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Carbon dioxide Sources - Land-use Change

It is estimated that man-made changes in land-use have, until now, produced a cumulative global loss of carbon from the land of about 200 thousand million tonnes. Widespread deforestation has been the main source of this loss, estimated to be responsible for nearly 90 percent of losses since the mid-nineteenth century. Losses primarily occur due to the relatively long term carbon sinks of forests being replaced by agricultural land.

The conversion of land from forested to agricultural land can have a wide range of negative effects as far as greenhouse gas emission is concerned. Soil disturbance and increased rates of decomposition in converted soils can both lead to emission of carbon to the atmosphere, with increased soil erosion and leaching of soil nutrients further reducing the potential for the area to act as a sink for carbon.

Human Impact

Man's need for wood, for fuel and construction, and our ever increasing need for agricultural land has led to systematic clearances of forests across the planet in the last few hundred years. Today the pressure on forested areas is huge, with a rapidly growing human population requiring food and the land necessary for its growth.

Potential for control

Land-use change is driven by a host of social, political and economic factors around the world. Increased awareness of the most sensitive way to manage land and the better agricultural practice, combined with political agreement on food trade and avoidance of deforestation, are required if land-use change is not to continue being a net global source of carbon to the atmosphere in years to come. Indeed, having degraded large areas of the terrestrial carbon sink, sensitive land-use change may in fact provide a sink for atmospheric greenhouse gases in the future.


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