Southern Hemisphere temperature trend in association with greenhouse gases, El Niño Southern Oscillation, and Antarctic Oscillation

Abstract

In this study, the trend of mean seasonal and annual temperatures of the Southern Hemisphere was calculated based on the HadCRUT5 and NASA-GISS data networks, for the period 1901–2021 and 1951–2021. In order to determine the possible effects on temperature, man, or nature, the relationship with CO2 concentration, GHG (greenhouse gases) radiation exposure, and teleconnections ENSO (El Niño Southern Oscillation) and AAO (Antarctic Oscillation) was examined. The obtained results indicate that there is a significant increasing trend of seasonal and annual temperatures in the Southern Hemisphere, which intensified in the period between 1951 and 2021 (from 0.11 to 0.12 °C per decade). According to climate models, one of the indicators of the dominance of the anthropogenic greenhouse effect is the polar amplification (more intense temperature rise going from the equator to the poles). However, polar amplification was not recorded in the Southern Hemisphere, due to the fact that there was the smallest increase in temperature in the belt between 44°S–64°S. Moreover, in the mentioned zone, the positive trend was smaller in the period between 1951 and 2021 than in the period between 1901 and 2021, which was not to be expected. Nevertheless, the Southern Hemisphere temperature showed a statistically significantly strong correlation with the concentration of CO2observed at the Mauna Loa station. It was also found that there is a significant relationship between the energy impact of greenhouse gases and the Southern Hemisphere temperature, which is logical, because with the growth of GHG, positive radiative forcing increases. When it comes to the impact of telecommunications, both considered teleconnections (ENSO and AAO) have an impact on changes in the temperature of the Southern Hemisphere.