Last year, the United States experienced the largest drop in emissions since just after World War II, bringing USA greenhouse gas emissions down to below 1990 levels.
Carbon dioxide and other greenhouse gases trap solar radiation in the atmosphere, just like the glass traps heat in a greenhouse.
Global Carbon Project estimates that emissions of heat-trapping gases decreased by around 7% globally past year.
A report released by the Rhodium Group on Tuesday shed light on how coronavirus impacted the United States economy.
Transportation, the nation's largest source of greenhouse gases, saw a 14.7% decline in emissions in 2020 as millions of people stopped driving to work and airlines canceled flights.
Energy emissions also fell sharply, due to a decline in the use of coal.
Reduced travel in response to the COVID-19 pandemic previous year resulted in the lowest level of greenhouse gas emissions in the United States in three decades, according to a preliminary analysis released Tuesday.
Former President Barack Obama had pledged that the U.S. emissions would drop 17% below 2005 levels by 2020. The drop in emissions was much larger than what was seen during the 2009 recession, when emissions lid by 6.3 per cent. But this was mostly owed to the coronavirus pandemic and not because of any significant climate action - which means the USA still has a long way to go to get its emissions under control.
Previous year "certainly shouldn't be considered a down payment towards meeting the United States target under the Paris Agreement", the report says. Because of the pandemic, emissions were 21.5% lower in 2020, compared to 2005.
But that milestone comes with several caveats. Instead, they used more natural gas, which produces less carbon dioxide, as well as more solar and wind power.
It was a big year for renewable energy in the U.S., with many energy companies building a record number of wind farms and solar plants ahead of a deadline to claim a federal tax credit. Some sectors such as air travel and steel production are already rebounding in the US.
"Unfortunately, 2020 tells us little about what we can expect to see in 2021 and beyond", the report concluded.
"With coronavirus vaccines now in distribution, we expect economic activity to pick up again in 2021, but without meaningful structural changes in the carbon intensity of the United States economy, emissions will likely rise again as well", the report said.
Scientists warn that even a big one-year drop in emissions is not enough to stop global warming. As if to underscore that warning, European researchers announced last week that 2020 was quite likely tied with 2016 as the hottest year on record.
The concentration of greenhouse gases in the atmosphere actually surged to a new record high a year ago, the World Meteorological Organization said in November.
"This [emissions] decline didn't happen as a result of strong government policies or major penetration of clean energy technologies - this decline happened mainly as result of the economic downturn [and] pandemic", Fatih Birol, executive director of the International Energy Agency, said at a news conference on Monday. "That calls for decisive action this year, next year and indeed every year to 2050".