The World Meteorological Organization has warned that hundreds of millions of people will be affected by the deterioration in air quality predicted this century, due to the increase in fires and the intensity and duration of heat waves.
In its annual air quality bulletin, issued on the occasion of International Clean Air Day, the United Nations agency warned that the increase in particulate pollutants, linked to climate change, could have consequences as serious as global warming.
“As global temperatures rise, wildfires and related air pollution are expected to increase, even in a low-emissions scenario,” with consequences for human health and ecosystems, said the organization’s secretary-general, Petteri Taalas. .
The paper, based on 2021 data, shows sharp increases (above 30 micrograms per cubic meter of air) in particle concentrations in areas that have experienced severe fires in the past year, especially in Siberia (northern Russia), Canada and the west. of the United States, compared to the average for the period 2003-2020.
Measurements also recorded an above-average increase in emissions caused by activities such as generating heat and burning agricultural stubble, especially in the winter months in India and other parts of South Asia.
In western North America, wildfires between May and September in some areas caused additional concentrations of up to 20 micrograms of PM2.5 pollutants (the most harmful to health) per cubic meter, four times the level recommended by the World Health Organization. (WHO).
It is feared that this year will see similar increases in the concentration of polluting particles in regions such as Europe and China, hit by heat waves and forest fires, which in the European case are known to have caused the emission of 6.4 megatons of carbon.
The observed data “is an anticipation of the future as the frequency, intensity and duration of heat waves are expected to increase further, which could further worsen air quality,” Taalas said.
This deterioration in air quality linked to global warming is referred to by experts as a “climate sanction”, and the World Meteorological Organization expects the most targeted regions to be located in parts of Asia, where a quarter of the world’s population lives.
“Climate change can exacerbate episodes of surface ozone pollution, resulting in adverse health effects for hundreds of millions of people,” predicts the UN meteorological agency.
Air quality and climate are intertwined, even if pollution phenomena tend to be sudden and global warming is more gradual and long-term, the annual bulletin recalls.
For example, burning fossil fuels is a major source of emissions of carbon dioxide, the main greenhouse gas, while also emitting nitrogen oxide, a precursor to ozone and more harmful particulates.
At the same time, air quality can harm the health of ecosystems, as air pollutants can deposit concentrations of nitrogen, sulfur and ozone on the earth’s surface that can affect water, biodiversity, carbon storage or crops. .
Despite predictions, the same document highlights that the area burned annually has shown a decreasing trend in the last two decades, as a result of fewer fires in savannas and grasslands, although there have been notable increases in some regions, such as North America. , Amazon and Australia.
The Intergovernmental Panel on Climate Change has already warned in recent reports that climate change could increase the severity and frequency of “catastrophic wildfires”, such as those that occurred in Australia in 2019 or the western United States in 2020-21.
