US-China power rivalry mars super pollutant goal

The US wants China to play a greater role in mitigating what it says is the other half of global warming — climate super pollutants — and talks are picking up ahead of the Cop 29 UN climate conference later this year. But trade friction is growing, and Beijing has other priorities.

The US' chief climate adviser, John Podesta, and deputy special envoy for climate, Rick Duke, will visit China for talks with their Chinese counterpart Liu Zhenmin later this year. This follows discussions in May that focused on curbing methane emissions. The US unveiled a plan on 23 July to reduce the environmental impact of methane, hydrofluorocarbons and nitrous oxide (N2O) — greenhouse gases (GHGs) considered far more potent than CO2 — and Podesta, who is expected to focus on N2O when he next meets Liu, has stressed the importance of engaging China. "The world is looking to us to find ways where we can work together… like in these non-CO2 spaces," Podesta says.

Methane is over 80 times more potent than CO2 over the first two decades after its release. N2O is 270 times more potent than CO2 and takes more than 100 years to break down. Almost two-thirds of global adipic acid — an intermediary for nylon 66 and polyurethane — production occurs in China and the US. China accounts for about 94pc of global annual N2O emissions or 134mn t/yr of CO2 equivalent (CO2e) — owing to a lack of abatement — mainly from adipic acid production. The rest of the world accounts for just 8.5mn t/yr of CO2e.

China has had the largest increase in N2O emissions between 1980 and 2020, while emissions from Europe have declined and those from the US have remained relatively stable, according to Oceanic and Atmospheric Research.

China's energy sector, dominated by coal mining, contributes about 45pc of its total methane emissions, while agriculture accounts for another 40pc share. But Chinese coal mines employ more than 1.5mn workers, and output accounts for half of global production, San Francisco-based Global Energy Monitor estimates.

Chinese president Xi Jinping might prefer to keep unemployment low in an economic downturn. China's second-quarter GDP grew by 4.7pc, lower than a 5pc forecast for the year. In agriculture, the state council's action plan aims to boost grain output by 50mn t to nearly 750mn t by 2030, from a record 695mn t last year. The country's first food security law, which requires provinces to incorporate food security into development plans, came into effect in May.

Walking the talk

Ultimately, Beijing needs to assimilate reliable pollution data to tackle global warming, but it stopped publishing methane emissions data in 2014, and has no credible N2O emissions data, although it hopes to better regulate carbon emissions reporting through a new plan. China also has no firm target for methane or N2O emissions reductions. It released its first methane plan in November but is not part of the Global Methane Pledge and its current nationally determined contributions do not cover non-GHGs.

Then there is the familiar US-China rivalry, although Podesta is optimistic. "We are obviously in a period of competition across a range of issues… particularly in the clean energy space but we also need to find ways we can at least understand where each side is going," Podesta says.

Whether Donald Trump or Kamala Harris becomes the next US president, China's green industrial policy is likely to provoke more protectionist measures. And its new subsidy-backed stimulus policy to propel electric vehicle (EV) sales could exacerbate this. Xi said he wants the country to focus on boosting consumption growth in the second half of the year and EVs feature strongly in this agenda.

China's heat-trapping emissions by gas (2020)