…Clouds and Global Warming…
Do clouds affect global warming?
The Svensmark hypothesis asserts that cosmic rays entering the Earth’s atmosphere affect cloud cover, which, in turn, affects temperatures on the Earth, and, further, that the sun has an effect on the number of cosmic rays entering the Earth’s atmosphere.
Strong solar activity, as evidenced by a larger number of sun spots, increases the strength of the solar wind and the sun’s magnetic field which blocks, or deflects, cosmic rays from entering the Earth’s atmosphere.
- Strong solar activity would permit fewer cosmic rays, which would result in the formation of fewer clouds.
- Weak solar activity would have the opposite effect and result in more clouds.
Clouds reflect sunlight back to space and also shade the Earth.
Therefore, more cloud cover results in lower temperatures on the Earth. This effect would seem obvious to anyone who has been outdoors on a sunny day when a cloud passed overhead, and the temperature suddenly fell.
Many scientists challenged the Svensmark hypothesis by claiming cosmic rays would not affect cloud cover, while also claiming there were fewer clouds before the industrial revolution.
There was a belief that sulfuric acid aerosols were key to the forming of clouds by cosmic rays, and that it was the burning of fossil fuels with the advent of the industrial revolution that resulted in the presence of sulfuric acid aerosols.
If correct, this would upend the Svensmark hypothesis. Some supporters of Svensmark had speculated that the Little Ice Age, which occurred during the Maunder Minimum when there was a dearth of sun spots, provided empirical evidence that cosmic rays affected the Earth’s temperature.
The debate surrounding the Svensmark hypothesis led to an experiment at the CERN research center.
The CERN research center in Europe derived its name from the acronym for the French “Conseil Européen pour la Recherche Nucléaire”, or European Council for Nuclear Research.
This premiere research center conducted an experiment to determine whether cosmic rays could form clouds and under what conditions cloud formation would occur.
The results of the CLOUD experiment established two facts.
The first upended, not the Svensmark hypothesis, but the long held belief that there were fewer clouds before the industrial revolution.
The second proved cosmic rays could form clouds.
It was learned from the experiment that hydrocarbons released by plants could provide the necessary conditions for cloud formation and that sulfuric acid aerosols were not needed.
Here is a direct quotation from a summary report:
“[The scientists] introduced a mixture of natural oxidants present in the air and an organic hydrocarbon released by coniferous plants. The hydrocarbon was rapidly oxidized. The only other ingredient allowed in the chamber was cosmic rays, high energy radiation from outer space, which made the molecules clump together into aerosols. Sulfuric acid was not required. In fact, even when the researchers introduced low concentrations of sulfuric acid to the chamber such as might be found in unpolluted air, the aerosol formation rate was unaffected. In a second CLOUD experiment published simultaneously in Nature, researchers showed these same oxidized molecules could rapidly grow the particles to sizes big enough to seed cloud droplets.”
These are the two facts derived from the CLOUD experiment.
Anything else is conjecture.
- Conditions existed before the industrial revolution that permitted cloud formation
- Cosmic rays can form clouds
The CLOUD experiment provides scientific support for the Svensmark hypothesis.
While this experiment may not prove that solar activity, as exhibited by sun spots, affects the Earth’s temperatures, it does demonstrate that it is entirely possible.
The Svensmark hypothesis goes a long way toward explaining the significant temperature variations that have occurred over the past 10,000 years, which is something the CO2 hypothesis can’t do.