The conversion of the planet’s ecosystems into cropland — particularly in tropical rainforests — is stretching the Earth’s ability to store carbon, according to a new study. The demand for new agricultural land is growing most rapidly in the tropics, due to growing populations, changing diets, food security concerns, and a rising demand for biofuels.
But not only is the crop yield weakest in those regions, the clear-cutting of tropical forest results in twice as much carbon released into the atmosphere per unit of land as in temperate regions, since the forests act as massive carbon sinks, according to the study published the Proceedings of the National Academies.
“In terms of balancing the needs of food production and slowing carbon dioxide emissions, this is a tough tradeoff,” said Jonathan Foley, director of the University of Minnesota’s Institute on the Environment and co-author of the study, which researchers call the most comprehensive analysis on the tradeoff between carbon storage and crop production.
Researchers suggest a better alternative to clearing new cropland is more efficient use of existing farmland.