Post-Glacial Development of Climate and Forest Ecosystems

Abstract

Climate is one of the driving forces of environmental and ecosystem changes and, thus, its evolution has to be considered in relationship to the historical development and expansion of forest ecosystems. Apart from ongoing human impacts on the climate system (Chap. 4), there exist a number of external and internal factors that cause long- and short-term changes of the Earth’s climate. Among them are variations in the cosmic ray and material fluxes, variations in solar radiation (solar constant) and solar activity (sunspot activity), variations in the seasonal and latitudinal distribution of solar radiation due to changes of the Earth’s orbit and ecliptic (eccentricity, obliquity, precession), and variations of tidal forces, the cryosphere and the sea level. However, there are factors that are instead caused by the Earth itself and exert strong influences on the climate and its variability. These factors include the changing distribution of land and ocean surfaces (due to continental drift), orographic features (such as those caused by mountain formation), variations in the albedo (reflectivity) of the Earth’s surface, volcanic activity and the occurrence of Vegetation flres. These factors influence the atmospheric concentration of radiatively active gases and aerosols, cloud parameters, terrestrial Vegetation cover and changes in oceanic and atmospheric circulation and oceanic salt content (Schönwiese 1979; Flohn 1985; Kutzbach and Webb 1993; Bradley and Jones 1995).