The numbers of wasp stings is rising in Fairbanks, the largest city in the interior of Alaska.

Wasps used to be an uncommon sight in Fairbanks until two years ago. Then huge numbers of them swarmed on the city, ten times more than normal. The number of stings grew so bad that outdoor school events were cancelled, 178 patients were treated in hospital for stings and two people died.

A study now reveals that wasp stings across northern Alaska have increased sevenfold over the past few years.

And they are also occurring farther north than ever before. In 1994 a wasp was found inside the Arctic Circle of Canada, causing huge excitement among the local Inuit community, who had never seen one before and had no word for wasp. So bizarre was the sight that the local radio station had to broadcast warnings not to touch it.

These are yet more worrying signs of climate change. Large parts of the Arctic are warming up more rapidly than anywhere else on Earth. Many roads, power lines and buildings that were built on permafrost (frozen ground) are now subsiding as the ground melts. And as frozen tundra thaws it releases huge amounts of methane that add to the global warming problem.