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Methane emissions from permafrost thaw lakes limited by lake drainage
Thaw-lake expansion is enhanced by climate warming, which boosts methane emissions, contributing a positive feedback to climate change. However, a new modelling study of the life cycle of Siberian thaw lakes indicates that drainage strongly limits lake expansion, suggesting that methane emissions from thaw lakes are likely to be substantially lower than previous estimates.

Darwin researchers Ko van huissteden, Frans-Jan Parmentier, Han Dolman and colleagues show this in an article in Nature Climate Change.

Methane (bog gas) is a strong greenhouse gas, with a 25 x stronger warming effect as carbon dioxide. An important source of methane are the wetlands on the permanently frozen soils (permafrost) in Siberia, Alaska and Canada. Emission of methane increases when this frozen subsoil starts thawing. Since the arctic climate will warm three times as much as the global average, this thawing will occur over large areas, in particular in the vast frozen landmass of Siberia. The released methane will further amplify the greenhouse effect.


When permafrost melts, large scale lake creation occurs (thaw lakes or thermokarst lakes). The cause is the large amount of ground ice in the soil of many permafrost areas. These lakes are strong methane sources.  Accurate estimates of future expansion of these lakes is therefore highly important to improve knowledge of the climate of the future.


We developed a model to compute future expansion of these lakes. The model has been tested on a tundra area in Northeast Siberia, where we also measure methane and carbon dioxide emission from the tundra soil. The model reproduces the development of thaw lakes resulting from climate change in the past quite well.


For computing future development of thaw lakes we coupled the model to several climate models. The outcomes are surprising.

-        The thaw lake surface increases rapidly in the future (from 8 to 25%), but there is a limit: approximately 25%. The lakes show limited expansion because after some time they expand into river areas and are drained subsequently. 

-        The good news from our model is that methane emission from lake area increase is lower than earlier estimates. We arrive at an estimate of 1.8 megaton of methane per year, maximally 3.3 megaton per year. By comparison, this is 4-7% of the yearly production from all gas fields in the Netherlands. Earlier estimates resulted in 50-100 megaton per year, which is more than a factor 10 higher. The difference can be explained by a much lower prediction of future lake area from our model. Moreover, we also have accounted for the existing methane production from non-thawed tundra wetlands, that we measures in our study area.

-        The bad news is that we do not see a positive effect from curbing present-day human greenhouse gas emissions. Whether there is a continued increase of human greenhouse gas emission or a stabilization, the increase in lake area is approximately the same. This is caused by the present warming which is supposed to continue for the coming decennia according to all climate models. Unfortunately, the damage to the permafrost areas is irreversible.

Although the effect of the thaw lakes on climate is smaller than predicted before, it is a disastrous for the population of the permafrost areas. Our model predicts a threefold increase of lake area. This could have large consequences for nature, animal migration routes and human infrastructure like oil industry, transport and agriculture. 

Methane emissions from permafrost thaw lakes limited by lake drainage - J. van Huissteden, C. Berritella, F.J.W. Parmentier, Y. Mi, T.C. Maximov and A.J. Dolman - Nature Climate Change - published online: 1 May 2011