Greenhouse gases generated by the U.S. economy will slide 9.2 percent this year, tumbling to the lowest level in at least three decades, a new BloombergNEF study says.

Battered by the coronavirus pandemic, the stalled economy is projected to have generated 5.9 billion metric tons of emissions, about the same level as 1983, according to the private research organization.

As a result, the United States has been inadvertently pushed back on track to meet the commitments the Obama administration made at the Paris climate agreement in December 2015, despite the fact the Trump administration pulled the country out of the pact. Before 2020, the United States had fallen badly behind its targets under the accord.

Still, net emissions are expected to be 6.4 percent lower after taking into account the unusually extreme forest fires that swept the West Coast and Rocky Mountains earlier this year, pumping carbon dioxide and other pollution into the air and offsetting much of the drop in U.S. greenhouse gas emissions.

An economic rebound in 2021 could further negate the drop in greenhouse gas emissions, the BloombergNEF study says. Without the impact of the coronavirus, greenhouse gas emissions this year would have been only 1 percent lower than 2019, the organization says.

Scientists agree rising greenhouse gases linked to human activity are driving up global temperatures and, left unabated, will cause irreversible damage to the planet.

“Like all major crises, there is a chance to turn this temporary downturn in emissions to a more permanent one by making investments and changing policy, but it won’t just happen on its own,” Sarah Ladislaw, director of the Energy Security and Climate Change Program at the Center for Strategic and International Studies, said in an email.

“Nothing about the economic hardship coming from COVID-19 points the way forward on climate change except that it points out how we often discount our own systemic vulnerability,” she said. “Tackling climate change requires a systematic and complete overhaul of our energy system.”

The BloombergNEF analysts said the effects of the economic disruption would linger through 2021 and emissions in the coming year could still be 5 percent lower than 2019 emissions. That level, said Thomas Rowlands-Rees, BloombergNEF’s head of North American research, could become a “new normal” if people change driving habits and the power sector continues to shift to renewable power.

But the study says the United States could take little comfort from that.

“The amount of pain we’ve had to go through for a relatively modest drop shows that there needs to be more smart policy and smart thinking about emissions,” said Ethan Zindler, BloombergNEF’s head of Americas. “The emphasis has to be not on how to reduce demand, but how to make supply more green.”

That is happening to some extent in the power sector, the study said. The sector’s 11 percent drop in emissions was “not purely attributable to a fall in consumption,” it said. “It is a reflection of long-term reductions in the emissions intensity of the U.S. power sector.”

The biggest drop in emissions this year came from the transportation sector, where emissions fell 14 percent, dragged down by a steep drop in air travel and automobile trips.

Kevin Book, a managing director and head of energy research at ClearView Energy Partners, played down the latest figures. “You can get in shape or you can starve. Either way you lose weight,” Book said. “The point of energy is to go places, do things, make things, enjoy things and we haven’t been going, doing, making or enjoying nearly as much.”

“This is the way it feels to cut emissions in the worst way possible,” he said. Cutting emissions through a worldwide pandemic “still isn’t enough to change the atmospheric stock of carbon.”

President-elect Joe Biden has pledged that on his first day in office, he will reenter the United States in the Paris accord. But the BloombergNEF study cautions the United States would still “need stronger policy commitments outside of the power sector in order to hit the 2025 target.”

Correction: A previous version of this article incorrectly said the economy is projected to have generated 5.9 million metric tons of emissions this year. It is projected to have generated 5.9 billion metric tons.