Air quality impacted by changing climate

A new report from the World Meteorological Organization, or WMO, reveals that climate change is significantly impacting air quality, human health, and the environment by heightening the intensity and frequency of heat waves, and exacerbating wildfires and desert dust.

Highlighting heat waves and their often overlooked yet equally damaging impacts of resulting pollution, the 2023 WMO Air Quality and Climate Bulletin, the third in an annual series, underscores the consequences of high temperatures.

The report illustrates how heat waves last year sparked wildfires in the northwestern US and led to dangerous air quality due to desert dust in Europe. It also highlights Brazilian case studies demonstrating urban parks and trees' ability to enhance air quality and lower temperatures.

"Heat waves worsen air quality, with knock-on effects on human health, ecosystems, agriculture and indeed our daily lives," said WMO Secretary-General Petteri Taalas. "Climate change and air quality cannot be treated separately. They go hand-in-hand and must be tackled together to break this vicious cycle."

"What we are witnessing in 2023 is even more extreme. July was the hottest ever month on record, with intense heat in many parts of the northern hemisphere and this continued through August," he said.

"Wildfires have roared through huge swathes of Canada, caused tragic devastation and death in Hawaii, and also inflicted major damage and casualties in the Mediterranean region. This has caused dangerous air quality levels for many millions of people, and sent plumes of smoke across the Atlantic and into the Arctic."

Climate change is amplifying heat waves, escalating the likelihood and intensity of future wildfires, the bulletin said.

"Smoke from wildfires contains a witch's brew of chemicals that affects not only air quality and health, but also damages plants, ecosystems and crops — and leads to more carbon emissions and so more greenhouse gases in the atmosphere," said Lorenzo Labrador, a WMO scientific officer in the Global Atmosphere Watch network that produced the bulletin.

In a separate news post on Wednesday, the WMO reported that global sea surface temperatures have reached unprecedented highs for the third consecutive month, Antarctic sea ice extent remains at a record low for the year, and the Earth just experienced its hottest three months on record.

Measurements from the Copernicus Climate Change Service, a project funded by the European Union and carried out by the European Centre for Medium-Range Weather Forecasts, or ECMWF, showed last month was the hottest August on record by a significant margin, and it was the second hottest month ever, following only July 2023.

According to the Copernicus service, the whole of August is estimated to have been about 1.5 C warmer than the pre-industrial average recorded between 1850 and 1900.

August experienced an all-time monthly high of global sea-surface temperatures at 20.98 C, surpassing the previous daily record of March 2016 every day.

"What we are observing, not only new extremes but the persistence of these record-breaking conditions, and the impacts these have on both people and planet, are a clear consequence of the warming of the climate system," said Carlo Buontempo, director of the Copernicus Climate Change Service, ECMWF.