Countries launched a coal phase-out initiative Thursday at UN climate talks in Bonn, offering an antidote to the defence of Earth-warming fossil fuels by US President Donald Trump's administration.

Spearheaded by Canada and Britain, the "Powering Past Coal Alliance" commits more than 20 nations, cities, and regions to weaning themselves off a commodity that produces 40 percent of the world's electricity -- a major contributor to global warming caused by greenhouse gas emissions.

The list includes Angola, Belgium, Finland, France, Italy, the Marshall Islands, the Netherlands, New Zealand, Portugal, and Mexico, the regions of Ontario, Quebec, and Alberta, and the city of Vancouver.

The state of Washington is the sole American signatory.

"This is another positive signal of the global momentum away from coal, benefiting the health of the climate, the public and the economy," said Jens Mattias Clausen of Greenpeace.

"But it also puts on notice the governments who lag behind on ending coal, or those who promote it, that the world’s dirtiest fossil fuel has no future."

The Trump administration insisted Thursday it was "committed" to limiting greenhouse gas emissions, as long as this does not threaten energy security or the economy.

"Our guiding principles are universal access to affordable and reliable energy, and open, competitive markets that promote efficiency and energy security, not only for the United States but around the globe," US acting assistant secretary of state Judith Garber told the conference.

To this end, it would "support the cleanest, most efficient power generation, regardless of the source," she said.

Garber was the most senior US administration representative at the "high-level segment" of the annual UN climate huddle. Most other countries were represented by heads of state or ministers.

On Monday, White House officials drew the ire of observers and delegates in Bonn by hosting a sideline event defending the continued use of fossil fuels at a forum whose very purpose is the drawdown of carbon emissions.

- Protecting US interests -

Trump announced in June that the United States will withdraw from the climate-rescue Paris Agreement championed by his predecessor Barack Obama and endorsed by the world's nations to cheers and champagne in 2015. The rules determine that no country can exit the pact before November 2020.

Garber said Washington still intends to withdraw "at the earliest opportunity", but remained "open to the possibility of rejoining at a later date under terms more favourable to the American people."

An Obama-era official who helped deliver the agreement -- a feat that took more than two decades of tough negotiations -- lashed out Thursday at Trump's "wrongheaded" decision.

"Climate change is a huge challenge, we all know that," Todd Stern, who was Obama's special envoy for climate change, told AFP on the sidelines of the conference he attended as an observer. He left government in 2016.

"We are in a... race against time to transform the economy faster than the bad stuff of climate change. Trying to say it's a hoax, or it doesn't mean anything, or it's a terrible agreement and the rest of the world is laughing at us, is just so.. ridiculous," he said -- citing some of Trump's stated reasons.

The United States is the world's biggest historical greenhouse gas polluter, and second only to China for current-day emissions.

The US presence at the Bonn talks has not been universally welcomed, especially as it has taken a tough line on a demand from developing countries for a firmer commitment to climate finance.

Trump has also renounced an Obama-era promise to deliver $2.5 billion dollars into the Green Climate Fund.

Many question why the US is at Bonn at all, given its rejection of the Paris Agreement.

The State Department explained Washington wished to "ensure a level playing field that benefits and protects US interests."

- Three degrees -

The Paris Agreement commits countries to limiting average global warming to under two degrees Celsius (3.6 degrees Fahrenheit) over Industrial Revolution levels, and 1.5 C if possible, to avert calamitous climate change-induced storms, drought and sea-level rises.

Nations submitted voluntary emissions-cutting commitments to bolster the deal, but scientists say the pledges placed the world on course for warming of 3 C or more.

Since Monday last week, bureaucrats have haggled over a Paris Agreement "rule book", which must be finished next year and will specify how countries calculate and report their emissions cuts.

Energy and environment ministers descended on Bonn Wednesday for the final three days, tasked with resolving tough issues above the pay grade of rank-and-file negotiators.

"The Paris Agreement is a global pledge to hand over a healthy planet to future generations, and now the time has come to show that we will honour this pledge," European Union climate change commissioner Miguel Canete told delegates on Thursday.

Source: AFP