Permafrost: The ground is thawing much faster than anticipated
Climate change is transforming our planet faster than expected, which is especially apparent in the permafrost regions. In the Arctic and in regions like the Alps, we can see with the naked eye how the frozen soil is now thawing – in many cases, for the first time in millennia. In alpine regions, falling rocks and landslides are among the first and most obvious effects, since the ground ice that previously held the stones, pebbles and soil together is now disappearing. The situation is similar in the taiga and Arctic tundra, where, during our expeditions, we can increasingly see how the ground thaws to a depth of several metres, eventually collapsing. As a result, new moors and lakelands are being formed, bluffs are crumble, lakes running dry, and rivers are washing away huge amounts of soil. This development is especially dramatic for the residents of the Arctic: the ground is collapsing under bridges and houses, streets and roads have become impassable, and some vital grazing areas and hunting grounds are now almost impossible to reach safely.
Our climate models aren’t yet capable of simulating these abrupt changes, and therefore most likely underestimate the extent to which thawing permafrost soils are intensifying climate change. Permafrost can still be found below roughly a quarter of the land mass in the Northern Hemisphere. These frozen soils store an estimated 1,600 billion metric tons of carbon in the form of frozen animal and vegetable matter. That’s twice the amount of carbon currently in the atmosphere (as carbon dioxide). When that organic matter begins to thaw, it is broken down by microbes, a process that releases greenhouse gases like carbon dioxide, methane and nitrous oxide (laughing gas) and contributes to global warming. In this regard, over a 100-year timeframe methane can be up to 28 times as powerful as carbon dioxide in terms of warming the environment – and especially large amounts of methane are released when permafrost soils thaw abruptly. In turn, laughing gas is 265 times as potent as carbon dioxide and can also be emitted by thawing permafrost – though we still don’t know how much of it is released.
In order to stop this trend, we human beings have no choice but to reduce our greenhouse gas emissions and comply with the stipulations of the Paris Agreement. Putting the brakes on anthropogenic emissions will also reduce subsequent emissions from the permafrost. The international permafrost research community is now called upon to improve its models and forecasts, so that we can better judge what long-term consequences the transforming Arctic will have for us and our planet’s climate.
Prof Guido Grosse, Head of the Permafrost Research Division at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research in Potsdam