Science and Technology Correspondent
Slowing down the effects of global warming will depend on getting Western countries to stabilise their use of fossil fuels and limiting the use of such fuels by developing giants such as China, say scientists and pressure groups. Their calls follow the latest report by the United Nation's Inter-governmental Panel on Climate Change (IPCC) in Madrid, which said rises in global temperatures exceed natural variation.
Evidence that global warming is under way in earnest has been building up in the past year, amidst a number of notable changes in weather patterns. While Britain revelled in one of the longest, hottest and driest summers on record, other parts of the world suffered.
In the US a heatwave in Chicago caused a number of deaths, especially among the elderly. Pacific Ocean countries endured a record number of typhoons, while the Atlantic spawned hurricanes well into October - the season usually ends in September. Spain suffered a drought. Storms, cyclones, floods and natural disasters are reckoned to be costing insurance companies 14 times more than they were 30 years ago.
A number of countries also saw unusual flora and fauna: hammerhead and thresher sharks were caught in the Channel for only the second time this century, while in Britain birds, insects and plants were found further north than usual.
Global warming is now reckoned to have increased average temperatures worldwide by 0.5C in the past 100 years. But scientists believe this gradual change is causing abrupt changes in weather systems. "Rising temperatures might mean that events like the hurricane which hit Britain in 1987 will happen more frequently," said David Viner, a senior researcher at the Climatic Research Unit at the University of East Anglia (UEA). "And as sea levels rise, floods that might have happened once every 50 or 100 years will be more likely. Most floods are actually caused by surges rather than gradual rises in the sea level."
Now that the IPCC has agreed at this week's meeting that global warming is occurring, scientists are trying to predict the rise in sea levels expected as glaciers melt and the seas expand.
"It's very difficult to predict with any accuracy," said Dr Viner, one of the UEA team which investigated the topic in a 1992 report for the pressure group Greenpeace. "For Britain, you might get a rise in mean sea level of 10cm off East Anglia, yet of 20cm off Northern Ireland because there is also the movement of undersea tectonic plates and localised warming of the sea to take into account."
But slowing down global warming will prove hard, scientists agree. Predictions based on the best models available suggest that mean surface temperatures will rise by between 1C and 3.5C by 2100.
"Governments have to take on policies to reduce emissions of carbon dioxide, methane and oxides of nitrogen, which are all greenhouse gases," said Dr Viner. However, developing countries such as China and India pose a huge problem for Western governments eager to impose cuts in emissions by reducing the use of coal, gas and oil-fuelled power stations and road vehicles. A Greenpeace spokeswoman said: "These countries are saying 'You benefited from industrialisation over the last 100 years - now it's our turn'."
China is understood to be opening an average of two coal-fired power stations every week as it sprints towards a capitalist economy. "China has massive coal reserves and wants to exploit them," said Dr Viner. "Who will pay for it not to?"
Pressure groups for the nuclear lobby have argued for years that nuclear power does not contribute to global warming. However, environmental groups, as well as some Western governments, oppose the spread of nuclear technology. And as Dr Viner said: "It has its own associated environmental problems."
Western governments aiming to stabilise and then reduce emissions of greenhouse gases may start by putting economic pressure on modes of power generation and transport which are comparatively polluting. For example, aircraft create eight times more pollution than cars, and 22 times more than electric trains, per passenger mile.
Some countries whose economies depend on fossil fuel exports are still fighting a rearguard action against the suggestion that the rise in global temperatures is due to humans. But Geoff Jenkins, head of the climate prediction programme at the UK Meteorological Office, said: "There's no argument that in the past 100 years global temperatures have risen. The argument is now only how much man has influenced that. But all our simulations now point to humans being the cause of warming. There is natural variability as well. It's just a question of the proportion."