People in Britain have begun to think the unthinkable. That climate change is actually here.

As huge swaths of the country are under water, with many communities without power or water people are asking whether this is a freak of nature or this is climate change. In may places over a month’s rain fell in one to two hours.

Well now the Independent has said a major new scientific study later this week will reveal that the heavier rainfall is being caused by climate change.

These intense rainstorms across parts of the northern hemisphere are being generated by man-made global warming, the study has established for the first time ­ an effect which has long been predicted but never before proved.

The new study, carried out jointly by several national climate research institutes using their supercomputer climate models, including the Hadley Centre of the UK Met Office, does not prove that any one event, including the rain of the past few days in Britain, is climate-change related.

But it certainly supports the idea, by showing that in recent decades rainfall has increased over several areas of the world, including the mid-latitudes of the northern hemisphere, and linking this directly, for the first time, to global warming caused by human emissions of greenhouse gases.

The study is being published in the journal Nature on Wednesday, and its details are under embargo and cannot be reported until then. But its main findings have caused a stir, and are being freely discussed by climate scientists in the Met Office, the Hadley Centre and the Department for Environment For Environment, Food and Rural Affairs.

One source familiar with the study’s conclusions said: “What this does is establish for the first time that there is a distinct ‘human fingerprint’ in the changes in precipitation patterns ­ the increases in rainfall ­ observed in the northern hemisphere mid-latitudes, which includes Britain.

“That means, it is not just the climate’s natural variability which has caused the increases, but there is a detectable human cause ­ climate change, caused by our greenhouse gas emissions. The ‘human fingerprint’ has been detected before in temperature rises, but never before in rainfall. So this is very significant.”