Speleothems Reveal 500,000-Year History of Siberian Permafrost

摘要

Permafrost regions (in which the ground is frozen throughout the year) cover 24% of the Northern Hemisphere land surface and hold -1700 Gt of organic carbon. When it thaws, permafrost releases CO_2 and CH4, turning a long-term carbon sink into a source and enhancing the greenhouse effect (1, 2). Permafrost degradation also intensifies thermo-karst development, coastline erosion, and liquefaction of ground previously cemented by ice. The latter endangers infrastructure, including major Siberian oil and gas facilities (3). An ability to predict the extent of future permafrost degradation is desirable.