The Arc de Triomphe in Paris, France, on 4 April 2020 at the height of lockdown
Cyril Marcilhacy/Bloomberg via Getty Images
Global lockdowns to halt the spread of the coronavirus will have a negligible impact on rising temperatures due to climate change, researchers have found.
Lockdowns to stop the spread of the coronavirus caused huge falls in transport use, as well as reductions in industry and commercial operations, cutting the greenhouse gases and pollutants caused by vehicles and other activities.
The impact is only short-lived, however, and analysis shows that even if some lockdown measures last until the end of 2021, global temperatures will only be 0.01°C lower than expected by 2030.
But if countries choose a strong green stimulus route out of the pandemic, it could halve the temperature rises expected by 2050, says a team led by Piers Forster at the University of Leeds, UK.
That gives the world a good chance of keeping temperature rises to the 1.5°C goal that countries signed up to under the international Paris climate agreement to prevent the most dangerous impacts of global warming.
Forster started working on the analysis with his daughter Harriet after her A-level exams were cancelled due to school closures. They used mobility data from Google and Apple to calculate how 10 different greenhouse gases and pollutants changed between February and June in 123 countries, before a wider team helped with detailed analysis.
The team also modelled options for post-lockdown action, ranging from a fossil-fuelled recovery to two different levels of green stimulus.
Emissions of carbon dioxide, nitrogen oxides and other pollutants fell by between 10 and 30 per cent, the analysis said. But because the reduction was only temporary, the impact on warming driven by the long-term build up of greenhouse gases in the atmosphere will be very small unless countries take action.
“The choices made now could give us a strong chance of avoiding 0.3°C of additional warming by mid-century, halving the expected warming under current policies,” says Forster. “This could mean the difference between success and failure when it comes to avoiding dangerous climate change.”
“Our paper shows that the actual effect of lockdown on the climate is small,” says Harriet Forster. “The important thing to recognise is that we’ve been given a massive opportunity to boost the economy by investing in green industries – and this can make a huge difference to our future climate.”
Journal reference: Nature Climate Change, DOI: 10.1038/s41558-020-0883-0
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