Christoph Schar of the Swiss Federal Institute of Technology in Zurich and his colleagues investigated the effects of greenhouse gases on weather variability as well as general overall temperatures. Their results suggest not only that temperatures in central Europe will rise over the next century but also that temperatures will show more variability. In this scenario, extreme summers like the one that befell France in 2003 are more common.
Our results demonstrate that the European summer climate might experience a pronounced increase in year-to-year variability in response to greenhouse-gas forcing, the scientists write. Such an escalation, they conclude, would strongly affect the incidence of heat waves and droughts in the future.