Scientists say there is no evidence of catastrophic man-made global warming
Contact:
Dr. Sallie Baliunas, Astrophysicist
The Harvard-Smithsonian Center for Astrophysics, c/o Tel: (202) 546-4242
Dr. Willie Soon, Physicist
The Harvard-Smithsonian Center for Astrophysics, Tel: (617) 495-7488
Laura Jones, Director, Centre for Studies in Risk and Regulation
The Fraser Institute, Tel: (604) 714-4547, Email lauraj@fraserinstitute.ca
For Release: 1 November 2001
VANCOUVER, BC— The popular hypothesis that increases in carbon dioxide in the atmosphere resulting from increased industrial activity have caused global temperatures to rise over the past century and, if unchecked, will cause catastrophic warming is incorrect, according to a new book Global Warming: A Guide to the Science, released today by The Fraser Institute.
Temperature Changes over the Last Century Largely a Natural Phenomena
The temperature at the surface of the earth, measured by thermometers placed on land and sea at locations around the globe, has risen by about 0.5°C to 0.6°C over the last one hundred years-before most of the greenhouse gases were added to the air by human activities such as the burning of fossil fuels. Temperatures peaked by around 1940, then cooled until the 1970s. Since then, there has been a surface warming.
"Since approximately 80 percent of the rise in levels of carbon dioxide during the twentieth century occurred after the initial major rise in temperature, the increase in carbon dioxide cannot have caused the bulk of the past century's rise in temperature. Most of the warming must have been natural," explains Dr. Sallie Baliunas, co-author of the book. Dr. Baliunas is an astrophysicist at The Harvard-Smithsonian Center for Astrophysics and Deputy Director at the Mount Wilson Observatory.
"What is even more unsettling is the fact that the primary impact of the greenhouse effect of added carbon dioxide is in the lower atmosphere (rather than surface), but accurate measurements of that layer of air by U.S. National Oceanic and Atmospheric Administration or NOAA satellites over the last 22 years have not shown any hint of global warming. In other words, the whole idea of carbon dioxide causing global warming just does not add up," Baliunas continues.
The Inadequacy of Climate Change Models
Concern that the continued increase in the concentration of carbon dioxide in the air will lead to a disastrous rise in the global temperature stems mainly from computer-based simulations of the climate system, forecast through the next century. The common tool for a computer simulation of the climate is the General Circulation Model (GCM). The climate models are an integral part, not only of the science of climate change, but also of the policy debate.
However, current models are not sufficiently accurate in forecasting future climate change. At present, it is impossible to isolate the effect of an increased concentration of atmospheric carbon dioxide on climate.
"It is not surprising that it is still impossible to reliably calculate the impact of increases in the concentration of atmospheric carbon dioxide on our climate. At any moment, around five million different variables have to be followed in a computer mock-up of the climate. All their important impacts and interactions must be known, yet it is certain that they are not all known," says co-author, Dr. Willie Soon. Dr. Soon is a physicist at The Harvard-Smithsonian Center for Astrophysics and a senior scientist at the George C. Marshall Institute.
The aggregate outcome of various computer climate models is often listed as between a 1.5°C and 4.5°C rise in global temperature for a doubling of atmospheric carbon dioxide. However, Soon points out "given the substantial uncertainties associated with the modeling enterprise, the outcomes of these models, which are subject to large systematic errors, cannot be averaged and represented as a consensus result."
Furthermore, a number of different approaches give results lying outside the range of temperature change normally output by GCMs. For example, analysis of the climatic response to volcanic eruptions suggests a climatic system yields a climatic sensitivity of only 0.4°C for a doubling of carbon dioxide in the air.
Increased Atmospheric Carbon Dioxide Beneficial
Based on extensive evidence from agricultural research on enhanced carbon dioxide environments both in the field and in laboratories, increases in carbon dioxide should cause many plants to grow more quickly. In experiments doubling the air's carbon dioxide content, the productivity of most herbaceous plants rises 30 percent to 50 percent, while the growth of woody plants rises more so. In addition, most plants tend to use water more efficiently under air with higher carbon dioxide concentration.
"In the case of recent fears of anthropogenic carbon dioxide, science indicates that, at most, a little warming and, certainly, better plant growth will result from the projected future increase of carbon dioxide content in the air, " concludes Dr. Baliunas, "an optimal warming and enhanced plant growth should be of great benefit to mankind and the environment."
The Risk Controversy Series
Global Warming: A Guide to the Science is the first publication in The Fraser Institute's Risk Controversy Series, which will explain the science behind many of today's most pressing public-policy issues. The purpose of the Risk Controversy Series is to promote good policy, based on sound science and sound economics, by providing readers with information from scientists about the complex science involved in many of today's important policy debates. Upcoming issues of the Risk Controversy Series will investigate genetically modified food and misconceptions about the causes of cancer.
Established in 1974, The Fraser Institute is an independent public policy organization based in Vancouver with offices in Calgary and Toronto.