• Portfolios / Non-CO₂ Mitigation

    Improving indoor and outdoor air quality can help avoid 6.8 million premature deaths each year.

  • Portfolios / Non-CO₂ Mitigation

    Enhancing emissions controls on marine vessels can help preserve Arctic sea ice and slow dangerous sea-level rise.

  • Portfolios / Non-CO₂ Mitigation

    Limiting ozone pollution could save enough grain worldwide to feed 1.5 billion people per year.

Annual Emissions Reductions Potential / 2030 Breakdown by ClimateWorks Priority Regions

Annual Emissions Reductions Potential / 2030 Breakdown by ClimateWorks Priority Regions

Annual Emissions Reductions Potential / Breakdown by ClimateWorks Priority Regions

Key Data Points

Rapidly reducing non-CO₂ emissions could cut global warming 0.6°C by 2050 and save millions of lives.


The Montreal Protocol cut chlorofluorocarbons more than 80%, and can do the same for F-gases.


Existing technology can reduce methane leakage from oil and gas production by 70%.

The Non-CO₂ Mitigation Portfolio

The Non-CO₂ Mitigation Portfolio seeks rapid and steep reductions of black carbon, F-gases, and methane emissions in China, India, Europe, and the Americas, with a focus on seven strategic areas.


There are several ways to reduce F-gas (hydrofluorocarbons) emissions from refrigeration, air conditioning, foam production, and other industrial processes. These include national regulations, sector-specific rules, incentive mechanisms, and international treaties like the Montreal Protocol. In all cases, the availability of cost-effective alternatives is crucial. ClimateWorks and its partners are making the economic and technological case for these less harmful, more sustainable alternatives. Simultaneously, we are advocating for changes in government regulation, business practice, and consumer behavior.

Diesels Vehicles & Engines

Diesel exhaust is loaded with black carbon, also known as soot. Particulate filters combined with low-sulfur fuel can cut black carbon emissions from diesel vehicles and engines by 99 percent. Rapid, worldwide introduction of these technologies and the retirement or retrofitting of older, dirty diesels are essential to slowing climate change and protecting public health. ClimateWorks and its partners are supporting efforts to speed such technologies to market, while advancing parallel efforts to increase efficiency, promote clean vehicle technologies, and deploy smarter mass transportation systems.

Methane Leakage

The US shale development boom has heightened public concern about methane emissions. Fortunately, cost-effective technology, strong regulations, and effective enforcement can substantially reduce methane leakage from oil and gas production. Minimizing such leaks is also needed to achieve the full climate benefits of substituting natural gas for coal or heavy fuel oil. ClimateWorks and its partners are advocating for methane controls at both the state and national levels. Once best practices have been established and implemented, these efforts will expand to other oil and gas producing regions around the globe.

Marine Emissions

Ocean-going vessels are a small but growing contributor to total global warming pollution. Vessels transiting through northern shipping routes pose an additional threat since their sooty emissions deposit on Arctic snow and ice, hastening the melting process. Increased fuel efficiency, lower sulfur fuel, improved engine design, and exhaust after-treatment can significantly reduce marine-related emissions. ClimateWorks and its partners are advocating for stronger global regulations by the International Marine Organization and by individual coastal nations.  Through media campaigns, we are also raising consumer awareness of the full climate footprint of shipped goods, inland ferries, and pleasure cruises. 

India Brick Kilns

Rudimentary brick kilns are inefficient and emit substantial amounts of black carbon, which harms public health and increases global warming. India has a large proportion of traditional bull trench kilns, which are in urgent need of upgrading. Accordingly, ClimateWorks and its partners are promoting brick kiln modernization in India, encouraging businesses to upgrade or retire old kilns and seeking corresponding changes in environmental policy. But since that is only a partial solution, we hope to help India ultimately shift the country towards more sustainable walling materials, such as concrete blocks with high-fly ash content.

European Residential Heating

Wood heaters and boilers are the largest remaining source of black carbon in Europe, accounting for 50 percent of the total. The emissions from these stoves are accelerating the melting of Arctic sea ice and contributing to regional air pollution. To address this problem, ClimateWorks and its partners are promoting tighter European Commission Directives for residential solid fuel use, eco-labeling programs, and ultimately the use of small, insertable exhaust pipe catalysts.

Alignment & Data Gathering

ClimateWorks is not the only player in the non-CO₂ mitigation space. Close coordination with other funders – including but not limited to like-minded foundations, the Climate & Clean Air Coalition, and the World Bank – is needed to maximize returns on non-CO₂ investments. Similarly, there is a need for good data and thoughtful analyses. ClimateWorks and its partners are generating and making available improved data on non-CO₂ mitigation methods, and demonstrating their applicability to various geographies to help advance increasingly ambitious strategies.

Non-CO₂ Mitigation Program Team

ClimateWorks' Non-CO₂ Mitigation Portfolio is coordinated by experts in public policy, environmental regulations, science, politics, and philanthropy, in collaboration with ClimateWorks' funding and regional partners.

Contact us to learn more.

Jason Anderson

Director, International Engagement and Non-CO₂ Initiatives

Ruth Sego

Program Associate, International Engagement and Non-CO2 Mitigation

Ruth Cherono Sego is a Program Associate in the International Engagement and Non-CO2 portfolios where she brings over four years of experience in global environmental policy and multi-lateral environmental engagement. At ClimateWorks, Ms. Sego co-ordinates the Non-CO2 Initiative’s campaign to reduce global greenhouse gas emissions and Black Carbon from maritime transportation and shipping and helps to co-ordinate strategic climate policy initiatives for the International Engagement portfolio. She also provides technical assessments for grant-making in both portfolios. Ms. Sego was previously based at the global headquarters of the United Nations Environment Programme (UNEP) in Nairobi where her work focused on strategic communications and global environmental policy.

Ms. Sego holds a Master’s in Environmental Management from Yale University’s School of Forestry and Environmental Studies with a concentration in Energy and Climate.

Catherine Witherspoon

Senior Advisor

Catherine Witherspoon advises ClimateWorks on the linkages between air quality management, short lived climate pollutants, and climate mitigation. Previously, she served as the program director for ClimateWorks’ non-CO₂ fast action campaign. She has 26 years of regulatory, legislative, and management experience in the air quality field. Ms. Witherspoon started as a student assistant at the California Air Resources Board in 1981, and eventually rose to Executive Officer (2003-2007). In that role, she managed a staff of 1,100 and an annual budget of $350 million. Ms. Witherspoon was directly involved in the drafting of the California Clean Air Act and California’s landmark Greenhouse Gas Solutions Act.  In the mid-1990s, she left state government and served briefly as an Expert Consultant to the U.S. Environmental Protection Agency (Region 9), Legislative Director for the South Coast Air Quality Management District, and sole proprietor of her own consulting firm, before returning to CARB in 1999 as Senior Policy Advisor to the then-Chairman Dr. Alan Lloyd.  Ms. Witherspoon has a BA in Politics from the University of California at Santa Cruz.