A study released Wednesday by the WMO -- a specialized climate science agency of the United Nations -- says the world is experiencing record numbers of extreme weather events, such as droughts and tornadoes.

Laying the blame firmly at the feet of global warming, the agency warned that the number and intensity of extreme weather events could continue to increase.

Citing examples, the WMO said the 562 tornadoes which hit the United States in May this year was a record -- far higher than the previous monthly peak of 399 in June 1992.

Far colder and wetter conditions than normal also prevailed in the eastern and southeastern part of the U.S. for much of May and June.

And a pre-monsoon heatwave which hit India earlier this year caused peak temperatures of between 45 and 49 degrees Celsius (113 to 120 degrees Fahrenheit), killing more than 1400 people.

In Sri Lanka, heavy rainfalls from Tropical Cyclone 01B exacerbated already wet conditions, causing flooding and landslides and more than 300 fatalities.

Last month Switzerland experienced its hottest June in at least 250 years while in the south of France average temperatures were between 5 and 7 degrees Celsius (9 to 13 degrees Fahrenheit) warmer than the long term average.

England and Wales also experienced their hottest month since 1976.

On their own none of these events is truly remarkable. But when viewed together they represent a clear and alarming trend towards wilder weather, according to the WMO.

"These record extreme events [high temperatures, low temperatures and high rainfall amounts and droughts] all go into calculating the monthly and annual averages which, for temperatures, have been gradually increasing over the past 100 years," the WMO said in its statement.

Warning

However, the weather events of 2003 had proved so remarkable, officials say the organization felt compelled to issue a generalized warning of the emerging pattern.

The WMO said new analysis of data for the northern hemisphere showed the increase in temperature in the 20th century was likely to have been the largest in any century during the past 1,000 years.

"It is also likely that, in the northern hemisphere, the 1990s were the warmest decade and 1998 the warmest year," it said.

"While the trend towards warmer globally averaged surface temperatures has been uneven over the course of the last century, the trend for the period since 1976 is roughly three times that for the past 100 years as a whole.

"Global average land and sea surface temperatures in May 2003 were the second highest since records began in 1880," the WMO warned.

Last year much of Australia was hit by the longest drought in recorded history, which devastated crop yields and sparked continual bushfires which threatened major cities.

Conversely, many parts of China and East Asia were hit by severe flooding resulting in thousands of deaths.