US carbon emissions increased in 2021

David L. Ryan/Globe Staff/file

Scientists have made it clear that the world must urgently curb carbon emissions to avert climate catastrophe. But it looks like last year, the US moved in the wrong direction. The nation saw a 7 percent increase in greenhouse gas pollution from energy last year, according to new federal projections.

That increase came despite the US making big climate promises last year at the Glasgow climate talks and on the federal stage.

“These sobering figures demonstrate what climate activists have been saying for decades — tinkering around the edges won’t get the job done,” Collin Rees, senior campaigner at Oil Change International, said. “To meet the drastic emissions reductions we needed for global climate targets, we need drastic federal action to slash emissions, phase out oil and gas production, and end the fossil fuel era.”

Independent data show a similar trend. Research outfit the Rhodium Group estimated US emissions increased by 6.2 percent compared with the previous year in a preliminary estimate published Monday morning. According to Carbon Monitor, an international group of scholars who track emissions, the nation’s greenhouse gas pollution increased by more than 7 percent from January through October. Meanwhile, the Global Carbon Project, another academic organization that produces annual emission estimates, projects an 8 percent increase in emissions over the course of last year.

This increase follows a historic drop in US carbon pollution in 2020. (Global carbon pollution also fell sharply.) That plunge was linked to covid-19 lockdowns. Amid the pandemic, there were fewer cars on the roads and planes in the air, and entire industries came to a screeching halt. As a result, the country’s energy use plummeted. But now that restrictions are easing up, pollution levels are bouncing back.

“This year’s [emissions] increase shows that going back to normal cannot be the goal because normal was already a crisis,” Tim Donaghy, senior research specialist at Greenpeace USA, said in an email.

Pollution is still below 2019 levels according to all three new datasets, but they’re getting close. Carbon Monitor’s data shows in the first 10 months of 2021, they were only about 4% less than they were in the same months of 2019 before the spread of covid-19 began.

Steven J. Davis, a co-lead at Carbon Monitor and professor of Earth System Science at University of California Irvine, explained that different sectors’ emissions rebounded at different rates. For instance, while energy and transit-related emissions had the sharpest increase, pollution from air travel is rebounding more slowly.

“The main story is that emissions are recovering as US economic activities resume (e.g., offices reopen, people travel more), but that it’s not quite back to pre-pandemic levels, especially in the case of air travel,” he wrote in an email. “We can see persistent decreases in road transportation emissions in places like California and New York where people are apparently still not driving as much as they did prior to the pandemic.”

Experts are concerned that 2021′s rise in pollution could put emissions targets farther from reach. By the end of the decade, the Biden administration has pledged to halve carbon pollution from 2005 levels. With each passing year of increasing emissions, that goal will be harder to achieve, requiring steeper cuts.

“We are heading in the wrong direction during a critical window of time when the climate crisis has officially put us on the clock,” said Cabell Eames, political director of the state climate organization 350 Massachusetts.

Further, leading climate scientists say that to avert the worst impacts of climate change, the world must be on a path to reduce emissions by about 45 percent by 2030 and 100% by 2050. As the biggest historic carbon emitter, UN scientists and advocates alike say the US should lead the charge to curb global emissions and outpace the UN’s suggested timeline. Yet in 2020, the nation’s emissions growth outpaced the global average, according to Carbon Monitor. While the world emitted 5.97% more carbon, the US emitted 7.60% more.

Tim Cronin, Massachusetts state director at the climate education and advocacy nonprofit Climate XChange, said he wasn’t surprised by the increase.

“We didn’t have a climate-friendly national administration until 2021,” he said. “Even states like Massachusetts that are ahead, have only recently updated their climate goals to reflect new science.”

It’s not too late to change course. Donaghy said the US could begin to do so by passing the Build Back Better act — an ambitious spending package that would usher in historic climate investments — and by ending fossil fuel subsidies. Rees said Biden should also block the construction of new fossil fuel infrastructure.

On the state level, Eames called on leaders to ensure federal funds are used in ways that will result in immediate emissions cuts.

“Every second that we waste will cost us more in the future, she said, “and by the looks of this data, tomorrow isn’t necessarily promised.”