08 January 2009

Trees Will Save the World

We need more trees. This is what they did 500 years ago:

The massive depopulation of the Americas via smallpox, hepatitis and other diseases introduced by Westerners (perhaps as much as 95 percent of the existing population died in vast pandemics) and the large landscape-altering scale of agriculture practiced across the "New World" by pre-Columbian cultures are two of the big themes of "1491." Both popped up in a presentation made by two scientists at the annual meeting of the American Geophysical Union last December. (Thanks to MongaBay for the tip.)

The scientists contend that after the die-off, massive reforestation on abandoned agricultural land occurred on a large enough scale to contribute significantly to the period of global cooling between 1500 and 1750 known as the "Little Ice Age."

After examining soil samples and sediment cores from numerous locations in Central and South America, Richard Nevle, a visiting scholar at Stanford's Department of Geological and Environmental Sciences at Stanford, and Dennis Bird, also from Stanford, concluded that the reforestation sequestered as much as 10 to 50 percent of the carbon necessary to cool the earth. Up until 1500, the soil samples showed a steady increase in charcoal content, likely generated from human-caused fire used to clear forest. After 1500, the scientists discovered a drastic drop in charcoal content. No more burning.

The good news is that we've cut down so many trees, there's huge scope for harnessing this effect to mitigate climate change by planting lots of trees.

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