You may have seen this week’s post on how new evidence from northern Canada about Earth’s greenhouse past was a smoking gun in a 250 million year old mystery – how 90 percent of everything alive on the planet could have gone extinct, in a massive, nightmarish spasm known as the Permian Extinction.
Over the last few decades, a growing body of evidence has come to light indicating that the Permian was not, like the much more recent extinction that killed the dinosaurs, the result of an asteroid strike, but rather, a volcanically kick-started Greenhouse event.
A few years ago, Neil DeGrasse-Tyson, astrophysicist and Project Scientist at New York’s Hayden Planetarium, hosted a NOVA piece that outlined the major puzzle pieces of what we know about this catyclysm, and why it matters today.
Can we drop the “CO2 was higher in the past, so it’s harmless” crock, now?
Here are a few of the other cases in the fossil record where rising levels of carbon dioxide levels appear to have resulted in mass extinction:
55 Mya, Paleocene-Eocene Thermal Maximum – North Atlantic Basalts
65 Mya, end-Cretaceous event – Deccan basalts (India)
183 Mya, Toracian Turnover (a lesser warming and extinction event in the Early Jurassic period) – Karoo Basalts (Africa)
201 Mya, End Triassic Extinction – Central Atlantic Magmatic Province
360-375 Mya, Late Devonian Extinction – Viluy Traps (Eastern Siberia, more tentative according to Rampino below)
For a more extensive list, please see:
Vincent E. Courtillot and Paul R. Renne (2003) On the ages of flood basalt events, C. R. Geoscience 335, 113–140
http://www.mantleplumes.org/WebDocuments/CourtRenne2003.pf
For a recent commentary:
Michael R. Rampino (April 13, 2010) Mass extinctions of life and catastrophic flood basalt volcanism, PNAS, vol. 107, no. 15, pp. 6555-6556
http://www.pnas.org/content/107/15/6555.full
For a more recent article specifically on the End Triassic Extinction, please see:
Jessica H. Whiteside (April 13, 2010) Compound-specific carbon isotopes from Earth’s largest flood basalt eruptions directly linked to the end-Triassic mass extinction, PNAS, vol. 107, no. 15, pp 6721-6725
http://www.pnas.org/content/107/15/6721.full
Oftentimes climate deniers will point to the last million years of the paleoclimate record and state that temperature always rises first, then carbon dioxide. This is afterall the big criticism of Al Gore’s chart showing the two closely tracking one-another. Defenders of science will say that this is true, but whatever the initial forcing carbon dioxide amplifies the effect, making the climate system warm more than it otherwise would. But it isn’t true that temperature always rose first. There have been numerous times in the paleoclimate record where carbon dioxide clearly rose first — and they resulted in mass extinctions.
I dealt the the “temp leads carbon” crock here:
http://www.youtube.com/watch?v=hWJeqgG3Tl8
thanks for the links.
will be posting more on next week’s “Graph of the day”
Peter, I am sorry but I seem to have forgotten the “f” on the end of the link for the first article.
got it. thanks
Science knows about 5 mass extinction events and prior to 1980, they were all believed to be caused by climate change (global warming). Then Walter and Louis Alvarez published their paper about the K-T extinction being caused by a planetary impact which was later confirmed as being Chicxulub, Mexico (just north of the Yucatan Peninsula). This caused many people outside of the field of science (and a smaller ratio within) to believe that all extinctions were caused by impacts. But every decade more evidence proves that the other 4 were still caused by global warming.
Now to be fair, the Permian extinction is believed to have been caused by volcanoes in the Russian Traps which were active for more than a million years. All volcanoes are different and it is not known how much much CO2 these volcanoes released each year but a million years seem to have tipped the balance.
We now need to know if the activities of 7 billion modern humans can (1) produce a similar effect (2) and do it in a shorter amount of time, and I fear the answer to both questions is “yes”.
neilrieck wrote:
“Science knows about 5 mass extinction events and prior to 1980, they were all believed to be caused by climate change (global warming)…”
Those were just the major extinctions — but there were others. There are 16 Large Igneous Provinces (LIPs) listed here in table one:
Vincent E. Courtillot and Paul R. Renne (2003) On the ages of flood basalt events, C. R. Geoscience 335, 113–140
http://www.mantleplumes.org/WebDocuments/CourtRenne2003.pdf
They are the remnants of eruptions that were or at least appear to have been associated with extinction events. The Siberian Traps associated with the End Permian Extinction of 251 million years ago (MYA) has a volume of 1.6 million cubic kilometers. The smallest LIP listed is the Columbia River Flood Basalts and it appears to be associated with the End Early Miocene 16 MYA. The volume of that structure is roughly 170,000 cubic kilometers.
In contrast the the ejecta from the explosive eruption of Mt. St. Helens had a volume of one cubic kilometer, Pinatubo ten cubic kilometers, and the Yellowstone Caldera of 600,000 years ago roughly 1000 cubic kilometers. These are on an entirely different scale from the flood basalt eruptions.
The flood basalt eruptions are generally thought to be the result of the collision and breakup of tectonic plates. For example, the End Cretaceous of 66.5 MYA is associated with the Deccan Traps in India caused by the collision of the Indian plate with Eurasia — which also resulted in the formation of the Himalayas.
Peter Sinclair wrote:
The argument that the only reason why we expect higher temperatures when we raise levels of carbon dioxide is due to the correlation between temperature and carbon dioxide levels is probably my greatest pet peeve. It entirely ignores the fact that we have a deep understanding of the mechanism involved that is tightly woven together with large parts of physics. The argument that temperature always leads carbon dioxide is just the same nonsense on stilts.
I appreciate the fact that the close correlation underscores the relationship of reciprocal causation whereby higher temperatures raise carbon dioxide levels but higher carbon dioxide levels raise temperature. I appreciate that Hansen et. al predicted that at least within the recent paleoclimate record greenhouse gases would lag temperature as both greenhouse gas and ice sheet feedback are needed to explain the magnitude of climate change given the weakness of orbital forcing
I believe it is also worthwhile to point out that we understand the physical mechanism and that the expectation isn’t simply based on correlation. And I believe it worthwhile to point out that there have been times in the remote past such as with the Permian Triassic Extinction where temperature lagged carbon dioxide. Recalling the existence of such periods is useful not simply in terms of illustrating how rising levels of carbon dioxide bring about higher temperatures — but also what rapid warming is capable of. Whether in is in terms of the severe droughts and flooding, the ocean anoxia or the dangerous shift to an anoxic, hydrogen suflide producing ocean ecology.
I appreciate your bringing this home with an episode of Climate Denial Crock of the Week. However, I also found this particular piece rather informative personally. Looking at the list of large igneous provinces there have certainly been instances of flood basalt volcanoes responsible for a far greater volume of lava and in all likelihood directly responsible for more carbon dioxide.
There are of course the shallow water methane hydrates, but methane has a residence time in our atmosphere of roughly ten years. Given the production of methane at a sufficiently high rate it is possible to deplete the supply of hydroxyl radicals responsible for the short residence time, but according to Gavin Schmidt the production of methane must be maintained at a fairly high rate — which from his calculations still makes explaining these earlier episodes somewhat problematic.
However the burning of large quantities of coal (as evidenced by the dated ash) is something I hadn’t heard of before. It may help to explain the singular severity of this particular event, a point that well-earned the title of The Great Dying.
I may be updating the “Temp Leads Carbon” piece soon.
Thanks for your comments.