Governments must take into account the people they govern when they move to reduce their carbon footprint, the new managing director of the World Bank told AFP on Monday, warning particularly of the economic fallout from cutting energy subsidies.

Axel van Trotsenburg, who is joining more than 50 finance ministers at the UN climate change conference COP25 in Madrid, urged countries that had committed to financing the fight against global warming to make good on their pledges.

"This COP is at an inflection point. What you are seeing around the world in social unrest will need to be taken into account," he said in an interview before the finance minister's meeting -- the first such gathering at a climate conference.

"One needs to think not only in technical terms but very much what is happening in societies themselves so climate action takes into account social components."

The last 12 months have seen a wave of popular unrest as commuters and workers reliant on stable petrol prices reacted angrily to government cuts on fossil fuel subsidies.

Van Trotsenburg, a Dutch-Austrian national who took over as the bank's second-in-command in October, said it was incumbent on power holders to ensure that economic reform in the name of climate did not leave those with the most to lose footing the bill.

"We need to look very much at the political economy of the country and secondly one needs to look at the people affected," he said.

"The most vulnerable need to be shielded from the impact of these measures."

He said passing reforms without due consideration could disproportionately affect vulnerable people -- and it was understandable that this led to resistance.

"Looking too exclusively at one measure and not taking other matters into account may backfire," he added.

Delegates are in Madrid to agree a common rulebook for delivering on the promises they made in the 2015 Paris climate agreement -- which included mitigating the worst effects of rising temperatures and helping vulnerable nations to adapt.

The key is now to decide how to fund these efforts and who should pay.

On Monday more than 50 nations -- who control around 30 percent of global GDP -- said they were accelerating their own transition towards low-carbon economies.

Governments at COP25 will also discuss how to become more ambitious in the future -- a particularly pressing matter for nations already affected by climate-related disasters.

"We would like to see ambition in action so that what you've announced, you implement, and do it well and in a timely manner," Van Trotsenburg said.

"It's more important than ever that we are making good on these commitments."