Fossil Record Provides Evidence Linking Mass Extinction Events with Climate Change
24 October 2007
Researchers at the Universities of York and Leeds have identified a close association between Earth's climate and mass extinction events in a study that examines the relationship between the two over the past 520 million years—almost the entire fossil record available.
Matching data sets of marine and terrestrial diversity against temperature estimates, evidence shows that global biodiversity is relatively low during warm greenhouse phases and extinctions relatively high, while the reverse is true in cooler icehouse phases.
The research, published in the latest issue of Proceedings of the Royal Society B, was carried out by University of York student Gareth Jenkins, together with his supervisor, Dr Peter Mayhew, and University of Leeds Professor Tim Benton, both of whom are population ecologists. Proceedings B is the Royal Society’s main biological research journal.
Our results provide the first clear evidence that global climate may explain substantial variation in the fossil record in a simple and consistent manner. If our results hold for current warming—the magnitude of which is comparable with the long-term fluctuations in Earth climate—they suggest that extinctions will increase.
—Dr Peter Mayhew
Future predicted temperatures are within the range of the warmest greenhouse phases that are associated with mass extinction events identified in the fossil record.
Of the five mass extinction events(Cretaceous-Tertiary, End-Triassic, End-Permian, Late Devonian, Ordovician-Silurian), four—including the one that eliminated the dinosaurs 65 million years ago—are associated with greenhouse phases. The largest mass extinction event of all, the end-Permian, occurred during one of the warmest ever climatic phases and saw the estimated extinction of 95% of animal and plant species.
The long-term association has not been seen before, as previous studies have largely been confined to relatively short geological periods, limited geographical extents and few groups of organisms. But the evidence is striking.
—Professor Tim Benton
| Five Worst Mass Extinctions | |||
|---|---|---|---|
| Event | Date Million years ago | Cause | Toll |
| Cretaceous-Tertiary | 65 | Caused or aggravated by impact of large asteroid on the Yucatan Peninsula and beneath the Gulf of Mexico. | 16% percent of marine families 47% of marine genera 18% of land vertebrate families, including the dinosaurs. |
| End-Triassic | 200 - 214 | Most likely caused by massive floods of lava erupting from the central Atlantic magmatic province - an event that triggered the opening of the Atlantic Ocean. The volcanism may have led to deadly global warming. | 22% of marine families 52% of marine genera Vertebrate deaths are unclear |
| End-Permian | 251 | Cause hotly debated. Earth’s worst mass extinction. | 95% of all species 53% of marine families 84% of marine genera 70% of land species such as plants, insects and vertebrate animals. |
| Late Devonian | 364 | Cause unknown. | 22% of marine families 57% of marine genera |
| Ordovician-Silurian | 439 | Caused by a drop in sea levels as glaciers formed, then by rising sea levels as glaciers melted. | 25% of marine families 60% of marine genera |
Paleontologist Peter Ward of the University of Washington outlined some of the potential linkages between climate change and mass extinction events in his book published earlier this year, Under a Green Sky.
Resources
The news just gets better and better every day. >_<
Posted by: domenick | 24 October 2007 at 04:12 AM
Of the five mentioned extinction events the end Permian event is the one that most closely resembles the current situation of manmade global warming. The reasons are:
Reason 1) Just prior to the end Permian event both the average global temperature and the atmospheric level of CO2 was almost exactly as the preindustrial average global temperature and atmospheric level of CO2.
For a graph of this see > http://mysite.verizon.net/mhieb/WVFossils/Carboniferous_climate.html < and go down the page to the figure labeled “Global Temperature and Atmospheric CO2 over Geologic Time”.
Reason 2) The least contested scientific explanation of the climate change that caused the mass extinction of the end Permian event is that it started with massive burning of fossils caused by massive volcanic activity in a fossil rich part of Siberia 251 million years ago. This burn off increased CO2 levels and subsequently temperatures with 5 degrees Celcius and that caused some of the mass extinction but not the bulk of it. Manmade global warming will burn even more fossils than during the end Permian event because we are digging up all of the fossils globally not just in one limited area of the planet.
