Global mean temperature can be estimated from surface and from tropospheric measurements. Much has been written recently concerning trends in the various time series over short (10–15 year) periods. This paper compares the surface, 850–300 mb and the microwave sounding unit (MSU) channel 2R measurements on the ‘global’ scale. The various series show marked differences in their trends over the 1979–93 period with the surface data showing significant warming and the troposphere no change. The difference can be explained by the shortness of the record and by the transitory nature of volcanic and El Niño/Southern Oscillation effects on global temperatures. Correcting or factoring out these influences and extending the period of analysis leads to a greater conformity in the results, which show temperatures have risen by about 0.1°C per decade since 1958.