A decade ago, the world got together and decided to fix the climate crisis by adopting the Paris Agreement.

I remember it like yesterday. This was December 2015 at the UN climate talks in Paris. I was standing in front of a CNN camera as the news came through an earpiece: Nearly every country on Earth agrees to cut emissions to net zero by 2050 — holding warming short of catastrophic levels. A hilariously on-the-nose green gavel hit a desk. The convention center erupted in applause. Diplomats wept and hugged. Even Al Gore managed to not look all that wooden.

My column the next morning trumpeted this headline: “This is the end of fossil fuels.”

Somehow, it doesn’t feel like 10 years and some 300 gigatons of carbon have floated by since then.

Paris was not the end of fossil fuels, of course. From the perspective of the atmosphere, the last decade could accurately be described as a slow-moving fever dream — one in which pollution from fossil fuels has continued to rise year after year. All those emissions drive global heating and make the planet more dangerous.

And in this dangerous decade climate disasters have continued to intensify — from the massive hurricane that walloped Puerto Rico in 2017, to Jamaica this October where the most powerful Atlantic storm on record came aground.

Residents gather amid debris in the aftermath of Hurricane Melissa on a street in Black River, Jamaica, Thursday, Oct. 30, 2025. - Matias Delacroix/AP

It’s a decade in which new fossil fuel projects continued to be approved by the very governments that had promised to slash emissions; and one in which the United States twice elected a climate-denier to the nation’s highest office. This fall, US President Donald Trump, after cancelling billions toward clean energy projects and moving to open a swath of the Arctic for oil extraction, bucked the scientific consensus on global warming again by falsely stating that climate change is the “greatest con job ever perpetrated on the world.”

Ironic, then, that this has also been a decade during which scientists realized that, if anything, they underestimated some of the threats of climate change.

Just last month, for example, researchers reported that Earth had crossed one of its first climate tipping points, with such a massive percentage of coral reefs struggling amid warning that we’re entering a “new reality” in which those reefs won’t be able to recover.

One key goal of the Paris Agreement was to prevent this sort of thing, by limiting global warming to 1.5 degrees Celsius above preindustrial levels. A group of especially climate-vulnerable countries, calling themselves the High Ambition Coalition, banded together to push for that target. In Paris, delegates carried the rhyming theme over to wearing buttons that said, “1.5 to stay alive,” a reference to the existential threat warming poses, especially to low-lying areas that are flooding as ice melts and oceans rise.

Two tourists face the melting Rhone Glacier on September 12, 2025. Switzerland’s glaciers are disproportionately impacted by climate change and have shed a quarter of their mass in the past decade alone. - Fabrice Coffrini/AFP/Getty Images

That “1.5 to stay alive” target, we now know, is almost certainly out of reach. Either we’ve crossed that line already or we’re well on the way. Does that mean we’re “dead”? That we’ve failed to “stay alive”?

No — thankfully, the world doesn’t burst into flames at 1.51 degrees of warming.

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We do know that every ton of heat-trapping pollution makes the world more dangerous. But, conversely, every ton of it we save makes the world safer for future generations. Yes, by many metrics, we’ve backslid in the years since Paris. Jamie Henn, co-founder of 350.org and director of Fossil Free Media, told me that if climate action is Star Wars then “I think we’re in the Empire Strikes Back episode of the trilogy” — where it all falls apart.

But it’s still possible to adjust the lens and bring other storylines into focus.

“We’ve come an incredibly long way since Paris,” said Jean Su, energy justice director and senior attorney at the Center for Biological Diversity. Of note, Su told me, is the fact that world leaders in 2023, at the COP meeting in Dubai, added language to the Paris Agreement that calls for moving away from fossil fuels. At that meeting, “we really reached a pinnacle in terms of addressing the root causes of the climate emergency,” she said.

Workers install solar panels near Marburg, in western Germany, on August 6, 2025. - Hannes P. Albert/AFP/Getty Images

Just because Trump thinks climate change is a scam, doesn’t mean the rest of the world agrees.

Henn, the climate activist, pointed to renewable energy as a bright spot. In the first half of 2025, renewables overtook coal as the world’s top energy source for the first time. Wind and solar power — which don’t produce the heat-trapping pollution of coal and gas — are expected to meet 90% of new electricity demand this year.

“The transition is moving even faster than people predicted back in 2015,” Henn said. Fifteen times faster, in fact, if you’re looking at solar power installations, according to the non-profit Energy and Climate Intelligence Unit.

Likewise, it continues to be crystal clear how the public feels about this issue: 89% of the global public surveyed in a 2024 study favored stronger political action on climate change.

“That is a supermajority,” said Mark Hertsgaard, executive director of Covering Climate Now, the group behind a media collaboration called the 89 Percent Project. “And it’s a [super]majority that doesn’t know that it’s a majority. People in that majority think that they’re 29% of the population. They think they’re a minority.”

But even in the United States, positive trends hold: 79% of registered voters surveyed in May 2025 said they support the US being part of the Paris Agreement and 75% support regulating carbon dioxide as a pollutant.

Climate advocates are planning new efforts to make use of this supermajority. Among them is a push for a Fossil Fuel Nonproliferation Treaty. Alex Rafalowicz, executive director of that initiative, told me the idea for a treaty builds on an International Court of Justice decision earlier this year that held nations legally responsible for curbing climate-heating pollution.

“The economics do demonstrate that the transition [to clean energy sources] has an inevitability about it,” Rafalowicz said. “But the question is whether it is fast enough, and whether it is fair enough. That is part of the problem we’re trying to solve.”

A meeting about that treaty is likely to happen next spring in Colombia, he said. Meanwhile, the UN is prepping for COP30, in Brazil, which begins November 10. Plenty of the delegates there will remember that green gavel moment from Paris. I’ll be thinking of it as I watch news from the summit, too.

The main entrance of the COP30 UN Climate Change Conference at night in Belem, Para State, Brazil on November 7, 2025. - Mauro Pimentel/AFP/Getty Images

On the day the Paris Agreement was adopted, I spent hours with the delegation from the Marshall Islands, a nation of low-lying islands in the Pacific that fears being subsumed by rising seas. I’d visited the country earlier in 2015 for a CNN article. I’ll never forget a woman telling me that the sound of the ocean, which used to lull her to sleep, had become threatening after waves crashed through her home and flooded it. Her family had decided to move to Arkansas to get far away from the water and that sound.

The Marshallese delegation in Paris gave me a palm frond ribbon to remember them by. I kept it in my pocket as I relayed news of the agreement to viewers around the world.

It’s sitting on my desk as I type this, 10 years later.

It reminds me that the optimism and the urgency of that moment have not been forgotten.

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