The hypothesis that rising CO2 levels result in a direct increase in temperature originated in 1896 with Swedish chemist, Svante Arrhenius. However, the concept was abandoned in the 1940s because global temperatures had not even remotely matched the 1°C rise predicted by the theory. Since then, the rate of global warming has slowed despite the acceleration in industrialization and CO2 emissions.
A good example of the sort of misinformation that is being publicized regarding this topic is seen in the following quote from Dr. (Zoology) David Suzuki in the June 21, 2002 version of his "Science Matters" column that appeared in newspapers across Canada: "Increased concentration of carbon dioxide, the most important heat-trapping gas, has pushed up global temperatures, which will continue to rise unless emissions are stabilized and reduced."
Dr. Tim Ball, environmental consultant and climatology professor at the University of Winnipeg for 32 years, responds, "The Suzuki comment displays an ignorance of climate science. Even the Greenpeace report on global warming concedes that water vapour is the most abundant and most important greenhouse gas. Water vapour is ignored because the models can't include clouds. Imagine recommending devastating economic and therefore social policy based on a climate model that can't even include clouds!" In fact, CO2 is less than 3 percent of greenhouse gases (GHG). Water vapor constitutes 97 percent. Other GHG are methane, nitrous oxide, ozone and trace gases.
It is very revealing that an increase in the production of water vapor at the equator during the 1998 El Niño climate event caused worldwide average temperatures to spike by almost 1°C that year. The human contribution to the atmosphere's total water vapor content is trivial by comparison. A study by Dr. Kevin Telmer, Assistant Professor in the School of Earth and Ocean Sciences at the University of Victoria, and Dr. Jan Veizer, Professor of Geology at the University of Ottawa, demonstrates that the larger amounts of water vapor in the atmosphere at higher temperature permit more CO2 to be absorbed by plants (see
www.spacedaily.com/news/greenhouse-00zf.html). Thus, we have a self-regulating system that helps keep the climate in check.
Of the 0.7°C global temperature rise in the past century, half of it occurred before 1940, although most of the buildup in human-induced CO2 has occurred since then. It is also important to understand that our
Sun, the ultimate source of all atmospheric warmth, is currently brighter than at any time in the past 400 years. Dr. Tim Patterson, professor of earth sciences (Paleoclimatology) at Carleton University concludes, "With our star's variability accounting for about half of all the recorded warming in the last hundred years, only 0.3°C is left over for everything else, including urbanization and land use. The amount is even less if an additional 0.1-0.2°C of natural temperature fluctuation is factored in. If increased C02 levels have contributed to global warming at all in the past century, its contribution must have been very minor indeed."
Dr. Sallie Baliunas and Dr. Willie Soon of the Harvard-Smithsonian Center for Astrophysics blame variations in the Sun's brightness, not CO2 levels, for most of Earth's climate change. This idea is further supported by climatologists Marcel Fligge and Sami Solanki who demonstrated in a recent edition of the respected journal, Geophysical Research Letters, that
the warming or cooling of the Earth during the past four centuries closely matches variations in the Sun's brightness. Whether they were looking at the Little Ice Age of the latter seventeenth century, the rapid warming in the early part of the twentieth century or the relatively unchanging temperatures of recent decades, our star's output and global temperatures were closely correlated. NASA's Paal Brekke explains, "... the Sun may be a much more important contributor to global climate change than previously assumed." Dr. Ball sums up, "Ignoring the Sun and water vapor as causes of climate change is like ignoring the transmission and engine when the car is not working."
Like carbon cycle modelers, Dr. Ball and Dr. Veizer believe that CO2 merely responds to temperature changes; it does not cause them. Here is some of the evidence that supports this hypothesis:
Global mean atmospheric concentration of CO2 has been found to lag behind changes in tropical sea surface (and hence atmospheric) temperature by six to eight months. As the ocean warms, it is unable to hold as much CO2 in solution and consequently releases the gas into the atmosphere contributing to the observed CO2 level rise;
Ice core records show that, at the end of each of the last three major ice ages, atmospheric temperatures rose several hundred years before CO2 levels finally increased;
At the beginning of the most recent glacial period, about 114,000 years ago, atmospheric CO2 remained relatively high even as temperatures plummeted.
Finally, recent publications in the prestigious journals, "Science" and "Paleoceanography" show that CO2 levels were higher at the end of the last ice age than during the much warmer Eocene period, 43 million years earlier. These studies also found that CO2 levels are far higher today than they were during the relatively hot Miocene period, 17 million years ago.
Clearly, variations in the Sun's brightness should be far more interesting to those concerned about future climate change than the relatively trivial and inconsistent effect of changes in atmospheric CO2 levels.
Dr. Petr Chylek, Professor of Physics and Atmospheric Science at Dalhousie University in Nova Scotia, concludes, "It is highly probable that global average temperature will go up and down during future years regardless of what we do."
