An Empirical Approach to the Analysis of Climate Data Dynamics in the Last 60 Years

Abstract

The relationship between global temperature increases and the rise in greenhouse gases (GHG) is assessed by a simple statistical analysis of measured data (20-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. This is done by evaluating a differential quotient of temperature increase divided by GHG increase. Three different global temperature data bases are analyzed, i.e. GISTEMP, NOAA and HadCRUT5. All data sets show a very strict linear behavior (standard error relative to straight line ~1% for five 20-year-averaged values) if only CO2 is considered. 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). The role of other GHG and of aerosols is also discussed. According to the dynamic behavior of the temperatures in the last 60 years their influence seems to be smaller than assessed by the AR6 report for the time period of the last 170 years.