WASHINGTON - From a hill four miles outside Boston, World Resources Institute economist Michelle Manion says she can read the letters on top of the Prudential building, a city landmark.
"I've never been able to do that," she said. "It's really amazing."
Since Massachusetts Gov. Charlie Baker began ordering schools and businesses to close on March 24 to staunch the spread of COVID-19, traffic on area highways is down by roughly two-thirds.
The air pollution that goes along with it is down, too.
"People are not commuting," Manion said. "It's a huge difference."
From Boston to Washington, DC, levels of nitrogen dioxide, one form of air pollution, are down by roughly 30% compared with the previous five years, according to NASA satellite data.
Dramatic drops in road traffic and air travel have slashed oil consumption worldwide. In the United States, the world's largest consumer, demand is down by a record-shattering 31% from the average for January to mid-March, according to the U.S. Energy Information Administration.
The drop in fossil fuel use may lower greenhouse gas emissions by 5.5% this year, according to an estimate by Carbon Brief. It would be the largest reduction ever by far, more than four times greater than the decrease during the 2008-2009 Great Recession. The global oil crash accounts for more than half of the drop.
Don't expect it to last.
"The general expectation is that most of this will pick up once the crisis is over," said Michael Gerrard, director of the Saban Center for Climate Change Law at Columbia University.
Satellite imagery already shows air pollution rebounding over China.
In the meantime, the pandemic has slowed the transition to cleaner energy.
BloombergNEF, an energy research organization, lowered its 2020 forecast for new wind power construction globally by 12% and new solar power by 8%. Investment in renewables has dried up. Electric vehicle sales are down by two-fifths compared to last year.
The downturn is likely temporary. Renewables still make economic sense.
"The cost of building solar and wind has plummeted so much in recent years that it's highly competitive. It's really often outbidding fossil fuels," Gerrard said. "That hasn't changed. We've seen a slowdown in the construction. But I think that should pick up once people are fully back to work."
However, BloombergNEF's forecasts for global renewable energy installations show the world falling far short of what's needed to keep the planet from warming more than 2 degrees Celsius, the target in the 2015 U.N. Paris climate agreement.
And BNEF's forecasts are more optimistic than most, according to the firm's head of clean energy, Logan Goldie-Scot. The deeper the economic downturn from COVID-19, the farther off target the world will likely be.
"If it ends up delaying or making it harder to finance and build renewable energy projects, then this will make what was already a challenge even harder," he said.
The impact of the oil price crash isn't clear.
"Ordinarily if gasoline is inexpensive, people are likely to go out and buy expensive gas guzzling cars," Gerrard said. "But these days, they aren't buying much of anything." Sales of all vehicles are down about two-fifths, not just electric vehicles. Automakers have announced a few delays, but they're mostly sticking to their plans to release new electric models.
It's too soon to say, but the pandemic may bring about societal changes that could affect greenhouse gas emissions.
Unprecedented numbers of white-collar workers are telecommuting. "A lot of these folks are like, 'You know what? This is great,'" Manion said. After the crisis, "I think that there will be a pretty strong demand on the part of workers" to keep it up at least part time.
"That's an area where you could see reduction in emissions from commuting," she added. "You could also see companies starting to maybe shrink the amount of commercial office space they're using by 10 or 15 percent" because less of the workforce is in the office at a time. That would cut down on emissions from buildings.
Before the crisis, growing numbers of large corporations had made commitments to reduce their greenhouse gas emissions. The environment often takes a back seat to economic growth in tight times. But Goldie-Scot says he has not seen companies abandoning their plans.
"It may result in some delays here and there, but it's not a structural shift," he said.
One concern is that the COVID-19 crisis will push the climate crisis off the radar.
"Before the virus crisis, there was a tremendous buildup of momentum around the world in public activism and public interest about climate change," Gerrard said. "Obviously, attention has switched to the coronavirus crisis." The loss of political pressure could do long-term damage to efforts to transition to clean energy, he said.
Governments around the world are pouring unprecedented amounts of money into propping up their cratering economies.
The U.S. government invested billions into clean energy in the stimulus bill during the 2008-2009 financial crisis. Big stimulus packages are expected this time around, too. Experts say the right investments could put the world closer to reaching its climate goals.
On the other hand, Goldie-Scot said, "If large sums of recovery money goes into sustaining technologies that are detrimental to those longer-term decarbonization goals, this will end up being a setback."
“We're at a point where we can turn this ship in one of two ways," Manion added. "I'm hoping that we see some leadership."