The Emphasis on Man-made Global Warming
The possibility that CO2 may affect climate was first put forward nearly 100 years ago. More recently, James Hansen focused attention on anthropogenic (man-made) CO2 as a cause of global warming. In that same year (1988) the United Nations established the Intergovernmental Panel on Climate Change (IPCC). The Panel has issued six Assessment Reports, in 1990, 1996, 2001. 2007, 2013 and 2021, hefty collections of scientific papers by individual researchers with a variety of opinions. With the Assessment Reports the IPCC typically issues a "Summary For Policy Makers" (SPM) for the media and policy makers. Unfortunately, these contain very little science, are compiled largely by UN bureaucrats and political representatives and do not convey the lack of consensus on science questions that often exist. The net result is that politicians and the media ignore the scientific panel reports (which are confusing to them) and read only the politically biased SPMs.
The CO2 - Global Warming Hypothesis
Hansen (1988) suggested that increasing levels of CO2 produced from burning of fossil fuels would lead to catastrophic warming of the earth's atmosphere. To support that claim, some scientists point to the increase of atmospheric CO2 from 280 ppm in the pre-industrial time (1850-1900 average) to 416 ppm in 2021, and suggest this was the cause of a global temperature rise, purported to be on the order of 1.1 °C according to HadCRUT5, which includes urban warming.
Computer simulation models of the atmosphere, called General Circulation Models (GCM's), incorporate projections of ever-increasing CO2 levels with many other parameters in efforts to forecast climate into the future. These models suggest increasing temperature levels, which the IPCC and others attribute to CO2.
Problems with the CO2 - Global Warming Hypothesis
|Global temperatures for the past 1000 years
An examination of published scientific data show many inconsistencies between the climate record and the CO2 - Global Warming hypothesis. Some of these are:
- The major greenhouse gas is water vapour, and the nature of CO2 / water vapour interactions is not clearly understood. Moreover, James Hansen (2000) downplayed the role of CO2 as a greenhouse gas.
- Antarctic ice cores in one study show carbon dioxide concentrations increased by 80 to 100 ppm about 600 years after the warming of the last three deglaciations, while in another study Antarctic ice core data show that CO2 levels lag an increase in temperature by 900 to 1200 years.
- World Climate Report shows that annual growth in concentrations of CO2 in the atmosphere have remained essentially flat from 1975 to the present - during a time of maximum production of CO2 from fossil fuels. This casts doubt on the claim that rapid and dramatic build-ups of CO2 will occur in the future.
- We know that CO2 from the burning of fossil fuels was not the cause of dramatic historical climate changes, for example, 1000 years ago, in the Medieval Warm Period or in the Little Ice Age that followed from about 1350 to about 1860. We are still emerging, in an oscillating fashion, on the warming trend that came after the Little Ice Age. Global historical temperature data is readily available, for example Canada, Mediterranean, Alaska, China and Canadian Rockies.
- In the 20th century, there was little correlation between temperature changes and CO2 levels. Some surface temperature measurements show a 0.5 °C rise over the past 100 years. However, that average hides some significant details. From 1905 to 1940, a rise of about 0.5 °C was measured, during which time there was an imperceptible rise in CO2. From 1940 to 1975, the temperature decreased about 0.2 °C, while CO2 levels started to increase more rapidly. The out-of-sync relationship is obvious.
Observations on Climate Change
Global climate change has been a constant throughout the history of the Earth, driven by a variety of global and astronomical natural factors. The variability of and interactions among these factors are the subjects of active research, but are still very poorly understood by climate scientists. Observations of past climatic variations show much better correlation with astronomical variables such as solar activity and orbital changes than they do with atmospheric CO2 levels. Bruno Wiskel does an excellent job of explaining, in laymans language, these complex natural factors and their historical effect on climate in his publication "THE EMPEROR'S NEW CLIMATE". To obtain a copy, in the main menu of his website, click on Gift Shop, then Books by Bruno.
Since the beginning of the 20th century, the concentration of CO2 in the atmosphere has increased, but it is impossible to determine how much this increase is due to human activities. The best attempts to remove biases from temperature data still do not show a good correlation between changes in atmospheric CO2 and changes in global temperatures.
Global circulation models attempt to represent climatic influences with numerical equations, and are used to predict future climate variations. However, they are hampered by our poor understanding of the relationships and feedback loops among many of the key variables.
These observations suggest that global climate change is a natural and fundamental part of earth history, and that the effects of human activities on global climate are no more than a poorly understood fourth-order factor.
In terms of the recent public debates about global climate change, there is no body of evidence, and certainly no consensus in the scientific community, that man-made CO2 emissions are a significant contributor to climate change.
Possible Explanations For Global Climate Change
If the burning of fossil fuels was not the cause of earlier changes in climate, what might the possibilities be?
Total Solar Irradiance (TSI): Soon et al (1996) found an excellent correlation between global temperatures and the sun's variable radiant energy, while Baliunas and Soon (1996) found a near perfect fit between solar magnetic cycle length and earth temperature and Usoskin describes in Physical Review Letters (91/21) a millennium scale sunspot reconstruction; evidence for an unusually active sun since the 1940s. Click here
Orbital Cycles: Earth's distance and angle of exposure to the sun vary in several fashions: Orbital eccentricity; precession of the equinox, the so-called "wobble"; and variations in the tilt of the earth's spin axis.
Ice Sheets: The interactions of ice sheets and global temperature variations are not well understood. Increasing temperatures would increase oceanic evaporation, and thus may increase accumulation rates of snow and ice on the polar ice caps.
Ocean Currents: Currents are critical agents in the distribution of heat across the Earth's surface. Broecker and more recently, Gagosian of the Woods Hole Institute, have highlighted the possibility that a reorganization of the Gulf Stream in the North Atlantic might cause an abrupt cooling in North America and in Europe.
Solar Activity Most Likely The Principal Driver Of Climate Change
Dr. Jan Veizer, Ottawa-Carleton Geoscience Centre, University of Ottawa, Canada, and Institut fuer Geologie, Mineralogie und Geophysik, Ruhr-Universitaet Bochum, Bochum, Germany, reinforces the concept of natural causes for climate change in an important article published in GSA TODAY on July 2003. It deals with cloud formation through charged nuclei provided by cosmic ray flux, which itself is subject to variation in the sun 's magnetic field.A later article by Dr. Jan Veizer: Celestial Climate Driver: A Perspective From Four Billion Years Of The Carbon Cycle - SOLAR ACTIVITY MOST LIKELY THE PRINCIPAL DRIVER OF CLIMATE CHANGE was published in March 2005 in GEOSCIENCE CANADA. Full Article HereOther scientific articles which provide evidence of the importance of solar activity include The Varying Sun & Climate Change by Soon & Baliunas, and Length of Solar Cycle- An Indicator of Solar Activity Closely Associated With Climate by E.Friis-Christensen & K. Lassen.