⁍ Satellites recorded this year’s sea ice minimum at 3.74 million square kilometers on Sept. 15.

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⁍ The rate of ice loss during those six days was faster than any other year on record.

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⁍ The loss of sea ice also threatens Arctic wildlife, from polar bears and seals to plankton and algae.

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– The amount of Arctic sea ice shrank to its second-lowest extent in four decades this year, according to researchers at the National Snow and Ice Data Center. “It’s fairly devastating that we’ve had such consistently low sea ice,” a glaciologist tells Reuters. “But unfortunately, it’s not surprising.” Sea ice reached a record low of 3.74 million square kilometers on Sept. 15, the National Snow and Ice Data Center says, only the second time the ice has been below 4 million square kilometers in 40 years of record keeping. The loss of sea ice was especially sharp between Aug. 31 and Sept. 5, thanks to a heat wave in Siberia. The rate of ice loss during those six days was faster than during any other year on record. Another team of scientists found in July that the Siberian heat wave would have been all but impossible without human-caused climate change. As the Arctic sea ice vanishes, it leaves patches of dark water open. Those dark waters absorb solar radiation rather than reflecting it back out of the atmosphere, a process that amplifies warming and helps to explain why Arctic temperatures have risen more than twice as fast as the rest of the world over the last 30 years. The loss of sea ice also threatens Arctic wildlife, from polar bears and seals to plankton and algae. “The numbers that we’re getting in terms of extent of sea ice decrease each year put us pretty much on red alert in terms of the level of worry that we have, our concern for the stability of this environment,” says a polar wildlife expert.