As the United Nations climate summit enters its last hours, there is modest progress on reducing reliance on fossil fuels and giving aid to countries most at risk from extreme weather. But stubborn divisions over the details of key issues remain.

In what would be a first in decades of such negotiations, nations could call for an end to using coal and subsidizing fossil fuels. Despite some weaker language, those two elements remain in the most recent draft being circulated for consensus agreement among the more than 100 participating countries.

The summit in Glasgow, Scotland, is scheduled to end Friday, but could extend into the weekend as negotiators try to nail down agreement on a range of thorny issues for their final statement.

Still, it appears that the conference, known as COP26, is set to fall far short of its overall goal of keeping global warming from rising more than 1.5 degrees Celsius, or 2.7 degrees Fahrenheit. In an interview with the Associated Press, United Nations Secretary-General Antonio Guterres says that goal is "on life support." Beyond 1.5 degrees Celsius of warming, scientists say the world faces catastrophic and potentially irreversible damage from extreme heat, drought and flooding.

No COP agreement until now has even mentioned fossil fuels, the main source of climate-warming emissions. Having that in the final text would be a breakthrough. But negotiators have struggled to find language acceptable to all countries, especially those with significant fossil fuel reserves.

An earlier version of the agreement called on countries to "accelerate the phasing out of coal and subsidies for fossil fuel." The new language calls for "the phaseout of unabated coal power and of inefficient subsidies for fossil fuels."

The term "unabated" would make room for carbon capture systems on coal-fired power plants, like one in Texas. While that one technically worked, it shut down because it was unprofitable. And "inefficient subsidies" leaves room for countries that subsidize energy for low-income residents, but also countries that want to continue subsidizing fossil fuel companies.

"The fact that we've got the phaseout of fossil fuel subsidies and the phaseout of coal in the text is really new and important," says Helen Mountford with World Resources Institute.

But other environmental groups that want to see more dramatic action, including a fossil fuel non-proliferation treaty, are upset by the change. "The credibility of these talks is in question if landmark language around fossil fuels gives them a lifeline through carbon capture technologies and continued subsidies," says Jean Su with the Center for Biological Diversity.

Activists from developing countries also are critical of how negotiations among the nearly 200 nations are shaping up.

"Humanity will not be saved by promises"

An activist from Uganda gave voice Thursday to the fears many have that the Glasgow summit will amount to just another series of pledges, without urgent action driving them.

"Humanity will not be saved by promises," Vanessa Nakate told political and business leaders gathered at the summit. "We must reduce global CO2 emissions by somewhere between 7% to 11% this year, and next year, and every year after year, until we get to zero."

Nakate said if countries fail to meet goals set in the 2015 Paris climate agreement, heat stress will hurt people where she lives because temperatures will regularly reach 35 degrees Celsius (95 degrees Fahrenheit). "At that temperature the human body cannot cool itself by sweating," she said.

Secretary-General Guterres also put pressure on countries Thursday, urging them "to pick up the pace."

Guterres did praise an agreement between the U.S. and China to work together on cutting emissions, reaffirming their commitments to keep global warming well below 2 degrees Celsius and aiming for 1.5 degrees.

That agreement focused on methane, which is a much more potent greenhouse gas than carbon dioxide, though it does not stay in the atmosphere as long. Scientists say reducing methane pollution now could quickly rein in some global warming.

Last week the Biden administration proposed stricter regulations on oil and gas companies to reduce methane emissions. Under the new agreement with the U.S., China says it intends to develop a "National Action Plan on methane, aiming to achieve a significant effect on methane emissions control and reductions in the 2020s."

Both countries say they'll meet in the first half of next year to nail down specifics. Guterres called this an important step. But he warned that "promises ring hollow when the fossil fuels industry still receives trillions in subsidies, as measured by the IMF [International Monetary Fund]. Or when countries are still building coal plants," said Guterres.

The U.S. Special Presidential Envoy for Climate John Kerry defended the agreement in an interview with NPR, saying it's "bigger than some people think." If the U.S. and China reach their goal of reducing methane emissions 30% by 2030, Kerry says "that is the equivalent of taking all the cars in the world, all of the trucks in the world, all of the airplanes in the world, all ships in the world, down to zero."

Calls for wealthier nations to take more responsibility

The high stakes if countries fail to act boldly was on display in dramatic ways during this summit.

The foreign minister of Tuvalu, a Pacific island nation, delivered his speech knee-deep in water to show how the rising ocean already affects his country. "Climate change and sea level rise are deadly and existential threats to Tuvalu," said Simon Kofe.

In the final days of negotiations, nations still aren't seeing eye to eye on the issue of climate finance, a $100 billion fund for developing countries. Wealthier countries promised to deliver that amount annually by 2020, an acknowledgment that they are responsible for the bulk of climate-warming emissions over the past century and a half.

The funds help vulnerable countries reduce their emissions with renewable energy and cleaner transportation, as well as help them prepare communities for climate impacts, like extreme storms and floods. The latest draft agreement expresses "deep regret" that richer countries so far have fallen short of that goal.

Several new funding commitments were announced in Glasgow, and wealthier countries say they'll reach the $100 billion mark in 2022 or 2023. But developing countries say much of that has been in the form of loans instead of grants, putting an added burden on nations to pay it back.

Developing countries estimate climate-related damage will hit $5-to-9 trillion by 2030 and are pushing for more details about what the next funding goal will be. They want to see more transparency about where climate finance is coming from, as well as assurances that much of it will be offered as grants.

"The level of ambition on climate finance required is simply not there yet," says Fekadu Beyene of Ethiopia, representing a group of the 46 poorest countries at the talks. "Vulnerable countries are already experiencing devastating impacts at 1.1 degrees Celsius of warming and are struggling to recover. We cannot expect to build resilience to the impacts we will feel at 1.5 degrees Celsius without additional resources."

Developing countries are also pushing for compensation for the increasing damage that climate change is already causing. They're seeking a dedicated "loss and damage" fund, which could be used by countries struggling to rebuild after disasters. Scotland announced the first contribution, 2 million pounds, at the Glasgow summit. But other wealthier countries, including the U.S., are wary of being held liable for climate change damages and oppose creating a separate fund.

Countries are headed toward "catastrophic climate change"

The modest progress made so far may be the best that can be expected from an international negotiation process where every country must agree on a final statement. But the scientific reality of a warming climate is unforgiving, and demands swifter action.

The group Climate Action Tracker earlier this week factored in new pledges countries had made so far to cut heat-trapping emissions. It found that even if everyone kept their most ambitious promises, warming would still be 1.8 degrees Celsius, which is above the 1.5 degree goal. When analysts mapped out what countries are actually doing now, the picture was bleaker.

"With all the policies that are currently implemented, our temperature estimate is 2.7 degrees" of warming, said Niklas Höhne, founding partner of NewClimate Institute. "That is catastrophic climate change. It's a situation that we simply cannot handle."

Höhne was among those in Glasgow who said leaders must go back home and put practices in place to meet the promises they've made to each other.

In the U.S. President Biden has proposed an aggressive climate plan that aims to meet the goals of the Paris agreement, but much of the legislation needed to implement it is stalled in Congress.