Doyle Rice

USA TODAY

Arctic sea ice set a record wintertime low for the second straight year because of global warming, scientists at the National Snow and Ice Data Center and NASA announced Monday.

“I’ve never seen such a warm, crazy winter in the Arctic,” data center director Mark Serreze said in a statement. “The heat was relentless.”

Arctic temperatures this winter were up to 15 degrees higher than average, according to NASA.

Sea ice is frozen ocean water that melts each summer and refreezes each winter. It typically reaches its smallest "extent" in September and largest in March of each year. It is tracked by the data center located in Boulder, Colo.

Sea ice extent over the Arctic Ocean measured 5.607 million square miles on March 24, beating last year’s record low of 5.612 million square miles.

Records for sea ice began in 1979.

Why do we care about sea ice? Because it affects wildlife as well as people who live in the Arctic, the data center said. It also influences weather here in the U.S.

The amount of sea ice in the Arctic has been steadily shrinking over the past few decades due to man-made global warming, according to the National Oceanic and Atmospheric Administration.

"The Arctic is in crisis," said Ted Scambos, lead scientist at the data center. "Year by year, it’s slipping into a new state, and it’s hard to see how that won’t have an effect on weather throughout the Northern Hemisphere.”

Globally, even though Antarctic sea ice has gotten larger, sea ice has declined overall.