High yield crops keep carbon emissions low

June 14, 2010

The Green Revolution of the late 20th century increased crop yields worldwide and helped feed an expanding global population. According to a new report published in the Proceedings of the National Academy of Sciences, it also has helped keep greenhouse gas emissions at bay. The researchers estimate that since 1961 higher yields per acre have avoided the release of nearly 600 billion tons of carbon dioxide to the atmosphere.

"That's about 20 years of fossil fuel burning at present rates," says study co-author Steven Davis of the Carnegie Institution's Department of Global Ecology. "Our results dispel the notion that industrial agricultural with its petrochemicals are inherently worse for the climate than a more 'old-fashioned' way of doing things."

Agriculture is a major source of greenhouse gases. The high-yield crop varieties developed during the Green Revolution produced a bounty of food, but they also increased agriculture's reliance on pesticides, fertilizers, and mechanization. The research team, which also included lead author Jennifer Burney and David Lobell of Stanford University, investigated the net effect of crops on emissions during the period between 1961 and 2005.

They found that although the various inputs to modern farms require more energy and greenhouse gas emissions per unit of food output than did the lower-input methods of the past, have increased by 135%, reducing the amount of cropland needed to produce the same amount of food. Without these advances, the conversion of vast natural areas to agriculture would have caused much more greenhouse gas emissions—the equivalent of nearly 600 billion tons of CO2 since 1961.

"Converting a forest or some scrubland to an agricultural area causes a lot of natural carbon in that ecosystem to be oxidized and lost to the atmosphere" says Davis ."What our study shows is that these indirect impacts from converting land to agriculture outweigh the direct emissions that come from the modern, intensive style of agriculture."

The researchers also calculated the benefits of investing in agricultural research as a strategy for reducing greenhouse gas emissions. They estimate that since 1961 agricultural research has averted carbon dioxide emissions at a cost of about $4 per ton of CO2. The potential for emissions reduction compares favorably with other strategies. Agricultural advances have prevented about 13 billion tons of emissions each year, much more than the estimated 1.8 billion tons obtainable by improvements in energy supply or the estimated 1.7 billion from improved transportation systems.

"Agricultural research is one of the cheapest ways of preventing ," says Davis. "And if the past few decades are a guide, it is also a large source of potential reduction."

Explore further: U.S. greenhouse emissions up 1.7 percent

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not rated yet Jun 15, 2010
This is great news. The increase in runoff emissions from pesticides, fertilizers, genes, drugs needed to grow these crops is irrelevant. It is good for the climate. Oh, They don't mention the huge amount of water needed. Ah well, who needs clean water to live? The climate will be ideal when people eventually die from cancers after eating these high yield crops. Didn't I read somewhere that these food crops will be made into biofuel. Its more profitable than people. This gets better. What a brilliant way to reduce earth's population. Isn't science wonderful?
not rated yet Jun 18, 2010
Hey Tan0r5, your rhetoric is flawed. The only way to build up to the type of analysis you are implying means that one must first conduct each of the sub-studies. Then one can have a complete Life Cycle Assessment including pesticides, fertilizers, water, etc.
not rated yet Jun 18, 2010
One thing not mentioned is the fact 'higher output' crops have less food value/lb thus negating the 'increase'. Faster growing crops just have more water weight, size rather than more food value.

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