An objective review of facts and fictions

Part II: Some Historic Climate Facts 

In Part I (Can be found posted following this) we looked at the more prevalent misconceptions that power the climate change alarm regularly sounded in most media articles about earth’s alleged rapidly warming atmosphere from increasing human-caused CO2. These same allegations are parroted by the UN, many individual world governments and assorted politicians as they make the case for immediate draconian government tax and control actions they claim imperative to save the human race from cooking itself in an overheated climate.

The Climate in Earth’s Geologic History

 A principal claim by those promoting rampant Climate Change (aka Global Warming) states modern day human activities that involve the burning of fossil fuels (coal, oil, natural gas) are adding huge amounts of carbon dioxide (CO₂) to the atmosphere. Since CO₂ is a “greenhouse gas” (a name derived from its ability to trap some of the earth’s heat that otherwise would be radiated back out into space), has been labeled by some scientists as the cause of the earth’s alleged rapidly heating climate.

These scientists also make the claim that today’s alleged “soaring” climate temperatures are unprecedented in the earth’s history and therefore can only be accounted for by human impact and fossil fuel use. 

Given this alarming context, it becomes important to explore some facts about the history of the earth’s climate that scientists have documented.

The immediate questions that arise are, first, is the current climate change really “unprecedented”;  And, second, is warming caused solely by human activity in burning fossil fuels?

Or have there been previous similar climate changes in the CO2 content and/or temperature of the atmosphere over the course of the earth’s history that pre-dates humans?

Fortunately, paleo geologists, botanists, and climatologists have been able to determine and document the earth’s historic climate so that we can have objective insight into what both the earth’s temperatures and CO2 were like during the period of several hundred million years that predate modern times.          

And, we know that past natural history is often a window that shows us what can be expected in the future.  So by looking at the earth’s climate before there was any human presence, we can see what happened under purely natural influences. And, from a study of the scientific facts about what affected the earth’s “natural” past climate, we can begin to identify the factors that caused it to change, and thus better understand how those same factors may be influencing our climate today.

Some Basic Geological Facts

According to paleo scientists, there have been five ice ages identified in the Earth’s geologic history. An ice age is defined as an extended time of recurring glacial episodes during a specific named geological period. (For example, the present Ice Age is in the Quaternary Period)

Within each of these historic ice ages, there have been successive periods of substantial glaciation and intervening temperate conditions, each lasting many tens of thousands of years and known respectively as glacial and interglacial periods.

Glacial periods are characterized by a frigid global climate resulting in the formation of polar and continental ice sheets–some as much as a mile thick!–over extensive portions of the earth’s surface, particularly in polar and sub-polar regions. During interglacial periods the climate warms causing the glacial ice to retreat. 

Between the Ice Ages themselves, the global climate historically has warmed significantly, substantially reducing, if not eliminating, the glacial ice on the earth’s surface.

What all this means in layman’s terms is that we know from documented scientific evidence that there have been times when the earth was very cold with lots of ice, and times when the earth was very warm; warm enough to melt the ice from all, or almost all, of the earth. 

To obtain this historical data, scientists use surrogates, such as specific chemicals in ice and sediment core samples, the presence and amount of which provides a measure of the relative temperatures and atmospheric CO2 content for the historical time period of the sample. While the surrogate temperature values cannot be converted to precise equivalents of  F or C degrees, a reasonable approximation can be made for the purpose of relative temperature comparisons. 

The earth currently is in the fifth of its historic Ice Ages.  Climate scientists have designated this present one as the Quaternary Ice Age, and our climate presently is consistent with the warming of an interglacial period.

Figure 1 displays the temperature of the earth’s climate over the past 1 million years.  (The present is on the left.)  The cyclic nature of the successive warming and cooling of the climate is readily apparent.

It is also relevant to note that the transition from a cold glacial period climate to a warm interglacial one typically occurs with little or no variation and over a shorter time-span than that when the warm climate changes to a cooling phase and enters a glacial period.

Figure 1.  Graphic representation of the relative historical global climate temperature over the 1 million-year time period up to the present. (Ticks at the top and bottom margins are 100,000 years apart.) The red indicates warm climate temperatures of interglacial periods when glacial ice sheets retreated, the blue the glacial periods when the climate cooled to the point where precipitation resulted in extensive glaciation. Purple indicates a period of transition between the two.  (Note: the full extent of present warming (extreme left edge of the graph) is obscured slightly because of the graph’s time-scale.)  

