CARTAGENA, Colombia – A small group of climate pollutants– including the air pollutants black carbon, methane, and ozone – are responsible for nearly half of global temperature increases to date. 

Reducing these emissions, which only remain in the atmosphere for a few weeks to decades, could serve as the “emergency brake” critical to halting runaway climate change, said experts Monday on the eve of the second WHO Air Pollution and Health Conference.

Although these pollutants exert enormous 20-year climate-warming potential that is 80 to 2,000 times greater than carbon dioxide (CO2) per ton of emissions, their lifespan is far shorter than CO2, which remains in the atmosphere for a century or more.

These pollutants are also projected to continue warming the climate with greater potency than CO2 over the next century.

“If you reduce them today, we’ll see impacts in our lifetimes,” said Claire Henly, executive director of the Super Pollutant Field Catalyst, a US start-up NGO, at a media briefing ahead of the conference. 

While CO2 has received the overwhelming amount of climate mitigation attention, Henly and others argued that addressing a class of “super pollutant” greenhouse gases and particles, also known as “short-lived climate pollutants,” offers the greatest opportunity to have a rapid, and meaningful impact on both health and climate.

Henly and others identified ozone, black carbon, and methane as super pollutants because of their wide-ranging impacts on food security, health, and climate change. Slowing the rate of climate change would make it easier for the “world to adapt to climate change,” said Henly. 

Nexus of climate change, air pollution and health

It is also the nexus where health, climate, and food security concerns directly converge – leading scientists to dub them “super pollutants” precisely due to those wide-ranging impacts. 

Black carbon is a sub-component of dangerous particulate matter, associated with some 7 million deaths annually from air pollution. 

Ground-level ozone, formed as pollutants emitted by vehicles, industry and waste, is a leading factor in respiratory illness, particularly asthma, as well as damaging some 90% of global crop production every year. Methane, emitted by waste dumps, agriculture, and oil and gas flaring, is a leading precursor to ozone formation.  

Slowing emissions would also slow the rate of climate change, buying time for the world to transition to cleaner energy sources and other longer-range climate solutions, said Henly. 

Two leading super pollutant gases, methane and nitrous oxides (N2Ox), are formally recognized in the Paris climate agreement as powerful greenhouse drivers with a climate forcing potential that is 80, and 270, times more than CO2 respectively in the next 20 years. But black carbon is ignored, leading to a fragmented approach.  

Similarly, the shared concerns of climate and health sectors around super pollutant emissions are often siloed, said Sergio Sanchez, senior policy director at the Environmental Defense Fund. Greater recognition of super pollutants as detrimental to both health and climate could help break through the barriers to more climate action, he said.

Reducing these pollutants could avoid four times more warming by 2050, as opposed to decarbonization policies alone – and also prevent some 2.4 million deaths a year from air pollution. 

Yet emissions of super pollutants, including methane, are currently on the rise.

Agricultural sector is getting more attention

Most attention on super pollutants has focused on methane leaks from the fossil fuel industry. These occur at nearly every stage of the extraction and production cycle, with natural gas flaring the most glaring example of methane emissions. 

However, another key source of potent methane emissions is the agricultural sector, which accounts for  40% of global human-made methane emissions, with livestock, rice cultivation and crop debris being key sources. 

People often forget the fact that in some regions, such as the European Union, the agricultural sector accounts for 54% of methane emissions, noted Pierpaulo Mudu, WHO scientist.

Another 34% of global methane emissions comes from fossil fuels and 19% from rotting urban and household solid waste. Some methane is also emitted by natural sources, such as peat bogs and wetlands. Overall, two-thirds of global methane emissions come from human activities, according to the Global Carbon Project. 

Methane emissions from agriculture harder to track

Methane emissions from agriculture, however, are much harder to track and monitor than emissions from the oil and gas sector.

“In agriculture, these pollutants are not emitted in high concentrations,” said Henly. 

“The emissions are distributed, and the kind of detection, whether it’s through on the ground sensors or remote detection, is just a bit more challenging than in the oil and gas coal sectors.

Whereas previously, only big methane spikes or leaks from oil and gas installations could be detected, that is changing now, Henly said. 

Recently, new technology, in the form of higher resolution satellite imaging, has opened the way for more granular estimates from sources like agriculture.

This week’s WHO conference will therefore feature the first session ever about the links between methane emissions in agriculture, climate, and health.  Solutions that can be promoted,, experts say, include biogas capture from anaerobic digestion of crop waste and manure as well as improved compost management – so that methane gas is not produced at all.

Ozone chokes crops

But agriculture is also impacted by super pollutants, particularly ozone. It’s now estimated that ozone leads to a loss of 12% of wheat, 16% of soybean, 4% of rice, and 5% of corn production every year.  

