Tuesday, June 20, 2006

Earth's Climate Is Always Warming or Cooling

From the WSJ Letters page today (subscription required):

Earth's Climate Is Always Warming or Cooling

Roger C. Altman ("The Beltway's Energy," editorial page, June 16), a Treasury official in the Clinton administration, says he is no climatologist, but then calls for energy policies that assume catastrophic global warming from carbon dioxide emitted in fossil-fuel burning. He doesn't reveal his sources of information -- perhaps they are just various "experts" quoted in the press, or perhaps even Al Gore. But Mr. Gore, in his movie and elsewhere, never asks the key question: How much of current warming is due to natural causes? And how much is really human-caused? Anthropogenic warming is simply taken for granted as part of a claimed but nonexistent "complete" scientific consensus.

The current warming trend is not unusual: Climate is always either warming or cooling, and ice is either melting or accumulating. But thermometers can't talk and tell you the cause of climate change. This requires a comparison of the patterns of the observed warming with the best available models that incorporate both anthropogenic (greenhouse gases and aerosols) as well as natural climate forcings.

Fortunately, the U.S.-Climate Change Science Program, funded at $2 billion annually, has done just that in its first report: http://www.climatescience.gov/Library/sap/sap1-1/finalreport/default.htm.

It is based on the best current information on temperature trends. So how well do observations confirm the results of greenhouse models? The answer: not at all. The disparity between theory that predicts a climate disaster and actual data from the atmosphere is demonstrated most strikingly in the report's Fig. 5.4G (p. 111), which plots the difference between surface and troposphere trends for a collection of models and for balloon and satellite data.

Allowing for uncertainties in the data and for imperfect models, there is only one valid conclusion from the failure of greenhouse theory to explain the observations: The human contribution to global warming appears to be quite small and natural climate factors are dominant.

This conclusion should have a crucial influence on shaping our energy future. We hope that Mr. Altman, and the Bush team in Treasury, will pay attention to the science before advocating drastic energy policies that would kill economic growth.

S. Fred Singer
Arlington, Va.

(Mr. Singer, an atmospheric physicist, is professor emeritus of environmental sciences at the University of Virginia and former director of the U.S. Weather Satellite Service.)