Late last year, the U.S. 9th Circuit Court of Appeals in San Francisco ruled that the National Highway Traffic Safety Administration must consider the “risks of global warming” when setting gas-mileage standards for light trucks, minivans and SUVs.

Central to the court’s ruling was the claim that NHTSA, in violation of the National Environmental Policy Act, had ignored the benefits of reducing emissions of the greenhouse gas carbon dioxide (CO2).

Whatever their legal acumen, Justice Betty Fletcher and her colleagues on the bench demonstrated they have little expertise in climate science. Tighter restrictions on CO2 emissions cannot produce the imagined benefits. Greenhouse gas emissions occur globally: The court’s mandate will not measurably curb CO2 levels or global warming.

The court also assumed that human activity is the main cause of global warming. This has yet to be demonstrated by hard evidence.

The U.N. Intergovernmental Panel on Climate Change (IPCC) points to glacial melting, shrinking sea ice, and other consequences of global warming. But such “evidence” doesn’t tell us whether the causes are natural or manmade. Other evidence, such as the claimed correlation between temperature and CO2, is circumstantial; during much of the 20th century the climate was cooling while CO2 levels were rising.

A forthcoming report by the Nongovernmental International Panel on Climate Change (NIPCC), of which I am the editor, may provide needed balance. An independent organization, not sponsored by the United Nations, national governments, or industry, NIPCC—which includes many IPCC authors and expert reviewers—was created to provide a second opinion on the IPCC’s official findings, much as a physician’s diagnosis may warrant a second opinion.

Drawing on peer-reviewed publications in major scientific journals, NIPCC examined the data used in IPCC’s May 2007 climate-change assessment, as well as research ignored in the IPCC report or published subsequent to its release. NIPCC concludes that “evidence” to support public hysteria about human-caused greenhouse warming does not hold up to scrutiny. Among the findings, expected to be published early this spring:

  • Human activities—such as transportation and industrial production—contribute little to global warming. The claim that greenhouse gas emissions are responsible for rising global temperatures is based on computer models. But as NIPCC confirms, key temperature readings contradict the models. For example, while all greenhouse models show temperature trends rising with altitude in the tropical troposphere—the lowest portion of the Earth’s atmosphere—weather balloon data show the opposite: a cooling trend. The models are wrong.
  • Greenhouse warming has been significantly overestimated. NIPCC has found that the models exaggerate the warming effect of greenhouse gases by ignoring “negative feedback” from—that is, the possible cooling effects of—clouds and water vapor. Taking this into account, greenhouse warming might amount to no more than one-half of 1 degree Celsius by 2100, well within the climate’s normal range of ups and downs.
  • The leading cause of observed climate warming appears to be variability of solar emissions and solar magnetic fields. The U.N. panel ignored substantial recent research on the effects of solar activity on climate change. This evidence suggests climate changes are essentially unstoppable and cannot be influenced by controlling CO2 emissions.
  • Government efforts to curb greenhouse gas emissions will have little effect on the environment. The requirements of the 1997 Kyoto Protocol and the 2007 Bali Climate Declaration cannot influence the natural factors controlling the climate. Similarly, massive government efforts to replace fossil fuels with ethanol, biodiesel, and wind and solar power will little effect the climate. Besides, they are uneconomic and require large subsidies.

In view of these findings, the Justice Department should appeal the 9th Circuit’s ruling to the Supreme Court. Doing so would also provide an opportunity for the high court to revisit its April 2007 decision in Massachusetts v. EPA—in which it ruled that the Environmental Protection Agency has the authority to regulate CO2 as a pollutant.

This time around, the White House should be better prepared to argue its case. Science is on its side.