Until recently, conflicting studies suggested that temperatures measured by satellites revealed a slight cooling trend, whereas the surface temperature record showed a warming trend. This confounded the global warming issue.

Satellites began measurements in 1979 and the surface tempe- rature record, which reveals global warming of c. 1.1 degree F, dates back to about 1860. Satellite measurements are known to be influenced by ozone layer depletion, which has caused cooling of the upper atmosphere. Then scientists discovered that they had neglected some measurement and calibration problems with the satellites, including the fact that satellites were falling from their orbits, which produced an artificial cooling trend.

Correcting the satellite data for these problems reveals a small warming trend. These corrections bring the satellite record into better agreement with surface measurements. Any remaining discrepancies do not invalidate the fact that surface temperatures are rising.