Our difficulty in addressing climate change has often been compared to the tale of a frog placed in a pot of mild water that is slowly brought to the boil. The frog happily sits in the pot not realizing the danger until it is too late. This analogy stops short in one respect: the frog actually faces two dangers – the rising temperature and the toxicity of the water it is in.

In our world, the poisonous companion to climate change is air pollution. Our air is being simultaneously filled with planet-heating gases, such as carbon dioxide and methane, and with toxic gases and particles that penetrate into our lungs and damage our health.

Ten years ago, the Paris Agreement outlined goals and actions to deal with the planet-heating gases. During this time, about 80 million people have died as a result of their exposure to air pollutants produced alongside these gases. Tragically, more than 7 million of these deaths have been children under 5 years of age.

Air pollution actions benefit the climate

There is no global agreement to reduce air pollution, and the Paris Agreement itself is not tasked with addressing this. At the same time, the number of people facing early death and health harms from air pollution is a powerful indicator of whether the Paris Agreement is delivering action in the real world. Why? Because it is very difficult to deal with the causes of climate change without simultaneously reducing the air pollutants emitted alongside them.

Almost all major sources of climate heating gases also emit some air pollutants. The actions to reduce greenhouse gas emissions from our economies almost always also reduce air pollutant emissions as well. Replacing coal power plants with renewable electricity production avoids carbon dioxide emissions and the sulphur dioxide and nitrogen oxides that harm health. Replacing fossil fuel-powered vehicles with clean electricity-powered public transport cuts greenhouse gas emissions and particle matter from exhausts.

What then does this indicator show about progress on the aims of the Paris Agreement? It reveals a troubling picture. Over the past 10 years, millions of people continued to die from exposure to air pollution. In fact, air pollution’s ranking as a cause of disease increased. It is now the second-biggest risk factor for premature death, behind only high blood pressure, and it exceeds the health burden from smoking, deficient diets and malnutrition. Our collective failure to reduce planet-heating emissions, opened new avenues for air pollution to harm health. For example, air pollution-related deaths from wildfires in 2024 were 36% higher than the 2003-2012 average.

This is a missed opportunity. Tackling climate change can achieve the largest and fastest improvements in human health by reducing air pollution. Some countries are beginning to adopt this approach. See for inspiration the nationally determined contributions and plans of Cote d’Ivoire, Ghana and Nigeria. Some countries are setting targets for reducing key pollutants like black carbon. See for inspiration the plans of Chile, Colombia and Mexico.

Three changes to boost progress

Three practical steps can help bring this about. First, climate finance decision-making should include steps to evaluate and prioritize air pollution benefits. Using air pollution and public health as criteria for allocation of funds can ensure that – in spite of increasing disillusionment with the pace of climate action – citizens can benefit directly on a short timescale.

Second, the language of climate change negotiations and discussions should move beyond carbon dioxide alone. Though carbon dioxide is the most abundant greenhouse gas, other pollutants require attention. For example, methane, ozone and black carbon are also powerful greenhouse gases, responsible for about 45% of the global heating to date. They not only cause climate change, but they also have their own air quality and public health impacts. Overall, the contribution of these pollutants tends to be obscured by language that converts their heating into “carbon dioxide equivalents”. As a result, actions to reduce non-carbon dioxide pollutants lag far behind actions to reduce carbon dioxide.

Finally, climate change decision-making processes should start to account for the costs of inaction. The World Bank estimates that the cost of global air pollution is equivalent to 5% of global GDP – at least 4.5 trillion USD per year. This far outweighs the cost of implementing the actions needed to achieve the Paris Agreement goals.

If we continue to ignore the costs, human and economic, of the current systems, then we will continue to lack a key motivation to act.