Link between cosmic rays and global warming fanciful

Article on EnvironmentalResearchWeb includes:

In recent years much publicity has been given to the work of two groups of scientists - E Palle Bago and CJ Butler from the Armagh Observatory in Northern Ireland and N Marsh and H Svensmark from the Danish Space Institute - who observed that the amount of low altitude cloud seems to follow changes in the rate at which cosmic rays fall on Earth. ... Is this the "New Effect" which is needed to produce global warming if we assume that the models of the effects of greenhouse gases are wrong? ...

The first test of the potential "New Effect" that we did was to see if the decrease in cloud cover at the cosmic ray minimum in 1990 became more pronounced away from the Equator. This should happen if cloud cover is influenced by ionization from cosmic rays. We found that the dip in cloud cover does not change significantly in moving from the Magnetic Equator (figure 3). The line labelled NM, from neutron monitors used to measure the cosmic ray rate, shows how the depth of the cosmic ray dip increases on moving away from the Magnetic Equator (i.e. moving from right to left) . The dip in cloud cover should follow this line if cosmic rays influence cloud cover. So this observation does not corroborate the conclusion that changing cosmic rays are a significant cause of cloud cover. ...

The second test we performed was to study short-term changes in the cosmic ray rate to see if they could produce short-term changes in cloud cover. None were observed and this again provided no evidence to corroborate the proposal that cosmic rays are connected with cloud formation, implying that cosmic rays do not contribute significantly to global warming.

To conclude, we could find no evidence that changing cosmic ray rates contribute significantly to changing cloud cover and thereby to global warming. Therefore, cosmic rays are not the new effect that would allow us to declare that the IPCC is wrong. So it is back to cutting our greenhouse gas emissions if we are to avoid the future problems foreseen from climate change.

Could">]Could cosmic rays cause global warming?

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