Oil tankers anchor off the coast of Southern California as demand for oil and refined products plunge. Source: U.S. Coast Guard video by Petty Officer Third Class Aidan Cooney

A Pandemic That Cleared Skies and Halted Cities Isn’t Slowing Global Warming

By Laura Millan Lombrana and Hayley Warren

May 8, 2020, 12:00 AM EDT

In some ways, the dire lockdowns undertaken to stop Covid-19 have fast-forwarded us into an unlikely future—one with almost impossibly bold climate action taken all at once, no matter the cost.

Just months ago it would have been thought impossible to close polluting factories virtually overnight and slash emissions from travel by keeping billions at home. Now we know that clear skies and silent streets can come about with shocking speed.

The pandemic is a cataclysmic event so big and disruptive that it can be measured in the planetary metrics of climate change. As many as 2.6 billion metric tons of carbon dioxide emissions, about 8% of the estimated total for the year, will never be emitted into the atmosphere, according to estimates by the International Energy Agency. Pick any world-shaking event from 20th century history—none has produced a bigger decrease in emissions.

2.6B metric tons of CO₂ never emitted

It took weeks, not years, for skies in polluted cities to clear as emissions dropped. People in smog-choked towns in India shared photos of the suddenly visible Himalayas, which had been obscured by pollution.

Power plants responded to the lockdowns almost immediately, to the point that it’s been possible to trace the spread of the virus from the Chinese province of Hubei to Central Asia, Europe and the U.S. just by looking at grid activity. A pickup in power in Hubei in recent weeks is an indication that activity there has resumed after the lockdown ended. To see Europe’s emergence from lockdowns, simply note the recently shrinking gap between energy demand this year and last.

42% drop in power demand in Hubei, China

Global demand for energy is set to fall by 6%, seven times the decline seen after the global financial crisis of 2008, according to the IEA’s forecast. In absolute terms the drop is unprecedented—the equivalent to losing the entire energy demand of India for one year.

Satellites and sensors previously used to monitor climate change have become essential to track and understand the sudden changes in our most immediate environment. In cities, the effect of billions of humans at standstill has become evident in the Earth’s crust. Movements from everyday human activity create countless tiny vibrations in the ground. Seismometers close to or inside urban areas have registered reductions in movement.

The Earth vibrated less

Note: Sensors for Barcelona and Vienna are on the surface, while Brussels’ is located 100m underground

Sources: Jordi Diaz of Institute of Earth Sciences Jaume Almera, Thomas Lecocq of the Royal Observatory of Belgium, Observatories & Research Facilities for European Seismology (ORFEUS) and UN OCHA Humanitarian Data Exchange

The lockdowns have brought the tourism and travel sectors to a halt. With companies conducting a giant “meetings-that-could-have-been-emails” experiment, analysts and experts wonder whether the travel sector will ever fully recover. Before the pandemic, aviation accounted for more than 2% of global emissions.

10 million metric tons less CO₂ emitted from aviation

Feb. 1-March 19 compared with same period last year | Source: Australia Institute

Flights on Tuesday, March 10

4 p.m. to 8 p.m ET

Flights on Tuesday, April 7

4 p.m. to 8 p.m ET

Source: FlightRadar24

In Europe, flight activity has dropped more than 80% in major hubs such as the U.K., France, Spain and Germany, according to Europe’s Eurocontrol agency. Daily flights between Europe and the U.S. have come down to 90, from 485 before the pandemic. Over 16,000 passenger jets have been grounded worldwide, leaving airlines scrambling for spaces to store them.

With workdays relocated and shops closed, the world’s main avenues have emptied. Rush hour, an immutable fact of daily routine for hundreds of millions of people across the world, has simply vanished. Sometimes the culture of traffic has been slower to dissipate than the traffic itself. In Johannesburg, for example, where live radio reports tell drivers how to navigate constant gridlock in the Sandton business district, the broadcasts continue pointlessly, even without jammed roadways.

59% less traffic congestion in Mumbai, India

Thursday, April 23 at 12 p.m. compared with 2019 average | Source: TomTom

28% less traffic congestion in London, U.K.

Thursday, April 23 at 12 p.m. compared with 2019 average | Source: TomTom

In Europe, the first to go quiet was Milan, which on March 8 went under lockdown as the Italian government attempted to control the outbreak. Anonymous sensor data from moving devices collected by Mapbox reveals the moment the region came to a standstill.

Lockdown stopped traffic in Milan

Low–High driving activity index

With fewer planes in the air and cars on roads, demand for oil dropped by 5% in the first quarter of the year. By the end of March, when nationwide lockdowns started, global road transport activity had almost halved the 2019 average.

The plummeting demand for the world’s most important commodity, coupled with a price war between producers Saudi Arabia and Russia, resulted in negative oil prices for the first time in history. In a dramatic turn of events, traders in one type of oil had to pay up to $40 per barrel on April 20 just to get someone to take crude off their hands. This turnabout might foreshadow declining demand for oil brought on by cheap, abundant renewable energy and electric-vehicle batteries.

The pandemic transformed the soundscape in some of the world’s noisiest cities instantly, too, replacing engines and car horns with bird chirps. It made it easier in many places to hear the sad blare of ambulance sirens. But reduced urban noise, like reductions in fossil fuel use and CO2 emissions, is something that climate action can achieve. Mega-cities in China where electric vehicles and battery-power bikes have supplanted cars, buses and motorcycles demonstrate that this can be a permanent sonic state.

