From the BBC:

Research has thrown further doubt on the notion that cosmic rays are a major influence on the Earth's climate.

The idea that modern global warming is due to changes in cloudiness caused by solar influences on cosmic rays is popular with "climate sceptics".

But scientists found changes in cosmic ray flux do not affect cloud formation - the second such report in a month.

Separately, other researchers have found that particles from space may affect temperatures at the poles.

Both pieces of research were presented here at the European Geosciences Union (EGU) meeting.