President Donald Trump's words and actions are restricting global efforts to cut carbon, according to a new study.
The analysis says the US' withdrawal from the Paris climate agreement has created the political cover for others to go slow on their commitments.
The author says the world is in denial about President Trump's true impact.
The study comes as delegates begin two weeks of UN-led talks here on the future of the Paris pact.
President Trump has justified pulling his country out of the landmark climate agreement by asserting that he was elected to serve the citizens of Pittsburgh and not Paris.
However, other international leaders promised that there would be no going back, and that the US pull-out would galvanise efforts to cut carbon.
The sense of unity was underlined in November 2017 when Syria signed the Paris agreement, leaving the US alone in the world as the only country rejecting the deal./BBC