GENEVA — There is growing evidence of a link between global warming and natural disasters such as droughts and flooding, the head of the World Meteorological Organisation (WMO) said on Friday.

But Michel Jarraud, secretary general of the United Nations weather agency, said more research was needed into the links between global warming and extreme conditions like hurricanes.

Jarraud told a news briefing: "We know for certain that there is an intensification of the hydrological cycle, which translates into greater risk in some areas of a rain deficit and accentuated problems of drought linked to climate change."

"In other regions there is a higher risk of flooding and in others a risk of greater frequency of heat waves," he said.

The WMO said last week that greenhouse gases including carbon dioxide -- blamed for global warming and climate change -- had reached their highest levels in the atmosphere.

Scientists warn that greenhouse gas emissions must be slowed and reduced if the earth is to avoid climatic havoc with devastating heat waves, droughts, floods and rising sea-levels sinking low-lying island states and hitting seaboard cities.

Carbon dioxide, which the WMO says accounts for 90 percent of warming over the past decade, is largely generated by human activity involving the burning of fossil fuels.

"We must accentuate research efforts to better understand the links between climate change and a certain number of extreme phenomena," Jarraud said.

He noted 2005 was a record year for hurricanes in the Atlantic Ocean, including Hurricane Katrina which devastated New Orleans.

"There is not yet a consensus in the scientific community on the link between hurricanes and global warming, but there are leads. I am fairly confident that in two or three years we will have more credible answers," Jarraud said.

Research into the link between climate change and El Nino could take five years, he added.

El Nino, caused by interaction between abnormally warm or cool seas and the atmosphere, typically triggers drought in eastern Australia and Southeast Asia, and floods in western parts of North and South America.

Source: Reuters