Many proponents of the IPCC’s (United Nation's climate panel) AGW (human induced global warming) hypothesis consider the evidence for their theory incontrovertible and view it as “settled science.” They reject all skepticism as mere denial, and appeal to the consensus of the climate science community against the “deniers.’ There are, of course, crackpots on both sides of the issue who receive frequent attention from the media. However, the “skeptics” are by no means without credentials. They are former NASA scientists, university professors, physicists, climatologists, and National Academy of Science researchers, who are highly respected in their fields.
The media coverage of this issue might lead one to believe that the debate is over. But, papers and articles continue to be published by recognized scientists and authors like Roy Spencer, Roger Pielke Sr., Richard Lindzen, Douglas Hoyt, William Cotton, Robert Carter, and Willie Soon. These scientists maintain that (1) many of the projections put forth by the IPCC lack adequate scientific support; (2) too much emphasis has been placed upon the role of CO2; (3) the level of confidence in computer modeling is misplaced; and (4) the IPCC has overemphasized the anthropogenic contribution to climate change by underrating natural fluctuations in climate, some of which are not yet fully understood.
Scientists who disagree with the IPCC’s science do not necessarily rule out an anthropogenic contribution to climate change. What they do oppose, however, is reducing a complex problem like climate change to one primary forcing agent, namely, CO2. According to the National Academy of Science, other types of human activity such as land use changes (e.g., deforestation, urbanization) and aerosol pollution (e.g., soot, sulfur, etc.) may contribute significantly to human induced climate change, especially on a regional basis. The IPCC has largely ignored these factors. There is a wide range of opinions on the long distance effects of such regional forcings (teleconnections), and how much overall impact they have on global climate. Much more data would be needed in order to answer these questions. Nevertheless, these types of human activity demand very different intervention strategies than we are pursuing at present, with the reduction and sequestration of CO2 emissions.
In my view, the IPCC’s AGW hypothesis provides a foundation upon which a more complex model of climate change can be built. In the meantime, we should be cautious about placing our faith in climate models that vastly oversimplify the actual climate system. Supporting evidence for the IPCC’s projections does not warrant the high level (90%-95%) of confidence exhibited by its authors. Much less should these projections be used, at this point, for making public policy decisions. Though the latest IPCC report (2007) concludes that global warming, due to increased CO2, is a virtual certainty, the authors themselves raise fundamental doubts about our scientific understanding of radiative forcing agents and climate change, both past and present.
(Dr DiPuccio worked as a weather forecaster in the US Navy and as a Meteorological Technician for the National Weather Service (Dulles) and Central Weather Service (Chicago). More recently he has served as head of the science department for St Nicholas Orthodox School (Cuyahoga Falls, OH) which closed in 2006. He continues to write science curriculum, conduct summer science camps, and volunteer as a trained storm spotter.