The United States reduced emissions of climate-warming greenhouse gasses last year, after two years in which emissions rose. But the decline wasn't enough to meet climate targets set by the Biden administration. That would require much steeper cuts, most likely by significantly reducing the use of fossil fuels.

U.S. emissions declined 1.9% in 2023 despite a growing economy, according to new estimates from the research firm Rhodium Group. That continues a trend in which wealthy countries have managed to break the link between economic growth and climate pollution.

Under the 2015 international Paris Agreement, the U.S. has pledged to cut U.S. emissions 50 - 52% from their 2005 levels by the end of this decade.

U.S. emissions are currently just 17.2% below 2005 levels, Rhodium finds. That means future annual reductions need to be much larger than last year's 1.9%.

"To meet the 2030 goal, we need to see more than triple that every year," says Ben King, associate director with Rhodium Group's energy and climate practice. "We need to see 6.9% decreases starting in 2024 through 2030."

Emissions plunged more than 11% during the COVID-19 pandemic. Then they increased in 2021 and 2022, leaving them down 6% from 2019 levels.

Two big reasons for the 2023 decline were the country's continuing transition away from carbon-intensive coal-fired power plants and toward natural gas and renewable energy, King says. A relatively mild winter last year also meant less energy was required to keep buildings warm. King says transportation emissions rose 1.6%, primarily due to increasing air travel, and industrial emissions increased 1% because of more domestic oil and gas production.

King says he doesn't see evidence that the Biden Administration's signature climate legislation, the Inflation Reduction Act (IRA), is reducing emissions yet despite having passed more than a year ago.

"I think it's too early to see the impacts of a big bill like the Inflation Reduction Act," King says, because the legislation is still being implemented. Rhodium has estimated the IRA will help cut U.S. emissions up to 42% by 2030. That still falls short of the Paris goals, which aim to avoid the worst effects of warming.

"The science is clear that additional policies are needed — including policies to sharply curtail the expansion of fossil fuels — for the U.S. to meet its climate goals for 2030 and beyond," says Rachel Cleetus, policy director of the climate and energy program at the Union of Concerned Scientists.

That's unlikely to come from new legislation in 2024 with a divided Congress facing an election year.

The Biden administration hopes to use its executive power to further cut emissions, by tightening energy efficiency standards, and proposing new regulations to cut methane pollution from oil and gas drilling and further reduce pollution from power plants.

These efforts come against the backdrop of a rapidly warming planet. Last year was the hottest on record by a significant margin.

That increase is driving more frequent and intense extreme weather. The National Oceanic and Atmospheric Administration says in 2023 there were 28 weather and climate disaster events with losses exceeding $1 billion each in the U.S. That's well above the average of about eight billion-dollar events per year from 1980 to 2022.