Heatwaves and wildfires are not just scorching(灼烧的，炙热的) forests, they are adding to the tipping point(临界点，引爆点) risks in the world’s vast permafrost(永久冻土) regions, which contain three times more carbon than all the living vegetation on Earth.
热浪和野火不仅灼烧森林，还在加剧全球广袤永久冻土地区的临界点风险，这些地区储存的碳是地球上所有活植被的三倍。
This is a major concern for Gustaf Hugelius, a professor at the Bolin Centre of Climate Research at Stockholm University, Sweden, and a leading authority(权威，专家) on the risks from thawing tundra(苔原，冻原) and peatlands(泥炭地). In this Q&A, he explains why the world should pay attention(注意，关注).
这是瑞典斯德哥尔摩大学博林气候研究中心教授、研究解冻苔原和泥炭地风险的权威专家古斯塔夫·胡格利乌斯的主要担忧。在本次问答中，他解释了世界为何应予以关注。
What is permafrost?
什么是永久冻土？
Permafrost is ground that is frozen all year round(全年，整年). It is found mostly in Russian Siberia, Canada, Alaska and parts of Europe. The permafrost region is massive(巨大的，大规模的), covering 20m sq km(平方公里), which is five times the size of the EU.
永久冻土是全年冻结的地面。它主要分布在俄罗斯西伯利亚、加拿大、阿拉斯加和欧洲部分地区。永久冻土区面积巨大，达2000万平方公里，是欧盟面积的五倍。
Why is permafrost a climate concern?
为什么永久冻土是气候问题？
How can it reach a tipping point?
它如何达到临界点？
Can it not just refreeze later?
它不能以后重新冻结吗？
Could the whole system tip suddenly?
整个系统会突然崩溃吗？
How much greenhouse gas could be released from the permafrost this century?
本世纪永久冻土可能释放多少温室气体？
Are there even bleaker predictions than these?
还有比这些更悲观的预测吗？
What difference does it make if the permafrost releases methane rather than CO2?
如果永久冻土释放甲烷而非二氧化碳，会有什么不同？
What factors determine whether permafrost releases methane or CO2?
哪些因素决定永久冻土释放甲烷还是二氧化碳？
How much permafrost loss is already baked into the climate system?
有多少永久冻土损失已经注定？
What changes have we seen?
我们看到了哪些变化？
Are there benefits from thawing permafrost?
永久冻土解冻有好处吗？
What can be done?
我们能做什么？
How much scientific uncertainty is there?
科学不确定性有多大？
How do you feel about your research?
你对自己的研究有何感受？