The Dirt on Climate Change

Though they have always been prized by farmers, the dark soils of the Amazon were largely forgotten by science for a century after their discovery. They are now re-emerging as an important topic of study, not because they're an ethnographic or historical curiosity, but because they show an exceptional ability to store carbon, which in the form of carbon dioxide has rapidly turned into one of humanity's most pernicious waste products. As a result, they're joining the rapidly growing roster of tactics that might be used to combat climate change. Researchers around the world are considering whether people may, by engineering soils specifically to maximize carbon storage, be able to absorb substantial amounts of our emissions, increase the fertility of agricultural areas and dampen some of the effects of climate change. But it's not just plants and animals that hold carbon. Soils do, too, a lot of it — an estimated 2.5 trillion tons worldwide, or more than three times the amount floating around in the atmosphere and about four times as much as in all the world's living plants. About 60 percent of the soil's carbon is in the form of the organic molecules that compose living things, while the other 40 percent is in inorganic forms such as calcium carbonate, the crusty salt common in desert soils...read more