To partially answer that question, the Oct. 2007 issue of the Journal of American Physicians and Surgeons contained a comprehensive 12 page report analyzing the factual data of over 100 studies concerning effects of carbon dioxide (CO2) on the environment. Its title is ‘Environmental Effects of Increased Atmospheric Carbon Dioxide’ and written by Drs A. B. Robinson, N. E. Robinson, & W. Soon (of the Oregon Institute of Science and Medicine). Quotes from the report's Abstract and Conclusions are:
". . . . carbon dioxide . . . . increases during 20th and early 21st centuries have produced no deleterious effects upon Earth's weather and climate."
"Increased carbon dioxide has . . . . markedly increased plant growth.
"There are no experimental data to support the hypothesis that increases in human hydrocarbon use or in atmospheric carbon dioxide and other greenhouse gases are causing or can be expected to cause unfavorable changes in global temperatures, weather, or landscape.”
"The Earth has been much warmer during the past 3,000 years without catastrophic effects."
"The United States and other countries need to produce more energy, not less. The most practical, economical, and environmentally sound methods available are hydrocarbon and nuclear technologies."
"Human use of coal, oil, and natural gas has not harmfully warmed the Earth, and the extrapolation of current trends shows that it will not do so in the foreseeable future."
"We are living in an increasingly lush environment of plants and animals as a result of this CO2 increase. Our children will therefore enjoy an Earth with far more plant and animal life than that with which we now are blessed."
The entire report can be found at: http://www.jpands.org/vol12no3/robinson.pdf
Some more factual parts to the answer can be found in scientific data from Meteorology and Chemistry textbooks, the World Almanac, and publications of the Environmental Protection Agency and the National Oceanographic and Atmospheric Administration. These data show CO2 is only about 5% of Global Warming Greenhouse Gases (GWGG) (water is about 90%) and of that 5%, only about 8% is from fossil fuel combustion (the ocean releases about 60%). Doing the math (5% of 8% is 0.4%) shows that fossil fuel combustion CO2 causes much less than 1% of GWGG.
These scientific data along with others were ignored by that movie 'An Inconvenient Truth', which has been the main promoter of the GWGG hysteria, perhaps because of the ‘carbon credit’ brokering financial interests of its Producers (Al Gore for one). In 2007, a British court ruled that movie contained a number of ‘errors’ and false statements, not the least of which was the implication by their historic data curves showing rises in temperature following rises in atmospheric CO2, when in fact the actual data shows just the opposite. The Judge ruled the ‘errors’ must be brought out and discussed, with warnings about its political content, in school classes where the film is used.
Because this film is being shown in our public schools, it is suggested parents counsel their children who saw it (and were perhaps frightened by it), that a large portion of it was political fiction with no scientific basis (see www.balli.org/ew/cases/EWHC/Admin/2007/2288.rtf).
The opinion expressed in this essay is that of the author and not that of ECN.