Variations in solar activity, including cosmic rays, are not responsible for recent planetary warming. A major study in Proceedings of the Royal Society A, “Recent oppositely directed trends in solar climate forcings and the global mean surface air temperature” found:
There is considerable evidence for solar influence on the Earth’s pre-industrial climate and the Sun may well have been a factor in post-industrial climate change in the first half of the last century. Here we show that over the past 20 years, all the trends in the Sun that could have had an influence on the Earth’s climate have been in the opposite direction to that required to explain the observed rise in global mean temperatures.
Take that, Denyers (and you, too, Deniers).
The researchers looked at both solar output and cosmic ray intensity over the last few decades and compare those trends with the global average surface temperature record.
Britain’s Royal Society said in a statement:
At present there is a small minority which is seeking to deliberately confuse the public on the causes of climate change. They are often misrepresenting the science, when the reality is that the evidence is getting stronger every day.