Dear Maeve,
There’s just something special about those powerful, snow-white polar bears. That’s probably why it’s so hard to learn about what’s happening to their habitat.
I talked about that with my friend Anthony Pagano. He used to work with the grizzlies at Washington State University’s Bear Center. He studies polar bears in Alaska.
He told me that scientists classify polar bears as marine mammals—like whales, dolphins and other mammals that live in the ocean.
“They’re reliant on the sea ice that occurs over the Arctic Ocean,” he said. “They use the ice as a platform to catch seals.”
Polar bears spend most of their time on the ice. Even in winter when temps drop to negative 60 degrees, and it’s dark all the time, they stay out in the ice and snow.
That ice melts back a bit in the summer. To cope, most polar bears wander onto land to wait for the ice to return. They mostly don’t eat anything all summer long. They tank up on seals in the spring so they can survive by burning all the extra fat they stored.
Scientists monitor polar bears because, like you said, the Arctic ice is declining—and it’s happening fast.
The ice is melting because of global warming. When humans burn fossil fuels like oil and coal, a bunch of greenhouse gases go into the Earth’s atmosphere and stay there. It’s like putting a warm coat on the planet. It holds in heat and makes the Earth warmer over time.
A warmer planet is extra bad news for places covered with ice and snow.
Pagano told me the Arctic is warming two to four times faster than anywhere else on Earth. It’s happening more quickly because snow and ice are white and reflect the sun’s energy. When that snow and ice melt, it exposes the dark surface underneath. It could be the dark ground or the dark ocean. That dark surface absorbs the sun’s light and heat instead of reflecting it away. That warms the area even more—and that melts even more ice and snow.
Scientists expect a time will come when there’s no ice at all in the Arctic during the summer. That could happen as soon as 2050.
That will make summer even harder for polar bears. If the snow and ice can’t recover, it will leave polar bears with nowhere to live or hunt for seals. We could lose two-thirds of the polar bears we have now.
But we don’t have to lose the polar bears completely.
“At least some polar bear populations are likely to persist through the end of the century,” Pagano said. “That suggests that polar bears are unlikely to go extinct in the next 80 years or so. If we can develop a strategy to deal with greenhouse gas emissions, polar bears could recover.”
With any luck—and with the hard work of scientists like Pagano—we’ll be able to turn things around for these vulnerable marine mammals. The Arctic would be un-bear-able without them.
Sincerely,
Dr. Universe