“So we can see that the super pollutants are a real growing threat to food security,” said Rachel Huxley, Head of Climate Mitigation and Health at Wellcome Trust.

Ground level ozone (O3) is a product of the vicious cycle of super pollutant formation. Gases produced by cars and industry, crop and waste incineration, interact in sunlight, leading to ozone’s creation. 

Unlike the “good” layers of stratospheric ozone that protect the planet and people from harmful ultraviolet radiation levels, ground level ozone is harmful to crop production as well as human health. 

Inhaling ozone leads to respiratory and a host of other health issues. And when over farmland, the pollutant can dramatically disrupt staple crop growth, according to a 2025 report by the Clean Air Fund.

This week, for the first time ever, WHO is convening a meeting on agriculture, air pollution, climate and health, with the hopes of drawing more attention to these linkages within health and environment circles. 

“Everyone is obsessed with transport,” said Mudu, the WHO scientist leading the session. “Because of the visibility of the black smoke, but there are many different sources of air pollution with many sorts of invisible gases.”

Black carbon and snowmelt 

On the other side of the coin, when urban and household waste or crop debris is burned, rather than left to rot, it produces smoke – a mixture of gases and particles, including black carbon. 

The burning of rice crop debris regularly envelopes large parts of the Indian subcontinent in billowy smoke every autumn. Burning of household and urban solid waste is also a common practice in many developing regions. 

Waste burning, together with the use of wood and charcoal for household cooking and heating, as well as in traditional brick kilns, cast a chronic pallor of smoke or smog over cities and farmland in many other low- and even middle-income regions of the world – also contributing to the formation of ozone.   

But the tiny specks of black contained in the smoke do even more harm than other types of fine particles. They accelerate climate change in mountain regions, where they settle on snow and ice, absorbing additional sunlight and thus increasing snow and ice melt. 

Scientists estimate that  black carbon is responsible for 39% of glacier melt in certain Himalayan glaciers, and there are similar impacts being observed in the Himalayas, Alps, Andes and the Rockies, according to a 2025  Clean Air Fund report. 

Locally, glacier melt reduces the reliability of water sources that rural regions of Nepal and northern India rely on for crop irrigation as well as domestic use. 

But there are global implications as well. It is a major reason that the Arctic is warming four times faster than other parts of the world, increasing the chances of “dangerous climate tipping points being breached,” the report stated.

Regulation and action

Regulation of super pollutants is challenging – because so many pollutants, and sectors, are involved. In the case of ground level ozone, as well, the pollution is not emitted directly, but rather is a product of reactions between methane, nitrogen oxides, and volatile organic compounds. So the precursors need to be regulated. 

Despite such complexities, the fact that black carbon as well as methane, ozone and other powerful short-lived gases – only reside in the atmosphere for weeks to decades, makes Huxley hopeful that policymakers can see the “economic sense” in cutting back on such emissions. 

“This is one of the most effective ways to keep 1.5ºC alive,” she said, referring to the Paris climate agreement goal. “This is our emergency brake on climate change.” 

The Global Methane Pledge aimed at reducing the gas, was launched at COP26 by the United States and the European Union and has so far been supported  by over 150 countries, including over two dozen African nations. 

“Methane has been globally recognized as a super pollutant since COP26, thanks to the launch of the Methane Global Pledge and the commitments made by countries since then,” said Elisa Puzzolo, Super Pollutants policy manager at the Clean Air Fund.

“Now, is the time to raise our ambition and address all super pollutants, including black carbon and troposheric ozone, to protect the climate, safeguard public health, and support most-affected regions and communities.”

Super-pollutants ‘movement’

What Wellcome and the Clean Air Fund want to foster is a more coordinated super-pollutants “movement” that cuts across sectors – together with the UN Enviroment Programme-hosted Climate and Clean Air Coalition.

“Solutions are proven,” Puzzolo said. For super-pollutants though, the regulatory landscape is a bit more complicated. Black carbon, though harmful to health and the climate, is not included in the Paris Climate agreement because it is a particle.

“Reducing black carbon, alongside other super pollutants, is the fastest, most effective way to slow climate change, while also mitigating the enormous health impacts of air pollution,” said Jane Burston, CEO of the Clean Air Fund. “Yet to date not enough has been done.”

“Action on short-lived climate pollutants is a matter of time and temperature,” said Martina Otto, head of the secretariat at the Climate and Clean Air Coalition, which was founded over a decade ago specifically to spearhead awareness and action on superpollutants. 

“They have a higher warming potential than CO2 and don’t accumulate in the atmosphere. Cutting them turns down the heat within decades and reduces air pollution now. A double dividend that we cannot afford to miss.”

Image Credits: WHO/Diego Rodriguez, E. Fletcher/HPW, Climate and Clean Air Coalition, Punjab Enviornment Department, Climate and Clean Air Coalition, A. Bose/HPW.