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Global WarmingScience

Unexpected Impact of Green Revolution on Climate Change

The Green Revolution of the late 20th century saw advances in high-yield agriculture which scientists are only now realizing had a massive impact on climate change.

[social_buttons]Researchers have estimated that if not for the increased yield of crops the additional greenhouse gases that would have been entered into the planet’s atmosphere would have been equal to as much as a third of the world’s total output of greenhouse gases since the dawn of the Industrial Revolution.

“Our results dispel the notion that modern intensive agriculture is inherently worse for the environment than a more ‘old-fashioned’ way of doing things,” said Jennifer Burney, lead author of the research and study that will be published online by the Proceedings of the National Academy of Sciences.

Scientific Improvements

The improvements in crop yield reduced the need to convert more forests into farmland, which typically involves burning the forest to the ground, in turn releasing the carbon dioxide stored in the biomass into the atmosphere. In this way several billion additional acres of cropland were not needed.

“Every time forest or shrub land is cleared for farming, the carbon that was tied up in the biomass is released and rapidly makes its way into the atmosphere – usually by being burned,” she said. “Yield intensification has lessened the pressure to clear land and reduced emissions by up to 13 billion tons of carbon dioxide a year.”

And though agriculture accounts for about 12% of human generated greenhouse gas emissions, including the increased production and use of fertilizer, these emissions are insignificant compared to the amount generated if additional forest and grasslands had been converted to farmland.

Cost Effective Research

On top of the sheer amount of greenhouse gases avoided, high-yield crop research has been an unexpectedly cheap method to reduce greenhouse gases. The researchers calculated that for every dollar spent on agricultural development since 1961, which included the discovery of high-yield crop, emissions of the three main greenhouse gases dropped by the equivalent of about a quarter ton of carbon dioxide.

“When we look at the costs of the research and development that went into these improvements, we find that funding agricultural research ranks among the cheapest ways to prevent greenhouse gas emissions,” said Steven Davis, a co-author of the paper and a postdoctoral researcher at the Carnegie Institution at Stanford.

Not Alone

Despite the apparent cost effectiveness of high-yield crops on the reduction of greenhouse gases the authors were quick to note that only raising yields will not guarantee lower emissions. “It has been shown in several contexts that yield gains alone do not necessarily stop expansion of cropland,” Lobell said. “That suggests that intensification must be coupled with conservation and development efforts.

“In certain cases, when yields go up in an area, it increases the profitability of farming there and gives people more incentive to expand their farm. But in general, high yields keep prices low, which reduces the incentive to expand.”

Source: Stanford University

Image Source: KevinLallier




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