Since lockdowns were imposed globally due to the coronavirus crisis, they trigger a dramatic fall in global Carbon dioxide emissions; research has shown.
The first definitive study of global carbon output in the recent year disclosed that emissions of the greenhouse gas per day plunged 17% by early April compared with 2019 levels.
According to the findings, as large sections of the global economy brought to a near standstill, the world has experienced the sharpest drop in carbon output since records began. In some countries, emissions reduced more than a quarter (26%) on average when the lockdown was tight at its most. In the UK, the decline was about 31%, while for a period during April, emissions fell 28.3% in Australia.
“This is a really big fall, but at the same time, 83% of global emissions are left, which shows how difficult it is to reduce emissions with changes in behavior,” said Corinne Le Quéré, a professor of climate change at the University of East Anglia, and lead author of the study published in the journal Nature Climate Change. “And it is not desirable – this is not the way to tackle climate change.”
However, this unprecedented fall is possibly only temporary. As countries slowly resume regular activity, the annual decline is likely to be only about 7% over the course of the year, and that is also if some restrictions remain in place to stop the virus. And if they are lifted in mid-June, the fall for the year is likely to be only 4%.
It would probably be the biggest annual drop in emissions since the Second World War and represent a stark difference compared with recent trends of emissions that have been rising by about 1% annually. However, it would make “a negligible impact on the Paris agreement” goals, Le Quéré said.
According to the Intergovernmental Panel on Climate Change, achieving the goals of the Paris Agreement would require emissions to fall to net-zero by mid-century or soon after, and that would also restrict global heating from reaching catastrophic levels. The Covid-19 crisis-driven fall in carbon reveals how far the world still has to go, said Le Quéré.
The changes in individual behavior such as not flying, working from home and driving less than the crisis experienced so far, can only go part of the way required to cut emissions because the bulk of emission sources left intact by the lockdown measures left, she said, adding that the way people produce and use energy needs bigger shifts.
“Just behavioral change is not enough,” she said. “We need structural changes [to the economy and industry]. But if we take this opportunity to put structural changes in place, we have now seen what it is possible to achieve.”
There was a dramatic decline, of about 60% in the emissions from aviation, as international flights between many countries were grounded. Emissions from surface transport fell less sharply, by about 36%. Power generation and industry accounted for about 86% of the total decline in emissions.
However, the impacts on the climate from such an unprecedented fall are likely to be small. Last year, stocks of carbon dioxide in the atmosphere, which reached 414.8 parts per million, will rise further towards the danger threshold of 450ppm this year, though perhaps at a slightly slower pace.
“Carbon dioxide stays in the air a long time, so although emissions are smaller, they are still happening and so carbon dioxide is still building up, just a little more slowly,” said Richard Betts, the head of climate impacts research at the Met Office Hadley Centre, who was not involved in the paper.
“If we want to halt the build-up of carbon dioxide in the atmosphere, we need to stop putting it there altogether. It’s like we’re filling a bath and have turned down the tap slightly, but not turned it off.”
Though there were steep falls in energy demand due to the lockdowns, energy production has hardly been changed by the crisis, noted Mark Maslin, a professor of climatology at University College London, who was also not involved in the paper.
“The real lesson of this pandemic is that we must globally shift our energy production away from fossil fuels as quickly as possible if we are to ensure sustained year-on-year cuts to our global emissions,” he said. “The good news is that both of these will help to maintain the clean air and clear skies we have all rediscovered during the lockdown, saving many lives.”
The scientists from the University of East Anglia, Stanford University in the US, the Cicero Centre in Norway, as well as scientists in the Netherlands, Australia, France, and Germany conducted this comprehensive analysis.
The researchers used measurements of economic activity, energy generation, industrial production, transport, and other proxies to estimate the output of carbon dioxide. The six areas to focus are aviation, power generation, industry, surface transport, public buildings and commerce, and residential sources. Estimates include 69 countries, 50 US states, and 30 Chinese provinces, representing 97% of global carbon emissions.
Despite measuring the rising concentrations of carbon in the atmosphere regularly, they are subject to large natural fluctuations. They are unfit for the kind of snapshot analysis required to observe the happenings to the global carbon output over a relatively short period.