This year's UN climate summit in Glasgow must mark the start of a decade of action to address the environmental crisis, US envoy John Kerry said on Tuesday during a visit to the EU headquarters in Brussels.
After four fractious years under president Donald Trump, Mr Kerry's trip is a new start in transatlantic relations, which he and EU climate chief Frans Timmermans hope can reshape global efforts to tackle global warming.
"This is the moment. Glasgow is the last, best opportunity that we have and the best hope that the world will come together and build on Paris," Mr Kerry said, referring to the 2015 Paris Agreement on climate change.
"Scientists tell us this decade, 2020 to 2030, must be the decade of action."
Almost 200 countries committed under the Paris Agreement to halt the increase in global temperatures to levels that would avoid the worst effects of climate change.
But most large emitters are not living up to that goal.
On Tuesday, Mr Kerry and Mr Timmermans will discuss how the US and EU – the world’s second and third-largest emitters of greenhouse gases – can convince other big polluters to make tougher pledges to cut planet-warming emissions.
The November UN summit serves as a deadline for countries to make those pledges.
The eight months leading up to the summit are "absolutely essential for all of us", Mr Kerry said.
China last week announced a five-year plan that analysts said would lead to its emissions rising.
India, Japan, Russia and Brazil are all under pressure to commit to faster emissions cuts.
The EU has already upgraded its pledge. Its 27 member countries agreed in December to cut their net greenhouse gas emissions at least 55 per cent by 2030, from 1990 levels.
The US is due to announce its own pledge next month. EU officials and environmental groups are seeking a commitment to reduce emissions by at least 50 per cent below 2005 levels by the end of this decade.
"If it doesn't start with a 5, we don't consider that good," an EU diplomat said of the US pledge.