Air pollution in China nearly halved during the country’s coronavirus lockdown, new research involving NASA and UK scientists has shown.
The analysis provides a vision of what a drastic reduction in the burning of fossil fuels can mean.
From space, you can see the impact of a reduction in nitrogen dioxide over Wuhan in Hubei province.
It is the most populous city in central China and was placed under stringent lockdown as the epicentre of China’s outbreak and the place where the global pandemic began.
Image: Average nitrogen dixoide density over China in 2020
Nitrogen dioxide is emitted from cars and factories when fossil fuels are burned and levels of NO2 can be used as an indication of economic activity.
Previous imagery from NASA has shown the impact of the start of China’s lockdown but the new figures show air pollution throughout the shutdown was reduced across the country by 48%.
The research team included the University of Exeter.
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Professor Oliver Hauser, Associate Professor of Economics at the University of Exeter Business School, said: “This unusual period offers a rare counterfactual of a potential society which uses substantially less fossil fuels and has lower mobility.”
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Researchers used data from NASA’s Aura satellite and the European Copernicus Sentinel-5 Precursor satellite to measure the levels of nitrogen dioxide and looked at the period of February and March this year when very strict quarantine measures were put in place.
Image: Daily variations in seven-day moving averages of nitrogen dioxide over China
Around the time of the Chinese New Year, there is always a decline in industrial activity with people on holiday for the spring break. But this year the usual mass movement of humanity when people travel to be with family didn’t happen either.
Even taking into account the usual drop in NO2 associated with this time of year, levels have fallen 21% below the average for 2015 to 2019.
Dr Fei Liu, lead author of the study and NASA researcher, said: “This is the first time I have seen such a dramatic drop-off over such a wide area for a specific event.”
Image: Reductions in nitrogen dioxide along highways
As the world’s biggest emitter of greenhouse gases, China’s use of fossil fuels is central to tackling climate change. The air pollution study shows the impact of a decline in fossil fuels in a short space of time.
Previous studies have shown a significant emissions drop of around a quarter in China during its pandemic lockdown.
But efforts to supercharge the economy have left environmentalists downbeat that the lockdown emissions drop will be anything other than a blip over a longer period of time.
With its current policies China’s greenhouse gas emissions are projected to rise until at least 2030.
The choices it makes between the technology of the past and a future of renewables will have a lasting effect on the world’s ability to limit warming to 1.5C as set out in the Paris Agreement.
Source : Sky News