COLD COMFORT

The latest satellite imagery of the Arctic bodes very poorly for polar bears

Polar bears have long been the poster animals for climate protection. But this week, scientists who have been studying data from NASA and other satellite operators on changing environments had more bad news for the Arctic bears, and for reindeer, mountain lions, and other creatures suffering the effects of drought and warming seas.

Detailed satellite imagery is helping researchers identify changes, like loss of sea ice and plants affected by drought, that can’t easily be measured otherwise. It’s predicting habitat loss that’s going to lead to shrinking animal numbers, three research groups said at a meeting at the American Geophysical Union in San Francisco said.

First, those bears.

Right now, polar bear populations are declining in some areas of the Arctic, but stable or even growing in others—probably the areas which are richest in food and can withstand most change, the researchers said. But the loss of sea ice shown by the satellites leads the researchers to predict that polar bear numbers will shrink by 30% over the next 30 or 40 years. Since NASA started recording data in 1979, sea ice has shrunk at an average rate of about 20,500 square miles every year.

Ultimately, “polar bears need sea ice to be polar bears,” said Eric Regehr from the US Fish and Wildlife Service in Anchorage, Alaska, who led the study. “This study adds to a growing body of evidence that the species will likely face large declines as loss of their habitat continues.”

Zach Labe, a Phd student at Cornell University who tweets a lot about sea ice, used satellite data to model what sea ice loss looks like over time:

The news also isn’t good for reindeer, but in their case satellite imagery also gave some small grounds for hope.

Taimyr reindeer form the largest herd of wild reindeer in the world. They live in northern Russia, and are now moving even farther north, possibly to escape warmer weather and mosquitos, said Andrey Petrov, an associate professor at the University of Northern Iowa. That means more vegetation is destroyed in the areas where the animals end up, he said, though he noted that the plants are able to bounce back even from this higher-intensity grazing.

Nevertheless, reindeer populations are declining all over the world, “in some places catastrophically,” Petrov said. Taimyr has seen a 40% drop to 600,000 animals since the year 2000, he said.

In the US, meanwhile, more droughts will lead to falling numbers of mule deer and, as a result, the mountain lions that hunt them, said ecologists from Utah State University.

As the incoming US president begins to chart a course that relies on oil companies executives and climate change deniers at its core, there’s little cause for hope the country will help address the underlying causes of the animals’ decline.

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