Walter, K. M., Zimov, S. A., Chanton, J. P., Verbyla, D. and F. S. Chapin III. 2006.
Methane bubbling from Siberian thaw lakes as a positive feedback to climate warming
Nature. 443:71-75.
Abstract.
Large uncertainties in the budget of atmospheric methane, an
important greenhouse gas, limit the accuracy of climate change
projections. Thaw lakes in North Siberia are known to emit
methane, 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 estimated.
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) 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.
Email: D.Verbyla@uaf.edu
Last updated: September 2006