Playing Devil's advocate on climate

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In summary: Second, the insistence that the "deniers" are somehow conspiring to deceive the public and suppress the truth about climate change. Third, the false dichotomy of "skeptics" and "believers".In summary, this forum is fascinating, and the climate discussions are very interesting and educational. I couldn't help but notice however that it seems posters tend to line up along sides on the issue of AGW (or perhaps the degree to which they are skeptical of the consensus). I think it would be interesting to see people play devil's advocate and argue for the other position, or rather acknowledeld
  • #71
Xnn said:
Not sure if how significant other forcings are.

Neither is anyone else; there are significant uncertainties in other forcings. CO2 is the simplest forcing to evaluate and is known to quite high accuracy. Other forcings are known, but with larger bounds of accuracy. The bounds are sufficient to conclude with strong confidence that greenhouse effects are the largest forcing, and that CO2 is the largest contributor to that. But the lack of certainty in other forcings still means a large spread of uncertainty about total forcing.

I've given a widely repeated diagram in [post=2215403]msg #66[/post] of thread "Estimating the impact of CO2 on global mean temperature", outlining estimates and uncertainties for forcings. It can be found also as figure 2.20, on page 203 (chapter 2) of the http://www.ipcc.ch/ipccreports/ar4-wg1.htm" . The estimates are quantified, with 90% confidence bounds, in table 2.12, page 204.

Felicitations -- sylas

PS. As an added wrinkle... a forcing is a change from one time to another. The table I've shown is giving the forcings from 1750 to the present. But if you want to look at the last 30 years, then the picture changes again, generally making the greenhouse effects and CO2 in particular even more significant for the immediate rate of change. The immediate rate of change also is affected by changes in heat uptake in the ocean, which will impact rates of change in much the same way as a forcing.
 
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  • #72
The other explanation for the 20th century warming is a decrease in planetary clouds rather than AWG, in particular CO2.

The observations do not show a steady increase in the base line planetary temperature about which planetary temperature oscillates. Planetary temperature has in fact cooled slightly post 1998.

http://www.woodfortrees.org/plot/hadcrut3vgl/from:1980/to:2009.8/normalise


http://wattsupwiththat.com/2009/09/04/uah-global-temperature-down-in-august-181%C2%B0c-sh-sees-biggest-drop-of-0-4%C2%B0c/

As I noted further up in the this thread planetary temperature in the 20th century has strongly correlated with geomagnetic field change measured by the parameter Ak that is in turn modulated by solar wind bursts. The solar wind burst remove cloud forming ions by a process called electroscavenging. The sudden warming events in planetary temperature records and the longer term warming and cooling trends correlate with Ak.


http://www.atmos-chem-phys.org/5/1721/2005/acp-5-1721-2005.html


Analysis of the decrease in the tropical mean outgoing shortwave radiation at the top of atmosphere for the period 1984–2000

All cloud types show a linearly decreasing trend over the study period, with the low-level clouds having the largest trend, equal to −3.9±0.3% in absolute values or −9.9±0.8% per decade in relative terms. Of course, there are still some uncertainties, since the changes in low-level clouds derived from the ISCCP-D2 data, are not necessarily consistent with changes derived from the second Stratospheric Aerosols and Gas Experiment (SAGE II, Wang et al., 2002) and synoptic observations (Norris, 1999). Nevertheless, note that SAGE II tropical clouds refer to uppermost opaque clouds (with vertical optical depth greater than 0.025 at 1.02μm), while the aforementioned synoptic cloud observations are taken over oceans only. The midlevel clouds decreased by 1.4±0.2% in absolute values or by 6.6±0.8% per decade in relative terms, while the high-level ones also decreased by 1.2±0.4% or 3±0.9% per decade in relative terms, i.e. less than low and middle clouds. Thus, the VIS/IR mean tropical (30_ S–30_ N) low-level clouds are found to have undergone the greatest decrease during the period 1984–2000, in agreement with the findings of Chen et al. (2002) and Lin et al. (2004).


http://news.yahoo.com/s/mcclatchy/20090819/sc_mcclatchy/3295216

WASHINGTON — Has Earth's fever broken?
Official government measurements show that the world's temperature has cooled a bit since reaching its most recent peak in 1998.

