The shell of ice that expands atop the Arctic Ocean every winter has done all the growing it will do this season—and that hasn’t been much. In fact, the annual winter maximum sea ice extent this year has tied for the record lowest amount in the nearly 50 years that satellites have been keeping watch.
“This record low maximum gives a head start to the spring and summer melt season,” said Walt Meier, senior research scientist at the National Snow and Ice Data Center (NSIDC), in a press release.
The expanse of Arctic Ocean covered by ice grew to 14.29 million square kilometers (5.52 million square miles), likely peaking on March 15, NSIDC reported on Thursday. This is just below a past record low of 14.31 million km2 (5.53 million square miles) set last year, but anything within 40,000 km2 (15,000 square miles) is considered a tie.
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The record underscores the rapid loss of Earth’s northern polar ice cap, driven by the human-caused rise in global temperatures. This year’s winter low was 1.36 million km2 (525,000 square miles) below the 1981–2010 average. That’s a loss of ice about twice the size of Texas.
The disappearance of Arctic ice—which is even more pronounced in the summer months—not only threatens fragile polar habitats and the species that live there; it also exacerbates global warming. The ice is naturally reflective, sending some of the sun’s rays back out to space. But the darker open ocean absorbs those rays, raising temperatures and driving further ice melt.
“One or two record low years don’t necessarily mean much by themselves, but in the context of the significant downward trend that we’ve observed since 1979, it reinforces the dramatic change to Arctic sea ice throughout all seasons,” Meier said.
Some scientists have projected that the Arctic will experience its first ice-free day—defined as the moment when ice cover shrinks below one million km2 (386,000 square miles)—before the end of the decade. The pace of ice loss and the implications have spurred some researchers to see if we can refreeze the Arctic, for example, by pumping colder deep ocean water on existing sea ice.