What is Global Warming?
Global warming is a cyclical event that is in a constant state of flux. Global temperature fluctuations began millions of years ago as earth temperature changes shaped the amount of ice covering much of the world. We are currently enjoying a temporary reprieve from the deep freeze known as “the little ice age” that took place between the years 1400-1800 AD. A “temporary” warm period took place during the medieval period and lasted 400 years. Small-scale temperature cycles of about 40 years exist within larger-scale cycles of 400 years, which in turn exist inside still larger scale cycles of 20,000 years, and so on.
Approximately every 100,000 years Earth’s climate warms up temporarily. These warm periods, called interglacial periods, appear to last approximately 15,000 to 20,000 years before regressing back to a cold ice age climate. There are well known and explainable Astronomical Causes that are responsible for these cyclical climate changes. Without getting into too many mathematical details, the 3 major cycles are defined by variations of the distance between the sun and earth due to orbital movements:
- “Short” 21,000 year cycle: Earth’s combined tilt and elliptical orbit around the Sun (precession of the equinoxes )
- “Medium” 41,000 year cycle: Cycle caused by the +/- 1.5° wobble in Earth’s orbit ( tilt )
- “Long” 100,000 year cycle: Variations in the shape of Earth’s elliptical orbit
- ( cycle of eccentricity)
As illustrated in the figure below, over the past 800,000 years the Earth has undergone major swings in warming and cooling at approximately 100,000 year intervals, interrupted by minor warming cycles at shorter intervals. This represents periods of glacial expansion, separated by distinct but relatively short-lived periods of glacial retreat and warmer earth.
Except for two relatively brief inter-glacial episodes, one peaking about 125,000 years ago and the other beginning about 18,000 years ago (the long “100,000” year cycle), the Earth has been under an “ice spell” for the last 160,000 years as shown in the figure below.
It is evident that we are approaching the “end” of the current “short” 21,000 years “global warming” cycle, and should expect a “global cooling” period during the next 100,000 years or so. This period will include some temperature fluctuations caused by “short” and “medium” temperature cycles, but for the most part it will be significantly colder than our current stage. The ice cap size will increase significantly, sea levels will drop by 100’ or more, and the average air temperature will most likely drop by 3°C or more.
Global climate cycles of warming and cooling have been a natural phenomenon for hundreds of thousands of years, and it is unlikely that these cycles of dramatic climate change will stop anytime soon. We currently enjoy a warm Earth. Can we count on a warm Earth forever? The answer is most likely… no. In fact, based on historical evidence, the likelihood of a “global cooling” period in the next 1000-2000 years is very high.
Since the climate has always been cyclical and will likely continue as long as current earth orbital cycle remains intact, it is highly recommended to focus our resources on preparing for global cooling and the inevitable consequences of reduction in ocean levels, colder temperatures, and increased amounts of ice and precipitation, instead of crippling the U.S. economy by forcing major reduction in man-made carbon emissions to the atmosphere in order to achieve small temporary reductions in global warming.