UN Secretary-General Ban Ki-moon said action on climate change has become "unstoppable" and predicted that US President-elect Donald Trump would drop plans to quit a global accord aimed at weaning the world off fossil fuels.
At a meeting of almost 200 nations in Morocco to work out ways to implement the 2015 Paris agreement to limit greenhouse gas emissions, Mr Ban said US companies, states and cities were all pushing to limit global warming.
"What was once unthinkable has become unstoppable," he told a news conference of the Paris Agreement, agreed by governments last year, ratified in record time and formally adopted by more than 100 nations including the United States.
He said Mr Trump, as a "very successful business person", would understand that market forces were already driving the world economy towards cleaner energies such as wind and solar power, as they become cheaper and away from fossil fuels.
The Paris accord, aiming to phase out net greenhouse gas emissions this century, was a breakthrough after more than two decades of deadlock, driven by increased scientific certainty that man-made emissions drive heat waves, floods and rising sea levels.
Mr Ban said he hoped that Mr Trump would drop his view that man-made climate change is a hoax and his pledge to cancel the Paris Agreement.
"I am sure he will make a ... wise decision," Mr Ban said, adding that climate change was having severe impacts from the Arctic to Antarctica.
He noted this year is on track to be the warmest year since records began in the 19th century.
"I hope he will really hear and understand the seriousness and urgency of addressing climate change. As President of the United States I hope he understands this, listens and evaluates his campaign remarks," he said.
Former President Mary Robinson has said the mood at the UN climate talks is "strong" and there is a feeling that every country must step up and do as much as possible to tackle the issues of climate change.
The head of the Mary Robinson Foundation - Climate Justice said the deal that has been reached is a very fair one.
Speaking on RTÉ's News at One, Ms Robinson also said the election of Donald Trump as the next US president will not change all the work that has been done and there are many groups in the US who are determined that the country moves forward.
However, she admitted that there are concerns about how the annual funding that is needed to support developing countries can be raised, if the United States decides not to participate.
