re: #180 Pianobuff

Is there any data on permafrost loss that you are aware of? I’m still in the mushy middle on this… believe that there is AGW but rate/extent I’m not so certain about.

Hopefully some of your points will be discussed.

Well the biggest permafrost issue is the Canadian and Siberian icefields and the massive feedback that will be caused by trapped gases from the now thawed bog.

First of all it is a lot of methane and carbon trapped there.

sciencemag.org

And the effect is very bad. It frankly could double the present levels of carbon in the atmosphere and accelerate the warming into the worst case scenario projections. We simply do not know how bad, this very bad contribution will be yet.

sciencedirect.com

nature.com

Abstract:

Large uncertainties in the budget of atmospheric methane, an important greenhouse gas, limit the accuracy of climate change projections1, 2. Thaw lakes in North Siberia are known to emit methane3, 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. 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, 2, 4–6) 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.