What to tell environmental activists about agriculture…

The next time an environmental activist, or even just a curious consumer, asks you about the greenhouse gas emissions from modern production agriculture, direct them to this study, conducted by Stanford University.

The study reviewed how the advances in high-yield agriculture achieved during the so-called Green Revolution have not only helped feed the planet, but also have helped slow the pace of global warming by cutting the amount of biomass burned – and the resulting greenhouse gas emissions – when forests or grasslands are cleared for farming. Stanford researchers estimate those emissions have been trimmed by over half a trillion tons of carbon dioxide.

A few major points that research found:

  • Yield improvements reduced the need to convert forests to farmland.
  • Researchers estimate that if not for increased yields, additional greenhouse gas (GHG) emissions from clearing land for farming 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 in 1850.
  • For every dollar spent on agricultural research and development since 1961, emissions of the three principal GHG – methane, nitrous oxide and carbon dioxide – were reduced by the equivalent of about a quarter of a ton of carbon dioxide – a high rate of financial return compared to other approaches to reducing the gases.
  • Researchers found that without the advances in high-yield agriculture, several billion additional acres of cropland would have been needed.
  • Comparing emissions in the theoretical scenarios with real-world emissions from 1961 to 2005, the researchers estimated that the actual improvements in crop yields probably kept GHG emissions equivalent to at least 317 billion tons of carbon dioxide out of the atmosphere, and perhaps as much as 590 billion tons.
  • Without the emission reductions from yield improvements, the total amount of GHG pumped into the atmosphere over the preceding 155 years would have been between 18 and 34 percent greater than it has been.

To read more, the paper was released last week in the Proceedings of the National Academy of Sciences.

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