Blog 6 October 2025
Over the past few years, news headlines have sparked some confusion by claiming that cutting air pollution contributes to global warming. The stories claim reductions of sulphate aerosol particles from shipping regulations and China’s clean air efforts are heating the planet.
Is cleaning the air making global warming worse?
Anthropogenic aerosols are polluting particles in the atmosphere caused by human activities, such as burning fossil fuels. The impact of these aerosols and their role on climate systems has been carefully explored by scientists. A number of studies have evaluated the relationship between air pollution reduction and recent warming over different geographic regions (like China and the UK) and sectors, such as shipping. These studies have used state-of-the-art climate models, authoritative inputs and expert scientific methodologies to examine the complex interactions between air quality and climate.
Yet their findings are often oversimplified in the media’s reporting, perpetuating the misconception that air pollution reduction is to blame for recent warming. Our recent blog delves into the science behind shipping emissions and short-term global warming.
At first glance, it feels like a contradiction. How could removing particles of pollution make the planet hotter? The answer lies in understanding a phenomenon called “unmasking” — and it’s not as mysterious as it sounds. Let’s use an example from everyday life to demystify unmasking.
Analogy: A hot water bottle under blankets
Why this matters for climate action
It might sound paradoxical, but when a coal power plant is shut down to protect the environment, we expect to see a tiny bump in warming in the near term. That’s because these plants not only pump out carbon dioxide, but also release sulfur dioxide (SO₂), the pollutant that forms reflective aerosol particles in the atmosphere that act as a temporary “sunshade” for the planet. When the plant closes, that sunshade disappears within days to weeks, while the heat-trapping greenhouse gases linger for centuries.
A recent study predicts a short-term global increase in temperature if we completely phase out coal combustion worldwide. Another study has suggested in a realistic phase out of fossil fuel, modelling scenarios do not produce a substantial near-term increase in warming, and the phase-out can lead to a decrease in warming rates within two decades of the starting the transition. Shutting down the smokestack is absolutely the right thing to do for our health and our climate—we need to remember that any short-term rise in warming is just the blanket coming off, not a new source of heat.
The solution is to cut air pollution and tackle greenhouse gases
Unmasking is not a reason to stop air pollution controls. Air pollution is the largest environmental threat to human health, causing over 8 million premature deaths each year. It also damages the ecosystem by changing natural atmospheric processes: increasing amounts of polluting particles over the North Atlantic ocean were found to be the main driver for the Sahelian drought of the mid to late 20th century. Increasing air pollution over southern Asia has also been blamed for a 50-year-long negative trend of the Indian monsoon rainfall. Air pollutants also escalate extreme events like flood, drought, and heatwaves, which jeopardise food and water security for billions of people. These events are also responsible for infrastructure damage and the escalating risk of reaching climate tipping points.
Climate action needs to be cheaper, smarter and faster, which can be achieved by integrating clean air action into climate measures for more impact. If we clean the air and don’t reduce greenhouse gases, it’s like removing the blankets while leaving the water bottle fully hot. We need to:
- cut greenhouse gas emissions more aggressively to slow heating in the atmosphere in the long term.
- urgently target short-lived climate pollutants or super pollutants – like methane, black carbon and tropospheric ozone – to avoid near-term warming.
- Boost efforts in highly-polluting sectors (including energy, transport, manufacturing, waste and agriculture) to transition toward cleaner practices.
- Support communities to adapt, especially through addressing inequities and improving preparedness.
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