NCPA - National Center for Policy Analysis

California's Foggy Global Warming Forecast

July 24, 2002

Even though there are a lot of doubts about global warming -- Is it real? Are we responsible? Can we stop it? -- California has plunged ahead, becoming the first state to attempt to reduce carbon dioxide emissions.

Yet the computer models on which California's climate control policy is based are too primitive and theoretic to rely on. Sallie Baliunas, an astrophysicist and senior scientist at the George C. Marshall Institute, says ", these models are not reliable for forecasting climate."

For example, take computer models of clouds, which scientists think could ultimately account for half of any future temperature change. There is still no agreement as to whether clouds will ultimately cool or warm the climate, and there is also no effective way of modeling them.

  • In 1995, a leading British climate model predicted a temperature increase of 5.2 degrees Celsius if the carbon dioxide concentration doubled.
  • But when the scientists improved a few ways in which they modeled clouds, the computer predicted a rise of only 1.9 degrees.
  • But each climate model has five million variables, which can interact in 10-million trillion ways -- so scientists can only guess about the effects of most of them.

In the face of such uncertain science, politics has driven much of the debate. A good example is the 2000 U.S. National Assessment on Climate Change, the first report on what global warming means for the United States. The Assessment was put together by a team of scientists (containing only two credentialed climatologists) picked by the Clinton Administration. Although there are dozens of climate scenarios, the report picked the two showing the most extreme warming outcomes. The resulting report was described by Patrick Michaels, former president of the American Association of State Climatologists, as misleading, misstating, ignoring or underplaying many facts.

Source: Editorial, "California in the Clouds," Wall Street Journal, July 24, 2002.

For WSJ text (requires subscription),,SB1027473205149175760,00.html


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