Reducing industrial working hours and keeping construction sites and shops closed has curbed the use of coal and cut output of steel products in the country, which produces about 27 per cent of global greenhouse gases.
As China’s leaders have strived for economic growth, its carbon dioxide emissions have risen, hitting a record high in 2018.
But in the past two weeks, with cities under lockdown, coal use at the country’s power stations has hit a four-year low, and oil refinery operating rates in Shandong province are at their lowest level since 2015, statistics show.
Output of key steel products are at their lowest level for five years, and domestic flights have fallen by up to 70 per cent in a month.
The measures have also led to a drop of 36 per cent in levels of nitrogen dioxide air pollution over China, according to analysis by climate science website Carbon Brief.
Overall, the changes in Chinese society have caused a 40 per cent plunge in output across key industrial sectors, according to the study, which was based on official statistics.
Factories, offices, shops and schools all close for the Chinese new year holiday, but this year the holiday was extended in an effort to limit the spread of coronavirus, which has killed at least 2,236 people so far worldwide.
The reductions in coal and crude oil use have meant a drop in CO2 emissions of 25 per cent or more – 6 per cent of global emissions – compared with the same period last year, Carbon Brief found.
Dominic Moran, professor of agricultural and resource economics at Edinburgh University, told The Independent any falls in emissions would have a cumulative benefit, and the drop in flights was likely to change people's behaviour long-term.
"Some will say the pent-up demand for good will lead to a rebound splurge afterwards," he said. "But this could be a minor real effect - 20 per cent of the world economy is slowly shutting down, one if five global flights is being cancelled. I doubt it will catch up afterwards."
People's fear of being quarantined, for instance, would give them pause for thought and change their behaviour, he said. If one in five consumption decisions was not now being taken, that could also influence people's psychology for the better.
But Joeri Rogelj, a climate change and environment lecturer at the Grantham Institute, Imperial College London, said the changes would make no difference in the long term.
“This change in CO2 is not permanent,” he said. “In the grand scheme of things it won’t be visible in our total emissions.
“If there’s a silver lining to the virus, it’s that it’s a wake-up call in our society and intricate structures. We’re far from controlling our world as well as we think.”
The coronavirus showed how vulnerable our societies would be to sudden disturbances such as an epidemic, a sudden failure of “bread basket” grain harvests or the Amazon turning to savannah, Dr Rogelj added.
He said emissions can be cut by reducing demand for products by consuming less or consuming smarter – so designing towns and cities better so people need to travel less; and designing buildings and other products so the steel can be extracted and reused.
Melting steel requires the burning of large amounts of fossil fuels, but currently steel is hard to recycle when it is encased in concrete.
Caterina Brandmayr, senior policy analyst at the Green Alliance think tank, agreed the drop in emissions was very unlikely to be sustained in the long term once economic activity rises again.
“The crisis highlights the fundamental role that demand plays in driving emissions generation,” she said.
“In China’s case, energy consumption is strongly dominated by energy-intensive industries and freight, but ultimately these are driven by end consumers, be it individuals, corporates or governments, within and outside China.
“This reminds us that reducing emissions permanently will require substantial investment in clean energy, processes and products, but also addressing demand for goods and services to ensure the overall demand for energy and materials is reduced across the economy.”
With its current policies, China’s greenhouse gases are projected to rise until at least 2030, although the rate of increase is projected to slow towards the end of the 2020s, according to Climate Action Tracker.
Coal-fired power generation usually halves in the 10 days after the Chinese new year, but this year the fall in energy use has been prolonged, with no sign of rebound, Carbon Brief found.