Summers In EU Set To Destabilize - Expect More Wet, Dry Extremes - AFP

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Continental Europe's extreme summers of recent years, characterised by heavy floods or killer heatwaves, could be commonplace by the turn of the century, a climate study says. Its authors believe that changes in the complex relationship between air temperature and land moisture, driven by global warming, will cause European summers to suffer from chronic variability by 2100.

Publishing on Thursday in the weekly British science journal Nature, the Swiss research team say that the hot, dry climate zone of the Mediterranean rim is destined to creep northwards as temperatures rise. As a result, central and eastern Europe will suffer a "positive feedback mechanism" -- in essence, a vicious circle in which higher temperatures cause the soil to evaporate more and vegetation to breathe out more moisture.

In damp regions, more airborne moisture and warm air help to fuel the precipitation cycle, causing more and more rainfall and thus boosting the risk of flooding. But in dry regions, moisture is swiftly driven out of soil and plants, leaving nothing to cool the atmosphere. As a result, the effects of a heatwave worsen.

Complicating this process is the likelihood that as the climate changes, the vegetation that it supports will change, too. For instance, in drier areas, forests may be replaced by scrubby, heat-loving plants, and this in turn will affect the moisture-atmosphere exchange.

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