The first details of a potential, and possibly massive, climate agreement between the U.S. and China were announced at a climate summit at the White House on Tuesday. 

The initiative could significantly reduce emissions of nitrous oxide, a potent and largely overlooked greenhouse gas that also harms the ozone layer. Targeting this N2O pollution from a limited number of chemical plants in the two countries offers an opportunity to quickly reduce a large volume of greenhouse gas emissions at little cost.

Biden administration officials and climate scientists who track so-called super-pollutants say bilateral efforts targeting industrial N2O began after Inside Climate News reported on these emissions from factories in the U.S. and China, showing how a powerful source of greenhouse gas emissions could be easily eliminated.

If successful, the two countries could reduce greenhouse gas emissions equivalent to taking approximately 50 million automobiles off the road at a fraction of the cost of other emission reduction efforts.

“This is a big opportunity,” Manish Bapna, president of the Natural Resources Defense Council, said at an event hosted by nonprofit groups Tuesday morning prior to the summit. “The fruit is large, it’s low [hanging], it’s ripe.” 

“We are dealing with our emissions quickly in the United States, of industrial N2O, and rolling up sleeves to tackle a far bigger prize that’s also very tractable in China,” a senior Biden administration official who spoke on condition of anonymity said on a call with reporters in advance of the event.

The White House Summit on climate super-pollutants wasn’t limited to nitrous oxide. Announcements included initiatives to address methane and other potent greenhouse gases.

Sarah Kapnick, the chief scientist for the National Oceanic and Atmospheric Administration, announced a partnership with United Airlines that will place monitoring equipment for methane and nitrous oxide on one of the airline’s commercial airplanes to help NOAA better track concentrations of the pollutants in the U.S. 

Efforts outlined to reduce nitrous oxide rely heavily on voluntary industry participation. Prior efforts to curb the super-pollutant incentivized chemical plants to reduce their emissions in exchange for carbon credits they could sell to others that needed to offset their own pollution. Those efforts failed to achieve lasting emissions reductions, prompting some environmental advocates to question whether new voluntary measures and carbon offset credits would succeed.

“What is needed to curtail these dangerous emissions is sustained emissions reductions through strong regulations and enforcement,” said Avipsa Mahapatra, climate campaign director for the Environmental Investigation Agency US, a nonprofit based in Washington. “Offsets simply don’t work.” 

Nitrous oxide is the third leading driver of climate change after carbon dioxide and methane. On a pound-for-pound basis, N2O is 273 times more potent as a greenhouse gas than CO2. Unlike other climate super-pollutants like methane, it is long-lived, remaining in the atmosphere for more than a century.

Nitrous oxide is also the leading human-caused pollutant that depletes atmospheric ozone, which protects the Earth from harmful ultraviolet radiation from the sun.

Existing abatement technologies have the potential to reduce industrial N2O emissions up to 99 percent. 

The United States and China account for nearly 80 percent of industrial N2O emissions. Emissions come from a limited number of chemical plants that produce adipic acid, an ingredient in the manufacturing of high-strength nylon; nitric acid, used to make fertilizer; and caprolactam, a chemical used to make other polymers and in pharmaceutical and food manufacturing. 

The U.S. and China committed to cooperative efforts to reduce N2O emissions in November. In May, U.S. and Chinese officials led by John Podesta, Biden’s senior advisor for international climate policy, and Liu Zhenmin, China’s special envoy for climate change, agreed to “engage in technical cooperation and capacity-building for measurement and abatement solutions of other non-CO2 greenhouse gases, including industrial N2O.”

At the White House summit Tuesday on climate super-pollutants, and the separate nonprofit-organized event focused exclusively on nitrous oxide, U.S. policymakers, researchers, industry leaders and environmental organizations outlined a plan to significantly reduce industrial emissions in the next decade. The events focused on U.S. reductions that could help drive a bilateral U.S.-China effort. Hu Jianxin, a professor from Peking University, also participated remotely from China via a video call.  

U.S. companies showcased new actions that, by early 2025, will reduce overall U.S. industrial emissions of nitrous oxide by over 50 percent since 2020, according to a White House fact sheet. 

The White House said that Ascend Performance Materials, the largest producer of adipic acid in the United States, installed additional pollution controls at its Florida plant that have virtually eliminated N2O emissions.

Ascend had previously reduced nitrous oxide emissions at its adipic acid plant in Pensacola, Florida, by 67 percent from 2021 to 2022, the most recent year for which data is publicly available, Inside Climate News reported. Ascend made those reductions voluntarily and sells its emissions reductions as carbon offsets.

ClimeCo, the largest developer of industrial N2O abatement projects in the United States, announced new emission-reduction projects that will come online by early 2025 and reduce nitrous oxide pollution at three industrial facilities by approximately 95 percent.

Adipic acid plants in China destroyed nitrous oxide emissions under a carbon offset market administered by the U.N. in the mid-2000s. Participating plants abated virtually all of their nitrous oxide emissions, but the incentives they received, totaling more than $1 billion, created a perverse incentive that led to overproduction and distorted global markets. A 2020 Inside Climate News investigation found that when funding for the program dried up in 2012, Chinese factories most likely stopped using the pollution control systems already installed at their facilities.

One former industry insider who tried unsuccessfully to get adipic acid companies to voluntarily reduce emissions told Inside Climate News last year that he opposed new initiatives that incentivize emission reductions. Other adipic acid plants in Europe and the United States began doing so without incentives decades ago.

However, carbon market rules recently developed for trading nitrous oxide emission reductions have safeguards designed to limit misuse. Adipic acid manufacturers in China, for example, can only earn carbon credits for destroying the final 10 percent of nitrous oxide emissions at their plants; the first 90 percent must be abated without any financial incentives.

“With the right incentives and guardrails to ensure ambitious credible climate action, high integrity [voluntary carbon markets] can be an important tool in our common toolbox,” Podesta, Biden’s senior advisor for international climate policy, said at the nonprofit-led event Tuesday morning. “It’s not a lot of the time that we find ourselves with an affordable and relatively straightforward way to eliminate emissions quickly, equivalent to tens of millions of cars on the road. Cutting industrial nitrous oxide pollution is that opportunity. So I think we need to seize it together.”