Climate-carbon feedback tradeoff between Arctic and alpine permafrost under warming
2025-09-17
Whether greenhouse gas (GHG) emissions from permafrost will trigger positive climate feedbacks under warming remains unknown. Here, we synthesized the response of growing season carbon dioxide (CO 2 ), methane (CH 4 ), and nitrous oxide (N 2 O) emissions to experimentally manipulated warming of ~2°C for permafrost in alpine and Arctic regions. Warming weakened the GHG sink of alpine permafrost, thereby increasing (13%) its global warming potential, but strengthened the GHG sink of Arctic permafrost and decreased (−10%) its global warming potential. When warming caused drying of alpine permafrost soils, the CO 2 sink weakened but the CH 4 sink increased. In contrast, warming of relatively wet Arctic permafrost increased the CO 2 sink and CH 4 source. Warming led to much stronger increases of the N 2 O source in alpine than Arctic permafrost. Although keeping additional warming below 2°C in permafrost regions can avoid the positive permafrost-climate feedback, measures are needed to maintain fragile carbon sink of alpine permafrost ecosystems.