On the detection of temperature changes induced by increasing atmospheric carbon dioxide

Radiosonde data for approximately the past 25 years have been used to search for the lower‐stratospheric cooling and lesser upper‐tropospheric warming expected, according to many modelling studies, as a result of the increasing concentration of carbon dioxide in the atmosphere. There are no clear indications that the hypothesized temperature changes have occurred. Settling of volcanic dust after the 1963 eruption of Agung, and inhomogeneity in the data resulting from changes in design of radiosondes, may have caused observed loẃer‐stratospheric temperatures to fall in the late 1960s at some stations. Even in the absence of instrumental shortcomings, a further 35 years of radiosonde data, or 20‐25 years of satellite stratospheric sounding data, are a prerequisite for detection of temperature trends of the size predicted by global circulation models for the present rate of increase of atmospheric carbon dioxide concentration.