"It's entirely possible to have a period as long as a decade or two of cooling superimposed on the long-term warming trend," said David Easterling , chief of scientific services at NOAA's National Climatic Data Center in Asheville, N.C.

So far this year, the high has been 0.42 degrees Celsius (0.76 degrees Fahrenheit), above the 20-year average, clearly cooler than before.
 
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  • #73
Saul said:
As I noted further up in the this thread planetary temperature in the 20th century has strongly correlated with geomagnetic field change measured by the parameter Ak that is in turn modulated by solar wind bursts. The solar wind burst remove cloud forming ions by a process called electroscavenging. The sudden warming events in planetary temperature records and the longer term warming and cooling trends correlate with Ak.

The problem is that the planetary temperature in the 20th century also correlates with the logarithm of the average number of transistors on an Intel processor chip...
 
  • #74
vanesch said:
The problem is that the planetary temperature in the 20th century also correlates with the logarithm of the average number of transistors on an Intel processor chip...

Do you have a paper to show the correlation?

Please explain the cooling post 1998.

I provided papers that shows the correlation, papers that provide a cause to explain the observations, and papers to explain the mechanism.

What is your point? Or problem?
 
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  • #75
Galteeth's comment was:

This is a fascinating forum, and these climate discussions are very interesting and educational. I couldn't help but notice however that it seems posters tend to line up along sides on the issue of AGW (or perhaps the degree to which they are skeptical of the consensus). I think it would be interesting to see people play devil's advocate and argue for the other position, or rather acknowledge data that does not support their view (on both sides).

There are most definitely basic observations that do not support the AWG hypothesis. There have been a series of papers that have been written concerning the discrepancy between prediction and observations.

The science is interesting. A pointless sarcastic monologue is not.

Because there currently appears to be a deep solar magnetic cycle minimum, there should be observational evidence and papers to clarify the problem situation. We can have some fun reading and discussing those papers and discussing the observational evidence.

The competing scientific explanation for the 20th century warming is solar modulation of planetary cloud cover. As noted in the past cosmogenic isotopes changes correlate with abrupt planetary temperature change. There is smoking gun evidence at each of the cyclic abrupt climate change events.
 
  • #76
Saul said:
What is your point? Or problem?

The point is that finding a correlation doesn't indicate a causal relationship, and even if so, it doesn't even indicate which way. Now, there can (I didn't check) be a correlation with solar activity, why not. The mechanism you mention can be active.

However, you are not going to convince me that the mechanism of cloud formation through solar activity is simpler physics, which is less prone to modelling errors, and to which there are less complex feedback factors working, than the heat transport problem of an atmosphere containing some gases that interact with IR radiation, which is based upon rather elementary thermodynamics, and of which several basic aspects are easily checked and known for tens of years (like the lapse rate, or the black body properties of gases).

In other words, the warming of the last century can be for sure find its origins in many elements, but the CO2 is definitely a part in it, and it is probably the easiest part to calculate, because at least the forcing due to it is easy to estimate.

The point is that even if you had a straight-forward model that no-body can doubt because based upon very elementary physics for your solar activity stuff that gives you the expected change in cloud cover as function of the solar activity, calculated from first principles only, and not using any climate data, still you would be faced with exactly the same problem as the one with CO2: the climate sensitivity. Even if you had the perfect model that gives you without an ounce of doubt, from first principles, the cloud cover as a function of solar activity, the only thing you would be able to get from that, is a forcing (so many watts per square meter). The question of how temperature is dependent on that is exactly the same as for the CO2 forcing: the sensitivity.

Now, at least the forcing is easy to calculate with CO2, because for that there DOES exist a simple and straightforward physics model based upon first principles.

So it might very well be that your mechanism ALSO exists, and is ALSO a significant drive - I don't know. But to say that it is a *more straightforward* explanation than CO2 seems to me to push things, no ?
 
  • #77
Saul said:
Do you have a paper to show the correlation?

Please explain the cooling post 1998.

I provided papers that shows the correlation, papers that provide a cause to explain the observations, and papers to explain the mechanism.

