Two weeks of high-profile talks yielded a package that pushes countries to strengthen near-term climate targets and move away from fossil fuels faster. It insists that wealthy countries fulfill a broken promise to help vulnerable nations cope with the rising costs of climate change. And it cracks open the door to future payments developed nations might make for damage already done.
Saturday's agreement, however, does not achieve the most ambitious goal of the 2015 Paris accord - to limit Earth's warming to 1.5 degrees Celsius (2.7 Fahrenheit) above preindustrial levels. Instead, delegations left Glasgow with the Earth still on track to blow past that threshold, pushing toward a future of escalating weather crises and irreversible damage to the natural world.
And representatives from hard-hit nations feared that the deal still leaves their people facing an existential threat.
"The difference between 1.5 and 2 degrees is a death sentence for us," Aminath Shauna, the Maldives' minister of environment, climate change and technology, told the summit. "What is balanced and pragmatic to other parties will not help the Maldives adapt in time. It will be too late."
Organizers acknowledged that the hard-fought agreement doesn't go nearly far enough. But they argued that the progress made here creates a road map to a safer future and "keeps 1.5 alive."
"We're all well aware that, collectively, our climate ambition and action to date have fallen short on the promises made in Paris," Alok Sharma, the British minister of state and president of the Glasgow talks, told delegates Saturday.
But he insisted that the deal adopted by the nations would set out "tangible next steps and very clear milestones" to push the world closer to those goals.
Yet with global temperatures already up more than 1.1 degrees Celsius (2 degrees Fahrenheit), and extreme weather wreaking havoc around the world, it remains to be seen whether this agreement will be sufficient to deal with mounting calamities inflicted by climate change.
Negotiators leave Glasgow with key questions unanswered: Can nations muster the political will to deliver on the soaring rhetoric that marked the summit's start? And can the lurching progress of these annual conferences keep pace with the problem they were designed to solve?
Anything short of that will consign future generations to untold suffering, the European Union's top climate official, Frans Timmermans, told delegates in the waning hours of the summit. Timmermans said he had been pondering what life will be like in 2050 for his 1-year-old grandson.
"If we succeed, he'll be living in a world that's livable," he said. "If we fail - and I mean fail now in the next couple years - he will fight with other human beings for water and food. That's the stark reality we face."
The entire agreement appeared momentarily in peril when delegates from China and India proposed a last-minute change to crucial text around moving away from coal, saying they would agree only to "phase down unabated coal," rather than "phase out."
Uncertainty flooded the room, said Andrea Meza, Costa Rica's environment minister. Neither she nor many of her developing-nation allies knew the challenge was coming.
"We were very anxious," she said. "Everything is so fragile, these commitments. Then if you start taking [out] the pins, everything can fall down so easily."
Country after country rose to object to the 11th-hour change.
"This commitment on coal had been a bright spot in the package," said Marshall Islands climate envoy Tina Stege. "It was one of the things we were hoping to carry out of here and back home with pride. And it hurts deeply to see that bright spot dimmed."
Ultimately, Stege said that she would accept the language change "only because there are critical elements of this package that people in my country need as a lifeline for their future."
The episode was a reminder of how laborious the international effort to slow climate change can be, hinging on hard-fought compromises and sometimes a change to a single word.
Sharma, who had promised to shepherd the summit to a smooth end, appeared rattled. "I apologize for the way this process has unfolded," he told negotiators, his voice almost breaking. "But as you have noted, it is also vital that we protect this package."
Moments later, he put forward the agreement, including the "phase down" language, and then gaveled it into history.
The final agreement at COP26 did recognize the scientific reality that putting the brakes on climate change will require nations to almost halve emissions in the next decade, rather than merely commit to far off "net zero" targets.
It "requests" that leaders revisit their national climate goals as soon as next year - a not-so-subtle nudge to the world's biggest emitters to strengthen commitments that have proved insufficient. A joint pledge issued by China and the United States during the gathering also acknowledged the need to do more in this decade.
The deal also lays out a plan to resolve disputes around rules for global carbon markets that allow investors to buy and sell emissions reduction credits - a topic that for years has tripped up delegates at climate talks.
No sooner had the final gavel fallen in Glasgow than activists began picking apart the summit's failings, calling the pact little more than a parade of empty promises.
"I'm tired, I'm frustrated . . . but I am not surprised," said 20-year-old Nicki Becker, a Fridays for Future activist from Argentina who said the pact didn't do enough to protect those in at-risk countries like hers. "We always hear young people are the future. But they burn our present. They sell our present. They pollute our present."
Language calling for countries to end coal burning and fossil fuel subsidies - the first such references in years of U.N. climate talks - was diluted. A proposed fund to pay for irreversible "loss and damage" wrought by climate change in vulnerable countries was left out of the final text, angering delegates who say such reparations are long overdue. Instead, nations agreed to start a "dialogue" about the idea.
Some of the harshest condemnations were reserved for wealthy countries, which have released the bulk of greenhouse gases now in the atmosphere but have often resisted mandates to provide cash for developing nations and limit their massive pollution.
Rich countries have "pushed to transfer their responsibilities to the developing world," Bolivian negotiator Diego Pacheco Balanza said Saturday, accusing delegates from the developed world of "carbon colonialism."
Richie Merzian, a former Australian climate official, quipped this week of his coal-exporting nation, "The only thing Australia has brought to this negotiation is good coffee over at the Australian pavilion."
