What does the climate do do advocates have in common with fossil fuel companies, auto companies and agricultural lobbyists? Not much, yet all unite to promote “carbon agriculture” as a form of “regenerative agriculture”. The idea is to use cultivated plants and pasture grass to extract carbon dioxide from the atmosphere and move it underground, primarily through root systems. Factories do it naturally, of course, but advocates are now saying that the process, if handled properly by farmers, could significantly offset our greenhouse gas emissions from burning fossil fuels.
Al Gore, our main climate advocate and himself a farmer from Tennessee, is promoting this idea through an “underground carbon” initiative. The new chair of the United States Senate Agriculture Committee, Debbie Stabenow (D-Michigan), has pledged to make carbon agriculture a “priority. »President Joe Biden explicitly kissed this vision during his 2020 campaign, when he called for “decarbonizing the food and agricultural sector and leveraging agriculture to remove carbon dioxide from the air and store it in the soil”. A policy note linked to Biden’s transition team proposed a “carbon bankTo allocate $ 1 billion in taxpayer money to buy “carbon credits” from farmers who adopt approved practices.
Private companies are also getting involved. IBM, JPMorgan Chase, Cargill, General Mills, Bayer and Chevrolet plan to deliver on some of their corporate climate commitments by purchase of credits farmers who practice “regen ag”. It looks like the carbon-producing train is already leaving the station.
But before you put taxpayer dollars on this train, consider some inconvenient truths: First, carbon farming practices touted as something new have all been in use for decades and were all originally adopted for reasons. unrelated to climate change. Rebranding these practices as a climate solution should arouse suspicion.
We plant cover crops out of season to reduce erosion and manage soil fertility long before climatic fears arise. No-till farming took off during the energy crisis of the 1970s as a way to save on fuel costs and has now been renamed to suck carbon from the atmosphere. The same is true of “holistic grazing”, originally proposed in the 1970s as a means of protecting the arid lands of Africa from the fate of deserts.
Measuring the carbon gains sequestered over an entire agricultural field or large pasture is a major challenge. Soil types and conditions vary so much that soil samples must be taken from many places and from many depths. Cristine Morgan, Scientific Director of the Soil Health Institute, Explain that “you can walk a few feet, 100 feet, or 10 feet, and you have a different amount of carbon.” Even some organizations that currently promote carbon agriculture admit that this is a limitation. The American Farmland Trust concedes that detecting changes in soil carbon “can take many years and decades due to the measurement challenges caused by high spatial variability”. The carbon agriculture train got started in part because its claimed benefits were virtually impossible to prove or disprove.
However, some of these claims are highly suspect. Holistic grazing is a method of herding that brings animals together tightly, continuously moving them from place to place to mimic the way ruminants in Africa graze on the open plains. Proponents now say this method accumulates enough carbon in the soil to compensate for the large amounts of methane that animals spit out. They point to peer review study published in the journal Agricultural systems in 2018, but this study was based on an improbable rate of carbon capture nine times higher than the rate observed in previous studies of “intensive grazing management”.
Independent experts are deeply skeptical of the difference carbon farming can make. In May 2020, the World Resources Institute concluded that regeneration methods were generally good for soil health, but the “limited scientific understanding of what keeps soil carbon sequestered” leads to “uncertainty as to whether regeneration practices actually sequester additional carbon.”
This uncertainty will not bother farmers wishing to sell the credits, nor companies wishing to buy them. Farmers want money and businesses want to meet their climate commitments without having to change their own behavior. Write in the MIT Technology Review in June 2020, editor-in-chief James Temple warned that carbon farming could become bogus climate solution in which companies “claim credit for carbon dioxide extracted from the atmosphere, without reducing emissions from their own operations.” Temple noted that even some fossil fuel companies such as BP and Shell were stepping in.