What is your point? Or problem?


Denier blogs are not scientific papers. Therefore you have failed to meet the standards of this forum.

There is no cooling trend since 1998. 1998 was an anomalous year, influenced by a very strong el nino event. The long term trend did plateau slightly, but has remained positive.

global-jan-dec-error-bar-pg.gif
 
  • #78
vanesch said:
The point is that finding a correlation doesn't indicate a causal relationship, and even if so, it doesn't even indicate which way. Now, there can (I didn't check) be a correlation with solar activity, why not. The mechanism you mention can be active.

However, you are not going to convince me that the mechanism of cloud formation through solar activity is simpler physics, which is less prone to modelling errors, and to which there are less complex feedback factors working, than the heat transport problem of an atmosphere containing some gases that interact with IR radiation, which is based upon rather elementary thermodynamics, and of which several basic aspects are easily checked and known for tens of years (like the lapse rate, or the black body properties of gases).

In other words, the warming of the last century can be for sure find its origins in many elements, but the CO2 is definitely a part in it, and it is probably the easiest part to calculate, because at least the forcing due to it is easy to estimate.

The point is that even if you had a straight-forward model that no-body can doubt because based upon very elementary physics for your solar activity stuff that gives you the expected change in cloud cover as function of the solar activity, calculated from first principles only, and not using any climate data, still you would be faced with exactly the same problem as the one with CO2: the climate sensitivity. Even if you had the perfect model that gives you without an ounce of doubt, from first principles, the cloud cover as a function of solar activity, the only thing you would be able to get from that, is a forcing (so many watts per square meter). The question of how temperature is dependent on that is exactly the same as for the CO2 forcing: the sensitivity.

Now, at least the forcing is easy to calculate with CO2, because for that there DOES exist a simple and straightforward physics model based upon first principles.

So it might very well be that your mechanism ALSO exists, and is ALSO a significant drive - I don't know. But to say that it is a *more straightforward* explanation than CO2 seems to me to push things, no ?

vanesch,

I am not trying to convince you of anything. I am trying explain these observations.

Those advocating the AWG position (AWG caused 90% of the 20th century warming. Deny the cooling occurred or attribute cooling to satellite problems.) in this forum have not acknowledge the most basic fact which is that the 20th planetary temperature changes did not correlate with the CO2 changes. Changes in planetary cloud cover do correlate with the 20th century temperature rise.

A scientific mind ask why, is interesting in a scientific explanation. You and the other AWG supports in the forum do not acknowledge that there is a problem situation. Something that requires explanation.

The point is you write in capital letters. I do not understand the emotion. Science is science. The truth is the truth. What will happen will happen.

The are multiple observations (for example the current cooling trend and the increase in sea ice in the arctic and antarctic) and papers that do not support the AWG hypothesis.

http://www.woodfortrees.org/plot/hadcrut3vgl/from:1980/to:2009.8/normalise

http://wattsupwiththat.com/2009/09/04/uah-global-temperature-down-in-august-181%C2%B0c-sh-sees-biggest-drop-of-0-4%C2%B0c/



http://www.atmos-chem-phys.org/5/1721/2005/acp-5-1721-2005.html


Analysis of the decrease in the tropical mean outgoing shortwave radiation at the top of atmosphere for the period 1984–2000

All cloud types show a linearly decreasing trend over the study period, with the low-level clouds having the largest trend, equal to −3.9±0.3% in absolute values or −9.9±0.8% per decade in relative terms. Of course, there are still some uncertainties, since the changes in low-level clouds derived from the ISCCP-D2 data, are not necessarily consistent with changes derived from the second Stratospheric Aerosols and Gas Experiment (SAGE II, Wang et al., 2002) and synoptic observations (Norris, 1999). Nevertheless, note that SAGE II tropical clouds refer to uppermost opaque clouds (with vertical optical depth greater than 0.025 at 1.02μm), while the aforementioned synoptic cloud observations are taken over oceans only. The midlevel clouds decreased by 1.4±0.2% in absolute values or by 6.6±0.8% per decade in relative terms, while the high-level ones also decreased by 1.2±0.4% or 3±0.9% per decade in relative terms, i.e. less than low and middle clouds. Thus, the VIS/IR mean tropical (30_ S–30_ N) low-level clouds are found to have undergone the greatest decrease during the period 1984–2000, in agreement with the findings of Chen et al. (2002) and Lin et al. (2004).
 
