美国北亚利桑那大学的研究团队在阿拉斯加德纳利国家公园进行的长期研究表明，野火正在加剧永久冻土融化，形成危险的气候反馈循环。1 2013年6月一场闪电引发的大火在公园北部的冻原上蔓延近35000英亩，1 2016年的调查发现火灾最严重区域的融冻层比火灾外区域深1-2英尺。1
永久冻土储存约1.5万亿吨碳，相当于大气中碳含量的两倍，1 其融化带来的碳排放威胁全球气候。2020年的论文显示永久冻土可能突然融化而非逐渐融化，释放的碳可能是之前预期的两倍。1 2007年阿克图夫克河冻原大火释放超200万吨碳，约占全球冻原生态系统年碳吸收总量。1 研究人员发现约40%的北极-北方森林生物群已从碳汇转变为碳源，1 这意味着这些区域现已开始加剧而非缓解全球变暖。
长期加热实验进一步验证了这一趋势。1 施勋的13年加热实验在10×10米的试验地中发现土壤碳含量下降23%，地面下陷数英尺，1 他预期到2040年末整个试验地下方的永久冻土将深度融化。1 这些研究结果表明气候变暖与野火共同作用，正在加速北极地区从碳汇向碳源的转变。
Scientists at Northern Arizona University are documenting how wildfire and thawing permafrost create a dangerous climate feedback loop in Alaska. A lightning-sparked fire that swept across nearly 35,000 acres of tundra in the northern section of Denali National Park in June 2013 has become a focal point for long-term study on how combustion accelerates the release of greenhouse gases from frozen ground.1
Initial investigations in 2016 revealed that the most severely burned areas experienced permafrost thaw 1 to 2 feet deeper than unburned zones adjacent to the fire perimeter.1 The implications are sobering: permafrost globally stores approximately 1.5 trillion tons of carbon—twice the amount currently in the atmosphere.1 Research published in 2020 suggested that permafrost may undergo sudden collapse rather than gradual melting, potentially releasing twice as much carbon as previously anticipated.1 A particularly striking example occurred in 2007 when the Aktuftuk River tundra fire released over 2 million tons of carbon, equivalent to the annual carbon uptake of the entire global tundra ecosystem.1
The research team, including scientist Susan Nataali and colleagues, has found that approximately 40 percent of the Arctic-boreal forest biome has already transitioned from functioning as a carbon sink to operating as a carbon source.1 Complementary heating experiments conducted over thirteen years on a 10-by-10-meter plot demonstrated a 23 percent decline in soil carbon content, with ground subsidence of several feet observed.1 Projections indicate that by the end of 2040, permafrost beneath the entire experimental plot will experience deep-level thaw.1
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