CATO News 1000 Massachusetts Avenue, N.W. Washington, D.C. • 20001 TEL: 202-842-0200 FAX: 202-842-3490 COMPUSERVE: 76464,505 INTERNET. Cato@cato.org WEB STE: http://www.cato.org October 6, 1999 Cato scholar testifies that dangers of carbon dioxide are exaggerated Findings lead to inescapable conclusion that CO2 is not a 'pollutant,' and plausibly a net benefit “Is carbon dioxide a satanic gas? Absolutely not," Patrick J. Michaels, Cato's senior fellow in environmental studies, told a House panel today at a hearing on whether or not carbon dioxide is a pollutant and whether the Environmental Protection Agency has the power to regulate it. Michaels told the Subcommittee on National Economic Growth, Natural Resources and Regulatory Affairs of the House Government Affairs Committee that "negative" and "positive" impacts on climate are value judgments made by human beings. Summarizing his testimony, Michaels said: "This testimony demonstrates that the observed climate changes that have accompanied the enhancement of the natural greenhouse effect have been considerably smaller than they were originally forecast to be, and that they are likely to remain similarly small. Further, they are confined overwhelmingly to the winter, rather than the summer, and, during the winter, they are confined to the coldest, deadliest airmasses. There is no overall statistically significant warming in the average temperature of the United States, for which the record is 105 years in length. While the United Nations has stated that during the greenhouse enhancement, 'the balance of evidence suggests a discernible human influence on global climate,' I cannot view what has happened as a net negative; some might easily argue that it is a net benefit. Under neither interpretation does this qualify carbon dioxide as a climatic 'pollutant.' "In January 1989, over 10 years ago, I first testified on climate change before the House Committee on Commerce. I argued that the computerized climate models from that era were dramatically overpredicting future warming, and that the observed history of climate projected a much more moderate warming, of 1.0°C to 1.5°C, over the next century. I further argued that it would eventually be recognized that this moderate climate change would be expressed mainly in the winter at night, and that overall it was plausible to argue that the change conferred a net benefit upon our world. If I had the perfect vision of knowing what would have happened to the climate in the next 10 years, how the scientific literature evolved-I would have changed not one word." Michaels is professor of environmental sciences at the University of Virginia and past president of the American Association of State Climatologists. His recent studies include "Long Hot Year. Latest Science Debunks Global Warming Hysteria" (www.cato.org/pubs/pas/pa-329es.html) and "The Consequences of Kyoto" (www.cato.org/pubs/pas/pa-307es.html). The complete text of Michaels' testimony can be found at www.cato.org/testimony/ct-pm100699.html. The Cato Institute is a nonpartisan public policy research foundation dedicated to broadening policy debate consistent with the traditional American principles of individual liberty, limited government, free markets, and peace. Mr. FIELD. Chairman Calvert, members of the committee, I appreciate the opportunity to address this hearing. My remarks today will focus not on the legal issues, but on the plant physiology. I will emphasize three points. First, atmospheric CO2 is essential for life on Earth; second, the concentration of CO2 in the atmosphere has increased dramatically over the last century, as a consequence of human actions; and third, increasing atmospheric CO2 has a mixture of positive and negative effects on plant growth, food security, and natural ecosystems. Adding the prospect of human-caused climate change tends to make the overall impacts more negative. Let me explain each of these points. First, atmospheric CO2 is essential for life on Earth. I think we generally agree on that. Plants growth through photosynthesis, a process that uses the energy from sunlight to combine carbon dioxide from the air with water to make carbohydrates plus oxygen. The carbohydrates formed through photosynthesis feed not only the plants, but almost all other organisms on Earth, including those that eat plants and those that eat the animals that eat the plants. Of course, humans are included in the group that depends on the products of photosynthesis. Second, the concentration of CO2 in the atmosphere has increased dramatically over the last century, as a consequence of human actions. As Dr. Michaels has already explained, at the beginning of the Industrial Revolution, before the extensive use of fossil fuel by humans, the concentration of CO2 in the atmosphere was about 280 parts per million, or about 0.28 percent, and it has increased by about 30 percent, so that now a little less than 1 cubic inch of each cubic foot of the atmosphere is composed of CO2. We know, based on measurements in ice cores, that the current concentration of CO2 in the atmosphere is higher than it has been at any time in the last 400,000 years. The third point I want to make is that increasing atmospheric CO2 has a mixture of positive and negative effects on plant growth, food security, and natural ecosystems. I will comment first on food production. Most of the world's plants use a mechanism for photosynthesis that is through two sensitives. Photosynthesis, or CO2 fixation, increases when the CO2 concentration increases. For many crops, under current conditions this means that crop growth rate also increases. And in large number of experiments, crop growth under doubled atmospheric CO2 increases by 10 to 50 percent. The CO2 sensitivity does not apply uniformly to all crops. Some important crops, most notably corn and sugar cane, use a different photosynthesis pathway called C-4. For these crops photosynthesis does not increase with increasing CO2, and growth increases only a little bit. In the absence of other factors, the direct effect