Arctic sea ice shrank to its lowest level in 38 years last month, setting a record low for the month of May and setting up conditions for what could become the smallest Arctic ice extent in history, according to National Snow and Ice Data Center data released Tuesday.

“We didn’t just break the old May record, we’re way below the previous one,” NSIDC Director Mark Serreze said.

This graph shows Arctic sea ice extent as of May 31, along with daily ice extent data for previous years.
This graph shows Arctic sea-ice extent as of May 31, along with daily ice extent data for previous years.NSIDC

Compared to normal conditions, the Arctic ice cap was missing a Texas-sized slab of ice in May. It spread across 4.63 million square miles of the Arctic Ocean, Hudson Bay, and adjacent areas of the North Atlantic — an area 224,000 square miles smaller than the previous low record for the month set in 2004. May’s record low follows four previous monthly record lows set in January, February, and April.

Temperatures averaged about 3 degrees C (5 degrees F) above normal across the Arctic Ocean this spring. The warmth made daily sea-ice extents average about 232,000 square miles smaller than during any May in the 38 years scientists have been gathering data using satellites.

The Arctic, which saw unusually warm temperatures near-freezing during a severe storm in December, is warming twice as fast as the rest of the globe as the climate changes. This year’s extreme El Niño may also have helped crank up the heat.

Sea ice this year is melting at a pace two to four weeks faster than normal as pulses of warm air have been streaming into the Arctic from eastern Siberia and northern Europe, and sea ice has retreated early from the Beaufort Sea.

Barrow, Alaska, on the Beaufort Sea, recorded its earliest snowmelt in 78 years last month. Normally, snow begins to retreat in late June or July, but the snow began to melt May 13 — 10 days sooner than the previous record set in 2002.

The May 21 view of Arctic sea ice in the Beaufort Sea, showing early ice thinning and melting.
The May 21 view of Arctic sea ice in the Beaufort Sea, showing early ice thinning and melting.NASA

“The El Niño certainly had something to do with this,” Serreze said. “It can have impacts on weather conditions very far away from the tropical Pacific.”

These warm conditions at the beginning of the summer melting season have set up the Arctic sea ice to shrink below its all-time record lowest extent set in 2012, he said.

The extent to which the ice cap will melt this summer is entirely dependent on summer weather patterns that scientists have no way to predict more than 10 days in advance, he said.

“If we had a summer that is kind of cool and stormy, that will lead to less melt through the summer,” Serreze said. “That could keep you from reaching a new record.”

“Will we end up with very low sea-ice extent this September? I think pretty much absolutely,” he said.