Global weather extremes set to worsen

US: A monsoon dropped 35.6cm (14in) of rain in one day across many parts of South Asia this month

US:A monsoon dropped 35.6cm (14in) of rain in one day across many parts of South Asia this month. Germany had its wettest May on record, and April was the driest there in a century. Temperatures in Bulgaria reached 45 degrees last month and 32 degrees in Moscow in late May, shattering longtime records.

The year still has almost five months to go, but it has already experienced a range of weather extremes that the United Nations' World Meteorological Organisation (WMO) says is well outside the historical norm and is a precursor of much greater weather variability as global warming transforms the planet.

The warming trend confirmed in February by the Intergovernmental Panel on Climate Change (IPCC) - based on the finding that 11 of the past 12 years had higher average ground temperatures than any others since formal temperature recording began - appears to have continued with a vengeance in 2007. The WMO reported that January and April were the warmest worldwide on record.

"Climate change projections indicate it to be very likely that hot extremes, heatwaves and heavy precipitation events will continue to become more frequent," the organisation reported on Tuesday.

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The heavy rains in South Asia have resulted in more than 500 deaths and displaced 10 million people, and 13.5 million Chinese have been affected by floods, the report said.

In England and Wales, the period from May to July was the wettest since record-keeping began in 1766, resulting in floods that killed nine and caused more than €4 billion in damage.

The WMO, which is a co-sponsor of a series of meetings and reports on global climate change, is putting together an early-warning system for climate extremes and is establishing long-term monitoring systems and plans to help the countries most vulnerable to climate change.

"The average northern hemisphere temperatures during the second half of the 20th century were very likely the highest during any other 50-year period in the last 500 years, and likely the highest in the past 1,300 years," the report said.

The warming of the globe is expected to result in more extreme weather because of changes in atmospheric wind patterns and the ability of warmer air to hold more moisture, according to Martin Manning, head of the IPCC's working group on the physical science of climate change.

He said that 12 months of heavier-than-normal rains and warmer-than-usual temperatures say nothing definitive about climate change, but they are consistent with the long-term predictions of the IPCC.

"What we have projected is an increase in extreme events as the global temperatures rise," Mr Manning said. "Floods, droughts and heatwaves are certainly consistent with that."

The IPCC has also predicted that temperate zones such as Europe and the United States are likely to become more prone to flooding, while areas closer to the equator will experience more drought.

According to the WMO report, the extreme weather occurred in many parts of the world.

In May, a series of large waves estimated at three to four metres (10ft to 12ft) in height swamped almost 70 islands in 16 atolls in the Maldive Islands off south India, causing serious flooding and extensive damage.

Halfway around the globe, Uruguay was hit during the same month by the worst flooding since 1959 - floods that affected more than 110,000 people and severely damaged crops and buildings.

Two months later, an unusual winter brought high winds, blizzards and rare snowfall to parts of South America.

The WMO is the United Nations' authority on weather, climate and water issues. The report was based on information supplied by WMO members and was completed with the collaboration of the US National Oceanic and Atmospheric Administration's National Climatic Data Center, Germany's National Meteorological Service and the Met Office in Britain.

A more comprehensive report on the world's weather will be released at the end of the year. - (LA Times-Washington Post service)