Sharm el Sheikh, Egypt: US President Joe Biden will stick to his efforts to develop a greener economy even if Republicans win the midterm elections on Tuesday, his climate envoy John Kerry said at COP27.

Biden's Democrats are facing a gargantuan struggle to hang on to Congress against Republicans who are less favourable to international action on climate change.

A Republican victory could be a boon to former president Donald Trump, who had pulled the United States out of the 2015 Paris Agreement on climate change. Biden brought the United States back into the pact.

Speaking on the sidelines of the UN's COP27 climate summit in Egypt, Kerry said the administration hopes for a favourable outcome in the election.

"Even if we don't, President Biden is more determined than ever to continue what we are doing," Kerry said.

"And most of what we are doing cannot be changed by anybody else who comes along. ... The marketplace has made its decision to do what we need to do to respond to the climate crisis."

Some 100 world leaders were attending the summit on Monday and Tuesday but Biden will come on Friday after the midterms. He then heads to Cambodia for the annual US-ASEAN summit and then on to Indonesia for a G20 summit.

© Agence France-Presse