They are just two little words. They appear on just one page of an 11,000 word document.

But the inclusion of the phrase “fossil fuels” in the final agreement from COP28 marks a potentially trajectory-altering moment in the fight against climate change. The global pact calls for “transitioning away from fossil fuels in energy systems, in a just, orderly and equitable manner.”

For almost 30 years, negotiators representing nations from around the world had struggled and failed to reach an obvious consensus: that the burning of fossil fuels like coal, oil and gas should be wound down to avoid further catastrophic global warming.

But overnight, representatives from more than 170 countries arrived at a surprising deal, in Dubai of all places.

The text is not as clear as many leaders, activists and scientists had hoped. It includes caveats and wiggle room, and is nonbinding. Nevertheless, the inclusion of explicit language calling for a move away from coal, oil and gas is being hailed as a major breakthrough.

“After three decades of U.N. climate negotiations, countries have at last shifted the focus to the polluting fossil fuels driving the climate crisis,” said Manuel Pulgar-Vidal, who was president of COP20 in 2014, and now works for the World Wildlife Foundation. “This outcome must signal the beginning of the end for the fossil fuel era.”

The agreement to transition away from fossil fuels was reached in the United Arab Emirates, one of the world’s biggest oil producers. The president of COP28, Sultan Al Jaber, is also head of the U.A.E’s state oil company and he came under withering criticism for his conflict of interest.

But after two weeks of negotiations, it was Al Jaber who ultimately muscled language about ending fossil fuels into the final COP agreement.

“The much-criticized U.A.E. Presidency has pulled this off,” Myles Allen, a climate scientist at the University of Oxford, told Bloomberg. “Everyone seemed ready to write COP28 off just 24 hours ago, you have to hand it to them.”

In Dubai, many of the sleep-deprived diplomats celebrated the outcome.

“There is a strangely very optimistic feeling here compared with the angry mood just one and a half days ago,” one negotiator told me via Whatsapp, haggard after two weeks of nonstop meetings.

The celebrations are likely to be short-lived. This year was the hottest in recorded history, and scientists expect 2024 to be just as hot, if not hotter, as the El Niño climate pattern compounds the warming driven by fossil fuels. Oil, gas and coal production continue to rise. Fossil fuel companies are planning for decades of increased production, and many countries are still reliant on fossil fuels for revenue and economic growth.

For COP28 to truly makes a difference, it will take more than an aspirational statement. It will require policymakers to enact substantive changes in their countries, rapidly scaling up renewable energy and improving energy efficiency. It will mean sweeping changes to the global financial system to provide more capital to developing nations. There will have to be fundamental changes to the food system, serious efforts to protect nature and new technological advances.

But sometimes the arc of history can begin to shift with just two little words.

The world reacts to the new climate deal

Officials, advocates and scientists from around the world have reacted to the final COP28 declaration. Here is a selection of what they have said:

“The deal is not perfect, but one thing is clear: the world is no longer denying our harmful addiction to fossil fuels.” — Inger Andersen, executive director of the United Nations Environment Programme.

“Now a critical test is whether far more finance is mobilized for developing countries to help make the energy transition possible.” — Ani Dasgupta, president of the World Resources Institute.

“Every investor should understand now that the future investments that are profitable and long-term are renewable energy — and investing in fossil fuels is a stranded asset.” — Jennifer Morgan, Germany’s climate envoy, told Bloomberg.

“We have made an incremental advancement over business as usual, when what we really need is an exponential step change in our actions.” — Samoa representative Anne Rasmussen on behalf of the Alliance of Small Island States.

“This is a historic milestone on the journey to transitioning away from fossil fuels — a development that seemed all but impossible even two years ago. But we must be mindful that this is the bare minimum.” — Sir David King, founder and chair of the Climate Crisis Advisory Group.

“Some activists were disappointed we didn’t commit to an immediate fossil fuel phaseout. Still, without the trade, investment and finance to achieve it, it would either have hit developing countries hardest or been meaningless.” — Avinash Persaud, special climate envoy of Barbados.

“We are not happy but we all agree.” — Russian federation delegate Mikhail Gitarskiy, according to CNBC.

— Manuela Andreoni