Errors Cited in Assessing Climate Data

By ANDREW C. REVKIN

Some scientists who question whether human-caused global warming poses a threat have long pointed to records that showed the atmosphere's lowest layer, the troposphere, had not warmed over the last two decades and had cooled in the tropics.

Now two independent studies have found errors in the complicated calculations used to generate the old temperature records, which involved stitching together data from thousands of weather balloons lofted around the world and a series of short-lived weather satellites.

A third study shows that when the errors are taken into account, the troposphere actually got warmer. Moreover, that warming trend largely agrees with the warmer surface temperatures that have been recorded and conforms to predictions in recent computer models.