Early warning for global disasters

The world's leading climate scientists are gathering in the United States this week to hammer out plans to set up an early warning system that would predict meteorological disasters caused by global warming.

The meeting, in Boulder, Colorado, has been arranged amid fears that storms, hurricanes, droughts, flooding and other extreme weather events now threaten to trigger devastation in coming decades.

A series of meteorological catastrophes have dominated headlines recently, while scientists have warned that figures suggest this year will be the hottest on record.

Recent events include a record-breaking heatwave that has seen Moscow blanketed with smog from burning peatlands, the splintering of a giant island of ice from the Greenland ice cap, and floods in Pakistan that have claimed the lives of at least 1600 people.

Scientists say such events will become more severe and more frequent over the rest of the century as rising greenhouse gas emissions trap the sun's heat in the lower atmosphere and bring change to Earth's climate and weather systems.

But their ability to pinpoint exactly where and when the worst devastation will occur is still limited. The aim of the Colorado meeting is to develop more precise predictive techniques.

"The events in Moscow and Pakistan are going to focus our minds very carefully when we meet in Colorado," said Peter Stott, head of climate monitoring at Britain's Meteorological Office.

The meeting in Boulder will be the first full session of Ace, the Attribution of Climate-related Events, which has been set up by scientists from the world's three leading meteorological organisations: the US National Centre for Atmospheric Research, the British Met Office and the US National Oceanic and Atmospheric Administration.

The aim, said Dr Stott, would be to develop a modelling package that would allow scientists to forecast the kind of events that the world has been witnessing over the past few weeks before they struck. The fact that the British Foreign Office has been closely involved in setting up Ace reveals how seriously the issue is taken by politicians.

Although meteorologists have developed powerful techniques for forecasting general climatic trends - which indicate that weather patterns will be warmer and wetter in many areas - their ability to predict specific outcomes remains limited. It is this problem that will be tackled as a matter of urgency at the Ace meeting in Boulder.

An example of the complexity that faces meteorologists is provided by the weather system that scorched Moscow, said Dr Stott.

"Moscow has a stable high pressure system over it, much like the one that brought a heatwave to Europe in 2003.

"However, for a while the land around the city acted as a natural air conditioner, keeping the air cool through evaporation of moisture from the ground. But the land eventually dried out and there was no more cooling. Hence the soaring temperatures."

To forecast an event like that, scientists need to be able to quantify all the variables involved and also develop a very precise model of the land surface, added Dr Stott.

"These are the sorts of things we need to understand. We need to be able to forecast events weeks or months ahead of their occurrence so that people can mitigate their worst impacts ... Certainly, one thing is clear: there is no time to waste. The effects of global warming are already upon us."

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