Coastal erosion is picking up speed across the Arctic

Scientists at Universität Hamburg are providing new details about the extent of coastal erosion throughout the entire Arctic. The team used a combination of computational models to investigate the magnitude and speed of coastal changes across the rapidly warming region.

“We have run through a range of scenarios, depending on how much greenhouse gases humanity will emit in the coming years,” said study’s lead author Dr. David Nielsen.

“According to the study, not only is more and more land mass being lost in absolute terms; with each degree of temperature increase, the annual rate of erosion increases – in meters, but also in millions of tons of carbon released.”

As global warming causes an increasing amount of permafrost to thaw and sea ice to melt, the soil is becoming less stable and more likely to erode. Soil erosion damages infrastructure and threatens coastal communities. Erosion also releases carbon (which was once stored in the soil) into the ocean and the atmosphere, which can boost global warming in a reinforcing feedback loop. 

The new study shows that at the current rate of emissions, the rate of Arctic coastal erosion could more than double by the end of the century. This translates to enormous losses of up to three meters of soil per year.

“Our findings also show that a shift toward greater sustainability and significantly lower greenhouse gas emissions could slow the acceleration in the second half of the century. However, it won’t be possible to stop the loss of land mass entirely,” explained Dr. Nielsen.

In collaboration with experts at the Max Planck Institute for Meteorology, the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, and the German Meteorological Service, Dr. Nielsen has calculated the future balance for the entire Arctic coast. This is a challenging task, considering that coastal erosion varies greatly from one region to another. 

“In the Arctic, erosion is always a combination of thermal and mechanical factors,” explained Dr. Nielsen. “Depending on the location and shape of the respective coast, we expect to see varying wave heights. With increasing temperature, the range of the waves also increases, because the sea ice disappears. In addition, the ice-free period in the summer is lengthened, making coasts even more vulnerable.”

According to the study authors, entire villages in Alaska are already facing the need for relocation as a result of costal erosion. By the end of the century, different emission scenarios lead to substantially different projections in terms of societal impacts, said the researchers. While the exact consequences for humans and wildlife are uncertain, what is made clear in the study is that the pace of Arctic soil erosion is increasing alongside global warming. 

“The sensitivity of Arctic coastal erosion to climate change increases with time in our simulations, and is tightly related with the Arctic amplification after its onset,” wrote the study authors. “Arctic coastal erosion increases more rapidly in response to increasing global mean surface air temperature in the future scenarios than it does in the historical period.”

The study is published in the journal Nature Climate Change.

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By Chrissy Sexton, Earth.com Staff Writer