Global warming caused by greenhouse gas emissions has triggered heavy downpours in the UK, a group of leading scientists has reported, in a study presenting the strongest case yet that rainfall has been altered by human behaviour.

Scientists were unable to attribute the UK's floods over the past few weeks directly to climate change, as similar events have happened naturally in the past, but they have found a significant increase in rainfall in the regions north of 50 degrees of latitude, which includes the UK, Europe, Canada and Russia over the past century.

Nathan Gillett, lecturer in climate at the University of East Anglia, and co-author of the study, said: "While our study shows a human influence on rainfall at the global scale, the role of human influence in the recent UK flooding remains uncertain."

More research was being carried out to discover how the British climate was affected by global warming.

But the scientists' findings, in a paper entitled Detection of Human Influence on 20th Century Precipitation Trends, published in the peer-review journal Nature, suggest that rising greenhouse gas emissions are likely to bring greater increases in rainfall to the UK in the future.

Peter Stott, climate scientist at the University of Reading and one of the paper's authors, predicted that global warming would bring even greater increases in rainfall: "In the UK, wetter winters are expected, which will lead to more extreme rainfall, whereas summers are expected to get drier. However, it is possible under climate change that there could be an increase of extreme rainfall even under general drying."

Scientists warned that there was a greater risk of flooding this winter even if there were not as much rainfall than in recent weeks. The floods of the past few days could herald a winter of flooding, Barnaby Smith of the Centre for Ecology and Hydrology said, because the ground would be much wetter than normal at the start of winter.

"In the medium term it is likely that soils will remain wetter than the seasonal norm. This will lead to an early onset of the normal seasonal recovery of ground water levels in the autumn. This may be good news from a water resources perspective, but is likely to herald a longer winter flood season."

Climate experts called yesterday for research into the effects of climate change on rainfall and flooding. Chris Huntingford, climate modeller at the Centre for Ecology and Hydrology, said: "It has now been confirmed that the burning of fossil fuels has altered rainfall patterns at the global scale.

"Next we need to understand how these observed large-scale adjustments tranlsate to local changes in extreme rainfall events. Following that, we must project into the future to see how continued emissions of carbon dioxide may lead to further local rainfall changes."

The changes to rainfall patterns resulting from emissions were not detected in previous scientific studies because these tended to rely on global averages for rainfall. But increases in rainfall in some regions over the past century have been balanced out by less rainfall in others, so the averages have not told the whole story. This week's study looked in detail at regional precipitation patterns.

The study's findings were in line with those envisaged in the computer models that scientists use to predict climate change.