Air pollution cuts could cause climate change acceleration05 March 2020
Dramatic cuts to air pollution in Europe and Asia could cause a short-term spike in temperatures and rainfall, but doing nothing would be worse in the long run, scientists say.
In a study published in Environmental Research Letters, scientists predicted a more rapid increase in European and Asian heatwaves by 2050 as air pollution is cut sharply in Asia. The worst-case-scenario prediction indicated that the hottest day of the year may be up to 4°C hotter by 2050, compared to the present day, with 30-40% of this increase due to air pollution cuts.
Dr Laura Wilcox, co-author at the University of Reading, said: “The immediate health benefits of reducing air pollution are clear, but tackling air pollution can initially accelerate climate change.
“This warming side effect underlines the importance of reducing greenhouse gas emissions quickly to limit damaging climate change in the long term and give us a chance of meeting the Paris Agreement targets.”
New research led by Dr Wilcox, submitted to Atmospheric Chemistry and Physics Discussions, also predicts more rapid increases in rainfall during the tropical monsoon seasons in response to dramatic cuts in Asian air pollution. However, it confirms that acceleration of climate change is limited to the next few decades, after which the effect is swamped by the large response to greenhouse gas increases.
The effect of particle pollution on the atmosphere can already be seen in observations over Europe and China. In a separate study by Reading scientists, published in Nature Geoscience, measurements of sunlight at the Earth’s surface and from space between 1985 and 2015 suggest increased air pollution over Europe and China blocked sunlight from reaching the surface, but also heated the air higher in the atmosphere as the pollution particles absorbed more sunlight.
The study also implies that cleaning of this air pollution, first in Europe and increasingly now in China, has caused surface warming as more sunlight can reach the Earth, but reduced heating of the atmosphere as less sunlight is trapped.
Professor Richard Allan, co-author of the Nature Geoscience paper at the University of Reading, said: “Cutting air pollution is already having unintended consequences on the climate and makes it even more important to cut greenhouse gas emissions.
“This research is important because it explains the acceleration in rainfall increases and warming predicted by the computer simulations."
Dr Wilcox said: “This is very much of a case of short-term climate pain for long-term gain. It might seem counterproductive to prompt temperature rises by reducing pollution, but this research also shows this effect will disappear in a few decades.
“If we carry on emitting greenhouse gases into the atmosphere at the current rate, we will see bigger temperature rises that are far longer lasting. This would be incredibly difficult for society to adapt to, and would cause devastating environmental damage.”