesonline.co.uk/tol/news/science/article6905082.ece)

At the risk of repeating myself, this is about prediction studies, particularly "Extinction risk from climate change", Nature 2004, linked above.

And I agree that that paper makes overestimates.

It is not true that "climate influences on species loss are overblown," except in the context of prediction.

But that is not how climate influence on species loss is generally understood. Certainly not in ecology. It is understood by watching climate change cause species loss. And this is not overblown.

You replied to my post with
attributing to me the claim that 'ecosystems have not been destroyed.' I did not say any such thing.

Right. Because you were referring to predicted species loss.

If you were claiming that observed species loss was overblown, it would necessarily be a claim that ecosystems have not be destroyed (by climate change). I thought that that is what you were saying.

In conclusion, yes, predicted species loss is overestimated by the 2004 nature paper mentioned in your linked press article, and also linked above.

But the paper in your linked press article does not talk about the observed species loss due to climate change, or the unobserved, but yet to date species loss due to climate change.

[Evo]

BW, the number of species we know today have risen due to recent concentrated efforts to log species. The resulting figures showing what we think are losses of these species are also due to the recent concentrated efforts at tracking. Not that there has been any increase in extinctions, just an increase in tracking.

It's meaningless.

You want to see mass extictions, look at the fossil record.

Do you know that we have had extinctions on earth that wiped out an estimated 95% of all life on the planet? This was the Permian-Triassic extinction. The earth bounces back. Nothing man has done can even come close to the natural disasters that have hit the earth in the past.

We're coming out of an ice age. Of course things are changing, they always change. Go back and learn about past climate events on earth if you want to discuss current climate with any semblance of credibility. Someone here made the statement "Global Climate Change - perhaps the greatest challenge ever faced by civilization."

Well, if they mean the Ice Age, yes, I guess it was, but man adapted to the horrific changes and survived.

[Bored Wombat]

BW, the number of species we know today have risen due to recent concentrated efforts to log species.
Sure
The resulting figures showing what we think are losses of these species are also due to the recent concentrated efforts at tracking. Not that there has been any increase in extinctions, just an increase in tracking.
No.
The living planet index follows the same species. So the same species are tracked as they were 40 years ago.

And it can't be your genuine position that there has been no increase in extinctions surely?

It's meaningless.
No it's not. It's a measure of biodiversity by looking at populations of vertebrates.

You want to see mass extictions, look at the fossil record.

There are five especially big ones there. And we're probably standing in the middle of the sixth ... but it won't be on the fossil record for a million years or so.

Luckily the number of species around at any given time has another source of data if that time is the present.

You can look at the species.

In some ways this is better than fossil data, that has confounding factors as some species fossilise more than others.

Do you know that we have had extinctions on earth that wiped out an estimated 95% of all life on the planet? This was the Permian-Triassic extinction. The earth bounces back. Nothing man has done can even come close to the natural disasters that have hit the earth in the past.
Well, nothing survived that that was bigger than about a cat. So if that's your standard of okay, then you're okay with the extinction of humans. Note that it would have been an unpleasant time to try to live through ... which is worth trying to avoid.

Also it doesn't bounce back very fast.

But this disaster is of a similar magnitude of the great extinctions of the past. One hopes not the Permian–Triassic, but it is difficult to imagine that this will look better than the Late Devonian extinction, which took about 70% of species. Given that we've lost about 30% in the 35 years to 2005, and there is no sign of that slowing yet.

So man can match some of the natural disasters that have hit earth in the past. And by 2050 you'll probably be able to count the worse ones over the entire 4 billion year history of life on earth, with one hand in your pocket.

[Evo]

Sure

No.
The living planet index follows the same species. So the same species are tracked as they were 40 years ago.

And it can't be your genuine position that there has been no increase in extinctions surely?


No it's not. It's a measure of biodiversity by looking at populations of vertebrates.



There are five especially big ones there. And we're probably standing in the middle of the sixth ... but it won't be on the fossil record for a million years or so.

Luckily the number of species around at any given time has another source of data if that time is the present.

You can look at the species.

In some ways this is better than fossil data, that has confounding factors as some species fossilise more than others.


Well, nothing survived that that was bigger than about a cat. So if that's your standard of okay, then you're okay with the extinction of humans. Note that it would have been an unpleasant time to try to live through ... which is worth trying to avoid.

Also it doesn't bounce back very fast.

But this disaster is of a similar magnitude of the great extinctions of the past. One hopes not the Permian–Triassic, but it is difficult to imagine that this will look better than the Late Devonian extinction, which took about 70% of species. Given that we've lost about 30% in the 35 years to 2005, and there is no sign of that slowing yet.

So man can match some of the natural disasters that have hit earth in the past. And by 2050 you'll probably be able to count the worse ones over the entire 4 billion year history of life on earth, with one hand in your pocket.
How can man match the cataclysmic events of comets and meteors striking the planet, multiple huge volcanoes erupting at once, gulf streams changed by the closure of a waterway due to volcanic activity? Not to mention the super fast Ice Age? Please post the proof that this is even feasable.

[mheslep]

Jumping in here:
BW, the number of species we know today have risen due to recent concentrated efforts to log species. The resulting figures showing what we think are losses of these species are also due to the recent concentrated efforts at tracking.Agreed.

Not that there has been any increase in extinctions, just an increase in tracking.
I don't think that's accurate. There have been some fairly long term studies (BW posted some peer reviewed references) looking at fixed species collections and they have definitely shown species loss in those collections. These collection sizes are in the thousands compared to the global ecosystem of millions, but they scientific studies none the less. We just don't know how representative those studies are of the world at large, but they can't be dismissed either.

You want to see mass extictions, look at the fossil record.

Do you know that we have had extinctions on earth that wiped out an estimated 95% of all life on the planet? This was the Permian-Triassic extinction. The earth bounces back. Nothing man has done can even come close to the natural disasters that have hit the earth in the past.
If we look at the entire history of Homo sapiens apparently our impact does indeed approach some of those lesser disasters.

You're referring here to the five major extincti (http://en.wikipedia.org/wiki/Extinction_event#Major_extinction_events)ons over geologic time, the last one the famous dinosaur killer 65mya. However, there are indeed several well known biologists calling the Homo Sapiens period a 'sixth' extinction event. They mean by this the period from now going back 40,000 years, still short by these time scales. The causes include the modern ones you listed earlier, but also, over the millennia, general predation by HS and the rapid introduction of invasive species to isolated ecosystems made possible only by HS travel. I make no comment here on whether of not this is simply nature's way, but the fact is we whacked a lot of the low hanging fruit (Mastodons) as we came down out of the trees. Many of those species were probably on the edge of existence independent of HS, but we as top predator pushed them over. Per some biologists, HS past action combined with modern habit destruction is indeed adding up to a reduction in species loss comparable to some of the lesser earlier extinctions.

I can't find a peer reviewed article making this point so take this for what its worth, and I won't post any non peer reviewed links here. However, a google search for 'sixth extinction' will bring up a lot of material written in popular form by working biologists.