Main physical processes and mechanisms responsible for the observable climate changes in the 20-21st centuries

Abstract

We discuss the issues of primary importance for understanding the nature of climate changes in the 20th century and main physical processes responsible for them. Special attention is paid to climate changes which occurred in 1943–1976 and 2000–2014. These periods exhibit the maximum increase in CO2 in the atmosphere, with virtually unchanged global temperature and its reduction in some regions. We study atmospheric and sea surface temperature effects of solar activity. The paper deals with results of the analysis of regularities and peculiarities of a tropospheric and sea surface temperature response to separate heliogeophysical disturbances as well as to long-term solar and geomagnetic activity variations. We also present results of the analysis of a change in sea surface temperature covering the time period 1854–2012 and their relation to solar activity variations. We find further evidence for the solar effect on climatic processes in the troposphere and ocean. We reveal a significant response in the major climatic characteristics, namely, surface air temperature and sea surface temperature (SST). It is established that the climatic response is characterized by significant space-time inhomogeneity, is regional and depends on the climate epoch. We discuss a role of wind stress and thermohaline circulation in the observable climate changes.