Nearly 200 nations made an appeal Thursday for the "highest political commitment" to combat climate change, at a UN gathering overshadowed by Donald Trump's threats to withdraw the US from a global pact to turn back global warming.

"We call for the highest political commitment to combat climate change, as a matter of urgent priority," 197 parties to the UN's climate convention stated in the "Marrakesh Action Proclamation" issued at the annual UN climate conference.

The parties -- 196 nations and the EU bloc -- urged one another to boost finance for projects to prevent worst-case-scenario global warming and cope with the effects of unavoidable climate change.

"Our climate is warming at an alarming and unprecedented rate and we have an urgent duty to respond," they warned.

The call came on the penultimate day of a conference tasked with drafting a blueprint for enacting the so-called Paris Agreement adopted last December and since ratified by 111 parties -- most recently Britain on Thursday.

The Paris pact sets the goal of limiting average global warming to 2.0 degrees Celsius (3.6 degrees Fahrenheit) over pre-Industrial Revolution levels, by cutting greenhouse gases from burning fossil fuels.

Countries, including the United States, have pledged to curb emissions under the deal by shifting to renewable energy sources.

But Trump has vowed to boost oil, gas and coal and "cancel" the global deal.

Thursday's proclamation noted "extraordinary momentum" underway on climate change, which it said was "irreversible".

"It is being driven not only by governments, but by science, business and global action of all types at all levels," said the document.

It urged all countries to "urgently" raise their commitments to reducing greenhouse emissions. Collectively, scientists say, current pledges place the world on course for warming of 3 C or more.

"We call for strong solidarity with those countries most vulnerable to the impacts of climate change," said the communique.

And it urged "strengthening cooperation amongst ourselves... to meet the long-term temperature goals of the Paris Agreement".

- Everyone's responsibility -

Experts say warming over 2 C will result in land-gobbling sea level rise, worsening storms and droughts, disease spread and conflict over ever-scarcer resources.

To highlight the stakes, US government scientists said Thursday that the first 10 months of the year were the hottest in modern times -- and 2016 will likely surpass 2015 as the warmest year on record.

"The Marrakesh Action Proclamation reaffirms the world's commitment to tackling climate change at a time when our resolve has been called into doubt," said Thoriq Ibrahim, environment minister of the Maldives -- and island nation at high risk of climate change-induced sea level rise.

"Every country has a responsibility to do their part to protect the climate that sustains us all."

Mohamed Adow, a climate negotiations expert for Christain Aid, said the declaration by so many heads of state, "demonstrates just what a global consensus there now is around climate change."

It also "underlines the determination of world leaders that they will not let the election of Donald Trump hijack the important work being done to secure the safe future of our planet," he said.

While waiting for the new US president to make his climate position clear, many now look to the rest of the world to bolster the Paris Agreement.

In a "high-level segment" of the gathering, starting with heads of state and government on Tuesday and ministers over the next two days, speaker after speaker recommitted their nations to the pact.

On Thursday, the BASIC group of Brazil, South Africa, India and China, stressed they would "continue and strengthen" their own actions, while stressing "there can be no backtracking on commitments from developed countries and no attempt to renegotiate the terms of the agreement reached in Paris".

With just a day of negotiations to go, finance from rich nations for developing country climate projects remains a thorny issue -- made trickier by the prospect of America withdrawing its cash commitments, running into billions of dollars.