A Cosmic Thermostat Controls Earth’s Temperature?
“In recent years, the idea that the climate is driven by clouds and cosmic rays has received plenty of attention. Interest in the idea was prompted by a Danish physicist named Henrik Svensmark, who first suggested it in the late 1990s.
Using satellite data on cloud coverage, which became available with the establishment of the International Satellite Cloud Climatology Project in 1983, Svensmark found a correlation between lower troposphere cloud cover and the 11-year solar cycle.
He proposed that cosmic rays initiate the formation of aerosols in the lower atmosphere that then form condensation nuclei for cloud droplets, increasing cloud formation from water vapor. Since low-level clouds increase Earth’s albedo (the amount of incoming solar radiation that is reflected back into space), more clouds mean cooler temperatures.
Svensmark claimed that this mechanism was responsible for virtually every climatic event in Earth history, from ice ages to the Faint Young Sun paradox to Snowball Earth to our current warming trend. Needless to say, this would overturn decades of climate research.
Cosmic “rays” are actually energetic subatomic particles. The solar wind shields the Earth from many of the cosmic rays coming from elsewhere in the Milky Way, so the number of rays that reach the Earth is modulated by variations in solar activity, such as the well-known 11-year solar cycle.
Early work by Svensmark and a group at CERN (we recently covered their initial results) has indicated that charged particles like cosmic rays can cause molecules of sulfuric acid, water, or other vapors to combine and form aerosols (particles about 1 nanometer in diameter). This provides a potential link between cosmic rays and cloud formation.”