Monday, February 13, 2012

Soil erosion increasing global warming threat

Nina Chestney in Reuters: Global warming will get worse as agricultural methods accelerate the rate of soil erosion, which depletes the amount of carbon the soil is able to store, a United Nations' Environment Programme report said on Monday. Soil contains huge quantities of carbon in the form of organic matter. which provides nutrients for plant growth and improves soil fertility and water movement.

The top meter of soil alone stores around 2,200 billion tonnes of carbon, which is three times the level currently held in the atmosphere, said the UNEP Year Book 2012. "Soil carbon is easily lost but difficult to rebuild," the report said.

"Soil carbon stocks are highly vulnerable to human activities. They decrease significantly (and often rapidly) in response to changes in land cover and land use such as deforestation, urban development and increased tillage, and as a result of unsustainable agricultural and forestry practices."

Such activities can break down soil's organic matter. When this happens, some carbon is converted to carbon dioxide, a greenhouse gas that is one of the main contributors to global warming, and it is lost from the soil. Around 24 percent of global land has already suffered from declines in health and productivity over the past quarter of a century due to unsustainable land use, UNEP said....

Soil in France, shot by Lionel Allorge, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported

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