  • #79
Skyhunter said:
Denier blogs are not scientific papers. Therefore you have failed to meet the standards of this forum.

There is no cooling trend since 1998. 1998 was an anomalous year, influenced by a very strong el nino event. The long term trend did plateau slightly, but has remained positive.

Skyhunter,
Science is the discussion of observations. Planetary temperature is dropping. Antarctic and Arctic Sea ice is increasing.

Name calling "denier blogs" is a sign that you are not interesting in the problem situation from a scientific standpoint. Why the emotion? The observations do not support the AWG hypothesis.

http://news.yahoo.com/s/mcclatchy/20090819/sc_mcclatchy/3295216

http://www.woodfortrees.org/plot/hadcrut3vgl/from:1980/to:2009.8/normalise

WASHINGTON — Has Earth's fever broken?
Official government measurements show that the world's temperature has cooled a bit since reaching its most recent peak in 1998.
 
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  • #80
Saul said:
Those advocating the AWG position (AWG caused 90% of the 20th century warming. Deny the cooling occurred or attribute cooling to satellite problems.)

This is not what I would call the defining position of AGW. AGW means, at least, that's how I understand it, that human emissions of greenhouse gasses are significant enough to cause an observable extra warming on top of all the other forcings that there might be, in the coming centuries. Then the scientific debate goes about how much exactly.

And then the non-scientific AGW debate goes about what this is going to do to humanity and the biosphere, and whether that is a bad thing in the first place, and if so, what, if anything, we should/can do about it.
 
  • #81
vanesch said:
This is not what I would call the defining position of AGW. AGW means, at least, that's how I understand it, that human emissions of greenhouse gasses are significant enough to cause an observable extra warming on top of all the other forcings that there might be, in the coming centuries. Then the scientific debate goes about how much exactly.

And then the non-scientific AGW debate goes about what this is going to do to humanity and the biosphere, and whether that is a bad thing in the first place, and if so, what, if anything, we should/can do about it.

The AWG position is that a doubling of from 280 ppm to 560 ppm will cause the planet to warm 3C to 5C.

The AWG position is not that an increase in CO2 from 280 ppm to 560 ppm will cause 0.75C increase in planetary temperature.

The scientific formula for CO2 forcing is logarithmic. The current increase (from 280 ppm to 380 ppm) will if the formula matches reality result in an increase in forcing of around 2.7 w/m^2 of the total calculated 3.7 w/m^2 that the formula predicts will result from a doubling from 280 ppm to 560 ppm.

Rather than discuss the recent planetary cooling, it is denied. There cannot be a long term cooling trend if there was an increase in forcing that never goes away of 2.7 w/m^2.

That is the problem situation from the AWG position. The CO2 must warm the planet every day if the mechanism exists as hypothesized.

What it appears based on the shape of planetary temperature change, is CO2 saturates or at least partially saturates from a perspective of the mechanism. The why and what will happen next due to the abrupt solar magnetic cycle change, is an interesting question.

The key question is the magnitude of up coming planetary temperature change.
 
  • #82
Saul said:
Skyhunter,
Science is the discussion of observations. Planetary temperature is dropping. Antarctic and Arctic Sea ice is increasing.

Name calling "denier blogs" is a sign that you are not interesting in the problem situation from a scientific standpoint. Why the emotion? The observations do not support the AWG hypothesis.

http://news.yahoo.com/s/mcclatchy/20090819/sc_mcclatchy/3295216

http://www.woodfortrees.org/plot/hadcrut3vgl/from:1980/to:2009.8/normalise

Denier blogs or fellowship for scientific truth, it doesn't matter what you call them. They are not credible sources and therefore against forum rules.
 
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  • #83
Skyhunter said:
Denier blogs or fellowship for scientific truth, it doesn't matter what you call them. They are not credible sources and therefore against forum rules.

