WMO Report Warns of Air Quality and Climate Link, Calls for Global Action

The Indo-Gangetic Plain, home to over 900 million people, has experienced longer and more intense fog episodes linked to pollution from vehicles, biomass burning, and construction.

 

The World Meteorological Organization (WMO) has released its 2025 Air Quality and Climate Bulletin, detailing the intricate links between air pollution and climate change, and warning of the urgent need for integrated policies to protect human health, ecosystems, and the global economy. Published on the International Day of Clean Air for Blue Skies (7 September), the report provides new data on particulate matter, aerosols, wildfires, urban smog, and shipping emissions, while stressing the importance of robust atmospheric monitoring worldwide.

Air Quality and Climate: A Vicious Cycle

According to the WMO, the relationship between air pollution and climate change is mutually reinforcing. Fossil fuel combustion and industrial activities emit both greenhouse gases and air pollutants like black carbon, nitrous oxide, and ground-level ozone. These pollutants worsen climate impacts while simultaneously degrading air quality.

“Climate change and air quality cannot be addressed in isolation. They go hand-in-hand and must be tackled together in order to protect the health of our planet, our communities and our economies,” said Ko Barrett, WMO Deputy Secretary-General.

She emphasized that pollution and climate impacts transcend borders: “Intense heat and drought fuel wildfires, which then worsen air quality for millions of people. We need improved international monitoring and collaboration to meet this global challenge.”

The stakes are high. The World Health Organization (WHO) estimates that ambient air pollution causes more than 4.5 million premature deaths annually, in addition to enormous environmental and economic costs.

Key Findings from the 2025 Bulletin

1. Particulate Matter (PM2.5) Trends

• PM2.5, tiny particles that lodge deep in the lungs, remain a major global health hazard.

• New data from three global models showed contrasting regional trends:

  • Eastern China recorded continued improvements thanks to strong mitigation policies.

  • Northern India remained a hotspot of severe pollution.

  • Wildfires in Canada, Siberia, central Africa, and especially the Amazon Basin drove sharp increases in PM2.5 levels in 2024.

• The Amazon fires were particularly destructive, with emissions degrading air quality in distant Brazilian cities, underscoring the transboundary nature of pollution.

2. Aerosols: Cooling and Warming Agents

Aerosols — microscopic airborne particles — have complex climate effects:

• Dark aerosols like black carbon trap heat and accelerate glacier melt.

• Lighter aerosols such as sulphates cool the atmosphere by reflecting sunlight but contribute to acid rain.

• Global aerosol concentrations peaked in the late 20th century but have since declined in North America, Europe, and East Asia. However, levels continue to rise in South Asia, South America, and Arctic regions, driven by industrial growth and wildfires.

• International shipping rules cutting sulphur in marine fuels have improved air quality and reduced premature deaths, but also lessened the cooling effect of sulphates — slightly accelerating global warming.

3. Winter Fog in South Asia

The Indo-Gangetic Plain, home to over 900 million people, has experienced longer and more intense fog episodes linked to pollution from vehicles, biomass burning, and construction. Once seen as a seasonal weather phenomenon, fog is now increasingly recognized as a pollution-driven hazard. The WMO urged governments to enforce stricter regulations on agricultural residue burning and expand clean energy access for cooking and heating.

4. Monitoring Infrastructure Gaps

The report stresses that satellite data alone is insufficient. Ground-based monitoring stations remain essential for calibration, validation, and real-time warnings. Yet, many developing regions still lack sufficient infrastructure. Expanding observation networks is vital for improving forecasts, managing risks, and designing effective policies.

Integrated Action for Health and Climate

The WMO calls for cross-border cooperation and integrated policy approaches to tackle air quality and climate together. Measures that cut emissions at their source — such as clean energy transitions, sustainable agriculture, and low-emission transport — can simultaneously reduce health risks, slow global warming, and protect ecosystems.

“Addressing air quality and climate together is a win-win for health, economies and the environment,” the Bulletin concludes.

As the world faces escalating wildfires, urban smog crises, and climate extremes, the WMO’s findings serve as both a warning and a roadmap. Without stronger international collaboration and investment in monitoring and mitigation, millions more lives and livelihoods will remain at risk.