Tourists chill out on tundra

Winds bring change to Alaskan winter.

A drop in wind speed may be boosting Alaska’s tourist trade. Some parts of the tundra feel five degrees warmer than they did 50 years ago, even though average winter air temperatures have risen only by one or two degrees since then, new research finds¹. This local trend hints that forecasts of the impacts of climate change may need to account for wind as well as temperature.

The temperature can still plummet to -40 °C in winter, but wind chill in most parts of Alaska and western Canada has fallen, say Frank Keimig and Raymond Bradley, climate scientists at the University of Massachusetts in Amherst.

Wind chill is a mathematical relationship between temperature and wind speed that describes the apparent temperature the body feels. Cool air carries heat away from the body; so to bare skin 0&176;C in a 30 mile an hour wind feels like -26&176;.

In most parts of Alaska and western Canada “it’s now a bit more comfortable in the winter months”, says Keimig. The duo analysed winter wind speeds and air temperatures between 1953 and 1999 from 15 locations across Alaska and Canada.

Slightly higher temperatures and lower winds have pushed up the apparent temperature in most parts, they find. In some regions, lower winds alone are responsible for the warming. Winds in eastern and northern Canada have changed little, though, and temperatures here have actually fallen slightly since the 1950s.

Weather watchers in Fairbanks, deep in the frosty Alaskan interior, agree that Keimig and Bradley are on to something. “It is feeling warmer in Alaska,” says Gerd Wendler, director of the Alaska Climate Research Center.

Measurements from Wendler’s institution also show lower wind speeds in the region. Wendler points out, however, that winter temperature increases have been getting smaller since about 1980, so the trend might not continue.

Whether or not Alaska’s falling wind is of global significance, it could well be affecting lifestyles in the region. There are more people outdoors, says Wendler: “Some winter tourism has even started over the past decade.”

He’s cautious about jumping to conclusions, however. “How much of this was caused by the observed climatic change, and how much by improved outdoor gear and the increasing popularity of snowmobiles, is hard for us to judge,” he says.

Model behaviour

Keimig and Bradley’s findings tell us little about climate in general, says Jean Palutikof of the Tyndall Centre for Climate Change Research in Norwich, England. “Wind chill is just about how you feel, not a physical measure of how the climate is doing,” she says.

But for scientists who are interested in the impacts of climate change on life, the finding hints that potentially important trends, such as wind chill, may be getting overlooked. Most existing climate models cope well only with temperature data, says Palutikof; new models are being designed to account for how winds might change.

References

1. Keimig, F. T. & Bradley, R. S. Recent changes in wind chill temperatures at high latitudes in North America. Geophysical Research Letters, published online (2002).