The crucial statistic is the rate at which methane outgasses from MELTED permafrost. I've been unable to find any info on this and I'd really appreciate any info anyone has.
Can anyone argue a convincing case why we WON'T end up with a PETM or Great Dying re-run? A 2009/1/27 dsw_s <[email protected]>: > > I don't see anything in the link to say how fast the thawing of > permafrost will be. It says accelerating, but that only means it will > go faster than it has been. Permafrost left over the last glaciation > has been thawing for thousands of years, so when he says that the > thawing will be faster than that, he's not saying much. The question > is how fast it will be compared to clearance of methane from the > atmosphere. The estimate of 100 years sounds fast for something > that's been going on 100 times that long, but then again we do expect > a big increase. If it's 100 years, that's still large compared to the > half-life of methane in the atmosphere. With interventions to > increase winter precipitation in permafrost areas, we may be able to > slow it down substantially. > > In all, it seems plausible that methane management will be more > important than CO2 management. It doesn't seem as though it provides > any reason to believe that a repetition of the K/T boundary is > inevitable. > > On Jan 26, 8:32 pm, Andrew Lockley <[email protected]> wrote: >> I've just clarified and inserted citations into the following section >> >> http://en.wikipedia.org/wiki/Runaway_climate_change#Current_risk >> >> If people could comment on the logic and sources used, I'd be very >> grateful. Once people are generally happy that the research is solid, >> I'll be copying this argument in appropriate forms to various wikis. >> Therefore, I really hope that anyone who's got the slightest doubt >> about the logic will shoot me down in flames - publicly! >> >> ---- >> >> The phenomenon of Arctic shrinkage is leading some scientists to fear >> that a runaway climate change event may be imminent, and may even have >> started[11]. Arctic sea ice is shrinking rapidly, and this will induce >> positive feedback mechanisms: >> Albedo effect, as white ice is replaced by dark ocean, possibly as >> early as 2013[12] James Hansen argues that geoengineering is the only >> way to save the Arctic sea ice , as we are likely already to have >> passed the tipping point and it is too late for carbon emissions >> reduction to work.[13] >> Arctic methane release from melting permafrost and clathrates. David >> Lawrence showed how rapid melting of the sea ice sets up a feedback >> loop that also rapidly melts arctic permafrost.[14] His models show >> that within 100 years, all of the permafrost also melts.[citation >> needed] It takes about 100 years for organic carbon in permafrost to >> be fully released as methane, and methane clathrates release probably >> much faster than that.[citation needed] >> Estimates of the size of the total carbon reservoir in Arctic >> permafrost and clathrates vary widely.[citation needed] However, it is >> suggested that is at least 9000 gigatonnes of carbon in permafrost >> worldwide.[15]. Further, there are believed to be around and another >> 400 gigatonnes of carbon in methane clathrates in permafrost regions >> alone.[16]. However, Buffett and Archer predict a much higher release >> of between 2,000 and 4,000 gigatonnes as a result of expected >> human-induced warming, as they include some deep-ocean clathrate >> stores in the expected release.[17] Should the more conservative >> estimate be correct or at least too low, then 1300 gigatonnes of >> carbon may potentially be released as methane from permafrost and >> clathrates as a result of human activity. As methane is a potent >> greenhouse gas, this is equivalent to a release of carbon dioxide very >> roughly 50 times the total emitted by humans since the Industrial >> Revolution. A release on this scale, or even a fraction of it, will >> create catastrophic climate change and is likely to lead to a complete >> collapse of human civilisation.[18] >> >> References >> >> ^http://www.guardian.co.uk/environment/2008/sep/23/climatechange.scien... >> ^http://www.guardian.co.uk/environment/2006/oct/18/bookextracts.books >> ^http://www.monbiot.com/archives/2008/08/22/identity-politics-in-clima... >> ^http://www.scenta.co.uk/nature/weather/cit/1737333/long-detailed-impr... >> ^ Physics of the Greenhouse Effect (March 10, >> 2008)http://chriscolose.wordpress.com/2008/03/10/physics-of-the-greenhouse... >> ^ How to kill (almost) all life: the end-Permian extinction event, >> Michael J. Benton and Richard J. Twitchett, Department of Earth >> Sciences University of Bristol UK, TRENDS in Ecology and Evolution >> Vol.18 No.7 July 2003, doi:10.1016/S0169-5347(03)00093-4 (full >> reprintPDF (506 KiB)) >> ^ Climate change: 'One degree and we're done for' - earth - September >> 27, 2006 - New Scientist Environment >> ^ S. I. Rasoonl and C. de Bergh, "The Runaway Greenhouse Effect and >> the Accumulation of CO2 in the Atmosphere of Venus," Nature, 226', pp. >> 1037-1039, 1970. >> ^ Venus - Stuart Robbins and David McDonald >> ^ Notes (created by Nick Strobel) for an introductory astronomy >> courses he teaches. >> Nick's new site >> Old site (The Wayback Machine) >> ^http://www.terranature.org/environmentalCrisis.htm >> ^http://news.bbc.co.uk/1/hi/sci/tech/7139797.stm >> ^http://www.independent.co.uk/environment/climate-change/the-earth-tod... >> ^http://www.ucar.edu/news/releases/2008/permafrost.jsp >> ^http://www.terranature.org/methaneSiberia.htm >> ^http://www.springerlink.com/content/r4w867922g607w2j/ >> ^http://adsabs.harvard.edu/abs/2005AGUSM.U33A..05B >> ^http://www.ecoearth.info/shared/reader/welcome.aspx?linkid=51491 > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. 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