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The last time soil health was perceived as a pressing public concern was at the peak of the Dust Bowl in the 1930s. Now, for the first time in nearly a century, it has once again piqued policymakers’ interest as awareness grows that the ground beneath our feet is a crucial carbon sink, making the soil a potentially powerful tool to fight the climate crisis. Speaking at an Earth Day summit last month, President Joe Biden said, the “soil of our Heartland [is] the next frontier in carbon innovation,” reflecting the momentum behind an idea known as “regenerative agriculture.” But just as the nation is waking up from its long slumber about the importance of soil, new research shows that the pesticides so commonly used in American agriculture are devastating the very organisms that ensure dirt becomes healthy soil and not just dust.
As a set of chemical poisons, pesticides pose an undeniable hazard to the life of soil. This new study—from Friends of the Earth, the Center for Biological Diversity, and the University of Maryland—is the first comprehensive review of the impact of pesticides on soil organisms. Researchers (including one of us) analyzed nearly 400 studies focused on the effect of pesticides (a term that includes insecticides, herbicides, and fungicides) on 275 species or groups of soil invertebrates, from beetles and earthworms to mites and ground-nesting bees. In 71 percent of cases, pesticides either directly killed the organisms being tracked or significantly harmed them; for example, by impairing their growth and reproduction or decreasing their abundance and diversity. These findings parallel previous research that illustrates pesticides’ impact on vital soil microorganisms like bacteria and fungi.
Other research reveals troubling trendlines: A recent study found that pesticides’ toxic impact on many invertebrates has nearly doubled in the past decade because of the increasing use of two specific classes of pesticides: neonicotinoids and pyrethroids. Some neonicotinoids are 1,000 times more toxic to bees than the infamous pesticide DDT, and they linger in the environment for months or years, creating a compounding toxicity in the environment. Another study found that since neonicotinoids were first introduced in the 1990s, US agriculture has become 48 times more toxic to insect life. Scientists warn that the loss of invertebrates threatens the collapse of ecosystems—and that biodiversity loss is a crisis on par with climate change.
The findings of this new study should alarm us not only because they further underscore the starring role pesticides play in the decline of insect populations, but also because the life of soil is at the heart of its ability to capture and store carbon. What do we mean by the “life of soil”? Plants breathe in carbon from the air, then store it in their bodies and exude it through their roots. Hidden from our view, a teeming ecosystem of microorganisms transfers carbon from roots to soil. Invertebrates such as earthworms and springtails feed on fallen plants, breaking them down and excreting carbon-rich casts and feces, mixing organic matter into the soil as they go.
The aliveness of soil also bolsters farmers’ resilience in the face of climate-change-driven weather extremes like droughts and floods. Invertebrates are ecosystem engineers: With their tunnels and burrows, they craft soil structures, enabling the flow of nutrients, air, and water below ground. This allows the land to readily absorb water during intense rains and retain it during times of drought, much like a massive sponge.
In short, healthy soil is living soil. So it should be no surprise that chemicals designed to kill are at odds with the objectives of regenerative agriculture. Research shows that the very farmers who are not using hazardous pesticides are among the most successful at capturing carbon. Organic farmers—who are expressly prohibited from using over 900 agricultural pesticides and who have long championed regenerative approaches like cover cropping, crop diversification, and composting—can sequester up to 25 percent more carbon in soil and achieve deeper and more persistent carbon storage than farmers using chemical approaches.
Yet some of the loudest voices in the national conversation on soil are the companies behind the world’s most toxic pesticides. Last month, pesticide giants including Bayer-Monsanto and Syngenta were among the prominent backers of the reintroduced Growing Climate Solutions Act (GCSA), a bill that would channel interest in regenerative agriculture into soil carbon markets.
That means farmers would be paid to sequester carbon—and then those “carbon credits” would be sold to polluters, allowing them to keep polluting. There’s no doubt that farmers should be supported in shifting to regenerative methods. But the evidence shows that using carbon markets to do so is an oversimplified and dangerous approach that will “let big polluters off the hook and fail the needs of family farmers,” says the National Family Farm Coalition. Carbon markets have repeatedly failed in their primary goal of reducing greenhouse gas emissions. They have been plagued by fraud, and in many cases they have worsened pollution in low-income communities and communities of color, even resulting in human-rights abuses across the globe. Moreover, measuring soil carbon in a uniform way to ensure integrity in soil carbon markets will likely remain an elusive goal because soil carbon fluctuates based on the seasons, and samples taken even from the same field can lead to very different results.
In light of this new study’s findings, another fundamental flaw of carbon markets is particularly concerning: They can be gamed by powerful players. Hence, the support from pesticide giants. Bayer, for instance, is pushing the passage of GCSA because the company stands to win big. If the bill passes, the US Department of Agriculture (USDA) would facilitate farmers’ participation in private schemes like the new Bayer Carbon Initiative. Farmers would enroll in Bayer’s digital agriculture platform, Climate FieldView, and implement certain practices—dictated by Bayer—to receive compensation. Bayer would then sell credits for farm-sequestered carbon to polluters. But programs like Bayer’s are designed to accommodate the largest industrial-style farms and depend on use of the company’s patented seeds and toxic pesticides like glyphosate, a weed killer with known impacts on soil organisms like earthworms. Even more perverse, Bayer may pay farmers in the form of credits to be redeemed in the Bayer PLUS Rewards Platform—credits that are most efficiently spent on more Bayer products.
While we celebrate that the conversation about soil and climate change is becoming mainstream, it’s imperative that the resulting policies are driven by science, not by the interests of agrochemical companies. The successful conservation programs that emerged from the Dust Bowl era can show us the way. Rather than spend billions of federal dollars creating market mechanisms that will enrich pesticide corporations and further entrench their power at the expense of family-scale farmers, the environment, and our health, we can invest in long-standing but under-resourced programs like the USDA’s Conservation Stewardship Program, Environmental Quality Incentives Program, and National Organic Program. And, we can update these programs to facilitate equitable participation of BIPOC farmers and to reflect the latest science on ecologically regenerative practices.
During the Dust Bowl, the crisis was visible: Plumes of dust from the plains swept across the country and darkened the skies in Washington, DC. Today, the soil story is hidden in the ecosystems beneath our feet, but the crisis is just as pressing. This study is an urgent missive that the renewed national interest in healthy soil must result in policies that support truly regenerative efforts that build healthy, living farming systems.