Olaf Otto Becker on Rising Temperatures

It is foggy and drizzling, as I leave our research ship late in the evening in August 2019. Although I have never in my life seen a landscape like this before, the place seems oddly familiar. The silence here is defined by small waves that you can only hear when the sea is calm; brown meltwater gurgles down all over the icy cliffs; and soil slips, sometimes very gently, sometimes thunderously, into the depths. There is a strange gaseous odor in the air. It smells of ice, rotting peat, and animal remains. As the thawing permafrost releases its treasures, one finds mammoth bones every­where here. The only sounds that do not belong here are the receding rumble of the diesel generator of our expedition ship Merzlovted, and my steady footsteps on the black-brown beach.

Matthias Fuchs, our expedition leader, has told me that these cliffs, up to 25 meters high, have formed over 40,000 years in an area that never underwent glaciation during the last ice age. These loess-rich deposits with a very high ice content are called “yedoma” or “ice complex.” Over 85 percent of the cliffs are ice, and that makes them particularly prone to erosion caused by high air and water temperatures in summer. Over recent decades, in particular, those high temperatures have been eating them away. Erosion rates in 2017 and 2018 were noticeably higher than in previous decades; in 2019, peak temperatures of over 30 degrees Celsius have already been measured in the Siberian Arctic, and the trend is set to continue. On the island of Sobo-Sise, the cliff has recently been eroding by up to 20 meters a year. 

But it is not just the permafrost cliffs on Sobo-Sise that are eroding; permafrost soils are now thawing across the Arctic. Large amounts of organic matter (mostly carbon) frozen since the Ice Age have accumulated in these soils and are now being released. Some of the carbon is converted by microorganisms and released as greenhouse gasses—carbon dioxide or methane. And they in turn will further raise global air temperatures. So this self-reinforc­ing feedback mechanism makes the thawing permafrost and the erosion of the yedoma cliffs relevant not just for the Arctic; it influences the worldwide climate, too.