U.S. Greenhouse Gas Emissions Bounced Back Sharply in 2021

WASHINGTON — America’s greenhouse gas emissions from energy and industry rose 6.2 percent in 2021 as the economy began recovering from pandemic lows and the nation’s coal plants roared back to life, according to a preliminary estimate published Monday by the Rhodium Group.

The rebound was not a total surprise: The nation’s emissions had plummeted more than 10 percent in 2020, the largest one-year drop on record, after the initial coronavirus outbreak triggered widespread lockdowns and energy use plunged to its lowest level in decades. As restrictions eased and economic activity picked back up, emissions were expected to bounce back.

“If anything, last year’s rebound in emissions was lower than it could have been because the pandemic is still causing disruptions and the economy isn’t back to normal,” said Kate Larsen, a partner at the Rhodium Group, a research and consulting firm. “Emissions are still well below 2019 levels.”

The uptick in emissions underscored the challenges President Biden faces in his quest to shift the nation away from oil, gas and coal and help avert a drastic rise in global temperatures.

Mr. Biden has set a goal of slashing the nation’s greenhouse gas emissions at least 50 percent below 2005 levels by 2030, which is roughly the pace that scientists say the whole world must follow to keep the Earth from warming more than 1.5 degrees Celsius (2.7 degrees Fahrenheit) above preindustrial levels and minimize the risk of catastrophic effects. The planet has already warmed 1.1 degrees Celsius over the past century.

But after last year’s rebound, U.S. emissions are now just 17.4 percent below 2005 levels, the Rhodium Group estimated. Several recent studies have found that the United States is likely to fall far short of achieving Mr. Biden’s climate goals without major new policies to speed up the transition to wind, solar and other clean energy.

Whether Mr. Biden can enact these policies is a major question: His Build Back Better Act — which contains $555 billion in spending and tax incentives for renewable power, electric cars and other climate programs — remains in limbo on Capitol Hill. Senator Joe Manchin III of West Virginia, a crucial Democratic swing vote, has so far balked at supporting the legislation, though Democrats are expected to try again this year. Republicans have uniformly opposed the bill.

Recent analysis led by researchers at Princeton University found that the bill, if passed in its current form, could potentially get the United States most of the way to its climate goal, by tripling or quadrupling the pace of wind and solar power installations, accelerating electric vehicle sales and spurring utilities to retire more coal plants over the next decade.

For now, however, the United States remains deeply dependent on fossil fuels to power its economy.

Transportation, the nation’s largest source of greenhouse gases, saw a 10 percent increase in emissions in 2021 after a 15 percent decline in 2020, the Rhodium Group estimated. Much of that rebound was driven by a rise in diesel-fueled trucks carrying goods to consumers as e-commerce surged, with freight traffic climbing above pre-pandemic levels last year.

Passenger travel in cars and airplanes has been slower to recover, as the uncertainty around new variants disrupted travel plans and kept many people at home. Gasoline consumption did not return to 2019 levels until October, while demand for jet fuel remains well below pre-pandemic levels.

There are some signs that vehicles on the roads are starting to shift: Sales of electric cars, a key technology for cutting emissions, increased to record highs in 2021, accounting for 5 percent of all new car sales in the third quarter, according to Atlas Public Policy, a research firm. But electric cars are not yet widespread enough to make a major dent in emissions, and few trucks have been electrified to date.

Coal, the most polluting of all fossil fuels, also made a big comeback last year, with emissions from coal-fired power plants rising 17 percent in 2021 after declining 19 percent in 2020. While America is still burning far less coal than it was a decade ago, the fuel is far from dead.

In the years before the pandemic hit, America’s electric utilities had been retiring hundreds of coal plants, replacing them with cheaper and cleaner natural gas, wind and solar power. Then, in 2020, electricity use sagged nationwide and many utilities ran their remaining coal plants far less often, since it was often the most expensive fuel.

But that dynamic reversed last year: As natural gas prices nearly doubled in 2021, driven in part by a cold winter and rising exports, many utilities switched back to running their coal plants more often. (On average, burning coal for electricity produces twice as much carbon dioxide as burning natural gas, though natural gas use also creates plenty of methane, a potent greenhouse gas.)

“It really illustrates how much we’ve depended on cheap natural gas prices to keep coal in decline,” Ms. Larsen said. “Overall, we still expect coal to decline further in the years ahead, but unless there are new policies put in place to clean up the power sector, the coal industry could see a bit of a lifeline if there are big swings in the gas market.”

A recent report from the U.S. Energy Information Administration projected that coal emissions would likely dip again next year if natural gas prices stabilize. Electric utilities have already announced plans to retire at least 28 percent of their remaining coal plants by 2035, the agency said. And power companies installed new wind turbines and solar panels at a record pace over the past two years.

Still, meeting Mr. Biden’s climate goals will be daunting: To do so, the Rhodium Group has estimated that the United States would need to cut emissions roughly 5 percent each year between now and 2030, which is a much faster pace than the country was achieving before the pandemic. Last month, the solar industry warned that new installations could slow in 2022 because of supply-chain constraints and rising material costs.

The Rhodium Group also noted that the United States has made scant progress in cutting emissions from two other major sectors: industry and buildings.

Emissions from heavy industry, like cement and steel, rose 3.6 percent in 2021 after declining 6.2 percent in 2020. Such factories, which account for roughly one-fifth of the nation’s emissions, could prove difficult to clean up without new technologies, and industrial emissions have stayed largely flat since 2005.

Homes and buildings also directly produce emissions by burning fossil fuels such as natural gas in furnaces, hot water heaters, stoves, ovens and clothes dryers. Building emissions rose 1.9 percent in 2021 after declining 7.6 percent in 2020.

The Rhodium Group report only looked at emissions from energy and industrial sources and did not look at sectors such as agriculture. It also did not account for any uptick in emissions resulting from last year’s wildfires in California, Colorado and the Pacific Northwest, which burned millions of acres of forests and grasslands, sending the carbon dioxide that had been locked away in all those trees into the atmosphere.

Using satellite data, the European Union’s Copernicus Atmosphere Monitoring Service estimated in December that last year’s North American wildfires emitted 83 million tons of carbon dioxide. While the forests that went up in flames may eventually grow back, absorbing carbon dioxide as they do, that process will take years. And scientists have warned that wildfires will become larger and more frequent as the planet warms.

The United States was not the only country to see a big rebound in fossil fuel use last year. In November, researchers at the Global Carbon Project estimated that global carbon-dioxide emissions from energy and industry rose 4.9 percent in 2021, after a 5.4 percent decline in 2020. China, India and the European Union all had major increases, suggesting that any climate effect from the pandemic was fleeting.