Observe that while the duration and temperature extremes of the glacial/interglacial cold and warm climate periods vary, the successive cyclic conditions have reoccurred with regularity over the million years shown. This is a strong indication that the causation is the result of one or more natural repetitive factors that affect the amount of solar heating.

Many scientists point to the cyclic variations of the Earth’s orbit around the sun as a primary contributor to these cyclic variations in climate temperatures. Known as Milankovitch cycles, these fluctuations in the earth’s orbit occur with regularity every 20,000, 40,000, and 100,000 years, and appear to generally coincide with the onset and end of historic glacial periods.

Also, it is important to note that the warming of our current global interglacial climate temperature is less than the warming of the climate that has occurred in many of the past interglacial periods in our current Ice Age.

Based on this data, the earth’s current climate warming is clearly not “unprecedented” in either occurrence, the rate of warming, or the temperature,  contrary to what has been claimed by “Alarmist” scientists!

And, as we shall explore further, the obvious cyclic nature of climate warming and cooling essentially rules out CO2 as the cause.

A more detailed timescale graphic picture of the relative global climate temperatures for that portion of the figure 1 graph for just the past 150,000 years is displayed in figure 2.

Figure 2. Graphic representation of earth’s relative climate temperatures for the past 150,000 years. Blue shows glacial periods, red interglacial periods. Purple indicates a time of transition between the two. 

The most recent glacial period (leftmost blue portion of the graph)  lasted about 60,000 years, reaching its maximum glaciation about 22,000 years ago, and it ended (and the current warm interglacial period began) approximately 11,700 years ago, with the climate temperature warming rapidly (on a geological timescale) to its modern-day range. The extreme left red portion of the graph line indicates the relative average global climate temperature which we are currently experiencing. 

Notice that our current average climate temperature is exceeded by the maximum climate warming that the earth experienced about 120,000 years ago during the last interglacial period. 

Turning to the issue of the role (if any) of CO2 in driving the  temperature of the earth’s climate, Figure 3 provides us with a graphic picture of the results of research by paleoscientists that documents both the carbon dioxide content and temperature of the earth’s atmosphere relative to that of the present for the past 4.6 billion years. Because of that timescale, both graphed lines appear smooth because they necessarily can depict only longer-term variations.  [To put Figures 1 and 2 in perspective with this graph,  both of those provide a higher resolution timescale detail for their respective portions of the present Quaternary Period (extreme right side of this graph)].

Figure 3. Shown are the atmospheric concentrations of CO2 (purple line) and the temperatures (green line) for the past 4.6 billion years. (The Present is on the right) Left arrows show temperature ranges.

The noteworthy point of these related graphs is that, contrary to the claims that CO2 is “the sole” or principal driver of Climate temperature, our planet’s geological history as displayed here shows that there is no continuous direct relationship between the two on a longer-term timescale, with temperatures largely indepedent of CO2.

It is also important to note that the present climate temperature (right edge of the graph) is near a geologically historical minimum range, and the earth’s climate has been naturally considerably warmer for literally billions of years in the past. Yet “Alarmists” claim with certainty that the only human activity is responsible for the current very small warming trend that started at the last glacial maximum 22,000 years ago, well before human activity began burning fossil fuels!

A Quick Summary

The point of the above has been to provide information that is readily available, yet clearly ignored by those scientists who obviously have to be aware of it, but by self-serving choice, promote the “CO2 is the only scientific explanation” reason for global warming. The very existence of the above research belies their contention that the CO2 cause is “settled science” and shines a spotlight on the deliberate disingenuous nature of  their position.  There clearly is a need for unbiased, open discussion,  with science-based issues on both sides to discuss. 

The media also must share in the deliberate coverup, for any cub reporter with an interest in exploring the Climate Change issue would quickly find that there are two sides to its probable cause.  Arbitrary editorial  policies have apparently decided otherwise.

In Part III which will be posted in the “near” future, we will look at the nature and basis of the ubiquitous “sky is falling” warnings that now regularly pervade political rhetoric and the mainstream media.

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