Existing research aimed at addressing global climate change often focuses on a single key greenhouse gas: carbon dioxide. However, several additional polluting gases also contribute significantly to planetary warming. These include short-lived climate pollutants or “SLCPs,”  which remain in the atmosphere for shorter periods of time yet still contribute to climate warming, including methane, black carbon, ozone, and fluorinated gases (F-gases). Combined, these pollutants may account for up to 45% of climate warming. These gases can also exacerbate other climate-related impacts, such as the melting of Arctic ice and local air pollution. 

The latest science from the Intergovernmental Panel on Climate Change indicates that it is imperative to address these short-lived climate pollutants as well as carbon dioxide in order to have a chance to meet the 1.5 degree Celsius threshold for warming to help stave off the worst impacts of climate change.

Increasingly, countries - including the U.S. and China - have set long-term net carbon neutrality goals. Reducing short-lived climate pollutants can be an important strategy in helping achieve these goals by mid-century. Notably, at a global financial forum last month, Chinese Climate Envoy Xie Zhenhua drew attention by becoming the first Chinese official to clarify that China’s long-term 2060 carbon neutrality goal also covers non-carbon dioxide gases, like methane and hydrofluorocarbons (HFCs). This is significant as many observers previously assumed the target was intended to cover only carbon dioxide emissions. 

Emerging research from The California-China Climate Institute provides a review of international best-practices on curbing short-lived climate pollutants,  including how action can be incorporated in long-term carbon neutrality plans. The report, “Opportunities to Tackle Short-lived Climate Pollutants and other Greenhouse Gases” describes quantitative modeling scenarios used to identify pathways for cost-effective emissions reductions over the near, medium, and long-term. 

As the world’s largest emitter of methane and second largest emitter of HFCs, China has a critical role to play in the abatement of these short-lived gases. In 2014, China, alone, accounted for more than 20% of global non-carbon dioxide (“non-CO2”) gases. Notably, at U.S. President Biden’s Leaders’ Summit in April 2021, China pledged to implement the Kigali Amendment to the Montreal Protocol, which aims to help phase down HFCs, and its 14th Five-Year Plan includes provisions for strengthening controls of non-CO2 gases. 

The Institute’s analysis finds, for example, opportunities for the following reduction potentials for China:

The authors highlight the importance of multi-policy and multi-gas strategies in their analysis, drawing out examples of these approaches from California, Canada, and The European Union. For example, California moved to reduce certain short-lived climate pollutant emissions 40%  by 2030 (below 1990 levels) through legislation and followed with a comprehensive Short-Lived Climate Pollutant Strategy. Meanwhile, earlier this year, the U.S. Environmental Protection Agency put forward a regulation to phase out HFCs from air conditioners and refrigerators - a model others could replicate.

The Institute’s research identifies four key international best-practices:

1. Addressing multiple greenhouse gases in tandem to achieve synergies across scales and sectors;
2. Developing clear quantitative targets to enhance implementation; 
3. Utilizing a mix of policy tools and levers to overcome barriers; and 
4. Implementing effective monitoring, reporting, and verification. 

The report reveals important avenues for traction and international collaboration on short-lived climate pollutants, including countries’ updating their Nationally-Determined Contributions under the Paris Agreement before COP26 to account for short-lived climate pollutants, and implementing the Kigali Amendment on Hydrofluorocarbons under the Montreal Protocol. 

To read the full report and learn more, click here.