Excerpts from the Statement to the U.S. Senate Environment and Public Works Committee by William Happer, Cyrus Fogg Brackett Professor of Physics Princeton University, made on February 25, 2009.
"The current warming period began about 1800 at the end of the little ice age, long before there was an appreciable increase of CO2. There have been similar and even larger warmings several times in the 10,000 years since the end of the last ice age. These earlier warmings clearly had nothing to do with the combustion of fossil fuels. The IPCC summaries for policy makers are not dispassionate statements of the facts of climate change. The IPCC has made no serious attempt to model the natural variations of the earth's temperature in the past.If you can't model the past, where you know the answer pretty well, how can you model the future?
By looking at ice cores from the Greenland and Antarctic ice sheets, one can estimate past temperatures and atmospheric concentrations of CO2. These records show that first the temperature goes up, and then the CO2 concentration of the atmosphere goes up. There is a delay between a temperature increase and a CO2 increase of about 800 years. This casts serious doubt on CO2 as a climate driver because of the fundamental concept of causality. A cause must precede its effect.
CO2 is not a pollutant and it is not a poison and we should not corrupt the English language by depriving "pollutant" and "poison" of their original meaning. CO2 is absolutely essential for life on earth. Commercial greenhouse operators often inject CO2 as a nutrient for their crops. Plants, and our own primate ancestors evolved when the level of atmospheric CO2 was about 1000 ppm far above our current level of about 380 ppm. We are all aware that "the green revolution" has increased crop yields around the world. Part of this wonderful development is due to improved crop varieties, better use of mineral fertilizers, herbicides, etc. But no small part of the yield improvement has come from increased atmospheric levels of CO2. Crop yields will continue to increase as CO2 levels go up, since we are still far from the optimum levels for plant growth of 1000 ppm.
Many of the frightening scenarios about global warming come from large computer calculations, "general circulation models," that try to mimic the behavior of the earth's climate as more CO2 is added to the atmosphere. Climate models use increasingly capable and expensive computers. But their predictions have not been very good. For example, none of them predicted the lack of warming that we have experienced during the past ten years. All the models assume the water feedback is positive, while satellite observations suggest that the feedback is zero or negative.
This brings up the frequent assertion that there is a consensus behind the idea that there is an impending disaster from climate change, and that it may already be too late to avert this catastrophe, even if we stop burning fossil fuels now. We are told that only a few flat-earthers still have any doubt about the calamitous effects of continued CO2 emissions. There are a number of answers to this assertion. First, what is correct in science is not determined by consensus but by experiment and observations. Historically, the consensus is often wrong. Secondly, I do not think there is a consensus about an impending climate crisis.There may be an illusion of consensus. The climate-catastrophe movement has enlisted the mass media, the leadership of scientific societies, the trustees of charitable foundations, and many other influential people to their cause. Hysterical op-ed's lecture us today about the impending end of the planet and the need to stop climate change with bold political action. Many distinguished scientific journals now have editors who further the agenda of climate-change alarmism. Research papers with scientific findings contrary to the dogma of climate calamity are rejected by reviewers, many of whom fear that their research funding will be cut if any doubt is cast on the coming climate catastrophe. Even elementary school teachers and writers of children's books are enlisted to terrify our children and to promote the idea of impending climate doom. Children should not be force-fed propaganda masquerading as science."