Pollution and climate change interact to increase risk of 'climate punishment'
Amid the heatwave that has ravaged Europe and China this year, steady high-pressure atmospheric conditions, sunshine and low wind speeds have all contributed to high pollution levels, said WMO secretary-general Petri Taalas.
"This is a rehearsal for the future, as we expect further increases in the frequency, intensity and duration of heatwaves, which will lead to worse air quality, a phenomenon known as 'climate punishment'," he said.
"Climate penalty" refers specifically to the amplified effect of climate change on ground-level ozone production, which adversely affects the air people breathe. The regions where the "climate penalty" is projected to be strongest (mainly in Asia) are home to about a quarter of the world's population.
Air quality and climate are interlinked, as the chemicals that cause air quality degradation are often emitted along with greenhouse gases. Therefore, if one party changes, it will inevitably cause the other party to change. Fossil fuel combustion, a major source of carbon dioxide (CO2), also emits nitric oxide (NO), which reacts with sunlight to form ozone and nitrate aerosols
Nitric oxide (NO), a major source of carbon dioxide (CO2), also emits nitric oxide (NO), which reacts with sunlight to form ozone and nitrate aerosols.
Air quality also affects the health of ecosystems through atmospheric deposition (as air pollutants are deposited from the atmosphere to the surface). Deposition of nitrogen, sulfur, and ozone can adversely affect services such as clean water, biodiversity, and carbon storage provided by natural ecosystems, and can affect crop yields in agricultural systems.
Wildfires pollute the air
The report specifically focuses on the effects of wildfire smoke in 2021. As in 2020, hot and dry conditions have exacerbated the spread of wildfires in western North America and Siberia, leading to widespread increases in levels of microscopic particulate matter (PM2.5) that are harmful to health.
Long-term inhalation of PM2.5 (particulate matter with a diameter of 2.5 microns or less) can cause serious health hazards. Sources of PM2.5 include emissions from fossil fuel combustion, wildfires, and windblown dust.
Intense wildfires in July and August 2021 in Siberia and Canada, as well as in the western United States, caused unusually high concentrations of PM2.5. Mainly driven by rising heat and dry soil conditions, PM2.5 concentrations in eastern Siberia have reached unprecedented levels.
future scenarios
The Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6) contains scenarios for the evolution of air quality with rising temperatures in the 21st century. According to the assessment, the probability of catastrophic wildfire events (such as those in central Chile in 2017, Australia in 2019, or the western United States in 2020 and 2021) could increase by 40-60% under high-emission scenarios by the end of the century %, which could increase by 30-50% under low emission scenarios.
If greenhouse gas emissions remain high, global temperatures will be 3°C above pre-industrial levels by the second half of the 21st century, and surface ozone levels are expected to increase in heavily polluted regions, especially in Asia. Among them, trans-Pakistan, northern India and Bangladesh will increase by 20%, and trans-eastern China will increase by 10%.
Share the air, act together
Today, less than 1 percent of people breathe air that meets the World Health Organization's strictest air quality guidelines, according to a joint statement Wednesday by the chief scientists of the World Health Organization, the International Union for Conservation of Nature, the World Meteorological Organization and the United Nations Environment Programme.
According to WHO estimates, air pollution kills 7 million prematurely each year, including around 600,000 children under the age of 15 – and that’s not counting the millions more living with air pollution-related chronic diseases people.
In 2021, a World Bank study found that the economic cost of air pollution’s health effects alone would reach $8.1 trillion, equivalent to 6.1% of global gross domestic product (Gross domestic product) in 2019.
Air pollution also affects other systems, such as ecosystems. The deposition of sulfur and nitrogen can lead to acidification and eutrophication of water systems. Tropospheric ozone can negatively impact ecosystems, lead to biodiversity loss, and negatively impact plant growth, vigor, photosynthesis, water balance, flowering processes, and the ability of vegetation to sequester carbon.
The IUCN Red List of Threatened Species contains a classification of threats to biodiversity, including subclasses of air pollutants. Of the 7427 threatened species of terrestrial vertebrates alone, 1181 are listed as threatened by pollution and 64 are specifically listed as threatened by air pollutants.
The study estimated the annual economic loss of 23 crops from ozone at $26 billion in 2006. Air pollution can even affect water systems when harmful concentrations of pollutants accumulate, or reduce the ability of vegetation to filter water systems.
The greatest impacts of air pollution typically occur in areas close to emission sources, but many air pollutants can spread or form in the atmosphere hundreds to thousands of kilometers away from emission sources, causing regional and continental impacts. For example, soil mineral dust and sand, which make up about 40% of total aerosols in the lower atmosphere, can remain in the atmosphere for up to a week, allowing them to travel between continents and have global impacts on health, agriculture, transportation, the economy and climate .
The chief scientists say that while air pollution is complex and requires a coordinated government response, it is a threat that can be prevented and controlled. While air pollution has not been addressed in any region and is a growing problem in cities and industrial areas in low- and middle-income countries, many cities and countries around the world have shown significant declines in emissions and pollutant concentrations due to strong Strong policies, regulations and monitoring systems are in place.
They stress that air pollution knows no cities or borders. The air we breathe truly connects us all, and tackling this threat in a sustainable way requires urgent action and cooperation on a global scale
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