The IPCC claims that man-made CO2 [less than 5% of CO2 emissions; 95% are natural] drives the water cycle to cause enhanced warming of the Earth.
In the video lecture below, Emeritus Professor of Geology Dr. Jan Veizer shows using data from arid and wet regions of the globe that the CO2 carbon cycle instead piggybacks on the water cycle, and that the water cycle is in turn modulated by solar activity. Professor Veizer demonstrates minimums in solar activity are followed by decreased precipitation, and that proxy data shows climate follows changes in solar activity, not CO2 levels.
Prof. Dr. Jan Veizer
Department of Earth Sciences, University of Ottawa