Slash-and-burn agriculture has been used in farming for thousands of years. But this age-old method of cutting down and burning forested areas and then planting crops among the ashes may have contributed enough carbon dioxide into the atmosphere to alter the earth's climate.
The report comes from researchers at the University of Maryland Baltimore County and the University of Virginia and was published in the Aug. 17 issue of Quaternary Science Reviews. The study also notes that modern agricultural practices use far less land than what was once required to grow crops in ancient times.
"They used more land for farming because they had little incentive to maximize yield from less land, and because there was plenty of forest to burn," says lead author William Ruddiman, professor emeritus of environmental sciences at the University of Virginia. "They may have inadvertently altered the climate."
Ruddiman has previously published research indicating that the actions of ancient peoples helped set in motion the current trends in global warming some scientists are observing today. His research, however, has been criticized by certain climate scientists who say the greenhouse gas emissions from this primitive farming techniques pales in comparison to the carbon dioxide being generated by human actions since the Industrial Revolution. Ruddiman's contention is that the actions of pre-Industrial Revolution societies ought to be factored in to climate change models.
Slash-and-burn farming techniques are still used in many developing and remote regions of the world, such as the rain forests. The practice helps temporarily drive away pests and boosts soil fertility. Fire is also used to rejuvenate prairieland used as range for cattle in parts of the American Midwest. This current science news could put a new spin on the climate change discussion, at least for those who agree that the contributions of this farming technique applied by ancient farmers added significantly to the planet's overall greenhouse gas emissions.
Read more about slash-and-burn agriculture here.
Watch a short video taken in March 2009 showing typical slash-and-burn farming in Brazil.
'Slash and Burn' agriculture, Castanheira, Brazil by global_nomad1
"Newly settled families, cut down the rain forest, burn it to reduce the woody debris and release valuable plant nutrient contained in the ash from the burn, and then plant food crops - here the bright green plants are upland rice, which will be followed by cassava, and eventually pasture." ~global_nomad1
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