British Prime Minister Boris Johnson hailed US President Joe Biden's pledge to cut greenhouse gas emissions in half by 2030 as a "game changer".
Mr Johnson was speaking at the Climate Leaders Summit on Thursday.
The online event aims to secure commitments on cutting greenhouse gas emissions, shifting to renewable energy and climate finance for developing countries.
Under Biden's plan, the US will aim to slash emissions by 50 per cent to 52 per cent from 2005 levels.
"I'm really thrilled by the game changing announcement that Joe Biden has made," Mr Johnson said, "for returning the United States to the front rank of the fight against climate change."
"It's vital for all of us to show that this is not all about some expensive politically correct, green act of bunny hugging," Mr Johnson said. "This is about growth and jobs."
The commitment from @POTUS today to cut US emissions by 50-52% by 2030 is a game-changer. It will have a transformative impact in the global fight against climate change.
— Boris Johnson (@BorisJohnson) April 22, 2021
I commend the President's leadership and look forward to working together for our planet ahead of @COP26.
The UK this week set into law the world’s most ambitious climate target, pledging to cut carbon emissions by 78 per cent by 2035, compared to 1990 levels.
Mr Johnson is calling on global leaders and businesses to match that level of ambition ahead of COP26 to limit global warming to 1.5°C above pre-industrial levels.
“The UK has shown that it’s possible to slash emissions while growing the economy, which makes the question of reaching net zero not so much technical as political," he said.
“If we actually want to stop climate change, then this must be the year in which we get serious about doing so, because the 2020s will be remembered either as the decade in which world leaders united to turn the tide, or as a failure.
“So let’s come to Kunming [in China] in October and Glasgow in November armed with ambitious targets and the plans required to reach them.
"And let the history books show that it was this generation of leaders that possessed the will to preserve our planet for generations to come."
The Climate Leaders Summit is an important moment to build momentum on the road to the COP Biodiversity Summit in China and the COP26 summit in Scotland.
As COP president this year, the UK is leading international efforts to secure ambitious 2030 emissions reductions targets in line with reaching net zero by the middle of the century.
Those goals will be supported by clear action plans and policy changes such as phasing out coal.
The UK will set out its Net Zero Strategy before COP26.
More than 120 countries have made net-zero commitments to date, covering 65 per cent of global carbon emissions.
That is more than triple the 20 per cent covered when the UK was nominated for the COP presidency in December 2019.
The UK government has also committed £11.6 billion ($16.16bn) in international climate finance to support developing countries over the next five years.
Before COP26, the UK is asking donor countries to deliver on their commitment to secure $100bn of public finance, and to work with businesses for private finance and expertise to ensure all countries can address climate change and deal with its effects.
