- The most immediate cause of climate changes would be changes in the total irradiance of the Sun.
"The new findings once again clearly underscore that the last several thousands of years are characterized by natural temperature cycles that are controlled by fluctuations in solar activity (see p. 68-75 in ‘Die kalte Sonne’). The logical continuation of these natural cycles through today shows that an important part of the warming of the last 150 years has to be attributed to the increase in solar activity. It is not a mere coincidence that the last decades have been the most solar active of the last 10,000 years.
The climate models used by the IPCC are not able to reproduce these millennial cycles because they assign only a very small climate impact to the sun. Also the recently introduced new climate model from the Max Planck Institute in Hamburg suffers from the same deficiency, and thus the results of that model are essentially unrealistic.”