13 Aug 1998 Study Challenging Validity of Satellite Global Temperature Data Flawed

A study released yesterday suggesting that satellite data showing a drop in the earth’s temperature over the past 18 years is wrong is fatally flawed. The study thus has no impact on the ongoing global warming debate.

The study, written by Frank J. Wentz and Matthias Schabel, claims that because NASA’s orbiting satellites can lose altitude as they circle the globe, temperature data collected by these satellites has been inaccurate. Wentz and Schabel further suggest that, with these altitude drops factored in, the temperature of the planet has warmed 0.13 degrees per decade rather than declined by 0.09 degrees per decade.

But there are several key problems with Wentz’s and Schabel’s conclusions, among them:

* The satellite measurements showing no global warming have been corroborated by weather balloon measurements. If this satellite data were significantly off, satellite and weather balloon measurements should have diverged.

* While Wentz and Schabel adjusted their data to take into account “false cooling” due to declining satellite altitudes, they failed to adjust their data for “false warming” caused by other factors.

* Wentz and Schabel used adjusted data in their study instead of raw data, overstating the impact of the satellite orbital decay in the process.

“The Wentz/Schabel study is fatally flawed and is thus of little use in the current global warming debate,” said David Ridenour, Vice President of The National Center for Public Policy Research. “The bottom line is that satellite data — which has consistently shown no warming trend — remains the most reliable means of measuring the earth’s temperature. Satellites cover 99% of the surface of the planet. By contrast, reliable ground temperature data over the past 100 years covers just 18.4% of the planet.”

The National Center for Public Policy Research is a non-profit, non-partisan educational foundation based in Washington, D.C.