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How Does the Sun Affect the Clouds?

The topic of the sun's effect on clouds has been hotly debated among the world's leading climate scientists. According to Henrik Svensmark, "A link between the Sun, cosmic rays, aerosols, and liquid-water clouds appears to exist on a global scale." Others in the field caution that more evidence is needed before long-standing climate trend forecast models incorporate theories from the emerging field called Cosmoclimatology.

  1. Cosmic Rays

    • Cosmic rays are sub-atomic particles that originate from outer space, possibly from stars that went supernova. Moving at nearly the speed of light, they enter the solar system where they fall under the influence of the magnetic fields of the Earth and sun -- and some of them penetrate the Earth's atmosphere. At times, the quantity of cosmic rays in the Earth's atmosphere decreases suddenly due to solar flare activity. These phenomena have been known and observed by climatologists and other scientists for more than a century, but there is new evidence emerging about their interaction with other materials in the atmosphere that has led some climatologists to think about global warming and cooling trends in new ways.

    The Solar Flare-Cloud Cover Connection

    • A new theory in climatology comes from the results of laboratory experiments conducted in Copenhagen, Denmark by physicist Henrik Svensmark. The experiments appear to indicate that sudden decreases in cosmic rays associated with solar flares may be directly affecting Earth's climate. These events, called Forbush Decreases, occur when magnetic fields affected by plasma “solar winds” draw cosmic rays away from the Earth's atmosphere.

    Aerosols

    • In his paper entitled "Cosmic Ray Decreases Affect Atmospheric Aerosols and
      Clouds," Dr. Swensmark stated that in the absence of the normal level of cosmic rays following solar flares there is a decrease in the concentration of atmospheric aerosols and in cloud cover. The net effect is warmer temperatures.
      Aerosols are minute particles suspended in the atmosphere that originate from many sources, including the burning of fossil fuels, volcanoes and sea spray. Without aerosols there would be no clouds because cloud formation requires the tiny airborne particles to act as "seeds" to initiate cloud droplets. In large concentrations, aerosol-laden clouds partially block sunlight from reaching the Earth's surface, which lowers temperatures.

    Cosmoclimatology vs. Carbon Dioxide Global Warming Theory

    • The theories of cosmoclimatologists are controversial because they diverge from the widely-accepted theory that holds carbon dioxide pollution to be the primary agent of global climate shifts. This view is based on research surrounding a global warming trend that took place between 1975 and 1998. In response to this apparent cause-and-effect relationship, reducing industrial emissions of carbon dioxide became an urgent public policy imperative in most industrialized nations.
      According to Dr. Svensmark, the findings of cosmoclimatologists are based on thousands of years of observed and recorded phenomena. He points out that, while there is a great deal of evidence to support both views; to date both theories remain unproven.

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