The rate at which the planet is warming has sped up since 2010, and now researchers say that China's efforts to clean up air pollution are inadvertently responsible for the majority of this extra warming
In the early 2000s, China had extremely poor air quality as a result of rapid industrialisation, leading to a public outcry in the run-up to the 2008 Beijing Olympics. In response, Chinese authorities fitted scrubbers to coal power plants to curb the dirtiest emissions and tightened rules governing vehicle exhausts, leading to a 75 per cent drop in sulphate emissions.
But there is a sting in the tail of this environmental success story. According to a new analysis, China’s dirty air had inadvertently been cooling the planet, and now that it is gone we are starting to see a greater warming effect.
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Sulphate aerosols, released by burning fossil fuels, cool the planet in two ways. The particles themselves reflect sunlight back into space, shielding Earth from solar radiation. They also influence the way clouds are formed, increasing the occurrence of whiter, longer-lived clouds that also reflect radiation. Removing these aerosols from the atmosphere therefore eliminates a cooling effect.
To tease out this effect, Bjørn Samset at the CICERO Center for International Climate Research in Norway and his colleagues used newly published emissions data that gives a more accurate picture of Chinese action on aerosol pollution since 2005. They used state-of-the-art models to simulate how the climate system would respond to rapid drops in aerosol levels, specifically in China. They then compared these results with real-world data, such as satellite observations and estimates of sulphate pollution drawn from emissions reports, and found the modelled scenario was consistent with the real-world data signals.
The Abstract reads: “Here I show that the spread in simulated aerosol absorption in the most recent generation of climate models (CMIP6) can be a dominating cause of uncertainty in simulated precipitation change, globally and regionally. Consequently, until improvements are made in scientific understanding of the key absorbing aerosol types, projections of precipitation change under future anthropogenic emission will have major, irreducible uncertainties.”
Or more likely they’re talking about this Cicero study that was coauthored by Samset in 2024 “Increased Asian Sulfate Aerosol Emissions Remarkably Enhance Sahel Summer Precipitation”
“Multi‐model simulations in the Precipitation Driver and Response Model Intercomparison Project (PDRMIP) show, compared to decreased European aerosols, that increased Asian aerosols similarly enhance the Sahel summer precipitation but with different large‐scale atmospheric circulation changes. Further analysis of the Sixth Coupled Model Intercomparison Project (CMIP6) simulations under historical attribution and various emission scenarios reinforces the results about the climate impacts of anthropogenic aerosols and suggests that in future scenarios with strong international cooperation and rapid climate mitigations (SSP2‐45), the Sahel drought will be intensified likely due to the decline in Asian aerosol emissions. Our results suggest that Asian anthropogenic aerosols are likely a non‐negligible driver of the recent recovery in Sahel precipitation amounts”
Sahel apparently being an interesting place whose climate is sensitive to global climate patterns.
Back to the article at hand:
It is important to note that China’s action hasn’t caused additional warming, Samset stresses. Rather, it has “unmasked” what was already there. “The warming was always there, we just had some artificial cooling from pollution, and in removing the pollution we are now seeing the full effect of the greenhouse-gas driven warming,” he says.
The pace of air quality clean-up in China has slowed in recent years. “There really isn’t that much air pollution left to remove from China,” says Samset. That should mean the rate of warming should fall back to near the 0.18°C per decade rate recorded before 2010, he says.
I say there’s certainly that “at what cost” slant from the author, but I wouldn’t just call the article China bashing. Certainly some of the nuance and uncertainty was left out.
While the article has some nuance, the title is completely inappropriate. A better title would’ve been: Dramatic cuts in China’s air pollution unmask surge in global warming.
When I look at the title I wholeheartedly agree with you. The implications of “driving” global warming are ridiculous and contradicted in the article itself when they quote Samset saying that China hasn’t “caused” additional warming. Leaving it up to the reader to parse the difference between driving and causing with no input from the author is poor reporting.
Sahel apparently being an interesting place whose climate is sensitive to global climate patterns.
Yes it goes through a cyclical motion of growing Savannah and then drought leading to desert - one of major reasons of human’s becoming bipedal was the decrease of tree coverage in africa. In fact in the future with rising temperatures the Sahel is likely to expand again due to more precipitation due to warmer oceans.
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I assume they mean Bjorn Samset’s 2022 Nature article: Aerosol absorption has an underappreciated role in historical precipitation change. https://www.nature.com/articles/s43247-022-00576-6
The Abstract reads: “Here I show that the spread in simulated aerosol absorption in the most recent generation of climate models (CMIP6) can be a dominating cause of uncertainty in simulated precipitation change, globally and regionally. Consequently, until improvements are made in scientific understanding of the key absorbing aerosol types, projections of precipitation change under future anthropogenic emission will have major, irreducible uncertainties.”
Or more likely they’re talking about this Cicero study that was coauthored by Samset in 2024 “Increased Asian Sulfate Aerosol Emissions Remarkably Enhance Sahel Summer Precipitation”
Sahel apparently being an interesting place whose climate is sensitive to global climate patterns.
Back to the article at hand:
I say there’s certainly that “at what cost” slant from the author, but I wouldn’t just call the article China bashing. Certainly some of the nuance and uncertainty was left out.
While the article has some nuance, the title is completely inappropriate. A better title would’ve been: Dramatic cuts in China’s air pollution unmask surge in global warming.
When I look at the title I wholeheartedly agree with you. The implications of “driving” global warming are ridiculous and contradicted in the article itself when they quote Samset saying that China hasn’t “caused” additional warming. Leaving it up to the reader to parse the difference between driving and causing with no input from the author is poor reporting.
Yes it goes through a cyclical motion of growing Savannah and then drought leading to desert - one of major reasons of human’s becoming bipedal was the decrease of tree coverage in africa. In fact in the future with rising temperatures the Sahel is likely to expand again due to more precipitation due to warmer oceans.