In a public session for ministers on Friday, even U.S. climate envoy John F. Kerry acknowledged that the biggest, richest emitters "do bear the greatest responsibility." President Joe Biden has pledged to boost U.S. climate aid to poor nations to more than $11 billion a year - a promise that will require help from Congress.
But behind the closed doors of negotiating rooms, representatives from multiple countries said, U.S. diplomats were among those opposed to establishing "loss and damage" payments for vulnerable countries. On Saturday, Kerry sought to assure skeptical nations that the United States would make "every effort in the world" to help those battered by climate change.
The talks in Glasgow unfolded in a world already irrevocably altered by human emissions. A landmark U.N. report published in August found that global temperatures are increasing at a unparalleled rate. The last time the level of carbon dioxide in the atmosphere rose this much this fast was 66 million years ago, when a meteor destroyed the dinosaurs.
"The alarm bells are deafening," said U.N. Secretary General António Guterres said at the time.
The scientific warnings seemed almost superfluous amid a year of monstrous hurricanes, raging wildfires and deadly heat waves. These crises cost nations hundreds of billions of dollars and took thousands of lives.
The gathering also took place against the backdrop of the coronavirus pandemic, which had delayed it by a year. Delegates in the cloistered "blue zone" were tested daily. Access to meeting rooms was restricted, angering activists who usually are able to observe such proceedings. And simmering tension over the pandemic's unequal global impact fueled developing nations' push for more help from wealthier parts of the world.
In the months leading up to COP26, organizers had described it as a global moment of truth - a "last best hope," in Sharma's words. "One minute to midnight on that doomsday clock," British Prime Minister Boris Johnson said.
Presidents and prime ministers showed up early in Glasgow and made new commitments to tens of thousands of attendees. The announcements included efforts to cut methane and halt deforestation, to phase out financing for coal plants, and help nations buffeted by the deadly trifecta of climate change, mounting debt and a deadly pandemic.
Heads of state mingled with movie stars and royal family members. The cafeteria served up vegan haggis and reusable cups of coffee. Beloved naturalist David Attenborough urged world leaders to "turn tragedy into triumph" by reversing decades of environmental decline. Mia Mottley, prime minister of Barbados, declared that warming of even 2 degrees Celsius (3.6 degrees Fahrenheit) would sink her island nation.
"Try harder," she told an auditorium brimming with powerful leaders. "Try harder."
Halfway through the summit, an estimated 100,000 protesters swarmed the streets of Glasgow, weathering the Scottish wind and rain to remind those inside that they were watching and expecting bolder policies.
Indigenous leaders in traditional dress, and grandmothers shouting expletives about the fossil fuel industry joined the swirling mass. Schoolchildren clutched their parents' hands and waved signs saying "Act now."
"Cut the crap," was emblazoned on a cart pushed by 55-year-old Malcom Strong. Inside the cart: a bucket of manure.
That excrement reflected how little faith many activists had in the process unfolding inside Glasgow's cavernous convention center. They dismissed the U.N. summit as a "conference of polluters," a "meaningless" event of "greenwashing" and "blah blah blah."
Throughout, "keep 1.5 alive" was a rallying cry for world leaders and activists alike. The success of COP26 would be measured, they argued, by how much closer humanity got to the collective goals it set six years ago in Paris.
"Paris promised," Sharma said repeatedly. "Glasgow must deliver."
But delivering, it turned out, did not come easily.
By the second week of the conference, the fanfare had given way to a sobering reality: Commitments made here, however promising, will depend on words becoming concrete action.
As negotiations stretched on, the U.N. Environment Program reported that COP26 would likely end with Earth on track to warm 2.5 degrees Celsius (4.5 degrees Fahrenheit) - though other analyses suggested the number could drop if countries take swift action to fulfill long-term pledges.
Despite a wave of vows to zero out emissions by the middle of the century, the U.N. analysis found, countries' plans between now and the end of the decade would give humanity less than a 20 percent chance of keeping warming to 1.5 Celsius.
Missing the target would be catastrophic. Warming beyond 2 degrees Celsius could trigger the inexorable collapse of the Greenland ice sheet. Coral reefs would virtually disappear. Natural disasters would escalate. Prolonged droughts and crop-destroying floods could put millions of people at risk of starvation.
Asked whether she believed the Glasgow agreement would keep the hope of 1.5 alive, University of East Anglia climate scientist Corinne Le Quéré said: "Just barely."
Ultimately, some of the same officials who once hoped for a profound leap in Glasgow, who saw COP26 as a defining moment, by Saturday night described it not as an ending but as a beginning.
"Glasgow ends today. But the real work begins now," said Seve Paeniu, climate minister for the low-lying atoll nation of Tuvalu.
Saturday evening, the spectacle that had once carried so many hopes started to fade.
Workers began to break down pavilions that had showcased various countries, including the installation of polar bears wearing life jackets - a reminder from Tuvalu that rising seas threaten its existence. Protesters who had chanted and banged drums, filled the streets and even once overtaken a plenary hall had dispersed. The man outside in a Darth Vader costume, singing karaoke each morning and surrounded by signs about solar radiation, had left his post.
A dwindling number of souls remained at the site alongside the River Clyde, where delegates from every corner of the planet had come to try to save it. They trudged down empty hallways, past a banner that read, "We can do this if we act now."
And nearby, a still-lit neon sign flashed its silent message:
"Hurry up please. It's time."