Alaska, hundreds of thawed lakes overflow

One of the many lakes formed by thawing permafrost on the Baldwin Peninsula, Alaska (credit: Alfred Wegener Institute / Ingmar Nitze)

A new study published in the journal The Cryosphere provides more evidence that the Arctic is melting much faster than expected. Researchers at the Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research (AWI) focused on the terrestrial permafrost of Alaska near the town of Kotzebue.

Hundreds of lakes all thawing

It is a region where there are hundreds of lakes that all thaw. These small lakes form when the permafrost ice thaws and becomes liquid. This water, along with that from snowfall and rain, collects in natural cavities in the ground.
While some of them are several thousand years old and most of them formed at the end of the last ice age, many of them are very few years old and formed during the period. recent due to the melting of the permafrost ice. The latter, as the researchers have certified, tend to melt mainly during the summer and no longer refreeze in the winter, as was the case before. This causes, among other things, the flow of water from the lakes, which leads to a certain instability of the soil and real flooding in a fortunately uninhabited area.

The 2017-2018 season, the hottest on record

Focusing on the 2017 and 2018 seasons, the AWI researchers found that around 190 lakes in total dried up in a single year, data that shocked the researchers themselves, such as admits Ingmar Nitze, AWI geographer and one of the study’s authors: “The winter of 2017/2018 was extremely humid and hot. Conditions were similar to what our climate models predict to be normal for the end of this century. In a sense, we got a glimpse of the future. By then, the general drainage of the lakes will have reached a catastrophic extent ”.
During the year 2017-2018, the average temperature in the region was approximately 5 ° C higher than the seasonal average.

The lakes are overflowing with too much water

In addition, due to the very humid conditions, there was a lot of snow during this time, which helped isolate the ground from the cold air above during the winter. During the winter, the permafrost that had thawed in the summer did not freeze again. Rising lake levels and several other factors then caused water to flow through the top layer of soil that still remained thawed, making the situation worse.

This is what we are going to see in the Arctic over the next several decades.

These events related to the drainage of water on permafrost, Nitze said, show just how severe global warming can be and what impact it can have on landscapes such as tundra and permafrost. Furthermore, what is happening around the Kotzebue region will happen, over the next decades and not just towards the end of the century, somewhat in all permafrost zones of the Arctic.

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