The Arctic—which spans the North Pole and surrounding landmasses—is one of Earth’s coldest regions. But it’s changing rapidly. Since the 1980s, the total amount of Arctic ice has declined by about 75 percent. The ice used to be at least
4 meters (13 feet) thick. Today, that ice has become thinner. In many places, it melts away completely in the summer (see Ice in Decline, below).
That’s a problem. Arctic ice acts like a mirror, reflecting the sun’s rays back into space. When there’s less ice, more of the ocean is exposed. The dark water soaks up the sun’s energy. This extra heat makes climate change even worse. It can also affect faraway places in unexpected ways.
Research suggests that a warming Arctic may lead to extreme weather in the U.S. and Europe, such as intense heat waves, says Heuzé. Warmer temperatures also cause more water to evaporate into the atmosphere. That could lead to snowier winter storms. “The Arctic is crucial for the entire planet,” she says.