The Svensmark Effect

Our planet is bombarded by high-energy cosmic particles (nuclei of atoms) from other stars and supernovas.

They are called cosmic rays.  

When solar activity is at its maximum, the Earth receives less cosmic rays.

When solar activity is at a minimum, the Earth receives more cosmic rays. 

The change in the amount of cosmic rays received by our planet is about 20% between the maximum and minimum solar activity.

Three Danish researchers (Knud Lassen, Eigil Friis-Christensen and Henrik Svensmark) used 1984 to 1990 data from three satellites to find the variation of cosmic rays entering the atmosphere correlated well with cloudiness. 

In 2011 the results of a CERN experiment called CLOUD showed that cosmic rays significantly affect the production of clouds.

During weak solar cycles, there are reduced solar winds, allowing more galactic cosmic rays to enter Earth’s lower troposphere.

More cosmic rays promote the formation of more clouds at low altitudes.

Low altitude clouds block some of the sunlight reaching the Earth, which leads to global cooling.

During strong solar cycles, the opposite effect occurs, leading to global warming.

The strongest 63-year string of solar cycles in 11,400 years was between 1933 and 1996 -- which may logically explain most of the 20th century global warming.

These 63 years of strong solar cycles ended in 1996 --
weather satellite data say the global warming trend ended in 1998.

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Cloudy skies reflect more sunlight back into space than blue cloudless skies -- that's obvious to anyone standing outside as a cloud moves over them.

Clouds that form at low altitude are relatively warm and composed of fine water droplets -- they cool the planet by reflecting sunlight back into space. 

The size and thickness of clouds, and the size and number of droplets inside the cloud, affects how much sunlight is reflected.

Clouds composed of large drops of water, or with a lot of water droplets, reflect the most sunlight back into space.