CNN

Right now, the Arctic is maxing out on sea ice -- the cold of winter has built up over months of darkness, and ice has spread as far south as it will all year. It’s the North Pole’s sea ice maximum, except this year, it’s alarmingly low.

There is roughly half a million square miles of ice missing in this year’s “max,” compared to average -- an amount twice the size of Texas.

It’s the latest profoundly worrying signal from the top of the planet, a region which has become a clear victim of the climate crisis as humans burn fossil fuels, and increasingly a geopolitical hotspot as melting ice opens up commercial and military opportunities.

Winter is when Arctic ice builds up, typically reaching its maximum extent in March. This year, when scientists from NASA and the National Snow and Ice Data Center measured it on March 15, they found the ice had reached 5.52 million square miles -- roughly nine percent lower than the average between 1981 and 2010.