The best of EcoWatch, right in your inbox. Sign up for our email newsletter!
How Carbon Farming Can Reverse Climate Change
Are there agricultural practices that might offer more potential than the ones commonly discussed in the “carbon farming” conversation? In a companion post, I wrote about what the science tells us about cover cropping and reduced tillage, two practices getting a lot of attention in what I’ve called the “carbon farming” rage. Here I want to address some more agroecological practices, those that incorporate ecological principles and what is known from field research about their ability to add carbon to the soil.
What Do We Know About Soil Carbon Potential Beyond the Basic Conservation Practices?
There is less research on the relationship of agroecological practices, such as crop rotations, agroforestry and improved grazing-based systems, with soil carbon—but what is known is very positive. A synthesis paper of global field studies found that crops in rotation plus cover crops increased total soil carbon by 8.5 percent. Some estimates have suggested that when land is shifted from use for growing agricultural crops to pasture for livestock, carbon increases significantly (by 19 percent, according to one study synthesizing several research sites). The same analysis found that returning some cropland to forest could lead to even larger soil carbon gains (up to 53 percent).
On grazing lands, which cover around 25 percent of lands globally, changes to management (for example, compost additions or improved grazing practices such as fertilizer additions or the use of native plant communities) can increase soil carbon such that small changes make a big difference when scaled up. Further, on the option of integrating of trees into agricultural lands, scientists have estimated the potential of agroforestry systems to increase soil carbon to be approximately 95 times greater than the conservation practices of no-till, cover crops and crop rotations (as estimated by one analysis that looked at many studies in the tropics).
This is quite impressive untapped potential, particularly when considering that many of these ecological practices receive a fraction of public research dollars. Of course, some of these practices require taking a small amount of land out of production, but if done strategically on low yielding unprofitable sections of a field, such diversification practices could offer a “win-win” in the form of cost savings for producers and environmental benefit for all.
Even With Complexities in the Science, Carbon Farming Deserves the Attention
Carbon farming is a topic of growing interest for both the research and policy communities. The science is complex. Researchers in the fields of ecology, agronomy, forestry, soil science and biogeochemistry, among others, dedicate entire careers toward this area. It can take a lot of soil sampling to detect changes, which is expensive and potentially difficult. Soils are highly variable from one location to another. The initial carbon content of soil heavily influences how much carbon can be increased.
It is important to note that there are other emissions linked to agricultural management decisions, so any net change in the carbon sink is just one piece of the overall greenhouse gas emissions picture. One example of this from my own work is that cover crops may lead to small increases in nitrous oxide emissions, depending upon management.
Finally, something else I found in my research was that the warmer temperatures resulting from climate change may drive increased carbon decomposition—all the more reason to get started sooner rather than later growing the soil carbon sink.
It is important to conclude explicitly that not all carbon farming practices are equal. Many equate to working around the edges rather than systemically changing our design of agricultural systems and landscapes. As I’ve discussed here and in a companion post, the current science indicates that the approaches offering the greatest opportunities to increase soil carbon are those which increase the amount of crops covering the soil in both space and time (which would increase the total carbon input to the soil “budget”) and/or incorporate multiple carbon farming principles. If the agriculture sector is going to get serious about soils as a sink for carbon (and agriculture as a net sink of greenhouse gas emissions), more comprehensive research, combined with appropriate policy and economic incentives, will be necessary.
Andrea Basche is a Kendall Science Fellow in the Union of Concerned Scientists food and environment program.
YOU MIGHT ALSO LIKE
EcoWatch Daily Newsletter
Global Banks, Led by JPMorgan Chase, Invested $1.9 Trillion in Fossil Fuels Since Paris Climate Pact
By Sharon Kelly
A report published Wednesday names the banks that have played the biggest recent role in funding fossil fuel projects, finding that since 2016, immediately following the Paris agreement's adoption, 33 global banks have poured $1.9 trillion into financing climate-changing projects worldwide.
