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Rain, rain...

The fallout of the much-debated phenomenon of global warming may not merely be a rise in temper- ature. it might result in devastating bouts of rainfall, say scientists at the US National Oceanic and Atmospheric Administration, Ashville, North Carolina, In a recent study. The days of "fight and moderate" rainfall over a prolonged period have come to an end. Countries of the northern hemisphere, especially the US, will now be hit by sporadic 1-day doudbursts of 50 rain or more.

The scientists analysed rainfall and temperature records dating since 1910, all over the US, China, Australia and the former USSR. They found, as average global temperature increased in recent decades, so did the 1-day heavy downpours.

"The modem warming (estimatad to be an approximately 0.50C rise in temperature) may have led to greater amount of evaporated moisture In the air,- speculates Thomas R Karl, lead author of the study. And the smaller gap between highs and laws would mean less opportunity for moisture release, until an atmospheric disturbance prompt& a sud. den, dramatic storm. That could help explain rainfall pattern shifts towards more inf requentr extreme downpours.

Some experts, however, don't buy this theory. 'The precipitation effects that Karl's team found are extremely small." says Patrick I Michaels, a Virginia-based chmatolagist. The change, even If it occurs, would be modest enough to go unnoticed by the average person, he contends.

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