Global Warming: The Sun is a variable star that causes the Earth’s major ice ages.
The global warming we are now experiencing is part of a major natural cycle of increased solar energy striking the planet, a phase of the sun’s natural cycle of expansion and contractions.
This natural rhythm of the sun is the cause of the major cold glacial and warm interglacial periods that geologists have determined, happened with remarkable “reoccuring regularity” over the past million years and probably throughout much of the life of the planet.
This “reoccurring regularity” is strong evidence that our sun is a variable star that is still expanding and contracting in fairly regular cycles. These expansions and contractions cause the total solar energy striking the planet to vary over very long periods of time. This natural rhythm of expansion and contraction have been happening ever since the sun was created billions of years ago although now at a very attenuated pace. If you could have measured the sun’s disk at the height of the last glacial age it would have been slightly smaller and the total solar energy would have been less. The Earth would have been slightly cooler. It does not take much to change the Earth’s climate drastically.
Scientists at Columbia University stated – “As the nuclear reactions began to release vast amounts of subatomic energy, the Sun was a quite variable star, varying in luminosity and surface activity as the result of the development of a radiative core and convective currents in its outer layers of gas. After a period of some 30 million years, its structure stabilized into the structure of a main-sequence star of one solar mass.”
I agree with the first part of this statement but I think the strong variability of the sun lasted quite a bit longer then a mere 30 million years. I feel the first billion years was a very hectic time and the sun only stabilized into a main-sequence star during the latter part of this time. The reoccuring ice ages are strong evidence that the very long expansion and contractions are still occuring at a very attentuated pace.
The major “Nebraskan” glacial age, that occured about a million years ago, was followed by a warm interglacial age that lasted well over 100,000 years. This was followed by the “Kansan” glacial age followed by another long warm interglacial age that lasted about 300,000 years which was followed by the “Illinoian” glacial age, etc.etc.. These major glacial cycles are a worldwide phenomena effecting both the northern and southern hemispheres simultaneously.
Milankovitch’s orbital eccentricity theory while causing very cold season when the earth is far away from the sun would also cause very hot season when the earth is closer to the sun. The stronger contrasts between seasons’ overall irradiance striking the earth would cancel themselves out and remain about the same. Glaciers need very cold summers to grow. There may be other causes such as precession and obliquity that also effect the climate changes but evidence indicates that the sun is a variable star and this is the main cause of the major global ice ages.
As far as historic levels of carbon dioxide levels are concerned, a study in the May 17, 2001 issue of Nature shows that CO2 levels were much higher in the geological past. During most of the Mesozoic era (the period from 65 to 259 million years ago), carbon dioxide levels were between 1,000 and 2,000 ppm, with occasional peaks that reached levels higher than 2,000 ppm. Currently concentrations are only about 370 ppm. Results from the middle Miocene, a warm period about 10 million years ago, also failed to show high CO2 levels.
For the last 50,000 years the planet has gradually been emerging from its latest “Wisconsin” glacial age into another warm interglacial age that may last for 100,00 years more or less. World wide, this warming trend has already caused a great reduction in the amount of land that was previously covered by the glaciers. Scientists estimate that up to 20 million square miles of land, were once covered by glaciers at the height of the “Wisconsin” glacial period some 50,000 years ago. At that time the glaciers covered much of the northern regions of North America and Europe.
The sea level of the oceans have already risen drastically during this global warming trend. At one time England was connected to Europe and Alaska was connected to Siberia. Much more land area around the world was above sealevel. The coast lines of countries around the world will continue to change as the sea level rises. Evidence of this can be seen where ancient harbors around the Mediterrean that were once above sea level, are now below sea level. The coast lines around the world will continue to recede as the warming climate releases more glacial ice back into the ocean. Perhaps there really was an “Atlantis” civilization 10,000 – 20,000 years ago when a lot more ice was locked up in glaciers and the sea level was much lower.
The polar regions have already become increasingly important because of warming climate trend. With the polar sea ice disappearing, seaports and trade routes are being planned along the far northern coast lines. Already commercial shipping is beginning to use the polar routes as the Artic Ocean becomes more navigatable. Cruise ships are even beginning to explore this area. Canada is planning to build a deep-water port at Iqaluit, the Arctic territorial capital. Political friction is already beginning to heat up over land claims in the Polar region. Russia has also begun to set its claims to this area.
We live on a very dynamic planet that is constantly changing. How long this global warming will last is anyone’s guess, it may be nearly over or it may go on for hundreds of years. What ever it is, the stable, warm interglacial period that follows, if it is anything like the previous major glacial cycles, will last for at least thousand centuries. A thousand centuries of warm mild climate , now if only mankind can last through this century.
Donald Hamilton, author of “The Mind of Mankind” http://novan.com/mind.htm