Some updated statistical assessments of the surface temperature response to increased greenhouse gases

Abstract

In an earlier study we analysed the surface temperature response to increasing atmospheric carbon dioxide (CO₂) concentrations based on long-term observational climate time series using multiple regression statistical techniques. Moreover, these assessments were compared with the results from general circulation model experiments. Recently we have used improved climate data sets, added ENSO (El Niño/Southern Oscillation) forcing to our multiple regression models, improved the volcanic forcing parameters and introduced phase shifts of the temperature response to the forcing parameter time series. In addition, we used not only CO₂ but also ‘equivalent’ CO₂ concentrations accounting for additional greenhouse gases. The results of these updated assessments are briefly summarized.