See also http://www.nature.com/nature/journal/v443/n7107/abs/nature05040.html Methane bubbling from Siberian thaw lakes as a positive feedback to climate warming
K. M. Walter1<http://www.nature.com/nature/journal/v443/n7107/abs/nature05040.html#a1>, S. A. Zimov2<http://www.nature.com/nature/journal/v443/n7107/abs/nature05040.html#a2>, J. P. Chanton3<http://www.nature.com/nature/journal/v443/n7107/abs/nature05040.html#a3>, D. Verbyla4<http://www.nature.com/nature/journal/v443/n7107/abs/nature05040.html#a4> and F. S. Chapin, III1<http://www.nature.com/nature/journal/v443/n7107/abs/nature05040.html#a1> Topof page<http://www.nature.com/nature/journal/v443/n7107/abs/nature05040.html#top> Large uncertainties in the budget of atmospheric methane, an important greenhouse gas, limit the accuracy of climate change projections1, <http://www.nature.com/nature/journal/v443/n7107/full/nature05040.html#B1> 2 <http://www.nature.com/nature/journal/v443/n7107/full/nature05040.html#B2>. Thaw lakes in North Siberia are known to emit methane3<http://www.nature.com/nature/journal/v443/n7107/full/nature05040.html#B3>, but the magnitude of these emissions remains uncertain because most methane is released through ebullition (bubbling), which is spatially and temporally variable. Here we report a new method of measuring ebullition and use it to quantify methane emissions from two thaw lakes in North Siberia. We show that ebullition accounts for 95 per cent of methane emissions from these lakes, and that methane flux from thaw lakes in our study region may be five times higher than previously estimated3<http://www.nature.com/nature/journal/v443/n7107/full/nature05040.html#B3>. Extrapolation of these fluxes indicates that thaw lakes in North Siberia emit 3.8 teragrams of methane per year, which increases present estimates of methane emissions from northern wetlands (< 6–40 teragrams per year; refs 1<http://www.nature.com/nature/journal/v443/n7107/full/nature05040.html#B1>, 2 <http://www.nature.com/nature/journal/v443/n7107/full/nature05040.html#B2>, 4 <http://www.nature.com/nature/journal/v443/n7107/full/nature05040.html#B4> –6<http://www.nature.com/nature/journal/v443/n7107/full/nature05040.html#B6>) by between 10 and 63 per cent. We find that thawing permafrost along lake margins accounts for most of the methane released from the lakes, and estimate that an expansion of thaw lakes between 1974 and 2000, which was concurrent with regional warming, increased methane emissions in our study region by 58 per cent. Furthermore, the Pleistocene age (35,260–42,900 years) of methane emitted from hotspots along thawing lake margins indicates that this positive feedback to climate warming has led to the release of old carbon stocks previously stored in permafrost. Topof page<http://www.nature.com/nature/journal/v443/n7107/abs/nature05040.html#top> 1. Institute of Arctic Biology, University of Alaska Fairbanks, Alaska 99775, USA 2. Northeast Science Station, Cherskii 678830, Russia 3. Department of Oceanography, Florida State University, Florida 32306, USA 4. Forest Science Department, University of Alaska Fairbanks, Alaska 99775, USA Correspondence to: K. M. Walter1<http://www.nature.com/nature/journal/v443/n7107/abs/nature05040.html#a1> Correspondence and requests for materials should be addressed to K.M.W. (Email: [email protected]). 2009/4/29 Stephen Salter <[email protected]> > > Hi All > > If you go to > http://scrippsco2.ucsd.edu/data/in_situ_co2/monthly_mlo.csv you can > get the March 2009 figure for CO2 at Mauna Loa. > > This is provisional and they may tweek it a bit after checking all the > calibrations but for now it is 386.44 ppm. > > Their figure for March 2008 was 384.31 ppm, so the increase is 2.13 ppm. > > The Svalbard increase is 'more than 2.5 ppm on 2008' which is greater > than the Mauna Loa increase by 17.4% so Vicky Pope's statement that "it > fits with the general increase in emissions" cannot be correct. > > There is not that much heavy industry on Svalbard or nearby. Could it > be that the extra is a result of methane releases breaking down? > > There was a report at > > http://www.independent.co.uk/news/science/hundreds-of-methane-plumes-discovered-941456.html > > Stephen > > Emeritus Professor of Engineering Design > School of Engineering and Electronics > University of Edinburgh > Mayfield Road > Edinburgh EH9 3JL > Scotland > tel +44 131 650 5704 > fax +44 131 650 5702 > Mobile 07795 203 195 > [email protected] > http://www.see.ed.ac.uk/~shs > > > > John Nissen wrote: > > > > Hi all, > > > > News from the Arctic. CO2 levels are rising sharply: > > > http://www.guardian.co.uk/environment/2009/apr/27/arctic-carbon-dioxide-levels > > > > Here are some extracts. > > > > [quote] CO_2 levels recorded in Svalbard tend to be higher than the > > global average, but scientists said the CO_2 level they had measured > > was unprecedented even for that location. "These are the highest > > figures collected in 50m years," said Johan Strom, professor of > > atmospheric physics at the government-funded Norwegian Polar > > Institute, which collected the data. "It is not the level of CO_2 > > that is the problem, because the earth will adapt. What is very > > worrying is the speed of change. Levels [here] are now increasing > > 2-3ppm a year. > > > > > > Dr Vicky Pope seems to suggest this doesn't matter because the growth > > in emissions is somehow confined to the Arctic: > > > > [quote] "These are quite large numbers. It sounds like this is an > > Arctic phenomenon," said Dr Vicky Pope, > > < > http://www.guardian.co.uk/environment/2009/feb/11/climate-change-science-pope > > > > head of climate change > > <http://www.guardian.co.uk/environment/climate-change> advice at the > > Met Office Hadley Centre in Exeter. "It fits with the general increase > > in emissions. You would expect the concentrations of CO_2 to grow." > > > > And she confuses growth in emissions with growth in concentrations. > > And she is adviser to the Government!! > > > > Then the article adds to confusion by suddenly bringing in CO2 > equivalent: > > > > [quote] The figures will concern policy-makers ahead of global talks > > on a successor to the Kyoto Protocol in December. Climate scientists > > advise that the world must prevent CO_2 levels from rising higher than > > around 450ppm CO_2 equivalent (a measure of global warming potential > > that incorporates other gasses such as methane and is higher than the > > measured CO_2 levels) to avoid a 2C increase on preindustrial global > > average temperature > > < > http://www.guardian.co.uk/environment/2009/apr/14/global-warming-target-2c > >. > > > > The 450ppm is a revised figure. So that begs the question, what is > > the CO2 equivalent level today. They don't tell you. Here's a figure > > from the Stern Review summary [2006]: > > > > [quote] “The risks of the worst impacts of climate change can be > > substantially reduced if greenhouse gas levels in the atmosphere can > > be stabilised between 450 and 550ppm CO2 equivalent (CO2e). The > > current level is 430ppm CO2e today, and it is rising at more than 2ppm > > each year.” > > > > So if the level is now rising as much as 3ppm per year, we could reach > > the revised 450 ppm limit within 7 years - or perhaps even within 5 > > years (since Stern published in 2006). > > > > Jeezzz. No wonder that scientists play down the seriousness of the > > situation. It's just too frightening. But then, why do they also > > play down geoengineering - when it must now be the only conceivable > > way out of our mess. Isn't there now be a race against time to get > > the geoengineering into deployment on sufficient scale, not only to > > keep greenhouse gases below 450 ppm CO2e (using carbon stock > > management), but also to save the Arctic sea ice (using solar > > radiation management)? > > > > What kind of advice is the government getting? Perhaps, Vicky Pope, > > you can answer for yourself. > > > > John > > > > > > > > > > > > > > -- > > > > > The University of Edinburgh is a charitable body, registered in > Scotland, with registration number SC005336. > > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/geoengineering?hl=en -~----------~----~----~----~------~----~------~--~---
