The Arctic Ocean is the smallest and shallowest of the Earth's five oceans. In recent years its surrounding commental kind masses have wanned rapidly. The consequences of this will he profound. The Arctic is now heating up twice as fast as the rest of our planet. This permits vegetation to move northward, increasing the rate of warming as reflective snow cover decreases. Then the warmer land lets subsurface permafrost thaw, releasing the potent greenhouse gas methane. It is a feedback-loop process that has greatly accelerated Arctic warming in the past half decade.
Until a few years ago, the wintertime Arctic Ocean and adjacent Bering Sea were completely ice-covered by seasonal and multiyear ice from 3- to 13-feet thick. In summer, the annual ice melt left about half this cover in place. Over the past five years, this has all changed. Winter ice cover is now decreasing at the rate of more than 3 percent a decade. The change is even greater in the summer. Since the 1970s, summer ice cover has decreased by 30 percent while the total volume of ice decreased by about 40 percent.