A Big History of Land Clearance and Deforestation

The gathering and hunting humans who evolved from earlier manifestations of Homo changed the distribution of forests on the planet through their use of fire to direct biological productivity to their sustenance, and through their contribution to the elimination of much of the global terrestrial megafauna. Land clearance at any scale awaited the development of agriculture, the several independent origins of which may indicate that it is an emergent outcome from the combination of a social animal who can transmit knowledge through generations and who lives in environments that support high numbers of food plants. The transition from uncleared forest and treeless land to land cleared for agriculture was slow, often reversed, and limited by the necessity to produce more energy in food production than in the inputs that created comestibles. Increases in cleared land until the nineteenth century were largely a product of the displacement of gathering and hunting people by disease-ridden European agriculturalists and world trade imposed on non-Europeans by colonialists. The explosion in fossil fuel usage from the nineteenth century onwards enabled exponential growth in human populations and cleared land, with the consequence of a crash in forest cover. Ironically, attempts to mitigate global warming caused by increased fossil fuel use, deforestation and land clearance have resulted in more land clearance for biofuels. While settlements, roads, logging, plantation establishment and dam construction have all contributed to the decrease in the native terrestrial cover of the planet, their contribution has been minor compared to the massive impact of agricultural development.