The United States brought greenhouse gas emissions down by an estimated 1.9% year-on-year in 2023, the Rhodium Group research center said in a report Wednesday – a welcome decline but not enough to meet Paris Agreement targets.

The world's second-biggest emitter has pledged to halve its emissions by 2030 compared to 2005 levels – meaning the 2023 rate of decline "needs to more than triple and sustain at that level every year from 2024 through 2030 in order to meet the US's climate target," the report stated.

For the moment, the fall since 2005 is 17.2 percent, according to this estimate.

The reduction in emissions in 2023, compared with 2022, is due, in particular, to the drop in coal-fired electricity generation, gradually being replaced by gas-fired power stations and renewable energies.

The fall is "a step in the right direction," the group said.

"But the deadline for the US 2030 climate target under the Paris Agreement of a 50-52% reduction in GHG emissions below 2005 levels is rapidly approaching, and achievement of that goal looks ever more challenging absent a major new policy push," it continued.

It points out that it is still too early to assess President Joe Biden's major investment plans for energy transition.

And while electricity production is falling, the transport sector, which leads the way in terms of greenhouse gas emissions, is still emitting more, notably with an increase in air traffic and rising gas consumption.

"To meet the Paris target, the US needs to average a 6.9% emissions reduction every year from 2024 through 2030 — more than triple the 1.9% drop in 2023," it said.

The United States is currently the second biggest emitter of greenhouse gases in absolute terms, behind China. But when historical emissions are taken into account, it remains in the lead.