By Patti Lynn
2018 was a groundbreaking year in the public conversation about climate change. Last February, The New York Times reported that a record percentage of Americans now believe that climate change is caused by humans, and there was a 20 percentage point rise in "the number of Americans who say they worry 'a great deal' about climate change."
England faces an "existential threat" if it does not change how it manages its water, the head of the country's Environment Agency warned Tuesday.
By Jessica Corbett
A new analysis revealed Tuesday that over the past two decades heat records across the U.S. have been broken twice as often as cold ones—underscoring experts' warnings about the increasingly dangerous consequences of failing to dramatically curb planet-warming emissions.
By Madison Dapcevich
Ask any resident of San Francisco about the waterfront parrots, and they will surely tell you a story of red-faced conures squawking or dive-bombing between building peaks. Ask a team of researchers from the University of Georgia, however, and they will tell you of a mysterious string of neurological poisonings impacting the naturalized flock for decades.
The initial cause of the fire was not yet known, but it has been driven by the strong wind and jumped the North Santiam River, The Salem Statesman Journal reported. As of Tuesday night, it threatened around 35 homes and 30 buildings, and was 20 percent contained.
The unanimous verdict was announced Tuesday in San Francisco in the first federal case to be brought against Monsanto, now owned by Bayer, alleging that repeated use of the company's glyphosate-containing weedkiller caused the plaintiff's cancer. Seventy-year-old Edwin Hardeman of Santa Rosa, California said he used Roundup for almost 30 years on his properties before developing non-Hodgkin's lymphoma.
"Today's verdict reinforces what another jury found last year, and what scientists with the state of California and the World Health Organization have concluded: Glyphosate causes cancer in people," Environmental Working Group President Ken Cook said in a statement. "As similar lawsuits mount, the evidence will grow that Roundup is not safe, and that the company has tried to cover it up."
Judge Vince Chhabria has split Hardeman's trial into two phases. The first, decided Tuesday, focused exclusively on whether or not Roundup use caused the plaintiff's cancer. The second, to begin Wednesday, will assess if Bayer is liable for damages.
"We are disappointed with the jury's initial decision, but we continue to believe firmly that the science confirms glyphosate-based herbicides do not cause cancer," Bayer spokesman Dan Childs said in a statement reported by The Guardian. "We are confident the evidence in phase two will show that Monsanto's conduct has been appropriate and the company should not be liable for Mr. Hardeman's cancer."
Some legal experts said that Chhabria's decision to split the trial was beneficial to Bayer, Reuters reported. The company had complained that the jury in Johnson's case had been distracted by the lawyers' claims that Monsanto had sought to mislead scientists and the public about Roundup's safety.
However, a remark made by Chhabria during the trial and reported by The Guardian was blatantly critical of the company.
"Although the evidence that Roundup causes cancer is quite equivocal, there is strong evidence from which a jury could conclude that Monsanto does not particularly care whether its product is in fact giving people cancer, focusing instead on manipulating public opinion and undermining anyone who raises genuine and legitimate concerns about the issue," he said.
Many regulatory bodies, including the U.S. Environmental Protection Agency, have ruled that glyphosate is safe for humans, but the World Health Organization's International Agency for Research on Cancer found it was "probably carcinogenic to humans" in 2015. A university study earlier this year found that glyphosate use increased cancer risk by as much as 41 percent.
Hardeman's lawyers Jennifer Moore and Aimee Wagstaff said they would now reveal Monsanto's efforts to mislead the public about the safety of its product.
"Now we can focus on the evidence that Monsanto has not taken a responsible, objective approach to the safety of Roundup," they wrote in a statement reported by The Guardian.
Hardeman's case is considered a "bellwether" trial for the more than 760 glyphosate cases Chhabria is hearing. In total, there are around 11,200 such lawsuits pending in the U.S., according to Reuters.
University of Richmond law professor Carl Tobias told Reuters that Tuesday's decision showed that the verdict in Johnson's case was not "an aberration," and could possibly predict how future juries in the thousands of pending cases would respond.