Anthropogenic impact on the climate since man began to hunt

Abstract

Processes, such as mountain building, changes in ocean gateways, natural changes in the carbon cycle and orbital changes, are ‘established’ mechanisms for climatic changes. This paper focuses on human contributions in Africa to climatic changes. When man began to kill megaherbivores (body weight above 1000 kg), about 3.5 Ma BP, he interfered with the ecological balance of the African continent. With the progressing loss of large game through hunting and ecological feedbacks, litter and vegetation could accumulate, providing fuel for devastating ‘natural’ fires: concomitant decomposition and, hence, fertilization declined. The intentional use of fire by man since about 1.5–1.9 Ma BP intensified the impact on the biosphere. The further eradication of game and use of fire led to an impoverishment of fauna and flora. Domesticated animals, imported during the Holocene, added to the ongoing environmental destruction. These animals emit significant amounts of methane (CH4), affecting the atmosphere, while wildlife releases hardly any CH4.