Greeny News

But the intensity of cosmic rays striking the Earth varies. When the sun is more active today, creates the stream of particles it produces, known as the solar wind, a stronger magnetic field deflects cosmic radiation. This means that less gets into the atmosphere.

"Our work leaves open the possibility that the cosmic radiation could influence the climate. But at this stage, there is absolutely no way we say that they can do," said Kirkby.

Philip Bull, of the Climate Processes Group at Oxford University, heads, said the study was "an experimental leap forward", but it was too early to discuss the implications for climate models or climate in general to speculate. He added that the study would inspire more research in this area.