Past, Present, and Future of Permafrost in a Changing World

Permafrost has received much attention recently because surface temperatures are rising in most permafrost areas of the earth, bringing permafrost to the edge of widespread thawing and degradation. The thawing of permafrost that already occurs at the southern limits of the permafrost zone can generate dramatic changes in ecosystems, in water and carbon cycles, and in infrastructure performance. If current trends will continue into the future, there are no doubts that warming of permafrost will eventually trigger widespread permafrost thawing. There is much uncertainty at what exact locations and areas permafrost will start to thaw first, what will be the rate of this degradation, and what exactly will be the consequences for other components of the Arctic, sub-Arctic and Global Natural Systems. To better understand the possible rates and pathways of permafrost degradation in the future we have to pay closer attention to permafrost development and disappearance in the past. In this presentation we will address what is known about permafrost development in Eurasia during the last glacial-interglacial cycle. Our recent observations obtained from North America and Northern Eurasia show a general increase in permafrost temperatures during the last few decades. Most of the sites show a substantial warming. This warming was different at different locations, but was typically from 0.5 to 2°C at the depth of zero seasonal temperature variations in permafrost. Thawing of the Little Ice Age permafrost is going on at many locations and there are some indications that the late-Holocene permafrost started to thaw at some specific undisturbed locations in the European North-East, in the northwest of West Siberia, and in Alaska. Some projections of possible changes in permafrost during the current century based on application of calibrated permafrost models will be provided in our presentation. The possible consequences of permafrost degradation will also be discussed.