Reason 3) The bulk of the mass extinction during the end Permian event was caused by a further temperature increases of 5 degrees Celsius bringing the total global warming to 10 degrees Celsius during the entire end Permian event. The consensus scientific explanation of the latter warming wave is that the oceans heated as a result of the first warming wave and this again caused the trapped methane at the ocean floors to bubble up and burn/oxidize in the atmosphere causing a further massive release of CO2 and thereby more global warming. There is reason to suggest that this scenario will be repeated with manmade global warming because a newly published study by Bruce Buffett and David Archer at University of Chicago say “Preferred values for these parameters are taken from previous studies of both passive and active margins, yielding a global estimate of 3*10^18 g of carbon (3000 Gton C) in clathrate and 2*10^18 g (2000 Gton C) in methane bubbles. The predicted methane inventory decreases by 85% in response to 3 degree C of warming.” see > http://geosci.uchicago.edu/~archer/reprints/buffett.2004.clathrates.pdf <
In other words, since the current global warming is on a fast track to increase the global average temperature with more than 3 degrees Celsius within the current century we should also expect that this will be enough to trigger the most potent mechanism of positive global warming feedback that exist on the planet, namely, the release of ocean methane.
It is difficult to say exactly how much mass extinction of life that manmade global warming will cause. However, it could be much more destructive than the end Permian event. The reason is that the warming period of the end Permian event took about 80000 years and the entire manmade warming period including the release of ocean methane should be much shorter because we are capable of burning off all of the planets fossils in less than 300 years. This is more deadly because the main killing mechanism in global warming is the SPEED of change that makes it impossible for life to adapt quickly enough to be fit for survival in the new environment.
*****
For an easy to read and reliable source on the end Permian extinction event I recommend this article by BBC. The conclusions and final explanations and given at the end of the article so it is important to read all of it.
http://www.bbc.co.uk/science/horizon/2002/dayearthdied.shtml
For a source on the deposits of fossils at the Siberian Basin see
Peterson, J.A. and Clarke, J.W., 1991. Geology and Hydrocarbon Habitat of the West Siberian Basin, 32. American Association of Petroleum Geologists, Tulsa, Oklahoma, 93 pp.
Posted by: Henrik | 24 October 2007 at 06:41 AM
They're stretching global warming theory too much. Along with greater changes than in earth's present changing atmosphere, the two most recent mass extinction events(asteroidal & mass volcanic eruptions) also had unimaginable heat, mechanical, surface & subterranean earth shift, dust, aerodynamic & hydrodynamic forces involved.
The second paragraph in particular is attributing mass extinctions only to global warming effects. Using just global climate change to explain these past extinctions CANNOT be done 'in a simple & consistent manner'.
I do believe in the present man-made warming effects. But I don't need tenuous connections to completely different past mass extinctions to believe such.
Posted by: litesong | 24 October 2007 at 06:46 AM
Climate cycles, with all their devastating effects, will happen again.
Will man made GHG contribute to accellerate and amplify the next cycle? It seems that we may very play a certain negative role but nature does not need our help to do it again. Combined man + nature forces will be a first and we don't realy know what the total results will be. It may be nasty.
Can we modify or neutralize enough major climate cycle factors to delay and/or reduce the impact of the next natural cycle? May be, but to what degree?
Can we produce a 100% man-made major climate cycle? May be we can but we are not foolish enough to do it.
Posted by: Harvey D | 24 October 2007 at 10:13 AM
litesong: The asteroid theory holds not that the impact released lots of heat (though it must have), but rather that it kicked so much dust into the atmosphere that solar radiation was blocked (i.e., "global dimming"). The asteroid theory is the most prominent proposed explanation for the end of the dinosaurs, but there are others. The same is true of theories regarding lava eruptions. In fact, the relatively recent Mount Pinatubo eruption is suspected of having induced a dimming effect.
Increases in atmospheric greenhouse gases may not seem like a sudden event, but if even happening over a fifty year period there is fear of it triggering feedback effects, e.g., large methane releases from the oceans and permafrost, reduction of reflectivity of disappearing ice cover, etc.
Posted by: Jim G. | 24 October 2007 at 10:21 AM
One glance look at this graph:
http://www.freerepublic.com/focus/f-news/1644060/posts
and all CO2 “apocalypse now” stories go to the rubbish bin.
