New research has concluded that the Sun’s output is not the cause of current climate change. The study has shown that the Sun’s output has decreased over the past 20 years with temperatures on Earth rising over the same time period.

In the past, temperatures have also been blamed by the Sun’s effect on cosmic rays. The study states that although climate may have been affected by cosmic rays in the past, they have not had an affect on current day climate.

Dr. Mike Lockwood and Claus Froelich are the two scientists behind the report. Dr. Lockwood said that part of his interest in the research was fuelled by the TV documentary ‘The Great Global Warming Swindle’ which featured the cosmic ray theory.

Talking to the BBC, Dr. Lockwood said, “All the graphs they showed stopped in about 1980 and I knew why - because things diverged after that. You can’t just ignore bits of data that you don’t like.”

The research looked at solar output and cosmic ray intensity over the last 40 years, comparing any trends they found in these areas with global average surface termperatures (which have increased by 0.4 degrees in the same period).

The Sun works on a 11 year cycle where activity fluctuates. This cycle sits on top of longer-term trends. Most of the 1900s showed a slow, steady increase in solar output however in 1985, this trend changed and solar output started to decline. During this downward trend, temperatures have continued to rise at the same rate, or even faster, as the previous 100 years. This indicates that solar activity has not caused all the warming in the past 40 years.

The IPCC brought out a report in February which concluded that greenhouse gases were about 13 times more responsible for rising temperatures than solar changes. The paper came under fire from many quarters for not factoring in the cosmic ray theory, however this new research appears to back the IPCC’s decision not to include the theory.

The cosmic ray theory states that cosmic rays help clouds to form by providing tiny particles on which water vapour can collect. These clouds, when formed, then help to cool the Earth down. When there is a lot of solar activity, cosmic rays are partially blocked by the Sun’s increased magnetic field. This means less clouds are formed therefore the Earth warms up.

Mike Lockwood himself is a believer in the cosmic ray theory however he doesn’t believe it has had an effect on recent temperatures. “I do think there is a cosmic ray effect on cloud cover,” he remarked. “It works in clean maritime air where there isn’t much else for water vapour to condense around. It might even have had a significant effect on pre-industrial climate. But you cannot apply it to what we’re seeing now, because we’re in a completely different ball game.”

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