北极土壤微生物产生的热能够促使冻土层融化以及加剧二氧化碳在大气中的释放，《Nature Climate Change》上一项研究发出上述警告。

随着全球气温上升和冻土层的融化，土壤中有机材料的分解速度也可能加快。但是，科学家一直没有弄清楚这类分解产生热量的过程。

Bo Elberling等人从格陵兰岛6个位置采集了21个天然有机冻土层样本并对其中的微生物热量产生情况进行了量化分析，试图确定能否通过增强微生物活跃度的方式，促使其产生足够热量影响到土壤分解速率。他们的模型模拟结果显示，土壤温度和碳分解之间存在一种反馈回路能够加速2012年到2100年间冻土层的融化以及微生物热量的产生。

研究人员还发现，该过程能够消除早期人类在北极活动时留在冻土层有机堆肥中的证据。（来源：中国科学报 张笑）

Permafrost thawing in organic Arctic soils accelerated by ground heat production

Abstract  Decomposition of organic carbon from thawing permafrost soils and the resulting release of carbon to the atmosphere are considered to represent a potentially critical global-scale feedback on climate change. The accompanying heat production from microbial metabolism of organic material has been recognized as a potential positive-feedback mechanism that would enhance permafrost thawing and the release of carbon. This internal heat production is poorly understood, however, and the strength of this effect remains unclear. Here, we have quantified the variability of heat production in contrasting organic permafrost soils across Greenland and tested the hypothesis that these soils produce enough heat to reach a tipping point after which internal heat production can accelerate the decomposition processes. Results show that the impact of climate changes on natural organic soils can be accelerated by microbial heat production with crucial implications for the amounts of carbon being decomposed. The same is shown to be true for organic middens with the risk of losing unique evidence of early human presence in the Arctic.

原文链接：http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2590.html