This is one of the best explanations I have seen of why man-induced carbon dioxide emissions ARE NOT causing global warming and hence, climate change. I recommend printing out the entire article and carefully reading it. The key point here is the numerous climate changes in the recent past, at least 33 glacial advances and retreats (global warming and cooling periods) in the last 2 million years, long before man was around burning fossil fuels and releasing carbon dioxide. I am only posting a few highlights from the article.
The Geologic Record and Climate Change
By Tim Patterson : 01 Jan 2005
The following remarks were delivered at the Risk: Regulation and Reality Conference by Dr. Tim Patterson, Professor of Geology at Carleton University. The conference was co-hosted by Tech Central Station and was held on October 7, 2004 in Toronto, ON.
I am a Quaternary geologist by profession. That is to say that my research interests are focused primarily on about the last 2 million years of Earth's history. An important aspect of my research is assessing past climate conditions. Thus I am also a paleoclimatologist. Earth's climate has varied considerably during the past 2 million years or so as indicated by the more than 33 glacial major advances and retreats that have occurred through this interval. Based on geologic paleoclimatic data it is obvious that climate is and has been very variable. Thus the only real constant about climate is change. It changes continually.
A primary role for climate researchers at present is to try and determine what the magnitude of natural climate variation is, and what sort of variation may be occurring at the present time is due to human induced causes. A major difficulty that we have is that the thermometer record only reaches back to the tail end of the 19th century. Unfortunately, many of the natural trends and cycles that occur in the natural climate system operate at scales that are longer than our thermometer record. A major question that needs to be addressed then hinges on determining whether the climate variability that has been observed through the 20th century -- during a warm-up that occurred at the end of the Little Ice Age that ended in the late 1800's, is unusual if you look at the larger paleoclimate record?
This is where paleoclimatologists like myself come in. Since thermometer records are so short we have to use what are termed proxy records. We look at records contained in the sediments, fossils, isotopes, etc. and then calibrate these records against thermometer records so that we can accurately determine past climate conditions in deep time.
A second example is that of North American land temperature trends. The very close correlation between sunspot number and temperature is very clear. At present there have been literally hundreds of studies carried out showing a similar correlation.
And so, the big question a person on the street might ask is, why hasn't it been acknowledged that the sun is the major control over climate variability? Why do so many fingers point to CO2 as the major climate control?
But if the sun is important to climate change what role do greenhouse gases play then? Greenhouse gases are really important. They make up something like 0.1 percent of our atmosphere and are a critical component of the Earths biosphere. If you listen to the rhetoric produced by some environmental groups one would come away with the understanding that , all greenhouse gases must be expunged. However, without them, the earth would be uninhabitable; it'd be too cold.
The media, special interest groups, and even some government produced literature all report that CO2 is the most important greenhouse gas. I was at the Canadian Museum of Nature a few months ago where a traveling display was set up that clearly, and erroneously I might add, indicated that CO2 was the most important greenhouse gas. The number one greenhouse gas is actually water vapor.
The bottom chart shows the range of global temperature through the last 500 million years. There is no statistical correlation between the level of carbon dioxide in the atmosphere through the last 500 million years and the temperature record in this interval. In fact, one of the highest levels of carbon dioxide concentration occurred during a major ice age that occurred about 450 million years ago. Carbon dioxide concentrations at that time were about 15 times higher than at present. (What caused the high CO2 values in the past? It couldn't have been man. Peter)
Let's move to a little bit more recent geological history. There have been about 33 glacial advances and retreats through the last two million years or so. Through the last 10,000 years we have been in the Holocene interglacial, a warm episode between the last glaciation and the next one that will begin in the relatively near, geologically speaking, future. The last glaciation peaked about 18,000 years ago with the ice sheets retreating rapidly over just a few thousand years. Before that there was another interglacial that began about 130,000 years ago and lasted about 10,000 years. In Europe that interglacial is known as the Eemian. Here in North America it is known as the Sangamon. As one goes back in time these intervals of about 10,000 years of interglacial interspersed with episodes of about 100,000 years of glaciation continue. (What causes the regular cycles of glacial advance (cooling) and glacial retreat (warming)? Man has only been around driving cars and burning coal for about the past 150 years. Peter)
What I would like to draw your attention to is the level of CO2 levels, as preserved in prehistoric air bubbles, from very high quality ice core records from Antarctica. When researchers first looked at the results from these cores they observed a repeating correlation between CO2 and temperature through several glacial/interglacial cycles. However, when they began to look at higher resolution cycles they say something different. They observed that temperature would go up first, with CO2 coming up later. This correlation indicates that as one might expect, as temperatures warm biological productivity increases, resulting in more CO2 in the atmosphere. The lag between CO2 and rising or falling CO2 levels is something like 800 years.
I teach a general climate change course. To get the significance of this correlation over to the students I use the following analogy. I tell the students that based on these records if you believe that climate is being driven by CO2 then they probably would have no difficulty in accepting the idea that Winston Churchill was instrumental in the defeat of King Herold by Duke William of Orange at the Battle of Hastings in 1066. If you can believe that this historical temporal incongruity could be feasible then you can have no problem believing that CO2 is what's driving Earth's climate system.
In conclusion, the geologic record clearly shows us that there really is little correlation between CO2 levels and temperature. Although CO2 can have a minor influence on global temperature the effect is minimal and short lived as this cycle sits on top of the much larger water cycle, which is what truly controls global temperatures. The water cycle is in turn primarily influenced by natural celestial cycles and trends.