2003 summer hottest in 500 years

Thousands of deaths were blamed on the heatwave

European researchers say last summer was the hottest on the continent for at least five centuries.

"When you consider Europe as a whole, it was by far the hottest," said Juerg Luterbacher of the University of Bern, Switzerland.

According to the study, published by this week's Science magazine, European winters are also getting warmer.

Average winter and annual temperatures during the past three decades were the warmest for 500 years, it says.

Mr Luterbacher and his team collected data from all over Europe to analyse the continent's temperature history.

"We don't make any analysis of the human influence... We only report what we find Climatologist Juerg Luterbacher

Their information included readings from tree rings and soil cores from the year 1500.

According to their study, there have been weather trends in both ways - towards cool and hot - in the last five centuries.

The second hottest summer in the period was in 1757, which was followed by a cooler spell.

Coolest summer

The year 1902 witnessed the coolest summer of the last 500 years.

Researchers report "an exceptionally strong, unprecedented warming trend" since 1977, resulting in last summer's heatwave.

Authorities in various European countries say thousands of people died last summer due to excess heat.

The Swiss study does not cover the controversial subject of human influence on climate change.

"We don't make any analysis of the human influence," Mr Luterbacher said.

"We don't attempt to determine the cause. We only report what we find."