Arctic in Peril

The Arctic is famous for ice, snow, and giant glaciers—not to mention polar bears. But Earth’s northernmost region is getting an unwelcome makeover, scientists say. New research shows that climate change is shifting Arctic conditions, from snow and ice to rain and ice-free seas. 

“The ice is only half as thick as it was 40 years ago,” says Markus Rex, a German scientist. Rex recently led a yearlong expedition in the Arctic. 

The international effort, nicknamed MOSAiC, was the largest and longest polar research expedition of its kind. Scientists wanted to learn more about how the Arctic is changing—and why.

The edges of the Arctic ice cap melt in the summer and then refreeze in the winter. But more of that ice is melting now than in the past, says Ola Persson, a MOSAiC scientist. This past summer, the expedition crew witnessed the second-lowest recorded Arctic sea ice extent—the area of ocean covered by ice (see map, below). 

The ice loss is a big factor in why the Arctic is warming twice as fast as the rest of Earth, scientists say. Sea ice’s bright surface reflects approximately 70 percent of the sunlight that reaches it back into space. But dark ocean waters absorb sunlight—soaking up about 90 percent of rays. So as the ice-free area of the Arctic Ocean increases, so does the amount of heat that its waters absorb. 

Plus, with less sea ice staying frozen year-round, there is more new ice in the winter than before. New ice is thinner than old ice, so it is more likely to melt, Persson says.

The Arctic’s roughly 4 million residents are already feeling the impacts of sea ice loss. In Alaska, eroding shorelines threaten villages. The changes are also affecting the Arctic ecosystem, including polar bears, which travel across summer sea ice to hunt. 

Without major efforts to halt climate change, Arctic summers could be ice-free within decades, Rex says. As a result, sea levels could rise, affecting coastal communities globally. And heat waves, droughts, and other weather events could last longer. 

But scientists hope the MOSAiC data will spur people worldwide to take action.

“Arctic sea ice is not only an important part of the global climate system, it is also a unique ecosystem and the basis of life for many Indigenous societies,” Rex says. “We should do everything within our power to preserve it.”