Why pollutants like black carbon and methane must be incorporated into NDCs

In 2019, the Intergovernmental Panel on Climate Change (IPCC) established that to keep warming under 1.5C, we must achieve net-zero emissions by mid-century. Science set the standard of what climate policies should aspire to, and these were either aligned or misaligned with the target. Since then, 145 countries have set net-zero goals, covering nearly 90% of emissions. Yet, on an equally pressing challenge—air quality—we are far from those levels of ambition.

In 2021, the World Health Organization (WHO) updated its air quality guidelines for the first time since 2005, and since then, only one country has adopted these recommendations as standards, despite 7 million people dying per year due to air pollution. As it stands, a net-zero world does not guarantee zero pollution or a resilient world. Yet many countries are seizing on the opportunities and synergies of tackling air pollution and climate simultaneously.

As former policy-makers who represented Chile during different administrations, we often heard our colleagues at home and abroad ask why we should act on climate 'if rich countries caused the problem'. We had other issues to tackle, too. For decades, we focused on air pollution, which was on the political agenda every winter. Our population mostly lives between two large mountain ranges, causing deficient ventilation and high pollution levels (mostly from wood burning and diesel).

It was clear early on that we could build our climate policy on our existing air pollution policy. This differs from the typical focus in countries in the Global North since air pollution problems manifested much earlier than the climate crisis. By the time climate policy started, extreme pollution (London killer fog in the 1950s or Los Angeles ozone in the 1960s) had already been addressed.

The lack of integrated climate policy and air quality management has been one of history's biggest environmental policy failures since it promoted false solutions, like wood-burning stoves and diesel vehicles. Wood-burning stoves have been promoted as climate-friendly, yet an individual conventional wood-burning stove generates methane and black carbon emissions equivalent to 1.7 tons of CO2eq per year (roughly the same as three motorcycles). A diesel car, known to be more efficient than gasoline and promoted in Europe as a climate solution, causes as much warming from the fuel as from the black carbon from the tailpipe (6 tons of CO2eq total). And, of course, both wood-burning stoves and diesel cars have far worse real-world emissions performance than laboratories.

The integration of policies not only accelerates the clean transition but also promises a brighter future. The Chilean power plant emissions standard that preceded the carbon and air pollution tax and energy auction reform contributed to the accelerated phase-out of coal power generation. No developing country has reduced coal emissions faster than Chile. The stringent emission standards for buses in Santiago made the jump to electric buses more achievable, making the city host the largest fleet of electric buses outside of China. Air quality policies have also accelerated the adoption of air-to-air heat pumps at breakneck speeds, replacing dirty wood-burning heaters with accessible split inverters. This integrated approach is the key to a cleaner, healthier, and more sustainable future.

This is also apparent in the nationally determined contribution (NDC) process and the recently promulgated climate change law. The current NDC and its recent update include specific targets for short-lived climate pollutants like methane and black carbon, and the law mandates a particular focus on targeting short-lived climate pollutants (SCLPs), especially in polluted cities. Chile has committed to reducing black carbon emissions by 25%, and in doing so will contribute to protecting the glaciers in the Andes Mountains that provide the majority of water for cities during drought and immediately reduce warming in cities. When air pollution and climate benefits of net zero are combined, this increases by a factor of five.

Short-lived climate pollutants (SCLPs) are not just super pollutants that trap more heat per molecule than carbon dioxide – they are the natural bridge between air pollution and climate policy. Reducing them is not just a solution to air quality problems; it is also the fastest way to reduce warming in the short term and keep the 1.5C goal alive. Contrary to carbon dioxide, where industrialized nations have contributed to most of the warming, nearly 80% of warming from SCLPs, like methane, has come from countries not part of the Organisation for Economic Co-operation and Development (OECD) countries.

SCLP mitigation, therefore, is an opportunity for the Global South to contribute to climate mitigation from the perspective of resilience development, contributing to cleaner air, energy security, and food security. In the case of methane, this means mitigation through better waste management, lower risk of landfill fires, lower exposure to harmful pollutants from oil and gas extraction, lower risk of explosions in coal extraction, reduced food loss and waste, improved productivity, and resilience in livestock and rice production.

We call on countries to include specific and ambitious mitigation targets for methane, black carbon, and other SCLPs in their new NDCs to increase transparency and robustness in reporting through biennial transparency Reports. Many resources can help guide those efforts, including guidance by CCAC and the Clean Air Fund. Collective ambitions on SLCPs will shave off 0.5C of temperature rise in the coming decades, much faster than decarbonization alone, significantly reducing the risk of temperature overshoot. However, lower-income countries should be recognized for these efforts while getting implementation support.

Development agencies, governments, and the private sector must realize that reducing these pollutants is as relevant as carbon dioxide mitigation and develop plans to fund implementation. This win-win approach is the simplest way to increase climate ambition in this NDC cycle, bringing local benefits to countries that take action. It will also help address the most significant environmental health challenge we face today, saving millions of lives while bringing forward development benefits such as improved living conditions, rural livelihoods, resilience, and healthier ecosystems.