Assessment of Measured Time Averaged Global and Regional Temperatures Including the Year 2023 and Determination of CO2 Sensitivities

As an extension of earlier investigations on the development of global temperature increase in the last 60 years an update is given as the temperatures for 2023 are now available and as a major update of NOAA temperature data is also available. The relationship between global temperature increase and the rise in greenhouse gases (GHG) is assessed by a simple statistical analysis of measured data (based on 20/21-year averaging). A purely empirically derived (transient) relationship for the last 60+ years, covering an interval of roughly 100 ppm CO2 plus equivalent other greenhouse gases, is calculated. Five different global temperature data bases are analyzed, all data sets show a rather strict linear behavior (standard error relative to straight line ~1-2% for twelve 20/21-year-averaged values) of temperature vs. CO2. An average value for this empirical “CO2 sensitivity” of the global temperature is around 0.011 °C/ppm CO2 (temperature including equivalent GHG and other effects). It is shown that this finding is equivalent to a similar linear relationship documented in the AR6 report of the IPPC (temperature vs. cumulative CO2 emissions). There are deviations from linearity when considering only global land and global ocean. The ratio of temperature increase of land to global seems to be higher than indicated in the AR6 report, at least in the last 50 years (more than 1.6). In addition, also “CO2 sensitivities” are calculated for many regions on earth. In the North of Asia/Europe, the temperature increase is even accelerated as a function of CO2.