The Purdue University study suggests the increasing hot conditions will occur if the current rate of greenhouse gas emissions continues. However, a reduction of such greenhouse gases could reduce the intensification of dangerously hot days by as much as 50 percent.
"Rare events today, like the 2003 heat wave in Europe, will become much more common as greenhouse gas concentrations increase," said Assistant Professor Noah Diffenbaugh, who led the study. "The frequency at which that scale of event occurs at high greenhouse gas concentrations is staggering. Rare events become the norm, and the extreme events of the future are unprecedented in their severity."
That 2003 heat wave caused 15,000 deaths in France and nearly 3,000 in Italy.
The study covered the entire Mediterranean area's 21 countries in Europe, Africa and Asia. Major cities included Prague, Zurich, Bucharest, Athens, Istanbul, Tel Aviv, Cairo, Algiers and Casablanca.
The results of the study appear in the June 15 issue of the journal Geophysical Research Letters.