When you imagine Santa’s workshop, you might picture it on solid ground. But at the North Pole, what looks like snowy land is actually a sheet of ice floating on the Arctic Ocean. And as the climate warms, it’s melting.

Walt Meier is a senior research scientist at the National Snow and Ice Data Center. He says the amount of ice in the Arctic has always ebbed and flowed.

“The ice grows in the wintertime and it melts in the summer,” he says. “But we’ve seen it melting back more and more on average.”

He says that over the last four decades, the Arctic has lost over 40% of its ice cover in the summertime.

“And we’re going to continue to see less and less ice until we reach a time when essentially the Arctic, at least during summertime, becomes ice-free,” he says.

Meier says that unless carbon pollution is sharply reduced, that’s likely to happen by mid-century.

“2040 to 2050 is a pretty good guess,” he says.

The loss of sea ice threatens Arctic ecosystems, and the effects will be felt far beyond the North Pole. Ice reflects sunlight, but open water absorbs heat, so when sea ice vanishes, the Earth warms more quickly.

And as for the North Pole’s most legendary resident?

“Santa may need a boat in the not too distant future,” Meier says.

Reporting credit: Sarah Kennedy/ChavoBart Digital Media.