Intensive farming and global warming

I am well aware of the many people who question the science promoting the concept that global warming is actually occurring. To you I beg your indulgence.

But for the many people who do accept global warming as fact, a recent study conducted by Stanford University puts modern agriculture in a favorable light for lessening the contributions to global warming.

According to the study led by two Stanford earth scientists, advances in high-yield agriculture over the latter part of the 20th century have prevented massive amounts of greenhouse gases from entering the atmosphere — to the tune of 590 billion metric tons of carbon dioxide. Now that’s pretty impressive.

To many people modern agriculture represents a giant contributor to ecological and environmental degradation, with its large-scale farms and reliance on petroleum-based fertilizers. But, as pointed out in this study, the alternative may do much more damage. The researchers note that a less-productive agricultural system would destroy more acres of wild land, drive up greenhouse gas emissions and wreak havoc on biodiversity. Optimistically, the study suggests that further agricultural intensification will play a critical role in the future in addressing global warming.

The study was published in mid-June. For the many advocates who like to criticize the various practices of modern-day agriculture, the research points out that the myriad advances in high-yield agriculture achieved during the so-called Green Revolution have not only helped feed the planet, but have also 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.

The notion that increasing crop yields preserves forests and other native lands dates back to the father of the Green Revolution, the late U.S. plant scientist Norman Borlaug, and is known as the Borlaug hypothesis.

“In the beginning, we weren’t even sure whether the carbon savings from land use would outweigh the increased agricultural emissions,” says David Lobell, an agricultural scientist at Stanford University and co-author of the study. After all, the fertilizers used in intensive farming increase emissions of greenhouse gases. All told, agriculture was responsible for about 12 percent of human-caused greenhouse gas emissions.

“Yet the balance turns out to be favorable,” says Lobell, “and the carbon savings are quite large.

The yield improvements reduced the need to convert forests to farmland, a process that typically involves burning of trees and other plants, which generates carbon dioxide and other greenhouse gases. The researchers estimate that if not for increased yields, additional greenhouse gas emissions from clearing land for farming would have been equal to as much as a third of the world’s total output of greenhouse gasses since the dawn of the Industrial Revolution in 1850. Also, all other things being equal, the researchers found that agricultural advances between 1961 and 2005 spared a portion of land larger than Russia from development.

Furthermore, the researchers also calculated that for every dollar spent on agricultural research and development since 1961, emissions of the three principal greenhouse gases – methane, nitrous oxide and carbon dioxide – were reduced by the equivalent of about a quarter of a ton of carbon dioxide – a high level of financial return compared to other approaches to reducing the gases.

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

“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 being burned,” she notes. “Yield intensification has lessened the pressure to clear land and reduced emissions by up to 13 billion tons of carbon a year.”

To evaluate the impact of yield intensification on climate change, the researchers compared actual agricultural production between 1961 and 2005 with hypothetical scenarios in which the world’s increasing food needs were met by expanding the amount of farmland rather than by the boost in yields produced by the Green Revolution.

“Even without higher yields, population and food demand would likely have climbed to levels close to what they are today,” says Lobell. “Lower yields per acre would likely have meant more starvation and death, but the population would still have increased because of much higher birth rates,” he says. “People tend to have more children when survival of those children is less certain.”

The Stanford researchers concluded that improvement of crop yields should be prominent among a list of strategies to lessen global greenhouse emissions.

“The striking thing is that all of these climate benefits were not the explicit intention of historical investments in agriculture,” Burney notes. “This was simply a side benefit of efforts to feed the world. If climate policy intentionally rewarded these kinds of efforts, that could make an even bigger difference. The question going forward is how climate policy might be designed to achieve that.”

The Stanford study represents yet another good example of agriculture’s positive contributions to protecting the planet while feeding a hungry world. Industry detractors should learn, from the information in this research, that modern agriculture is not the monster it’s been made out to be. For those of us working inside agriculture, this is just another shining example that we are on the right track.

TAGS: Management
Hide comments


  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.