Speaking to CNN at COP22, U.N. Secretary General Ban Ki-moon urged Trump to "really work for humanity."
"I hope the President-elect Trump will really see the reality, will consult with his senior advisers and world leaders and take wise and correct decisions for their future involvement in world affairs," he said.
"I count on the US continued engagement and leadership to make this world better for all," he added.
Delegates, business leaders and members of state gathered in Morocco for the summit are concerned that the President-elect might pull out of the Paris Agreement, the fruit of more than two decades of international negotiations often painstaking and tortuous.
Earlier this week, more than 350 US businesses including Starbucks, General Mills, Nike, Mars and Intel issued an open letter
to Trump, Obama and the members of Congress, urging them to "continue US participation in the Paris agreement," and warning that "Failure to build a low-carbon economy puts American prosperity at risk."
And on Wednesday, Chinese Vice Foreign Minister Liu Zhenmin reiterated that climate change was not a hoax
-- a reference to Trump's 2012 claims -- adding that it's possible for Republicans to continue to support the process of addressing it.
However, there were some positives from the summit. Japan, Australia and the UK formally ratified the Paris agreement, joining the US and China, the world's biggest emitters of CO2, bringing the total tally of countries that have signed up to 111.
The Action Proclamation confirmed the goal for developed countries to jointly raise $100 billion per year by 2020 to help developing countries with climate change, and stated that there's been "extraordinary momentum on climate change worldwide, [...] driven not only by governments, but by science, business and global action of all types at all levels," and calls it "irreversible."
Here's what leaders and delegates from some of the countries that are significant contributors to global emissions had to say over the last week.
Secretary of State John Kerry, in a passionate speech, conveyed a firm determination to defend the Paris agreement: "No one should doubt the overwhelming majority of citizens of the US who know climate change is happening and we are determined to keep our commitments in Paris," he said.
Stressing that "time is not on our side," Kerry urged for more action, and noted that "At some point even the strongest skeptic has to acknowledge that something disturbing is happening."
He then highlighted the fact that clean energy means good business: "Most business people have come to understand that investing in clean energy makes simply economic sense. You can make money and do well at the same time."
Indirectly referring to Trump's support for the coal industry, he noted that "Coal is the single biggest contributor to global greenhouse emissions," before saying that "No one has a right to make decisions that affect billions based solely on ideology or without proper input."
His closing remark was even more direct: "I know the election has left some uncertain about the future. I can't speculate about what policies the President-elect will pursuit, but I've learned that some issues look a little bit different when you're in office compared to campaign. Climate change shouldn't be a partisan issue in the first place."
Jonathan Pershing, the US Special Envoy on climate change, said to UN delegates that "The transition to clean energy is inevitable.
While we have many profound challenges to wrestle with, the momentum is insurmountable: there is no stopping."
Speaking at the opening ceremony on Tuesday, French Prime Minister Francois Hollande called the Paris agreement "irreversible" and told the US that "as the second biggest greenhouse gas emitter, it must respect the commitments that have been made."
He added: "Not only it is their duty, but it's also in their interest and in the interest of the American people."
Beijing took the chance to hit back
at Trump's claim -- from a 2012 tweet -- that global warming is a Chinese hoax.
Chinese Vice Foreign Minister Liu Zhenmin reminded reporters that climate change negotiations began with the UN's International Panel for Climate Change in the 1980s, supported by the US Republican-led administrations under Ronald Reagan and George H. W. Bush.
It was the EU and the US who brought full climate change awareness to China, he said, according to notes sent to CNN by a Chinese delegate traveling with him.
Liu reiterated that climate change was not a hoax and that it was possible for Republicans to continue to support the process of addressing it, the delegate said.
Speaking to the press, UK Climate Change and Industry Minister Nick Hurd said: "I think it's very important that this COP sends a very clear signal to the world that everybody is still committed to the Paris Agreement."
Gian Luca Galletti, the Italian Environment Minister, said in the UN plenary hall in Marrakech that "Italy wishes to state before the nations of the world that there is no going back from the Paris agreement. We will raise the issue at the G7 in 2017, when Italy will assume the rotating presidency."
In a panel moderated by CNN's Isa Soares, Norway's Minister of Climate Vidar Helgesen said: "The tremendous climate leadership we've seen from the US is very likely to fade - we need to step up to protect the Paris agreement. China and the EU have already done that at this conference."
Speaking to CNN, COP22 President Salaheddine Mezouar said: "The Paris accord has entered into force and that creates a responsibility for countries and civil societies. We are in a fight for our planet and our future, not a political debate. I have no doubt that the US as a responsible country will maintain its commitment."
Aziz Mekouar, Former Moroccan Ambassador to the US and member of the steering committee of COP22, said: "I think that there is a full commitment to implement the Paris agreement and that's what we're expecting from all the countries that have ratified it."
Said Mouline, also a member of the COP22 Steering Committee member, told CNN: "We are switching, all over the world. You cannot stop that. It's a matter of economics and it wouldn't make sense for the US to not follow. This is a transition, not a rupture. We have coal plants in Morocco, we didn't close them overnight. This new economy can create more jobs."