nitrogen fertilizers Archives

May 12, 2023

Flaws in carbon credit programs for farms draw concerns

As fears about climate change grow, a new “gold rush” of carbon credit programs are incentivizing US farmers to slash greenhouse gas emissions generated by the practices they use growing crops and raising livestock. But experts say the programs face difficulty in ensuring that the credits provided truly match emission cuts.

The US Environmental Protection Agency (EPA) estimates that agriculture accounted for 11.2% of US greenhouse gas emissions in 2020. Greenhouse gases trap heat from the sun in the atmosphere, triggering harmful climate changes and increasing temperatures worldwide. Carbon dioxide is released when farmers till their fields, for instance, and nitrous oxide, a greenhouse gas with almost 300 times more warming potential than carbon dioxide, is released when farmers spread fertilizer or manure on their fields.

In one increasingly popular mitigation strategy, private carbon programs pay farmers for implementing practices known to reduce greenhouse gas emissions, generating credits that can then be sold to large corporations wanting to use the credits to offset their own emissions. One tradable carbon credit equals one ton of carbon dioxide, or the equivalent amount of a different greenhouse gas reduced, sequestered or avoided.

Many programs pay farmers for planting cover crops — a practice shown to limit the amount of carbon dioxide that soils release into the air. But few offer any incentives for farmers to reduce nitrous oxide emissions, though nitrous oxide is a highly potent greenhouse gas. A 2021 report estimated nitrous oxide made up for 2.4% of total global greenhouse gas emissions, while the EPA estimates nitrous oxide makes up over half of all greenhouse gas emissions from agriculture.

As the popularity of carbon credit programs grows, concerns and questions about the validity of the programs to truly reduce greenhouse gas emissions from farms are also emerging. Carbon credit schemes have been criticized for a lack of rigorous accounting of the amount of carbon dioxide lost from soils. Additionally, the difficulty of measuring nitrous oxide emissions could mean some businesses are paying for carbon credits that don’t really reduce emissions as much as promised.

That’s the “worst-case scenario,” said Eric Slessarev, a biogeochemist at the Lawrence Livermore National Laboratory. “We better hope we’re right, on average, because if we’re not right, then we’re in trouble,” he said.

January 19, 2023

Report finds “vicious cycle” between pesticide dependence and climate change

By Shannon Kelleher

Pesticide use is a significant factor in harmful climate change, contributing to greenhouse gas emissions in multiple ways, according to a report issued this week.

The report released by the Pesticide Action Network (PAN) North America found that greenhouse gases are emitted during production of these pesticides as well as when they are applied to crops, and later on, as they linger in the soil. In turn, climate change creates conditions that lead to greater pesticide use, creating a vicious cycle.

“Some pesticides themselves are powerful greenhouse gases,” Margaret Reeves, a senior scientist at PAN North America in California and an author of the report, said during the webinar announcing the report.

Reeves cited a pesticide called sulfuryl fluoride as an example. The fumigant has nearly 5,000 times the potency of carbon dioxide, and in 2018 alone, three million pounds of sulfuryl fluoride were applied in California for agricultural purposes, Reeves said.

A 2021 study found that sulfuryl fluoride remains in the atmosphere for about 36 years.

Last year environmental groups filed a petition urging the California Air Resources Board to phase out sulfuryl fluoride due to its impact on climate change, arguing that phasing out sulfuryl fluoride would provide the same climate benefits as taking 1 million cars off US roads each year.

Reeves said many pesticides also release volatile organic compounds (VOCs), which react with nitrous oxide to produce ground-level ozone, a greenhouse gas that harms human lungs and burns plant tissue. The US Department of Agriculture has found that ozone may damage plants more than all other air pollutants combined.

Synthetic pesticides are, in essence, petrochemicals, and the fossil fuel industry and pesticides are inextricably linked, according to Asha Sharma, organizing co-director for PAN North America in California and an author of the report.

“We can’t address climate without addressing the dependency that conventional agriculture has on fossil fuels and pesticides,” she said.