For more scientifically inclined there is article from MIT:
http://www.pnas.org/cgi/reprint/99/7/4167
page 4.
“The resulting CO2 signal exhibits no systematic
correspondence with the geologic record of climatic variations at
tectonic time scales.”
And yes, Antarctica ice fields host much higher biodiversity than tropical rainforest.
Posted by: Andrey | 24 October 2007 at 01:16 PM
Andrey has demonstrated elsewhere that he is incapable of understanding basic issues such as how you calculate a simple average temperature. This is why I do not bother anymore to reply to the never ending nonsense he writes regarding climate issues. He is a waste of time.
Posted by: Henrik | 24 October 2007 at 01:46 PM
One glance look at this graph:
http://www.freerepublic.com/focus/f-news/1644060/posts
Freeperville? Are you kidding?
Posted by: jack | 24 October 2007 at 02:10 PM
Andrey, if you were able to understand the MIT paper you point out, you would not consider it as a "proof" of your conspiracy theory.
Try to learn the notion of time scale, and what it means when you're talking of 500 million years instead of, let's say, only 100 000 years. There is MUCH more than CO2 levels triggering climate changes on that time scale.
Posted by: François | 24 October 2007 at 02:51 PM
Yes, Jim G...I agree with you about global dimming & cooling(my mention of dust). However, that is not what the article stated...only the effects of greenhouse gases. He failed to mention the role of world-wide concussive pressure waves & the sweeping away of large portions of atmosphere from earth. He failed to mention similar hydrodynamic waves casting huge quantities of water away from their basins. He failed to mention astounding worldwide earthquakes of a magnitude we have no realization for. He failed to mention the quick release of sulfur & other poisonous gases from so many simultaneously erupting volcanos.
He mentions none of the above or many other consequencies of monster asteroids or mega-numbered volcanos. He only mentions global warming gases so he can keep things 'in a simple & consistent manner'.
Posted by: litesong | 24 October 2007 at 03:53 PM
I'm puzzled by one thing: If the earth goes thru heating and cooling cycles and we can actually make it warmer, aren't we better off making if as warm as possible to subvert/lessen the coming ice age, which it seems to me would be more devastating than flooding?
Posted by: la | 24 October 2007 at 08:23 PM
Hi la....Your theory is 'nice'. The real hangup on global warming is that it seems to be happening so fast.
People living seaside are losing homes & incomes at increasing rates, people living on low islands are losing land(the poor in the Indian Ocean & Pacific islands), north people are losing their hunting & fishing opportunities to shifting & reducing icy terrain, farmer's lands & climates are changing, fresh water estuaries are inundated by salt waters, deltas are beginning to change in quick order....animals stressed by man's activities(or worse) have to deal with one more profound effect of man. Warm environment problems are creeping to new areas further north & south of the equator & to higher elevations. Mountain people are finding their lands changing.
All in all, where life is difficult & dependent on the environment, more stress is visited upon survivors when environment is in flux.
Sure we have our lives to live too. But conservation & efficient use of resources must be seen as good qualities to cultivate. To encourage technology to be more efficient & less impactful must be seen as good.
Posted by: litesong | 25 October 2007 at 08:26 AM
la: If the earth goes through gradual cycles, it doesn't mean that rapid, extreme changes are good for anything.
Re Andrey: One of the elements I recall from some of the Chixulub analyses is that the bottom of the sea in the region had, then as now, lots of methane clathrate deposits. The impact roiled and released much of them, so the "nuclear winter" from the dust was followed by a greenhouse heat wave from the methane (23x as powerful as CO2).
Posted by: Engineer-Poet | 25 October 2007 at 08:46 PM
E-P:
Methane decomposes in atmosphere quite fast (on geological scale).
Also, take a look at Wiki for Permian–Triassic extinction event:
http://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extinction_event
Non of the theories are able to explain massive extinction on earth and in the ocean by simple climate change (warming). Extinction on such scale required both failure of photosyntesis on land due to massive emission of dust and acidic aerosols, and intoxication of oceans, most probably by hydrogen sulphide. Massive emission of methane from hydrates could play a role in it, but most likely was by itself consequence of meteorite impact or mega volcanic event.
