Global Warming Debate: Refuting Common Arguments

[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 https://www.physicsforums.com/showpost.php?p=2419819&postcount=58" 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 https://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, 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 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 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 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:
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:
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 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:
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:
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 (http://rstb.royalsocietypublishing.org/content/360/1454/289/F7.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.

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:
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 overblown

No, 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:
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 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.

 

[heldervelez]

Earth is dominated since recent times by 'hot blood' animals that have internal solutions to be hotter than environment.

This is in contrast with extinguished solutions (cold blood) that, who kowns, could have solutions to be colder than environment.

To me it strongly suggest the long trend Earth's temperature declining.
And big extinctions could be tied to this fact.

 

[Sorry!]

Earth is dominated since recent times by 'hot blood' animals that have internal solutions to be hotter than environment.

This is in contrast with extinguished solutions (cold blood) that, who kowns, could have solutions to be colder than environment.

To me it strongly suggest the long trend Earth's temperature declining.
And big extinctions could be tied to this fact.

What exactly are you trying to say in this post?

 

[Sorry!]

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.

I've read this in a book I'll look through my collection to see if I can recall the title to reference for you; this is a very real situation though. It is different than the past extinction events occurring more due to pollution, changing landscape, us taking animals from one location and putting them in another, and of course 'over-hunting' (couldn't think of a better word haha).

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.

This extinction event wiped out approximately 54-58% of families around at the time. Probably something closer to 70-75% of species on Earth (some families are huge and some are small); not 95%.

Anyways aside from that you are comparing the greatest extinction event ever observed on our planet to what humans can cause. All of the other extinction events were much smaller (If my memory is correct only up to 24% of families going extinct average probably around 20%). I have no doubts in my mind that we are currently in a man-caused extinction event, I'll look for that book see the references in it. (the ones specifically relating to increase in temperature.)