Ole Humlum, emeritus professor of physical geography, University of Oslo, Norway: Temperature records for the Earth’s surface show that 2020 was a comparatively warm year, but that by the end of the year there was a marked cooling driven by natural ocean cycles in the Pacific. This cooling was also observed higher in the atmosphere.
Sea ice levels globally remained low, but are now increasing in the Southern Hemisphere. Global snow cover remained stable and there is still no significant trend in tropical storms.
“The weather and weather extremes we are experiencing are still dominated by natural fluctuations. Rapid and frightening changes are nowhere to be seen in the observational data as this annual review shows.”