Environmental Science and Engineering Seminar

Permafrost thaw beneath Arctic lakes leads to large emissions of methane, a potent greenhouse gas to the atmosphere. In turn, methane contributes to global climate warming, which leads to more permafrost thaw in a positive feedback cycle. This talk will uncover natural sources of methane in Arctic lakes, which come from both the organic matter decay activity of microoganisms in lake bottoms and from geologic sources deep within the Earth. This talk will also present mechanisms of carbon sequestration by the same permafrost thaw lakes, a natural process that mitigates greenhouse gas losses, and over the long term can lead to net climate cooling. I will consider the important balance between positive and negative feedbacks in fate of thermokarst lakes and climate change in the past (since the last deglaciation), present, and future (until year 2100).