Skyhunter what is your point or problem? You appear not to want to discuss the science and instead try to stop anyone else from discussing the science, the problem situation.

The AWG position is that a doubling of CO2 from 280 ppm to 560 ppm will cause the planet to warm 3C to 5C. Based on the AWG formula the increase from 280 ppm to 380 ppm should have resulted in an increase in forcing of 2.7 w/m^2 of the total 3.7 w/m^2, 24 hours a day, seven days a week.

The AWG forcing mechanism cannot appear in January and then disappear in June.

There is no evidence in the planetary temperature changes of a steady increase in of 2.7 w/m^2.

The other explanation for the 20th century warming is a change in planetary clouds. The forcing mechanism that increases and decreases planetary clouds can change and hence can explain the observations.

http://www.atmos-chem-phys.org/5/172...1721-2005.html Analysis of the decrease in the tropical mean outgoing shortwave radiation at the top of atmosphere for the period 1984–2000

All cloud types show a linearly decreasing trend over the study period, with the low-level clouds having the largest trend, equal to −3.9±0.3% in absolute values or −9.9±0.8% per decade in relative terms. Of course, there are still some uncertainties, since the changes in low-level clouds derived from the ISCCP-D2 data, are not necessarily consistent with changes derived from the second Stratospheric Aerosols and Gas Experiment (SAGE II, Wang et al., 2002) and synoptic observations (Norris, 1999). Nevertheless, note that SAGE II tropical clouds refer to uppermost opaque clouds (with vertical optical depth greater than 0.025 at 1.02μm), while the aforementioned synoptic cloud observations are taken over oceans only. The midlevel clouds decreased by 1.4±0.2% in absolute values or by 6.6±0.8% per decade in relative terms, while the high-level ones also decreased by 1.2±0.4% or 3±0.9% per decade in relative terms, i.e. less than low and middle clouds. Thus, the VIS/IR mean tropical (30_ S–30_ N) low-level clouds are found to have undergone the greatest decrease during the period 1984–2000, in agreement with the findings of Chen et al. (2002) and Lin et al. (2004).

http://news.yahoo.com/s/mcclatchy/20...latchy/3295216

WASHINGTON — Has Earth's fever broken?
Official government measurements show that the world's temperature has cooled a bit since reaching its most recent peak in 1998.

"It's entirely possible to have a period as long as a decade or two of cooling superimposed on the long-term warming trend," said David Easterling , chief of scientific services at NOAA's National Climatic Data Center in Asheville, N.C.

So far this year, the high has been 0.42 degrees Celsius (0.76 degrees Fahrenheit), above the 20-year average, clearly cooler than before.
 
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  • #84
The Earth is not cooling.

Short term trends are flat, not negative. As the current el nino event develops global temperatures are once again on the rise.

Saul said:
The CO2 must warm the planet every day if the mechanism exists as hypothesized.

This is a strawman argument.

There is nothing in the AGW theory that requires temperatures to rise everyday.
 
  • #85
Saul,

If you want to discuss science, then provide a scientific source.

We are not allowed to discuss psuedo-science on this forum.
 
  • #86
Skyhunter said:
The Earth is not cooling.

Short term trends are flat, not negative. As the current el nino event develops global temperatures are once again on the rise.

This is a strawman argument.

There is nothing in the AGW theory that requires temperatures to rise everyday.

Skyhunter,

The hypothesized 2.7 w/m^2 heating due to CO2 increasing from 280 ppm to 380 ppm does not go away. It is there 24 hours a day, seven days a week.

Fundamental science shows the CO2 greenhouse affect is logarithmic. Each additional CO2 molecule has less affect than the molecule that was added before. The majority of the climate forcing has already occurred based on the basic science.

Remember the AWG position is not only that additional CO2 will cause the planet to slightly warm (say 0.75C), but rather that the planet will warm 3C to 5C, due to a doubling of CO2 from 280 ppm to 560 ppm.

Significant planetary cooling this winter for example would be very difficult to explain if the AWG hypothesized mechanism is correct.
 
  • #87
Skyhunter said:
Saul,

If you want to discuss science, then provide a scientific source.

