By Michelle Nichols and Kate Abnett
UNITED NATIONS (Reuters) -A Supreme Court ruling on Thursday limiting Washington's authority to reduce carbon output from power plants will hurt global efforts to fight climate change by slowing America's emissions cuts and undermining U.S. leadership efforts on the international stage, according to diplomats.
The conservative court's 6-3 ruling, the latest in a flurry of controversial judicial decisions from the bench, comes as the administration of U.S. President Joe Biden seeks to decarbonize the U.S. economy and rally global ambition to move away from greenhouse gas-emitting fossil fuels to cleaner sources.
"It is very disappointing as it makes it very difficult for the U.S. administration to enforce the move to reduce emissions of GHGs," said Carlos Fuller, Belize's Ambassador to the United Nations. "It also puts the administration in a very weak negotiating position, as their attempts to get everyone to increase their ambition will be met with scepticism."
In a rare criticism of a member state, the United Nations on Thursday called the Supreme Court ruling "a setback in our fight against climate change."
"Decisions like the one today in the U.S. or any other major emitting economy make it harder to meet the goals of the Paris Agreement for a healthy, liveable planet," United Nations spokesman Stephane Dujarric said, referring to a 2015 international deal to curb warming.
"But we also need to remember that an emergency as global in nature as climate change requires a global response, and the actions of a single nation should not and cannot make or break whether we reach our climate objectives."
Scientists have said the world must dramatically reduce its emissions in the coming years in order to limit global warming to 1.5 or 2 degrees Celsius above pre-industrial levels, the threshold at which they say the worst effects of climate change become unavoidable.
Biden acknowledged in a statement that the ruling risked damaging the U.S. ability to combat climate change. But he added: "I will not relent in using my lawful authorities to protect public health and tackle the climate crisis."
"I have directed my legal team to work with the Department of Justice and affected agencies to review this decision carefully and find ways that we can, under federal law, continue protecting Americans from harmful pollution, including pollution that causes climate change," Biden said.
Yamide Dagnet, director of climate justice at Open Society Foundations, and a former climate negotiator for the UK and EU, said the world will be watching.
"To renew confidence in its leadership, the U.S. will need to swiftly pivot and keep its targets on track," she said.