Sound is off

In a park in Lisbon on April 12, sounds of bikes passing and music from a nearby mass can be heard.

In the main transit station in Frankfurt at noon on Friday, March 23, only the hum of the station can be heard as less journeys are made.

On a residential street in Toronto on April 6, birdsong from a robin prevails over sounds of traffic.

Sounds are from the radio aporee platform. Lisbon recording by Carlos Santos/aporee.org, Frankfurt by LIGNA/aporee.org, and Toronto by William Denton/aporee.org. Maps from Google Earth

Exactly which of these new features will stick when activity picks up remains to be seen. Carlo Buontempo, director of Europe’s Copernicus Climate Change Service, is closely watching the impact of the virus, especially through the agency’s Sentinel-5 Precursor satellite, which detects air pollution from space.

“There’s a deeper reflection on our relationship with the environment that has been triggered by the lockdown,” he says, expressing his personal feelings about the situation. “Many people have realized that things that were just impossible to conceive just six months ago actually are not too dramatic after all.”

Detecting the swift drop in pollution has underscored the extent to which it made us vulnerable to the virus in the first place. The burning of fossil fuel in vehicles, factories and power plants creates soot and other particles so small that they end up in almost every organ in the body, including the lungs.

Covid-19 is a respiratory illness that can cause pneumonia and result in severe, long-lasting lung damage. People infected with the novel coronavirus are more likely to die if they live in regions with high levels of pollution, according to two different studies. These early findings resonate with pre-pandemic research linking pollution to a long list of diseases.

Seven global cities—Delhi, Sao Paulo and New York among them—experienced 25% to 60% reduction in fine particulate matter known as PM2.5 during the lockdown, according to IQAir. Los Angeles experienced its longest stretch of clean air on record, finally meeting the World Health Organisation’s air quality guidelines.

42% reduction of PM2.5 in Mumbai, India

Compared with prior 4–year average | Source: IQAir

A flock of flamingos rest in a pond during the lockdown in Navi Mumbai on April 20. Photographer: Indranil Mukherjee/AFP via Getty Images

51% reduction of PM2.5 in Los Angeles, U.S.

Compared with prior 4–year average | Source: IQAir

MacArthur Park and downtown Los Angeles, California in the midst of the coronavirus pandemic, on April 15. Photographer: Mario Tama via Getty Images

55% reduction of PM2.5 in Delhi, India

Compared with prior 4–year average | Source: IQAir

India Gate during the lockdown on April 20 in New Delhi, India. Photographer: Mohd Zakir/Hindustan Times via Getty Images

Clean air and calmer cities are possible today, no dreadful virus required. There are proven technologies and successful policy tools for replacing coal plants with wind and solar farms, and combustion engines with batteries. While the pandemic has crunched car sales globally, there are early signs that battery-powered vehicles are maintaining momentum. EV sales in France, Germany, the Netherlands, Sweden and the U.K. surged in March and the first half of April, according to Bloomberg New Energy Finance.

The comeback of economic activity when lockdowns ease might wipe out these changes as fast as they happened. The first signs are visible in China, where cities have relaxed quarantine rules, factories have restarted and people have returned to work. That turnabout is good news—and it can be measured almost immediately in bad news for the planet.

The lockdowns dipped NO₂ levels

Note: Monthly averaged concentrations of nitrogen dioxide. Areas with more than 30% cloud cover have been removed

Source: Copernicus Sentinel-5P NRTI NO₂ via Google Earth Engine

What makes the breathtaking, planetary-scale transformations wrought by the pandemic so unsettling is that none of it registers in the biggest picture. The photographs of clear skies, the charts of falling emissions, the change in daily behavior by billions of people—none of this will slow the dangerous pace of global warming.

The level of CO₂ in the atmosphere, which drives our warming temperatures, has been rising steadily by an average of almost 2.5 parts per million a year since 2010. A significant cut in new emissions from 2020 won’t improve this all-important metric, now at 414 ppm. Even a 10% drop in emissions from this year would still translate to an increase of 2 ppm in the CO₂ count, according to estimates by Pierre Friedlingstein of the University of Exeter.

CO₂ in the atmosphere will continue to go up

Sources: NOAA, Scripps Institution of Oceanography

“Because of the inertia in the climate system, even if we were to significantly reduce or stop our emissions today, you would still see the increase in temperatures expected for the next 20 years almost unaffected,” Buontempo said. “In reality it is very likely that the total concentration of CO2 in the atmosphere will continue going up in the future.”

If an unprecedented event sweeps the planet and inadvertently reduces emissions by more than modern-day humans have ever managed to do intentionally, what does that mean for our climate goals? The strategies used to contain the virus can’t remain in place for long. Shutting down entire economies and sending millions of workers into unemployment are not sustainable solutions, especially when billions of citizens around the world aspire to the same living standards and comforts as those in developed nations.

The efforts will need to be titanic, even bigger than the ones it took to bring the world to a temporary halt in the face of Covid-19. Businesses will have to keep their green promises—and make new, more ambitious plans in the middle of the worst economic crisis in decades. People shocked by disruptions to daily life and widespread unemployment will need to rethink their daily behaviors. Nations will need to reach the sort of agreements that happen rarely in international gatherings such as the United Nations annual climate talks, now postponed until 2021 due to the virus. Governments planning to spend trillions in stimulus packages will need to invest in solutions that create jobs and growth while reducing emissions.

“The emotional and psychological impact is the one that has some chance of surviving after the end of the lockdown,” Buontempo said. “The most tangible long-term effect will probably be linked to our behavior and our priorities.”