Luke Walker reminds us that geological history includes evidence of mass extinctions from "killer greenhouse conditions":
"Readers of this blog are often witness to accusations of alarmism by those opposed to scenario projections using contemporary anthropogenic global warming theory.
Comfort is often taken in the world having survived substantial climate swings in geological time and that some species such as reef building corals have come through that turmoil.
So it is with some irony that the October 2006 issue of Scientific American has a major article by Professor Peter Ward at the University of Washington suggests that extinction events in geological history have been caused by killer greenhouse conditions. What’s this – geological alarmism? Is nothing sacred?
“More than half life on the earth has been wiped out, repeatedly, in mass extinctions over the past 500 million years. One such disaster, which includes disappearance of the dinosaurs, is widely attributed to an asteroid impact, but others remain inadequately explained.
New fossil and geochemical evidence points to a shocking environmental mechanism for the largest of the ancient mass extinctions and possibly several more: an oxygen depleted ocean spewing poisonous gas as a result of global warming”
Apparently five times over the last 500 million years most of the world’s life forms have ceased to exist. End of the Ordovician 443 My ago; close of the Devonian 374 My; the Great Dying at the end of the Permian 251 My where 90% of ocean dwellers and 70% of land dwellers were obliterated; the end of the Triassic 201 My; and the end of the Cretaceous at 65 My with a likely asteroid impact.
However, new analyses are showing that some sudden extinctions were not that sudden lasting several hundred thousands of years.
It theoretically works something like this:
1. Volcanic activity releases carbon dioxide and methane
2. Rapid global warming occurs
3. Warm ocean absorbs less oxygen
4. Anoxia destabilises the chemocline where oxygenated surface waters meet H2S permeated waters in the ocean, anaerobic bacteria flourish
5. Hydrogen sulphide gas (H2S) gas upwells through the ocean as the chemocline rises to the ocean surface
6. Green and purple sulphur bacteria in the surface ocean thrive while oxygen breathers suffocate
7. H2S gas kills land animals and plants.
8. H2S destroys the ozone shield
9. Ultra violet radiation from the sun kills remaining life.
“A minor extinction at the end of the Palaeocene 54My ago was already – presciently – attributed to an interval of oceanic anoxia somehow triggered by short-term global warming.” Evidence is also present at the end of Triassic, middle Cretaceous, and late Devonian.
So are these extreme greenhouse effect extinctions possibly a recurring phenomenon in the earth’s history. Atmospheric CO2 was 1000ppm when extinctions began in the Palaeocene. “
So if the modern earth got close to 1000ppm this might represent something for our children to deal with. But maybe that’s just geological alarmism for you.
I’m getting a Lotto syndicate going called “Killer Greenhouse”.
More reading:
Climate simulation of the latest Permian: Implications for mass extinction by Jeffrey T. Kiehl & Christine A. Shields Climate Change Research Section, National Center for Atmospheric Research, 1850 Table Mesa Drive, Boulder, Colorado 80305, USA
Abrupt and Gradual Extinction Among Late Permian Land Vertebrates in the Karoo Basin, South Africa
Science 4 February 2005:Vol. 307. no. 5710, pp. 709 - 714 by Peter D. Ward,1* Jennifer Botha,3 Roger Buick,2 Michiel O. De Kock,5 Douglas H. Erwin,6 Geoffrey H. Garrison,2 Joseph L. Kirschvink,4 Roger Smith3Photic Zone Euxinia During the Permian-Triassic Superanoxic Event, Science 4 February 2005:
Vol. 307. no. 5710, pp. 706 - 709 by Kliti Grice, Changqun Cao, Gordon D. Love, Michael E. Böttcher, Richard J. Twitchett, Emmanuelle Grosjean, Roger E. Summons, Steven C. Turgeon, William Dunning,Yugan JinMassive Release of Hydrogen Sulphide to the Surface Ocean and Atmosphere during intervals of Oceanic Anoxia. Kump, L.R., Pavlov, A., Arthur, M.A. Geology: 33:5:397-400. May 2005."