We are not allowed to discuss psuedo-science on this forum.

Skyhunter,
Your comment is irrational. Not logical. It does not match my comment. It makes sense if your objective is to try to stop me from commenting.

It has no connection with my comment scientifically. I am only interested in the science. I am not trying to change your personal point of view.

The other explanation for the 20th century warming is a change in planetary clouds. The forcing mechanism that increases and decreases planetary clouds can change and hence can explain the observations.

http://www.atmos-chem-phys.org/5/172...1721-2005.html


Analysis of the decrease in the tropical mean outgoing shortwave radiation at the top of atmosphere for the period 1984–2000

All cloud types show a linearly decreasing trend over the study period, with the low-level clouds having the largest trend, equal to −3.9±0.3% in absolute values or −9.9±0.8% per decade in relative terms. Of course, there are still some uncertainties, since the changes in low-level clouds derived from the ISCCP-D2 data, are not necessarily consistent with changes derived from the second Stratospheric Aerosols and Gas Experiment (SAGE II, Wang et al., 2002) and synoptic observations (Norris, 1999). Nevertheless, note that SAGE II tropical clouds refer to uppermost opaque clouds (with vertical optical depth greater than 0.025 at 1.02μm), while the aforementioned synoptic cloud observations are taken over oceans only. The midlevel clouds decreased by 1.4±0.2% in absolute values or by 6.6±0.8% per decade in relative terms, while the high-level ones also decreased by 1.2±0.4% or 3±0.9% per decade in relative terms, i.e. less than low and middle clouds. Thus, the VIS/IR mean tropical (30_ S–30_ N) low-level clouds are found to have undergone the greatest decrease during the period 1984–2000, in agreement with the findings of Chen et al. (2002) and Lin et al. (2004).

http://news.yahoo.com/s/mcclatchy/20...latchy/3295216

WASHINGTON — Has Earth's fever broken?
Official government measurements show that the world's temperature has cooled a bit since reaching its most recent peak in 1998.

"It's entirely possible to have a period as long as a decade or two of cooling superimposed on the long-term warming trend," said David Easterling , chief of scientific services at NOAA's National Climatic Data Center in Asheville, N.C.

So far this year, the high has been 0.42 degrees Celsius (0.76 degrees Fahrenheit), above the 20-year average
 
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  • #88
Saul,

You said:

That is the problem situation from the AWG position. The CO2 must warm the planet every day if the mechanism exists as hypothesized.

and

The AWG forcing mechanism cannot appear in January and then disappear in June.

and

Significant planetary cooling this winter for example would be very difficult to explain if the AWG hypothesized mechanism is correct.

These are strawmen arguments, red herrings. The AGW forcing does not alter the fact that climate has other shorter and longer term oscillations that account for daily, seasonal, annual, decadal, and millennial climate or temperature changes.
 
  • #89
Saul said:
The AWG position is that a doubling of from 280 ppm to 560 ppm will cause the planet to warm 3C to 5C.

?

I think you are fighting a straw man.
First of all, even the IPCC is not giving these limits (and I have - as I said earlier - my own doubts on the rigor by which these are "hard limits" or rather "to the best of our knowledge today" kind of indications). As far as I remember, they give something like 1.5 - 4.5 C with a 90% confidence limit or something. If human CO2 exhaust would double the atmospheric content and would warm only 1.5 degrees, that would also be AGW. Even 0.5 degrees in my book would be AGW, although the guys from the IPCC consider that, given their current understanding, rather improbable. However, 0.01 degree wouldn't. Because that's not noticeable or measurable.

Second, warming with respect to what ? Warming with respect to what there would have been without CO2 exhaust. The base line doesn't need to be constant. So even a cooling can be under AGW influence, if it cools less than it would have cooled without CO2 exhaust. But that's not directly measureable.

The AWG position is not that an increase in CO2 from 280 ppm to 560 ppm will cause 0.75C increase in planetary temperature.

I would think that it is still AGW, although several people tend to think it will be stronger.

The scientific formula for CO2 forcing is logarithmic. The current increase (from 280 ppm to 380 ppm) will if the formula matches reality result in an increase in forcing of around 2.7 w/m^2 of the total calculated 3.7 w/m^2 that the formula predicts will result from a doubling from 280 ppm to 560 ppm.

