Thawing sub‐arctic permafrost: Effects on vegetation and methane emissions

TLDR

Ecosystems along the 0 °C mean annual isotherm are highly sensitive to climate change, and mires in these regions emit substantial methane that is closely tied to temperature, hydrology, and permafrost coverage, so alterations in permafrost could dramatically affect emissions. Recent permafrost and vegetation changes in subarctic Swedish mires have increased landscape‑scale methane emissions by 22–66 % between 1970 and 2000.

Abstract

Ecosystems along the 0°C mean annual isotherm are arguably among the most sensitive to changing climate and mires in these regions emit significant amounts of the important greenhouse gas methane (CH 4 ) to the atmosphere. These CH 4 emissions are intimately related to temperature and hydrology, and alterations in permafrost coverage, which affect both of those, could have dramatic impacts on the emissions. Using a variety of data and information sources from the same region in subarctic Sweden we show that mire ecosystems are subject to dramatic recent changes in the distribution of permafrost and vegetation. These changes are most likely caused by a warming, which has been observed during recent decades. A detailed study of one mire show that the permafrost and vegetation changes have been associated with increases in landscape scale CH 4 emissions in the range of 22–66% over the period 1970 to 2000.