COVID-19 has caused people to greatly cut back on travel, thereby reducing the amount of carbon dioxide and other planet-warming gases they release into the atmosphere, but the pandemic isn’t likely to have more than a negligible effect on global warming, scientists say.
“Only about 0.01 degrees,” suggests Piers Forster, an atmospheric physicist at the University of Leeds, UK.
But, he writes in a paper in the journal Nature Climate Change, his findings also suggest that if a “green recovery” is used to rebuild the economy after the pandemic, behaviour changes learned from COVID-19 quarantine could be used as a springboard to cut global warming by as much as 50%, thereby keeping us from exceeding the 1.5 degrees Celsius global temperature increase targeted by scientists as a way to avoid the worst impacts of future climate change.
Forster got to wondering about the effects of COVID-19 on climate earlier this year when he and his high school daughter Harriet (now a co-author on the paper) found themselves with time on their hands. “I had a lot of work cancelled and she found exams cancelled,” he says. “So we had to think of something to do with our time.”
The first task was to figure out just how much COVID-19 lockdowns had reduced emissions.
Normally, Forster says, that would be done by looking for changes in such things as fossil fuel usage and air emissions. “But that data takes a very long time for industry and government to report. We do not normally find out until 18 months or so afterward.”
To shortcut the process, they turned to data on changes in people’s travel patterns, recently made public by Google and Apple from cell phone data. (The data, Forster says, is aggregated in ways that protect individual customers’ privacy.)
That allowed an estimate of the changes in gasoline usage, as well as emissions of 10 air pollutants. The calculation also included shifts in energy usage (such as heating, air conditioning, and electrical power) when people spend more time at home.
“We didn’t think it would work,” Forster admits. When he ran the calculations by a colleague, however, she was able to compare the results to figures being reported in news articles and other such sources, and found a surprisingly good match.
“The other thing that convinced us we were onto something is that we compared it to observations of air quality,” Forster says. “That gave us confidence that we could correlate [cell phone data] with emissions.”
Armed with that, his team put the resulting figures into a climate model and determined the overall impact on global warming, under the assumption that current levels of COVID-19 mobility restriction would continue for a total of two years.
That was what produced the depressing discovery that even current behaviour changes aren’t enough to produce more than a blip in the overall trend of climate change.
The reason, he says, is that greenhouse gases, especially carbon dioxide, persist a long time in the Earth’s atmosphere, and a couple of years’ dip in emissions won’t have much effect on their long-term buildup. “Although they were big changes in behaviour,” he says, “it doesn’t begin to affect the [greenhouse gas] concentrations unless you do it for a long time.”
But that’s not the end of the story. The long-term-effect depends on what we do when the pandemic finally ends.
In the aftermath of the 2008/09 financial crisis, Forster says, one of the methods used to reboot the economy was to stimulate the oil industry. “If we do that [again], we estimate that it would increase the temperature beyond what we were doing before,” he says. In other words, it would make things worse than if there were no COVID-19 slowdown.
But there are other options. “If we channelled that which went into fossil fuels last time into green investments like renewable energy, retrofitting our houses, building zero-carbon transportation systems, and putting in bicycle paths – and were to spend just 1.2% of GPD doing these green investments – we could potentially keep under the 1.5-degree target.”
And the pandemic might be just the incentive people need in order to do this. “With disaster, there is also opportunity,” he says. “I don’t think we realised before how vulnerable our society was.”
Currently, the overlooked vulnerability had to do with infectious disease. But now that we’ve realised our overall vulnerability, he says, maybe we will also realise that we aren’t immune to the consequences of climate change, either.
“The important thing to recognise,” adds Harriet Forster, “is that we’ve been given a massive opportunity to boost the economy by investing in green industries. This can make a huge difference to our climate future.”
Marc Hafstead, an economist at Resources for the Future, a nonpartisan think tank in Washington, DC, agrees. “The true impact of the COVID-19 pandemic will be determined by the policy response, or lack thereof, to the economic disruption caused by the pandemic,” he says.
Richard A Lovett
Richard A Lovett is a Portland, Oregon-based science writer and science fiction author. He is a frequent contributor to Cosmos.
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