The bill, which would see an unprecedented US$370 billion invested in cutting US emissions 40 percent by 2030, should provide a launchpad for green investment and kickstart a transition toward renewable energy in the world's largest emitter.

It passed the Senate on Sunday night after months of arduous negotiations and only after a number of tax and energy provisions were tacked on to Biden's original proposal.

Michael Pahle, from the Potsdam Institute for Climate Impact Research, said the bill was particularly relevant to EU lawmakers, who he said were on the verge of adopting "the world's most-ambitious climate policy" in the form of the bloc's "Fit for 55" plan.

"The EU's policy can only succeed -- economically and politically -- when major emitters and trade partners take similar action," he said on Monday.

"Especially in face of the changing geopolitical landscape, US-EU cooperation is key and the bill an important enabling factor."

The EU initiative – which envisages a 55-percent emissions fall by 2030 – has no set budget as yet.

But a recent assessment found member states would need to spend 350 billion euros ($357 billion) more each year than they did between 2011-2020 in order to hit the climate and energy targets.

Simon Lewis, professor of global-change science at the University College London, said the US bill showed how lawmakers can advance climate legislation while responding to voters' short-term concern over fuel-price inflation.

"It's really important that the world's largest economy is investing in climate and doing it as part of a package to generate jobs and a new, cleaner, greener economy," Lewis said.

"Part of that is a package tackling inflation. I think that shows the world how to get climate policy passed, by hitching it to things that really matter to ordinary people, to make sure it's part of an overarching package to make life better for people."

'Massive increase'

The independent Rhodium Group think tank said the "historic and important" bill -- officially the Inflation Reduction Act -- would reduce US emissions by at least 31 percent by 2040, compared with 2005 levels.

However, it said that with favorable macroeconomic conditions including increasingly high fossil-fuel prices and cheap renewables, a 44-percent emissions drop was possible.

"The cost of living is here partly because we didn't get out of fossil fuels early enough," said Lewis.

"This bill means that the transition away from fossil fuels is about to speed up."

Eric Beinhocker, director of the Institute of New Economic Thinking at the Oxford Martin School, said the bill would lead to a "massive increase" in clean technology and would drive the cost of renewables down even further.

"This is particularly important when the world is suffering not just from the climate effects of fossil fuels but also from their skyrocketing costs," he said.

The legislation provides millions to help conserve forests and billions in tax credits to some of the country's worst-polluting industries to accelerate their transition to greener tech.

It almost didn't happen, however, with the bill delayed for months after Democrat Joe Manchin blocked Biden's more expensive Build Back Better infrastructure plan.

Pahle said that a failure by the US to agree to an ambitious emissions cutting plan would have been a "major drawback on the viability of the Paris Agreement".

The 2015 accord enjoins nations to work to limit global temperature rises to "well below" 2 degrees celsius above pre-industrial levels and envisages a safer 1.5C heating cap.

With a little over 1.1C of warming so far, Earth is already being buffeted by extreme weather such as drought and storms supercharged by rising temperatures.

Just the start

Although acknowledging that the bill represented progress, scientists were quick to stress that it was far from perfect.

Michael Mann, director of Penn State's Center for Science, Sustainability and the Media, said the bill's commitment to build new gas pipelines was "a step backwards".

"It's difficult to reconcile a promise to decarbonize our economy with a commitment to new fossil-fuel infrastructure," he said.

Radhika Khosla, from the University of Oxford's Smith School, said that only action on a global scale could achieve the emissions cuts necessary to stave off the worst impacts of global heating.

"The effects of climate change are being felt by all of us," she said.

"This summer alone parts of the globe as disparate as China, the UK and Tunisia all saw record-breaking, deadly heat waves.

"Lasting change will require ambitious action from all of us as well," she said.