Permafrost, Lakes, and Climate-Warming Methane Feedback: What is the Worst We Can Expect?

Joint Program Report
Permafrost, Lakes, and Climate-Warming Methane Feedback: What is the Worst We Can Expect?
Gao, X., C.A. Schlosser, A. Sokolov, K. Walter Anthony, Q. Zhuang and D.W. Kicklighter (2012)
Joint Program Report Series, 15 pages

Report 218 [Download]

Abstract:

Permafrost degradation is likely enhanced by climate warming. Subsequent landscape subsidence and hydrologic changes support expansion of lakes and wetlands. Their anaerobic environments can act as strong emission sources of methane and thus represent a positive feedback to climate warming. Using an integrated earth-system model framework, which considers the range of policy and uncertainty in climatechange projections, we examine the influence of near-surface permafrost thaw on the prevalence of lakes, its subsequent methane emission, and potential feedback under climate warming. We find that increases in atmospheric CH4 and radiative forcing from increased lake CH4 emissions are small, particularly when weighed against unconstrained human emissions. The additional warming from these methane sources, across the range of climate policy and response, is no greater than 0.1C by 2100. Further, for this temperature feedback to be discernable by 2100 would require at least an order of magnitude larger methaneemission response. Overall, the biogeochemical climate-warming feedback from boreal and Arctic lake emissions is relatively small whether or not humans choose to constrain global emissions.

Citation:

Gao, X., C.A. Schlosser, A. Sokolov, K. Walter Anthony, Q. Zhuang and D.W. Kicklighter (2012): Permafrost, Lakes, and Climate-Warming Methane Feedback: What is the Worst We Can Expect?. Joint Program Report Series Report 218, 15 pages (http://globalchange.mit.edu/publication/15931)
  • Joint Program Report
Permafrost, Lakes, and Climate-Warming Methane Feedback: What is the Worst We Can Expect?

Gao, X., C.A. Schlosser, A. Sokolov, K. Walter Anthony, Q. Zhuang and D.W. Kicklighter

Report 

218
15 pages
2016

Abstract: 

Permafrost degradation is likely enhanced by climate warming. Subsequent landscape subsidence and hydrologic changes support expansion of lakes and wetlands. Their anaerobic environments can act as strong emission sources of methane and thus represent a positive feedback to climate warming. Using an integrated earth-system model framework, which considers the range of policy and uncertainty in climatechange projections, we examine the influence of near-surface permafrost thaw on the prevalence of lakes, its subsequent methane emission, and potential feedback under climate warming. We find that increases in atmospheric CH4 and radiative forcing from increased lake CH4 emissions are small, particularly when weighed against unconstrained human emissions. The additional warming from these methane sources, across the range of climate policy and response, is no greater than 0.1C by 2100. Further, for this temperature feedback to be discernable by 2100 would require at least an order of magnitude larger methaneemission response. Overall, the biogeochemical climate-warming feedback from boreal and Arctic lake emissions is relatively small whether or not humans choose to constrain global emissions.