Global Warming Is Making Arctic Lakes Disappear

The Arctic’s ice sheets normally reflect much of the sunlight that falls on them back into space, but the ice sheets are receding and exposing the land and sea underneath. The darker land and sea absorb more heat than ice, so they heat up still more, which causes the ice to melt even faster. Because of this, the Arctic is warming faster than any other region on Earth.

According to Larry Smith of the University of California, Los Angeles, the prevailing thought is that the warming will cause the permafrost to thaw and make the lakes more abundant. Some studies have shown that a few Arctic lakes are expanding.

Yet In 2003, Larry Hinzman and Kenji Yoshikawa of the University of Alaska Fairbanks discovered that global warming is causing lakes in Council, Alaska to shrink. Hinzman and Yoshikawa suggested that the permafrost is turning into porous soil, which is allowing the lakes to soak away. This study only encompassed a small region of the Arctic, so Hinzman, Yoshikawa and their colleagues looked at a much larger portion of the Arctic: a 515,000-kilometer area in Siberia. By comparing satellite pictures from the 1970s to those from 1997 to 2004, the team discovered that the total surface area of lakes there had decreased by 93,000 hectares. More than 1000 large lakes, each originally bigger than 40 hectares, have shrunk, while 125 others have disappeared. When looking at the northern part of the Arctic within their survey area, Hinzman and Yoshikawa’s team found that the total surface area of the lakes there had increased by 13,300 hectares. However, taken as a whole, more lakes are shrinking than growing in the region.

According to the researchers, the permafrost in the north is very thick. When it melts, deeper layers, which can contain the lakes, remain, so the lakes expand. However, the permafrost in the south is thinner and not continuous, so its thawing allows the lake to soak into the soil.