New Paper Corroborates the Solar-Cosmic Ray Theory of Climate

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%."

As pointed out by Dr. Roy Spencer, 

"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."

This new paper finds annual mean cloud nucleation rates may vary 6.8% over solar cycles, far more than the 1-2% change in global cloudiness required to change global temperature. 

The solar-cosmic ray theory of climate is only one of many solar amplification mechanisms described in the scientific literature. 

Effect of solar variations on particle formation and cloud condensation nuclei

OPEN ACCESS FOCUS ON HIGH ENERGY PARTICLES AND ATMOSPHERIC PROCESSES

Fangqun Yu and Gan Luo

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Part of Focus on High Energy Particles and Atmospheric Processes

The impact of solar variations on particle formation and cloud condensation nuclei (CCN), a critical step for one of the possible solar indirect climate forcing pathways, is studied here with a global aerosol model optimized for simulating detailed particle formation and growth processes. The effect of temperature change in enhancing the solar cycle CCN signal is investigated for the first time. 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 condensation nuclei larger than 10 nm (CN10), and number concentrations of CCN at water supersaturation ratio of 0.8% (CCN0.8) and 0.2% (CCN0.2) in the lower troposphere by 6.8%, 1.36%, 0.74%, and 0.43%, respectively. The inclusion of 0.2 °C temperature increase enhances the CCN [cloud condensation nuclei] solar cycle signals by around 50%. The annual mean solar cycle CCN signals have large spatial and seasonal variations: (1) stronger in the lower troposphere where warm clouds are formed, (2) about 50% larger in the northern hemisphere than in the southern hemisphere, and (3) about a factor of two larger during the corresponding hemispheric summer seasons. The effect of solar cycle perturbation on CCN0.2 [cloud condensation nuclei] based on present study is generally higher than those reported in several previous studies, up to around one order of magnitude.