Because methane hydrates are arrested in ocean floor, and deep ocean has thousand years upturn period, it will take thousand years to begin methane release by simple warming due to GHG, if any.
Posted by: Andrey | 26 October 2007 at 01:31 AM
Methane decomposes quickly in today's environment. What happens when the supply of hydroxyl radicals is overwhelmed by a 100x increase in the CH4 concentration? And even after it's oxidized, it yields CO2... enough CO2 to double the atmospheric inventory yet again.
Methane hydrate is exposed on the ocean floor in some places today. All it takes is for the current warming pulse to reach it and destabilize it, and another positive feedback system gets started. The ones on the surface (thawing of permafrost, activity of methanogens, leading to more thawing) are already under way.
Posted by: Engineer-Poet | 26 October 2007 at 03:35 PM
E-P:
Hydroxyl ions are quite abundant commodity in atmospheric and surface water. Do not forget, that methane has small, but measurable solubility in water, so precipitation will continuously wash-down atmospheric methane to the surface waters.
As for methane hydrates, I see your scenario extremely improbable. First, melting of methane hydrates requires a lot of heat, so simple destabilisation is out of question. Only stable supply of huge amount of heat could liberate methane from frozen state. Methane hydrates are buried under layer of sediments (could it be other way?), so heat transfer against gravitational convection could be facilitated only by heat conduction, which is weak. Oceans holds 2000 times more heat energy than atmosphere, so it will take tremendous amount of GHG heating and thousand years to deliver some heat down to the ocean floor, even to shelves only 300 meter deep.
And yes, if you know shallow sedimental methane hydrate deposits already starting to melt, you can be a trillioner.
Peace, bro.
Posted by: | 27 October 2007 at 03:05 AM
I am fully aware that further global warming from the release of ocean methane will take a lot of time possible a few 1000 years (the records indicate it took about 5000 years during the end Permian event). Still it does not give me much comfort that extreme mass extinction will be postponed by a few 1000 years. If humanity is able to survive relatively intact from the consequences of the first wave of global warming caused by burning of fossils I think there is plenty of time to prevent the final and most destructive event of the release of ocean methane.
However, the first wave of global warming that will occur in this century will increase temperatures by a further 1.1 to 6.4 °C (2.0 to 11.5 °F) according to the UN climate panel IPCC and they say themselves that these are conservative estimations. This may still be enough to overwhelm the global economy. How? We have already seen how heat waves in Europe and the US has created unprecedented forest fires and drought. This is the result of an already materialized global warming of 0.74 ± 0.18 °C (1.33 ± 0.32 °F) during the last 100 years. In 100 years from now you may see 95% of the forests on the planet burned off and become desert simply because the usual forest fires got bigger and bigger each summer. If most of our planet turns into a desert how should it be able to sustain the life of the almost 7 billion people on earth? This will not happen without global war and possible one that involves firing nuclear armed missiles at each other. In this event the few survivors of humans will not be able to prevent the second wave of global warming from ocean methane from happening even if they have several 1000 years to prepare for it.
There are very real reasons for alarm and to do drastic things ASAP to fight global warming.
Posted by: Henrik | 27 October 2007 at 07:04 AM
Posted by: Engineer-Poet | 27 October 2007 at 06:23 PM
Henrik:
So we are through about time scale of possible release of methane hydrates. Good.
You would be stunned to learn that IPCC numbers on climate sensitivity due to doubling of CO2 are junk science (I was). The only real empirical estimations of climate sensitivity so far were done by Idso ( yea, he is quite acidic for renowned scientist), and it is rather small:
http://www.warwickhughes.com/papers/idso98.htm
Current forest fires are not unprecedented, and are not correlated to current moderate warming whatsoever. Take a look here, for example:
http://www.fws.gov/midwest/Fire/wildfire02.html
Same with droughts, they are by all means not increasing:
http://www.co2science.org/scripts/CO2ScienceB2C/subject/d/summaries/droughtusaeast.jsp
As a side note, consider this.
