A paper published today in Environmental Research Letters corroborates the Svensmark cosmic ray theory of climate, whereby tiny 0.1% changes in solar activity are amplified via the effect on cosmic rays and cloud formation, which in turn may control global temperatures.
The authors find cosmic ray variations due to changes over solar cycles may have as much as 10 times larger effect than previous studies have estimated. The paper also finds that a tiny 0.2C temperature increase increases the cosmic ray induced cloud condensation nuclei by around 50%, thus acting as a natural homeostatic mechanism.
According to the authors, “The effect of solar cycle perturbation on [cloud condensation nuclei] based on present study is generally higher than those reported in several previous studies, up to around one order of magnitude [10 times]…Our global simulations indicate that a decrease in ionization rate associated with galactic cosmic ray flux change from solar minimum to solar maximum reduces annual mean nucleation rates, number concentration of cloud condensation nuclei larger than 10 nm… by 6.8%, 1.36%…respectively. The inclusion of 0.2 °C temperature increase enhances the CCN [cloud condensation nuclei] solar cycle signals by around 50%.”
“The most obvious way for warming to be caused naturally is for small, natural fluctuations in the circulation patterns of the atmosphere and ocean to result in a 1% or 2% decrease in global cloud cover. Clouds are the Earth’s sunshade, and if cloud cover changes for any reason, you have global warming — or global cooling.”