The global lockdown will have a “negligible” impact on rising temperatures but a green recovery could avert dangerous climate change, a study has said.
Lockdowns to stop the spread of 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 0.01C 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, the study published in Nature Climate Change said.
That gives the world a good chance of keeping temperature rises to the 1.5C goal that countries signed up to under the international Paris climate agreement to prevent the most dangerous impacts of global warming.
Recovery packages targeting low-carbon energy and energy efficiency and not giving bailouts for fossil fuels could “mean the difference between success and failure” on avoiding dangerous climate change.
Study lead author Professor Piers Forster, director of the Priestley International Centre for Climate at the University of Leeds, started working on the analysis with his daughter Harriet after her A-levels were cancelled.
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 10-30%, 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.
It is what happens now that is important, the researchers said.
Strong action to drive the recovery through green measures could lead to greenhouse gas emissions being 50% lower in 2030 than they would otherwise be, which would reduce expected warming by 0.3C by 2050.
It could set the world on track to keep temperature rises to no more than 1.5C above pre-industrial levels.
Beyond that threshold, scientists warn of worsening impacts of climate change, including increased droughts and extreme weather, spread of diseases, reduced crop yields, rising seas and harm to wildlife.
Prof Forster said: “The choices made now could give us a strong chance of avoiding 0.3C of additional warming by mid-century, halving the expected warming under current policies.
“This could mean the difference between success and failure when it comes to avoiding dangerous climate change.”
He added: “The study also highlights the opportunities in lowering traffic pollution by encouraging low emissions vehicles, public transport and cycle lanes.
“The better air quality will immediately have important health effects – and it will immediately start cooling the climate.”
Study co-author Harriet Forster, who has just completed her studies at Queen Margaret’s School, said: “Our paper shows that the actual effect of lockdown on the climate is small.
“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.”
Study co-author Corinne Le Quere from the University of East Anglia added: “The fall in emissions we experienced during Covid-19 is temporary and therefore it will do nothing to slow down climate change, but the Government responses could be a turning point if they focus on a green recovery, helping to avoid severe impacts from climate change.”