“[The U.S.] are not helping,” said former French environment minister Laurence Tubiana, who shepherded the 2015 Paris pact, adding that other countries are “waiting for the U.S. election. This type of thing, which really is pretty stupid ... creates an impact of ‘wait and see.’”

The U.S. cannot officially withdraw from the Paris agreement until Nov. 4, 2020, the day after the election. But Trump has repeatedly disavowed the pact, has dismissed climate change as a hoax and has begun dismantling the Obama-era regulations aimed at reducing the United States’ greenhouse gas output.

"We're in a very politically difficult time right now where we've got one key world leader denying climate change, so it's very hard to get other countries to move forward when you've got such a critical country playing a spoiling role," said Ian Fry, a delegate from the Pacific Ocean island nation Tuvalu. "That's the state of the world we're in at the moment."

The two-week conference, which ran two days past its expected end and was the longest ever, was widely viewed as a setback, dulling momentum for nations to boost their carbon-cutting goals at next year’s conference in Glasgow, Scotland.

"Many parties feel disappointed. The result here, I don't think anybody can be proud of," said Finnish Environment and Climate Change Minister Krista Mikkonen.

Nations such as China, India, Brazil and Saudi Arabia appeared emboldened to push their arguments that the industrialized world – not their own surging economies – should bear the greatest burden for cutting the greenhouse gases that it has spewed for over a century. Without the U.S. to corral them, those countries threw up roadblocks to delay making new climate commitments and softened language in a final agreement urging countries to pursue more ambitious cuts.

Ammar Hijazi, a Palestinian diplomat who helped lead negotiations for a huge bloc of developing countries, acknowledged that negotiators had struggled because of the disparate positions.

“I’m not saying that we are the angels in this process. We need to bring to the table that we are all in this spot together,” Hijazi said. “Somebody needs to show leadership because at the end of the day [rich countries] started the fire … and the fire is eating everything around us.”

The U.S. played a far smaller role in the Madrid talks than at previous climate conferences. The Trump administration sent no high-ranking political officials and held no public events, although House Speaker Nancy Pelosi led a congressional delegation during the talks’ early days. It was a big contrast with the efforts four years ago by Obama and then-Secretary of State John Kerry, who engaged in extensive negotiations with China to ensure that the world’s two largest greenhouse gas producers would lead the global efforts.

Delegates from small island states, many of which could become uninhabitable as sea levels rise, say the U.S. resistance to the global effort now had soured the talks.

“One of the biggest emitters in the world has begun the process of withdrawal,” said Janine Felson of Belize, which headed a bloc of low-lying and small island countries. “And I think there is a not unfair concern that now that we’re all in the Paris world and we all have to do something, we’ll let one big emitter off the hook. And I think a lot of the maneuvering is meant to address that larger issue.”

This year’s U.N. talks were meant to deal with outstanding small print of the rules for the Paris accord, the landmark 2015 agreement that for the first time brought the world’s nearly 200 countries together to make non-binding pledges to reduce greenhouse gas emissions. Those details included locking down agreement on how to use trading markets as one way to put an economic price on carbon pollution, and reviewing strategies for dealing with climate-related catastrophes like cyclones and floods.

But for the second straight year, countries punted on finalizing those carbon market rules. Although some modest softening in positions was noted in the final late morning hours Sunday,it was not enough to bridge substantial divides, and delegates will meet again in June to continue work on the issue, as well as at next year's Glasgow gathering.

"Many parties feel disappointed. The result here, I don't think anybody can be proud of," Krista Mikkonen, Finnish Environment and Climate Change Minister

Long-standing climate observers said growing global strains and political polarization among the world’s major powers — the U.S., China and the EU — had spilled into the negotiation rooms here. Emerging and traditional polluters faced off over how to divide responsibility to cut emissions, and developing countries accused rich countries of falling short on their promised billions of dollars in financial support.

“The U.S. is the largest climate finance provider. So some countries are stepping in to try to fill the gap, but they are not able," said Mohamed Nasr, an Egyptian diplomat who led negotiations for African countries. "If you look at just numbers then there’s a regression in climate finance. … Paris was about ambition, not regression."

The conference also sought to wrest new national commitments to match growing global angst over climate change. Dire scientific reports demonstrating the inadequacy of existing plans came out before the talks, seeking to build urgency.

But none of the biggest countries announced any new actions that would be needed to meet the Paris goal of keeping global temperatures from rising more than 2 degrees Celsius above pre-industrial levels – a target that already seems unachievable. And many large polluters pulled back into defensive postures, unwilling to go it alone with bold proclamations.

“What we don’t have is any call for countries to improve their climate action plans, and that is unacceptable,” said Mohamed Adow, director of Power Shift Africa, a Nairobi-based climate and energy think tank. “People around the world must rise to save the planet.”

That will leave considerable heavy lifting for next year’s conference in Glasgow, where countries are supposed to tender fresh blueprints for deeper emissions cuts.

Fences must be mended before then. The final outcome was a blow for vulnerable and island countries that are expected to be most at risk from more ferocious storms, rising ocean levels and devastating droughts, as developed countries like the U.S. blocked measures to deliver more money to help them adapt.

“What we continue to do at these [gatherings] is kick the can down the road — we know what needs to be done,” said Simon Stiell, environment minister for the Caribbean island of Grenada. “There are a few voices that are dictating the agenda of the many, and when we have what some may view as academic debates in the halls, it is people, it is people’s lives that are under direct threat.”

Frustration came to a boiling point mid-way through the second week when protesters who had staged a climate stunt in the halls were forced from the site, further souring the mood.

The climate summit was off to a rocky start from the beginning, after violent demonstrations in Chile, this year’s designated host, forced the talks to move to Madrid at the last minute.

Nations will next have to look for climate progress in two locales hostile to the subject: next year’s G7 summit set to be held in the U.S., where the Trump administration has already nixed climate change as a topic, and the G20 summit in Saudi Arabia, which contested a number of efforts in Madrid to tighten emissions accounting standards for carbon trading.

Some activists and officials hold out hope that next September’s European Union summit with China will yield results. German Chancellor Angela Merkel, who will take on the European Union presidency next year, has indicated that climate change will be a focus, coming just ahead of the Glasgow climate conference.

"We need China," Tubiana said. "How to get China without having the U.S. on board is something the European Union has to solve."