Climate change: Cold comfort | The Economist

By the end of this century, maybe much sooner, there will be frequent Arctic summers with almost no sea ice at all.

The science: Uncovering an ocean | The Economist

...According to the IPCC, the last time the polar regions were significantly warmer was about 125,000 years ago...

Biodiversity: Pity the copepod | The Economist

Up to 20% of the tundra is estimated to have switched to a boreal-forest climate since the 1980s.

Biodiversity: Pity the copepod | The Economist

How badly the bears will be hit by global warming is unclear. There is little evidence to support claims of bears drowning as the ice melts, but assertions that they are thriving are also nonsense. By one estimate, they gain two kilograms of body weight a day out on the ice, feasting on seals, and lose a kilogram a day on shore, scavenging for barnacle goslings and eggs, as the dearth of sea ice is increasingly forcing them to do.

The polar bear should not become extinct. Recent DNA testing, reported in Science in April, suggests that the species is 600,000 years old, much older than previously thought. That means it would have survived previous warm spells when there was probably less summer sea ice than there is today. But the DNA tests also provided evidence of evolutionary bottlenecks when polar bears were reduced to very low numbers, very likely in those same hot spells. That may happen again.

A record of the swimming feats in the Beaufort Sea of 52 polar bears fitted with radio collars, published in the Canadian Journal of Zoology in May, shows their resilience to reduced sea ice. A third of the bears logged swims of over 50km, and one swam 350km over nine days. But she lost 22% of her body mass and her cub drowned.  [How, specifically, does anyone know that the cub drowned?]

One man and his dogs | The Economist

The Inuit represent less than half the Arctic’s indigenous people, who in turn account for only 10% of the region’s population. Yet they still hog the headlines because their culture is under attack from climate change. So is that of Arctic herders, such as the Sami of Russia and Scandinavia, whose reindeer populations are crashing as the tundra thaws. Yet the Inuit’s plight is especially graphic. No sea ice means no seal hunt, which can mean no meat for sled-dogs.

They are also suffering a wider cultural decline that shows up in a high incidence of alcoholism, obesity and suicide. In Russia, where indigenous people get no special recognition, the outlook for all Arctic people is grim. Yet elsewhere the Inuit—by the admittedly miserable standards of indigenous peoples—are pretty well off. Because Europeans came late to the Arctic, the Inuit got rights, not smallpox-infected blankets. In Alaska most have a share in local companies, often worth several thousand dollars a year in dividends. Most Canadian Inuit, following a landmark reform in 1986, live in semi-autonomous provinces, with pipeline and mining revenues.