An Expensive Urban Legend

October 24th, 2009 by Roy W. Spencer, Ph. D.


I contend that the belief in human-caused global warming as a dangerous event, either now or in the future, has most of the characteristics of an urban legend. Like other urban legends, it is based upon an element of truth. Carbon dioxide is a greenhouse gas whose concentration in the atmosphere is increasing, and since greenhouse gases warm the lower atmosphere, more CO2 can be expected, at least theoretically, to result in some level of warming.

But skillful storytelling has elevated the danger from a theoretical one to one of near-certainty. The actual scientific basis for the plausible hypothesis that humans could be responsible for most recent warming is contained in the cautious scientific language of many scientific papers. Unfortunately, most of the uncertainties and caveats are then minimized with artfully designed prose contained in the Summary for Policymakers (SP) portion of the report of the UN’s Intergovernmental Panel on Climate Change (IPCC). This Summary was clearly meant to instill maximum alarm from a minimum amount of direct evidence.

Next, politicians seized upon the SP, further simplifying and extrapolating its claims to the level of a “climate crisis”. Other politicians embellished the tale even more by claiming they “saw” global warming in Greenland as if it was a sighting of Sasquatch, or that they felt it when they fly in airplanes.