Currently about half of antropogenic emissions of CO2 are not accumulated in atmosphere. It is adsorbed by oceans and plants. Since rate of such adsorption is primarily function of atmospheric CO2 concentration, in the case if we somehow manage to halve our CO2 emissions, atmospheric concentration of CO2 will begin to decrease OVERNIGHT. I truly do not think that in 100 years from now humankind will rely on fossil fuels somehow significantly for our energy needs (peak oil, anyway?).
BTW, how do you sleep at night with such terrifying thoughts about our future?!
E-P:
Liquid water in form of aerosols is present in atmosphere down to temperatures of -40 C.
Smog-precursor hydrocarbons are designated "non-methane organic gases" because methane is harmless, not because it is stable.
There are plenty of high activity radicals in surface waters to decompose even relatively stable methane.
Othervice, we are quickly descending into extremely complicated branch of quantative atmospheric chemistry, which is way over my head.
I give up.
Posted by: Andrey | 28 October 2007 at 04:46 AM
Andrey, it's obvious that you are a tool of carbon-emissions interests. I'm not surprised that a Russian would do this, given the importance of oil production and exports to the Russian economy, but it's still sad to see someone who will sell out the truth and his own future for a few dollars or even just some vague sense of patriotism.
Posted by: Engineer-Poet | 28 October 2007 at 06:09 AM
Henrik,
When you say, "We have already seen how heat waves in Europe and the US has created unprecedented forest fires and drought." don’t you think your reference frame may be a little faulty. While it may be unprecedented in terms of the most recent news cycle, similar occurrences of the fires and droughts have happened, and a few within the lifespan of some of those yet breathing.
I’m not again ya, but I’d caution that presentation be restrained to supportable facts. It doesn’t help your ability to persuade someone, when your claim to substantiating evidence can be disproved.
Posted by: WhiteBeard | 28 October 2007 at 01:15 PM
WhiteBeard
You are right. That phrase is lax an unclear. What I meant to say was that the simultaneous occurrence of unusual warming events in 2007 is unprecedented in records since the beginning of the industrialization. To be sure, in 2007 we have unusual hard drought in the US and Australia, and we have unusual large forest fires in California and Greece plus we have an unprecedented (since industrialization) low level of summer sea ice at the North Pole. It is difficult to objectively judge whether a combined string of events are more severe than another combined string of events so whether I am right or not can be seen most objectively when we get the average global temperature for 2007. I bet it will be a new unprecedented record or at least a nearly unprecedented record among the top 5 highest measurements since direct temperature records began.
I will try not to be that lax in the future. Thank you for reminding me about it. I mean it. Thank you.
Posted by: Henrik | 29 October 2007 at 02:33 AM
Engineer-Poet...Andrey isn't the only denial buff. Try some of the Auto owner commentary websites. So many owners take the anti-global warming stance of the auto companies. Many are happy the summertime Arctic icepack is disappearing so there will be short tanker routes between North America, Russia, Europe, Japan & China. They love to point out the rare glacier that is enlarging(never mentioning the vast # decreasing) & that the S. Hemisphere doesn't show as much warming as the N. Hemisphere. They love to comment that global conditions were warmer in some ancient inter-glacial eon for whatever reason. On general pollution: No one....I mean NO ONE ever comments when I point out recent studies showing inner-city children have more lung & heart disease & death the closer they live, play & school near freeways. Their reasoning is auto companies 'sacrificed' enough by inventing the 3-way catalytic converter & if I receive no comments, maybe I'll go away. But I don't go away.
Posted by: litesong | 29 October 2007 at 07:08 AM
Oh, yeah. One guy did comment. He said his grandchildren don't have lung disease, so he's not worried about vehicle pollution. He never said whether his grandkids were trapped in an inner-city environment near a freeway tho.
Posted by: litesong | 29 October 2007 at 08:58 AM
Remember, people, correlation does not imply causation. The researchers clearly state that climate explains a substantial amount of the variation in the fossil record. This is not the same as saying climate change, either proximally or ultimately, actually caused the variation in the fossil record. We would have to have been there to know for sure.
Nonetheless, the mechanisms for a P-T kind of extinction event seem to be fairly well understood. They would entail the catastrophic coincidence of several phenomena, one of them increase in mean surface temperature.
Posted by: Fraser Smith | 13 November 2007 at 03:52 PM