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Global Temperature Trends From 2500 B.C. To 2040 A.D.

By Climatologist Cliff Harris and Meteorologist Randy Mann
Article and Chart Updated:
December 6, 2015. Video made in April, 2014.

Until the early to mid 2000s, global temperatures were more than a degree Fahrenheit warmer when compared to the overall 20th Century mean. From August of 2007 through February of 2008, the Earth’s mean reading dropped to near the 200-year average temperature of 57 degrees. Since that time, readings have rebounded to the highest levels in recorded history in 2014 and 2015.

We, Cliff Harris and Randy Mann, believe that the warming and even the cooling of global temperatures are the result of long-term climatic cycles, solar activity, sea-surface temperature patterns and more. However, Mankind’s activities of the burning of fossil fuels, massive deforestations, the replacing of grassy surfaces with asphalt and concrete, the “Urban Heat Island Effect,” are making conditions worse and this will ultimately enhance the Earth’s warming process down the meteorological roadway in the next several decades.

From the late 1940s through the early 1970s, a climate research organization called the Weather Science Foundation of Crystal Lake, Illinois, determined that the planet’s warm, cold, wet and dry periods were the result of alternating short-term and long-term climatic cycles. These researchers and scientists also concluded that the Earth’s ever-changing climate likewise has influenced global and regional economies, human and animal migrations, science, religion and the arts as well as shifting forms of government and strength of leadership. (See Long-Term Chart below.)

Much of this data was based upon thousands of hours of research done by Dr. Raymond H. Wheeler and his associates during the 1930s and 1940s at the University of Kansas. Dr. Wheeler was well-known for his discovery of various climate cycles, including his highly-regarded “510-Year Drought Clock” that he detailed at the end of the “Dust Bowl” era in the late 1930s.

During the early 1970s, our planet was in the midst of a colder and drier weather cycle that led to concerns of another “Little Ice Age.” Inflationary recessions and oil shortages led to rationing and long gas lines at service stations worldwide. The situation at that time was far worse than it is now, at least for the time being.

The Weather Science Foundation also predicted, based on these various climate cycles, that our planet would turn much warmer and wetter by the early 2000s, resulting in general global prosperity. They also said that we would be seeing at this time widespread weather “extremes.” There’s little doubt that most of their early predictions came true.

Our recent decline in the Earth’s temperature may be a combination of both long-term and short-term climate cycles, decreased solar activity and the development of strong long-lasting La Ninas, the cooler than normal sea-surface temperature event in the south-central Pacific Ocean. Despite the recent rise, sunspot activity since in the late 2000s has averaged near the lowest levels since “The Little Ice Age” ended in the mid-to late 1800s.

By 2020, some scientists state that solar activity will plummet once again that could lead to much colder weather across the globe. This recent "cool spell," though, may have only been a brief interruption to the Earth’s overall warming trend. Only time will tell.

Based on these predictions, it appears that much warmer readings may be expected for Planet Earth, especially by the 2030s. It’s quite possible we could see an average temperature in the low 60s.

We at Harris-Mann Climatology, www.LongRangeWeather.com, believe that our prolonged cycle of wide weather “extremes,” the worst in at least 1,000 years, will continue and perhaps become even more severe over the next 5 years.

Dr. Wheeler also discovered that approximately every 102 years, a much warmer and drier climatic cycle affects our planet. The last such "warm and dry" peak occurred in 1936, at the end of the infamous "Dust Bowl" period. During that time, extreme heat and dryness, combined with a multitude of problems during the “Great Depression,” made living conditions practically intolerable.

Assuming there is a brief cool down around 2020, the next “warm and dry” climatic phase is scheduled to arrive in the early 2030s, probably peaking around 2038. It is expected to produce even hotter and drier weather patterns than we saw during the late 1990s and early 2000s.

But, we should remember, that the Earth’s coldest periods have usually followed excessive warmth. Such was the case when our planet moved from the Medieval Warm Period between 900 and 1300 A.D. to the sudden “Little Ice Age,” which peaked in the 17th Century. Since 2,500 B.C., there have been at least 78 major climate changes worldwide, including two major changes in just the past 40 years.

By the end of this 21st Century, a cool down may occur that could ultimately lead to expanding glaciers worldwide, even in the mid-latitudes. Based on long-term climatic data, these major ice ages have recurred about every 11,500 years. The last extensive ice age was approximately 11,500 years ago, so we may be due again sometime soon. But, only time will tell.

Global temperature chart was complied by Climatologist Cliff Harris that combined the following resources:
"Climate and the Affairs of Men" by Dr. Iben Browing.
"Climate...The Key to Understanding Business Cycles...The Raymond H. Wheeler Papers. By Michael Zahorchak
Weather Science Foundation Papers in Crystal Lake, Illinois.