Is Climate Change affected by Cosmic Rays?

March 11, 2010 · Filed Under news · Comment 

Many people want to believe climate change isn’t happening and use arguments such as:

“The climate is actually affected by cosmic rays.”

 But what  does the science – and the Royal Society – say?

Cosmic rays are fast moving particles which come from space, and release electric charge in the atmosphere. Any effect that cosmic rays could have on the climate is not yet very well understood, but if there is one, it is likely to be small.

Experiments done in a laboratory hint that cosmic rays could play a role in the development of tiny particles that could in turn play a part in the formation of clouds. If this happens in the same way in the atmosphere – which isn’t proven – it might lead to more clouds, which generally have a cooling effect by reflecting the sun’s rays back into space. Whether the whole chain of processes actually occurs in the atmosphere is speculative, but some of the individual steps are plausible.

It has been proposed that this process would act to enhance the influences of the sun on the climate. We know that when the sun is more active it’s magnetic field is stronger and this deflects cosmic rays away from the earth. So the argument is that a more active sun would lead to fewer cosmic rays reaching the earth, resulting in fewer clouds and therefore a warmer earth.

However, observations of clouds and galactic cosmic rays show that, at most, the possible link between cosmic rays and clouds only produces a small effect. Even if cosmic rays were shown to have a more substantial impact, the level of solar activity has changed to little over the last few decades the process could not explain the recent rises in temperature that we have seen.