Yes. So ? There can be long delays before the final value is reached. These delays can be of the matter of decades or centuries.

Rather than discuss the recent planetary cooling, it is denied. There cannot be a long term cooling trend if there was an increase in forcing that never goes away of 2.7 w/m^2.

Of course there could be if there were other forcings that were negative and larger. If tomorrow the sun "goes out" then it will for sure cool. But according to AGW, it will cool slightly less (fast) than it would without CO2. That's still AGW.

The anti-AGW position is rather that human CO2 exhaust doesn't have the slightest noticeable influence on the climate system.

But the other error is to think that you can do statistics over a decade or so. You need of the order of a century to be able to see small trends like these because the average values are only that: averages. And the statistical spread around them is very big. They are the "high frequency" components that are not understood, that are chaotic,...


That is the problem situation from the AWG position. The CO2 must warm the planet every day if the mechanism exists as hypothesized.

No, of course not. There must only a trend on the scale of centuries or many decades. And even then, a trend with respect to an unknown "base line" which is what there would have been without human exhaust, but which we can of course not measure.

Of course, the stronger the trend, and the less the baseline is supposed to change, the sooner the data will show up evidence.

The absolute temperature variation BY ITSELF doesn't say anything about AGW by itself.
 
  • #90
vanesch said:
?

Vanesch & Skyhunter,

I think we have beaten this subject to death. Let's agree to disagree.

Let's summarize.

I have provided papers that show the 20th century planetary warming could be due to a reduction in planetary cloud cover. See above if anyone is interested.

There is currently an abrupt interruption of the solar magnetic cycle which has reduced the strength of the heliosphere and has caused GCR to increase by 18%. There has not been an increase in planetary clouds because there has been a three times increase in solar wind bursts during this current solar cycle minimum. I have provided papers to support these statements.

The solar wind bursts have started to abate.

Based on the planetary cloud mechanism, planetary cloud should now start to increase, due to a reduction in the solar wind bursts and due to the increased GCR.

So rather than argue whether the solar modulation of planetary cloud mechanism exists or does not exist, we can just watch planetary temperature and see if it does drop. I am interested because I do not understand the delays in the mechanisms and I am unsure of the magnitude of the change.

I will keep an eye out for any interesting planetary temperature observations. Have you been watching the current Arctic and Antarctic sea ice cover anomaly?
 
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  • #91
Saul said:
I have provided papers that show the 20th century planetary warming could be due to a reduction in planetary cloud cover. See above if anyone is interested.

Your sources are not scientific, therefore may not be discussed here.

There is currently an abrupt interruption of the solar magnetic cycle which has reduced the strength of the heliosphere and has caused GCR to increase by 18%. There has not been an increase in planetary clouds because there has been a three times increase in solar wind bursts during this current solar cycle minimum. I have provided papers to support these statements.

I have been following the current solar minimum, solar winds have been relatively calm for the past year.

[edit] Although they have been much higher than during the cycle 23 minimum. [/edit]

Based on the planetary cloud mechanism, planetary cloud should now start to increase, due to a reduction in the solar wind bursts and due to the increased GCR.

Planetary cloud cover should have begun increasing 18 months ago according to the GCR hypothesis.

So rather than argue whether the solar modulation of planetary cloud mechanism exists or does not exist, we can just watch planetary temperature and see if it does drop. I am interested because I do not understand the delays in the mechanisms and I am unsure of the magnitude of the change.

I am uncertain that the mechanism even exists. And even if it does, since temperatures are still rising it has little effect on global temperatures.

I will keep an eye out for any interesting planetary temperature observations. Have you been watching the current Arctic and Antarctic sea ice cover anomaly?

I visit the NSIDC site 3-5 times a week.
 
  • #92
Skyhunter said:
Your sources are not scientific, therefore may not be discussed here. I visit the NSIDC site 3-5 times a week.

http://www.agu.org/pubs/crossref/2009/2009JA014342.shtml
Skyhunter,

You must have missed this paper. Let's agree to disagree about the prediction of what is about to happen. Let's wait until there is new planetary temperature data to discuss. I will keep an eye out for new papers.

