Dead Heat: The Science Is in on Global Climate Change, and the Picture Isn't Pretty
Athanasiou, Tom, Baer, Paul, Earth Island Journal
Severe climate change--and with it chains of storms, floods, heat waves, droughts, and even cold snaps--is now virtually inevitable, and will bring widespread ecological destruction, extinction, and human suffering. Continued dithering will lead to climatic instability on a truly terrifying scale. We're entirely dependent on science to understand the climate problem and the demands it makes upon our responses. Some strategies will work and others won't, and we need a good grasp of both the science and the politics to tell the difference.
So bear with us, if you will, as we discuss concentration caps, radiative forcing, climate sensitivity, and increased climatic variability. We'll try to make this as painless as we can.
The IPCC's assessments
The global-warming crisis has given rise to a unique scientific body, the Intergovernmental Panel on Climate Change (IPCC). The IPCC brings together thousands of scientists from around the world to provide assessments of the threat, the science that allows us to know the threat, and the uncertainty of that science.
So-called skeptics have attacked the integrity of the IPCC, but a recent report by the US National Academy of Sciences--one the Bush administration itself requested--strongly endorsed both the IPCC's process and its assessments, and denied that they have become politicized. Indeed, the NAS report Climate Change Science: An Analysis of Some Key Questions forced the administration into a position in which it either had to admit the seriousness of the climate change problem or be seen as turning its back on science. Only days after its release in June 2001, George W. Bush conceded that "the National Academy of Sciences indicates that the [temperature] increase is due in large part to human activity," but nevertheless went on to repudiate the Kyoto Protocol as "fatally flawed."
This move--from "the science is uncertain" to "the treaty is flawed"--is being forced upon the fossil-fuel cartel. "Climate skepticism" has come to remind even mainstream observers of a tobacco company PR campaign.
The Bush people hate the IPCC, and there are reasons why. The IPCC's tasks include the preparation of "state of the science" assessments every five years, and these reports have played a crucial role in making the situation clear.
Greenhouse gas basics
Human-generated (anthropogenic) greenhouse gases such as C[O.sub.2] warm the Earth by trapping additional solar radiation within the atmosphere. Many gases besides C[O.sub.2] act as greenhouse gases, most notably water vapor, but also methane (C[H.sub.4]), nitrous oxide ([N.sub.2]O), and fluorocarbons (some of which, the chlorofluorocarbons, or CFCs, are being phased out due to their ozone-destroying properties). The greenhouse effect is natural. Before humans started increasing the concentrations of these gases in the atmosphere, these gases worked together to create a "blanket" that kept the Earth far warmer than it would otherwise have been.
Unfortunately, once the Industrial Revolution began to leverage the cheap energy of fossil fuels, atmospheric concentrations of greenhouse gases began to rise rapidly. Since the 1700s, C[O.sub.2] alone has increased from about 275 parts per million (ppm) to over 370 ppm, and it continues to rise at about 1.5 ppm per year. The significance of this increase is measured first in terms of radiative forcing--the amount of additional energy trapped or reflected by the greenhouse gases that humans have added to the atmosphere.
Positive radiative forcing means an increase in the energy absorbed from the sun, and it produces the kinds of changes you'd expect--generally warmer temperatures, and changes in the patterns and variability of the weather. The current increase in radiative forcing attributable to humans for just C[O.sub.2] is about 1.4 watts of solar energy per square meter, almost half of the increase expected from a doubling of C[O. …