In the global battle against harmful air pollution, China is both a leader in production and reduction.
According to the 2023 Global Carbon Budget, shared by Our World in Data, the country was responsible for annual carbon dioxide pollution of over nine billion tons from coal in 2022. The next highest polluter, India, was responsible for two billion.
However, government controls on dirty fuel industries have resulted in a 70% reduction in aerosol emissions over the last 10 years, as Yale Environment 360 detailed.
It’s a slightly confusing state of affairs. What’s more confusing, though, is how that aerosol reduction has impacted ocean warming.
What’s happening?
According to analysis published by PNAS and shared by Yale Environment 360, improvements made in reducing air pollution by China have led to warming effects in the Pacific Ocean.
The decline in smog particles has offered less shading protection from the sun’s rays, which has increased the rate of ocean warming and set off a chain reaction of atmospheric events.
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As Yale Environment 360 detailed, aerosols can deter around a third of the warming that’s caused by greenhouse gases — which are different from aerosols as they trap heat rather than shade it.
Why is ocean warming concerning?
Since 2013, the Pacific Ocean has been witnessing a warming event known as “The Blob,” which periodically increases water temperatures between California and Alaska by as much as seven degrees Fahrenheit.
This has led to toxic algal blooms, reductions of fish stocks, sea lion displacement, and the forcing of whales into shipping lanes in the hunt for food, among other issues, according to Yale Environment 360.
The analysis suggests that the aerosol reduction in China is at least partly responsible for “The Blob.” Despite these negative effects, cutting the production of aerosol is still an important factor in curbing overall air pollution.
“Aerosol reductions will perturb the climate system in ways we have not experienced before,” atmospheric scientist at Texas A&M University Yangyang Xu, who was not involved in the study, told Yale Environment 360. “It will give us surprises.”
What can be done about rising ocean temperatures?
As Fred Pearce of Yale Environment 360 noted: “To be clear, nobody — but nobody — suggests that we should stop the cleanup of aerosols. The death toll would just be too great.”
The World Health Organization says that outdoor air pollution was responsible for 4.2 million premature deaths worldwide in 2019, and aerosols are a key contributor to that statistic.
With that in mind, Michael Diamond from Florida State University, an expert on aerosols and climate, has suggested that reducing methane immediately would mitigate against the warming created in the absence of aerosols.
According to NASA, around 60% of the world’s methane pollution is caused by human activities. Agriculture, landfills, and burning dirty energy are among the leading producers of this harmful gas, which is 28 times more potent in terms of planet-warming potential than carbon dioxide.
So, cutting our consumption of meat and dairy, keeping as many items from heading to landfills as possible, and ramping up the production of electricity from renewable sources are essential to keep methane levels down. If we can do that, we can offset the unusual heating effects that cleaning up aerosols is having on our oceans without compromising human health.
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