This should be an interesting scientific period if I understand the mechanisms.


If the Sun is so quiet, why is the Earth ringing? A comparison of two solar minimum intervals


Observations from the recent Whole Heliosphere Interval (WHI) solar minimum campaign are compared to last cycle's Whole Sun Month (WSM) to demonstrate that sunspot numbers, while providing a good measure of solar activity, do not provide sufficient information to gauge solar and heliospheric magnetic complexity and its effect at the Earth.

The present solar minimum is exceptionally quiet, with sunspot numbers at their lowest in 75 years and solar wind magnetic field strength lower than ever observed. Despite, or perhaps because of, a global weakness in the heliospheric magnetic field, large near-equatorial coronal holes lingered even as the sunspots disappeared. Consequently, for the months surrounding the WHI campaign, strong, long, and recurring high-speed streams in the solar wind intercepted the Earth in contrast to the weaker and more sporadic streams that occurred around the time of last cycle's WSM campaign.

In response, geospace and upper atmospheric parameters continued to ring with the periodicities of the solar wind in a manner that was absent last cycle minimum, and the flux of relativistic electrons in the Earth's outer radiation belt was elevated to levels more than three times higher in WHI than in WSM. Such behavior could not have been predicted using sunspot numbers alone, indicating the importance of considering variation within and between solar minima in analyzing and predicting space weather responses at the Earth during solar quiet intervals, as well as in interpreting the Sun's past behavior as preserved in geological and historical records.
 
  • #93
You are speculating that

  1. GCR drives cloud formation, as yet a still unproven hypothesis.
  2. The solar wind modulates this as speculative process.

Since the global temperature trend is still positive, and we are entering a positive ENSO phase, then it is likely that global temperatures will continue to rise.
 
  • #94
My take on this is, it's not a valid scientific experiment, there is no control subject and it it was "an experiment" that should be allowed to run it's course then what happens if the global warming does swing out of control.

talking about control, I see this as a feedback control loop issue, if you have 'tuned' a feedback control loop you generally have 2 knobs, gain and damping.

Too little damping and the process will go out of control, it will not just swing to one extreme it will begin to oscilate until it hardlines on one extreme.

Too little damping or too much gain will achieve the same result.

To me, cutting down CO2 absorbing trees is reducing the "damping" parameter, and releasing fossilised CO2 in increasing the gain in the system.

It's not an experiment, we don't have anywhere els to go if we are wrong, So possibly erring on the side of causion might be wise.

"Lets wait and see" is not good enough.
 
  • #95
Darryl said:
My take on this is, it's not a valid scientific experiment, there is no control subject and it it was "an experiment" that should be allowed to run it's course then what happens if the global warming does swing out of control.
What experiment are you talking about?

It appears you have a misperception of how the scientific method is employed in fields such as anthropology, astronomy/cosmology, and climatology/meteorology. We don't know how to build a time machine, and even if we did, going back in time and experimenting on Mitochondrial Eve would not be deemed as kosher. Anthropologists can only observe, and their observations are limited to ancient bones and shards of flint. Astronomers similarly cannot create in the lab galaxies that are billions of light years apart. They can observe them by telescope. Just because anthropologists and astronomers can't perform controlled experiments with all the trappings does not mean that anthropology and astronomy are not science.

The same goes for meteorology and climatology. Scientists can create scaled-down models of some phenomena, but scaling things down to lab size is always fraught with problems. (The scaling problem is why the aerodynamics industry likes to use full-scale wind tunnel as the ultimate test of what happens to a vehicle.) The best way to determine the weather and climate is to observe it. It is still science.
 
  • #96
Saul said:
This topic is interesting because there are competing scientific viewpoints in published papers and because there is currently an abrupt interruption to the solar magnetic cycle.

Saul,

I started a new thread.

https://www.physicsforums.com/showthread.php?t=346406

It is a new map of the heliosphere by the IBEX spacecraft . Since the heliosphere is a manifestation of the solar magnetic anomaly you might find the press conference interesting
 

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