GLASGOW (NYTIMES) - House Speaker Nancy Pelosi and nearly two dozen United States House Democrats barnstormed global climate talks here on Tuesday (Nov 9), claiming that "America is back" in the effort to slow global warming, even as their party remains divided over a US$1.85 trillion (S$2.49 trillion) budget Bill upon which their climate agenda depends.

Ms Pelosi noted that she was accompanied by a record number of lawmakers attending a United Nations COP26 climate summit and said they had flown to Glasgow "ready to take on the challenge, to meet the moment".

But they have not yet.

The stalled legislation includes US$555 billion in tax credits and incentives to promote wind and solar power, electric vehicles, climate-friendly agriculture and forestry programmes, and a host of other clean energy programmes.

Those measures would bring the country about halfway to President Joe Biden's goal of cutting the country's greenhouse gas emissions by between 50 per cent and 52 per cent from 2005 levels by 2030.

Ms Pelosi said it would be "the most ambitious and consequential climate and clean energy investment of all time".

She said House lawmakers intended to pass that Bill next week, but a handful of moderate Democrats have raised concerns about its price tag.

Meanwhile, the legislation has been held up in the Senate largely because of objections from one Democratic senator, Mr Joe Manchin of West Virginia.

Mr Manchin's state is a coal and gas producer, he has personal financial ties to the coal industry, and he has said he opposes policies that would harm fossil fuels.

Ms Pelosi noted that last week, Congress had approved a US$1.2 trillion infrastructure Bill that includes billions of dollars to help fortify communities against the impacts of climate disasters. But the money and policies to cut the emissions that are causing global warming are embedded in the legislation that has yet to pass.

In a series of meetings and speeches, lawmakers said they felt the weight of expectations from the rest of the world.

Of all nations, the US has pumped the most carbon dioxide, methane and other greenhouse gases into the atmosphere - pollution that is trapping heat and driving up average global temperatures.

It has also promised to act on climate change, only to fall short several times in past decades.

Representative Alexandria Ocasio-Cortez, who was among the lawmakers travelling with Ms Pelosi, said countries should hold the US to account for its promise to significantly reduce emissions from the burning of coal, oil and gas.

"We have to actually deliver to get the respect internationally," said Ms Ocasio-Cortez.

"We have to draw down emissions in order to get credit for being committed to climate change."

An earlier wave of lawmakers travelled to Glasgow last week to make a similar argument that the US was back in the climate fight, after four years of global disengagement under the Trump administration.

That group was heavily Democratic but included a handful of Republican House members and a lone Republican senator Lisa Murkowski of Alaska.

The Republicans said they may disagree with Mr Biden's policies but they were concerned about climate change, even if they did not support a move away from fossil fuels, which scientists say is needed to avert climate catastrophe.

"Republicans care deeply about this earth," said Representative John Curtis.

"We may not have learnt how to talk about it," he said, "but I promise you we care and we're serious about being part of the solution."

Other Republican attendees in Glasgow included Mr Dan Crenshaw of Texas and Ms Mariannette Miller-Meeks of Iowa, and representatives from conservative groups.

Ms Murkowski, in an interview, said she, like other Republicans, did not intend to vote for the US$1.85 trillion Bill that contains the president's climate agenda. But she said she did not object to clean energy tax credits.

Mr Biden has made climate action central to his presidency. If the pending legislation passes, analysts say, it will get the US about halfway to the president's targets. The rest will depend on a combination of things that are outside of Mr Biden's control, like the markets and regulations that could be overturned by the courts or reversed by a future administration.

Mr Michael Regan, the administrator of the Environmental Protection Agency (EPA), said in an interview on Tuesday that he would announce before the end of the year a "suite" of new policies to draw down emissions from electric utilities. After transportation, the power sector is the second-largest source of emissions in the US.

The Supreme Court is poised to weigh whether the EPA has the authority to regulate the emissions of greenhouse gases. The decision from the Conservative-leaning court could deliver a blow to the agency's ability to tackle climate change. Mr Regan said he was not planning to wait for a ruling before issuing new power plant regulations.

"We have pens to paper right now," he said.