Climate@home

Although personal computers use more than 8% of the US electricity market, most of the time they have nothing to do. Now a UK research consortium has launched the Web site climateprediction.net to improve the accuracy of climate simulations by harnessing that idle computer power.

The new site originated when Myles Allen of Oxford University wrote a commentary in Nature (volume 401, p. 642, 1999) calling on the science community to exploit home computers for research. Allen’s article was inspired by the SETI@home project, which now harnesses nearly 5 million home computers to process radio signals in the search for extraterrestrial life (see Physics Today, October 1997, page 96 ). Eventually, the UK’s main weather forcaster, the Exeter-based Met Office, worked on the project with the Rutherford Appleton Laboratory, Tessella Support Services, Oxford and Reading universities, and the Open University. So far, more than 50 000 individuals have registered on the Web site.

Visitors to climateprediction.net who run the Microsoft Windows operating system are invited to install a small program, nicknamed climate@home, onto their computers. The program contains a highly regarded climate model produced by the Met Office. Every version of climate@home that is downloaded has slightly different conditions in the climate model, which runs quietly in the background when the computer is not being used. Once the program has finished running—which can take between 10 and 22 days, depending on the speed of the machine and the length of time the computer is left on—the results are automatically sent back to the Web site for analysis and displayed on the user’s screen.

By running the model thousands of times with slightly different variables, the consortium hopes to find out how sensitive the Met Office model is to temperature and to atmospheric and biological processes such as the carbon cycle. “In the past, estimates of climate change have had to be made using one or, at best, a very small ensemble—tens rather than thousands—of model runs,” says Mat Collins, a Met Office climate scientist. “This experiment will give us the most comprehensive assessment of future climate change.”