of increased CO2 on crop growth would very probably lead to higher global food production. Now whether or not this is a benefit from the perspective of U.S. agriculture will depend on world market conditions. It is also very short-sighted to think only of the effects of CO2 on crop photosynthesis. At least three other factors need to be con sidered. First is losses to pests. Several studies show that insects fed plant material grown in elevated CO2 eat more than if fed the same plants grown at normal CO2. Thus, losses to pests could potentially increase, or investments in pest control could increase. Second is weeds. Weeds tend to be stimulated as much by elevated CO2 as the crops, and especially for crops such as corn with the C4 photosynthesis. Many of the major weeds have normal photosynthesis and would most likely be more stimulated than the crops. Third, and probably most important, is climate. Evaluating effects of CO2 on food production without considering CO2 effects on climate is like evaluating DDT based only on its short-term effects on insect control. DDT is a very effective insecticide, but its long-term impacts on other animals is so negative that it would be a big mistake to consider the effects on short-term insect control in isolation. The situation for CO2 is strongly parallel. The connection between atmospheric CO2 and climate is increasingly well-understood, with a vast body of evidence indicating that continued increases in atmospheric CO2 and other heat-trapping gasses will lead to gradual warming of the Earth, the exact amount is still somewhat uncertain. But the Earth has clearly warmed in the last century. And the consensus of the Intergovernmental Panel on Climate Change, which is the collaborative effort of the world's scientists asked to evaluate climate change for the world governments, is that this warming already has the signature of a human caused component. With a warming climate, many, or even all, of the stimulatory effects of elevated CO2 on crop photosynthesis may be eliminated. Recent models of the impacts on U.S. agriculture over the next century, with a combination of elevated CO2 and warming, indicate that the negative effects of climate change, changes in temperature and precipitation, will approximately cancel stimulatory effects of increased CO2. In natural ecosystems, elevated CO2 has similar effects to that on crops, increasing photosynthesis in most plants. In experiments where CO2 is increased, plant growth often increases, though the growth responses tend to be smaller, sometimes even absent in natural ecosystems. Very few experiments have examined the combined effects of elevated CO2 and climate change. This is an area where additional information is critical. If I could have 1 more minute, please. But plant growth is not the only important property of natural ecosystems. Features like recreational value, watershed protection, and biological diversity are also important, potentially sensitive to the direct and indirect effects of elevated CO2. Changes in these values are difficult to predict and could be highly variable from place to place, but some results are suggestive. In studies of California grasslands exposed to elevated CO2, weedy species, with profoundly negative effects on grazing and recreational values, tend to be those that are most strongly stimulated. Many studies report large differences among species and which ones are stimulated and which are not by elevated CO2, and, so far, it is really difficult to have any strong predictions of effects on elevated CO2 on biological diversity. If the winters are weedier introduced species, the effects on biological diversity could be strongly negative. In sum, atmospheric CO2 is a critical component of the atmosphere, but increases in concentration resulting from human actions can have both positive and negative impacts on agriculture and on natural ecosystems. Any negative impacts expressed through climate change will, of course, affect sectors other than agriculture and natural ecosystems. Thank you, Mr. Chairman. [The prepared statement of Mr. Field follows:] Christopher B. Field Department of Plant Biology 260 Panama Street, Stanford, CA 94305 phone: (650) 325 5121 x 213 fax: (650) 325 3748 email: chris@jasper.stanford.edu Testimony before: The House Committee on Government Reform's Subcommittee on National Economic Growth, Natural Resources and Regulatory Affairs and The House Committee on Science's Subcommittee on Energy and the Environment October 6, 1999 Honorable Members of the Committee; I am a staff scientist with the Carnegie Institution of Washington, a non-profit, private research foundation, and a professor by courtesy in the Department of Biological Sciences at Stanford University, where my research group is located. I have conducted research on the global carbon cycle, effects of elevated CO2 on plants and ecosystems, and effects of CO2 on climate for the last 10 years. publishing more than 50 peerreviewed scholarly papers on these topics, including 5 in the most prestigious scientific journals, "Science" and "Nature". My research is supported mainly through competitive programs administered by federal agencies, including the National Science Foundation, NASA, and the Department of Energy. I have also received funding from private organizations, including the US Electric Power Research Institute. Today, I speak as an individual and not as a representative of any agency or organization. I appreciate the opportunity to address this meeting on the topic, "Is CO2 a pollutant, and does EPA have the power to regulate it?" My remarks will focus not on the legal issues, but on plant physiology and physics of CO2 in the atmosphere. I want to emphasize 4 points. First, atmospheric CO2 is essential for life on earth. Second, the concentration of CO2 in the atmosphere has increased dramatically over the last century, as a consequence of human actions. Third, increasing atmospheric CO2 has a mixture of positive and negative effects on plant growth, food security, and natural ecosystems. 1 |