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Thanks Luke. And I'm going to add to your reading list: The Past is the Key to the Present: Greenhouse and Icehouse Over Time by Prof Ian Plimer, IPA Review, Vol 55, No. 1. March 2003, pgs. 9-12.
Last time I checked an actual greenhouse, the off-gassing was oxygen. Plants absorb carbon dioxide. So, why the hysteria over oxygen?
Gavin,
Some one liners are insightful and sometimes they are funny.
But people tire of nasty personal comment.
I particularly dislike comment that closes down discussion by suggesting a novel idea is somehow wrong because its not the consensus/accepted view.
I would like this blog to be about encouraging discussion of the novel idea, however, 'wrong' it may appear at first.
Jennifer: some of these pathetic little one liners are enough the put anyone off blogs for life.
In the early days of internet exchanges in public forums it was called “flaming”. Back then a chat room moderator would also shut down immediately on repetition. As intense discussion develops; most adults should know the value of self moderation. It’s normally expected since there is no point in making a bad point, such as we get here with contributors continuously ranting on about stuff outside their own particular discipline.
Another issue for consideration regarding readers just browsing a blog: if individuals insist on giving nothing more than mere opinion mostly based on their single handed review of someone else’s stuff then get them putting in something of themselves from time to time.
If I want mere opinion perhaps based on some consideration of your average passer by on an issue like AGW it’s so easy. I just ask my customers or do a private survey of people I run into down the street. In fact I often ask one or two as I go. Today was no exception. Let me humbly suggest it’s the best moderator. However my partner says I talk too much on the job and the blog.
Reckon she is biased hey.
Re your second last post - extract the digit mate and inform us. You may make a research comment too.
Re last comment: Yes I assume that. Bloody sepos ! We don't mind you yanks - it's just that you're so bloody loud. {P.S. Can we come and shoot up somewhere new with you guys soon}
Better still - why not annex us and make us the 51st state?
Luke,
What is more, us Yanks will probably do with energy technology what we did with biotechnology. We'll invent it, we'll deploy it, neophobes will deride it and protest against it, governments will legislate against it, and in the end, we'll still be the most innovative, energy-efficient, wealthy nation on Earth. And that's because we're on balance neo-liberals, not neo-conservatives. We don't view regress as progress. We're pragmatists. Except, of course, for the whacko Greenie fringe who are here becoming increasingly marginalized.
After the rest of the world ameliorates global warming by 0.00000658 Celsius through carbon initiatives, we'll have technology that makes efforts to grow more trees look pretty neolithic.
Luke,
I note with interest that your rant contains no positive claim about human abilities to change the climate, what the global temperature should be, or who justly ought to be the beneficiaries or casualties of temperature adjustment.
People who don't know what they want, how to achieve it, or whom their efforts might hurt have no business advocating anything in their back yard, much less on a planetary scale.
In fact, people that supremely ignorant should be held as far away from public policy as is humanely possible.
Schiller -
There' no point in calculating colder as (a) we not facing it and (b) short of nuclear winter or asteroid impact I don't think we could arrange it.
Impact scenarios have been undertaken for many sectors especially agriculture. Read the literature. Then you'll say but I don't believe the outcomes - so why ask?
"Warfare & climate control" - only a hypocritical neo-con astro-turfing yank would try that one. The most likely impact of continued emissions are beneficial to North America and not the rest of the world. Your emissions are likely turning my country into a desert - so go home yank ! And then you'll ge flogging your carbon-free technology to us at a premium. The really clever thing is that you guys are throwing huge amounts of money at carbon-free energy and will sell it to the rest of the world at an exorbitant profit after you navigate us into the melting pot with your deliberate political inaction. Howard is being suckered right down the line with your smooth line on this one. Your administration that supposedly doesn't believe in climate change action while going for broke on technological energy system transformation.