sydney • Rainfall will be abundant in key parts of the Middle East in future, according to a new study of climate change in the region, contrary to earlier projections.

Recent projections by the Intergovernmental Panel on Climate Change (IPCC) had raised fears that storm activity in the eastern Mediterranean would decline this century if global warming continues on present trends. In turn, that would have reduced rainfall by between 15 and 25 percent over a large part of the so-called Fertile Crescent in the Middle East. The area encompasses parts of Turkey, Syria, northern Iraq, and northeastern Iran and the strategically important headwaters of the Tigris and Euphrates rivers.

When University of New South Wales researcher Jason Evans analysed the IPPC projections, he found that the region's agricultural base faced significant challenges as a result.

About 170,000 square km of viable rain-fed agricultural land would be lost; a longer dry season would limit grazing on rangelands; and changes in the timing of maximum rainfall would force farmers in northern Iran to change cropping strategies and even crop types.

But the IPCC projections were based on the results of global modelling of climate change, which tends to obscure smaller-scale regional effects.

"The global models are good for investigating what's likely to happen on a planetary scale but the resolution is quite coarse when looking at a more localised regional scale," Evans informed. "It's a bit like enlarging a digital photograph until it becomes pixellated and all sorts of detail is blurred out."

In a far more detailed study, Evans used regional climate modelling specific to the Middle East, and the result was very different. It emerged that while storm activity over the eastern Mediterranean would indeed decline, moisture-bearing winds would be channelled inland more often and diverted by the Zagros Mountains, bringing an increase of over 50 percent in annual rainfall to the Euphrates-Tigris watershed.

"A 50 percent increase in rainfall in such an important agricultural area is certainly a more hopeful scenario than a 15 percent decline," said Evans.