A reader asks if the earth is getting closer to the sun. The earth's orbit is always changing, in accordance with several cycles, but these are of very long duration. They cause very long term climate changes but are not the basis of the very slight warming of the earth over the short time spans involved in the current climate change controversy.
The large planets Jupiter and Saturn exert a gravitational pull on the earth that makes the earth's orbit around the sun elliptical. These planets align to pull the earth away from the sun to the maximum distance of its orbit every 100,000 years. The earth's 3 degree change in its inclination to its rotational axis has a 41,000 year cycle. And the precession of its rotation, which exposes one pole or the other to more sunlight, has a 22,000 year cycle. (There is also a climate cycle of 135 million years that corresponds to earth passing through the arms of the Milky Way. The Milky Way galaxy, which is 100,000 light years across and 10,000 light years thick, has six arms spiraling out from its center like a pinwheel.)
While orbital changes produce long-term climate cycles by varying the distance of the earth from the sun, shorter term cycles are determined by changes in the surface of the sun itself. The sun's radiation is not uniform but varied by disturbances on the surface of the sun, called “sunspot cycles.” Magnetic fields rip through the sun's surface, producing holes in the sun's corona, solar flares, coronal mass ejections, and changes in the “solar wind,” the stream of charged particles emanating from the sun. The solar wind, by modulating the galactic cosmic rays which reach the earth, determines both the formation of clouds and the carbon dioxide level in the earth's atmosphere—which has nothing to do with emissions from factories or automobiles! Sunspot cycles cause only slight changes in the sun's radiation, but these changes are amplified many fold by interaction 1) with ozone in the upper stratosphere, and 2) with clouds in the lower troposphere.
Sunspot cycles have an eleven-year cycle as well as cycles of 87 years and 210 years. Superimposed, these cycles might add or cancel each other out. (After about 210 years, sunspot cycles “crash” or almost entirely die out, and the earth can cool dramatically.) Singer and Avery, in their best-selling book Unstoppable Global Warming, identify a global warming cycle of about 1,500 years (1,470, actually) based on the 87 and 210-year solar cycles. Seven of the 210-year solar cycles and seventeen of the 87-year cycles fit neatly into the observed 1,470-year climate cycle of the earth. And the Kyoto Treaty and all the proposals to limit carbon dioxide emissions will have no effect whatever on these climate cycles. In their arrogant ignorance, the politicians and the progress-is-the-villain ideologues propose expensive schemes that will waste trillions of dollars, reduce people's standard of living, reduce freedom and extend government control over people's lives everywhere.
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