James Hansen et al. (1998) in the 14 August 1998 issue of Science give an overview of the comparison of results from global climate models and surface, tropospheric, and stratospheric temperature measurements in light of recent corrections to satellite-based microwave sounding unit (MSU) temperatures (Correction to satellite based temperature record changes cooling trend to a warming trend) by Wentz and Schabel (1998). Wentz and Schabel (1998) corrected satellite data from 1979 to 1995 and concluded that, in contrast to the cooling trend shown by previous analyses of the lower troposphere, the corrected data show a warming trend that is more consistent with observations at the surface, middle troposphere, and lower stratosphere.
Hansen et al. (1998) compare the corrected observations with results from a global climate model that successively included effects of sea surface temperatures, stratospheric aerosols, increased greenhouse gases, ozone, and variation in solar irradiance. The model results with all these forcings are in good agreement with the corrected measurements, showing a warming in the troposphere and cooling in the stratosphere. The model atmosphere warms slightly more than the real atmosphere but the difference is within the uncertainty of the climate forcings, the model parameterizations, and the temperature observations.
Hansen, who in 1988 was the first climate modeler to express conviction that humans were contributing to global warming, and his co-authors conclude by stating:
"The bottom line of this convergence could be a sea change in the global warming debate. Until now, the MSU data have been the principal refuge for those who deny the reality of global warming. We believe that warming trends of both the surface and troposphere are now sufficiently clear that the issue should no longer be whether global warming is occurring, but what is the rate of warming, what is the practical significance, and what should be done about it."
Reference
Hansen, James E., Makiko Sato, Reto Ruedy, Andrew Lacis, and Jerry Glascoe, 1998: Global climate data and models: A reconciliation. Science, 281, 930-932.