Global warming is generating heavier rainfall over Britain of the sort that has triggered this week’s floods, scientists have confirmed for the first time.

While it has long been suspected that climate change is contributing to increased precipitation over midlatitude countries such as Britain, research has now conclusively linked greenhouse gases to heavier downpours.

The findings, from an international team including several British scientists, do not prove that this week’s flooding is the direct result of global warming: it is linked to weather patterns that have been known before.

It is consistent, however, with a much broader trend towards more rainfall, on which researchers have now found an unambiguously human fingerprint.

“The paper is saying there is a significant human influence on global rainfall patterns and this includes an increase of precipitation north of 50 degrees northern latitude, an area that includes the UK,” said Peter Stott, a climate scientist at the University of Reading who took part in the study.

In the study, which is to be published in the journal Nature, the scientists compared recorded changes in rain and snowfall over land with changes that are predicted by climate models that account for global warming caused by greenhouse gases.

The actual pattern of changes, with increased precipitation in latitudes north of 50 degrees, corresponds remarkably closely with the patterns that emerged from 14 different models. This suggests strongly that human-induced climate change has been responsible.

For the European region that includes Britain, the research team estimates that human activity has accounted for about two thirds of the observed trend. Other natural factors, such as volcanic activity, have also had an influence, but this is much smaller than that from people.

Dr Stott said that the study did not examine seasonal trends, but that other predictions suggest Britain will in general suffer wetter winters and drier summers, rather than multiple repeats of this year’s summer downpours, though significant uncertainties remain.

It is currently impossible to say whether the current bad weather is a result of global warming, and more research is needed into the origins of such extreme events.

“We looked at annual rainfall trends rather than any particular season,” Dr Stott said. “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.”

— There is no easy way to say this — summer is shaping up to be one of the most depressing in memory (Paul Simons writes). The weather forecast models for the next seven days look truly horrible, with more showers midweek and even more misery next weekend, with only brief respites. One ray of hope is a hint of some fine weather in early to mid-August, but even this may prove to be a false hope.

Britain is caught in something of a meteorological sandwich, stuck between high pressure systems to the north in Iceland and to the south in the Azores. Storm clouds are squeezing through a gap in between these two huge anticyclones, riding underneath the high altitude jet stream wind. The weather pattern is stuck in a rut and refuses to budge.

It is tempting to blame the appalling weather on climate change, which is believed to increase the chances of extreme rainfall events. But one wet summer on its own proves very little. In fact, the top ten wettest Julys all happened two or three centuries ago.

No, if there is a sign of climate change at work in all this misery it shows up in the truly remarkable temperatures this month. Despite all the rain, temperatures have averaged 15.5C (59.9F) for Central England up to July 22, only 0.5C below normal for the month. There is a good chance that without global warming we might be suffering an even worse summer.