Sea ice plays many important roles for the global climate: Its white surface can reflect energy back into space, helping the planet cool. It also acts like a blanket for the ocean, insulating it and preventing ocean heat from reaching the atmosphere. Less sea ice means more heat goes in Earth’s systems, warming the atmosphere and the oceans.

The Arctic reaches its maximum sea ice in March each year and then starts a six-month melt season. The National Snow and Ice Data Center said the peak measurement taken Saturday was 5.53 million square miles (14.

The Arctic Ocean likely had the smallest winter ice cover in 47 years of satellite records this season, with just 5.53 million square miles of sea ice covering the region at its peak on March 22.