That's the alarming prediction of British scientists who have carried out the first detailed research into Europe's June-August 2003 blaster.

Delving into climate records, the British team say 2003 was the hottest summer in southern, western and central Europe in at least five centuries.

From the eastern Atlantic to the Black Sea, the mercury was 2.3 Cabove the norm.

The event was such a statistical freak that, if carbon pollution in Earth's atmosphere remained at today's levels, it would take place only once every 250 years.

But: the heatwave will no longer be an anomaly just a few decades from now if the machinery of global warming continues to build up speed, they estimate.

The world's six billion humans are disgorging so much greenhouse gas from fossil fuels that a red-hot summer will soon become commonplace in Europe, they say.

According to their projection, crunched through one of the world's top models for climate change, by the 2040s at least one European summer in two will be hotter than in 2003.

"By the end of this century, 2003 would be classed as an anomalously cold summer relative to the new climate," the scientists write in the British weekly journal Nature, published on Thursday. Summer in 2100 will, on average, be some 6 C (10.8 F) hotter than today.

Separately, scientists at the French meteorological agency Meteo France told AFP that they expect summer temperatures in France to rise by between 4 and 7 C (7.2-12.6 F) by 2100.

"By the end of the century, a summer with temperatures as we had in 2003 will be considered a cool summer," said researcher Michel Deque.

If such estimates become true, Europe faces wrenching challenges to adapt -- and an astronomical price tag if it fails.

According to an international Red Cross report issued in October, the 2003 heatwave claimed up to 30,000 lives, many of them elderly people who died of dehydration and heat stress.

Estimates by the insurance industry say the drought conditions caused crop losses of 12.3 billion dollars, in addition to losses of 1.6 billion dollars from forest fires in Portugal alone.

The British findings are based on an updated computer model run by the Hadley Centre of Britain's Met Office, while the French findings are derived from a European project, Prudence, which is based on 10 different European models, including the Hadley Centre's.

Both are based on the so-called A2 scenario, in which atmospheric levels of carbon dioxide (CO2) will roughly triple compared to pre-industrial levels.

This is also called the "business as usual" scenario, in other words, if greenhouse gas emissions continue to increase at present rates.

It does not take into account efforts to curb pollution through international treaties, like the Kyoto Protocol, which is due to take effect from February 16 next year but will, at best, simply stabilise emissions among industrialised signatories.

"If the greenhouse gas levels are reduced, there will be a corresponding impact on temperatures," lead author Peter Stott, of the Hadley Centre for Climate Prediction and Research at Britain's Met Office, told AFP.

CO2 concentrations stand at 379 parts per million (ppm), according to measurements taken in March at a US observatory on Hawaii, which put the year-on-year increase at three ppm. This compares with the yardstick of 280 ppm of pre-industrial times.

Greenhouse gases are so called because they hang in the atmosphere like an invisible blanket, trapping heat from the Sun instead of letting it radiate out to space.

This warms the atmosphere, the sea and the land, with potentially major effects on the delicate climate system.

The UN's Intergovernmental Panel on Climate Change (IPCC) estimates a global temperature rise of between 1.4 and 5.8 C (2.5-10.4 F) by 2100 according to different CO2 levels.

But this is averaged out around the world and does not include regional variations, which may be very great.

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