This year's weather has smashed records across much of the world, but to see just how insane conditions have become, you need to look to the Bering Sea. In February we reported on the astonishing drop in ice this winter, but it's only now that scientists have put it in context, noting the serious effects on Alaskan populations.

Right from the start of winter ice formation in the Bering Sea was slow. Early in February, there was little more than half the average ice extent for the last 40 years. Still, ice extent was pretty close to the previous minimum recorded since satellite tracking began in 2017. Then, as NOAA climatologist Dr Rick Thoman put it, we fell “off a cliff”.

The International Arctic Research Center (IARC) has prepared a report, and it contains this chart. Not only does it reveal just how unprecedented this year's ice extent was, it also makes clear it didn't come from nowhere. Nobody expected a year like this, but the direction of the trend has been obvious for many years, as it has in the rest of the Arctic.

In early March there was a modest recovery in ice cover, but this reversed at the equinoix and by the end of April ice in the region was at just 10 percent of normal seasonal levels.

The report also reveals the reasons. South winds were much stronger than usual through the winter, bringing warm air with them, and driving warm (relatively speaking) water from the south-west against the coast of Alaska. Big storms caused serious damage to settlements like Little Diomede Island, and broke up the sea ice.

The familiar process where open water absorbs more heat than reflective ice set off a vicious circle.

There is reason to believe marine mammals that depend on ice to hunt will have suffered badly, but the IARC says the impact of this year's record is “not yet understood”. Analysis of the movements of animals carrying tracking devices should eventually tell us a lot.

It's a different matter for human populations in the area. For people from temperate regions, an unusually warm winter in Alaska might sound like a blessing, but life there depends on ice. “Travel between communities via boat or snowmachine was difficult and limited due to thin unstable sea ice,” the report notes. “At times there was not enough ice to harvest marine mammals, fish, or crabs. As a result of increased open water, storm surf flooded homes and pushed ice rubble onto shore.”

Of course, for oil companies looking to Arctic waters for more of the fossil fuels that created the situation in the first place, a longer drilling season is good news.