Policy Documents

Is the U.S. Surface Temperature Record Reliable?

March 1, 2009

The stakes in the debate over global warming are high. If human activities are causing a major warming of the earth’s atmosphere, then actions to reduce greenhouse gas emissions costing hundreds of billions of dollars would be necessary.

But how do we know if global warming is a problem if we can’t trust the temperature record?

This report, by meteorologist Anthony Watts, presents the results of the first-ever compre-hensive review of the quality of data coming from the National Weather Service’s network of stations. Watts and a team of volunteers visually inspected and took pictures of more than 850 of these temperature stations. What they found will shock you:

“We found stations located next to the exhaust fans of air conditioning units, surrounded by asphalt parking lots and roads, on blistering-hot rooftops, and near sidewalks and buildings that absorb and radiate heat. We found 68 stations located at wastewater treatment plants, where the process of waste digestion causes temperatures to be higher than in surrounding areas.

“In fact, we found that 89 percent of the stations--nearly 9 of every 10--fail to meet the National Weather Service’s own siting requirements ...”

The conclusion is inescapable: The U.S. temperature record is unreliable. And since the U.S. record is thought to be “the best in the world,” it follows that the global database is likely similarly compromised and unreliable.