Photograph by Darren Aronofsky

It depends on whom you ask. Quite a lot of people are excited about the Paris Agreement, as the treaty announced last Saturday at the close of the United Nations’ Paris climate summit will be known. “This marks the end of the era of fossil fuels,” said May Boeve, executive director of 350.org. “There is no way to meet the targets laid out in this agreement without keeping coal, oil, and gas in the ground.” Penn State climate scientist Michael Mann sounded a similar note: “Though the resulting agreement is modest in scale, by bringing the world together, it sends a clear signal to global energy markets: The age of fossil fuels is ending, and a new clean global energy economy is taking its place.”

An equal number of people seem to be disappointed with the outcome of the summit. “Someone please tell me what’s new and compellingly worthy of jubilation in this agreement,” tweeted Yeb Saño, the former Philippines climate negotiator. The Grassroots Global Justice Alliance, a coalition of U.S.-based advocacy groups, was harsher, releasing a statement that the accord had “failed humanity.” Former Bolivian climate negotiator Pablo Solón called it “a death sentence for many people.”

Neither the champions nor the critics were entirely sure what to make of the treaty. “The final text still has some serious gaps,” said Boeve. After airing his criticisms on Twitter, Saño added, “The Paris Agreement is not bad. But we were not rooting for ‘not bad.’” Mann, meanwhile, saw the accord in a more sanguine light: “While the commitments made in Paris aren’t on their own enough to stabilize greenhouse-gas concentrations at safe levels . . . Paris is a beginning of a process.”

The treaty is miraculous and horrible. It neither gives enough to the most vulnerable nor takes enough from the profligate, but it shifts the arrangement between them for the better. Many of its ingredients are the result of hard-fought battles by the Climate Vulnerable Forum and by the High Ambition Coalition, the latter an ad hoc group of nations that reached across the developed-developing divide to push for both the long-term goal of keeping warming within 1.5 degrees Celsius of preindustrial levels and five-year check-ins on emissions-reduction achievements. That Tony de Brum, the foreign minister of the Marshall Islands and leader of the High Ambition Coalition, became an influential force at the conference is amazing.

The Paris Agreement recognizes that profound change must occur—and it codifies some of that change. I don’t know how radical a treaty people imagined, but that Saudi Arabia and Russia, among other petro-states, signed an agreement that essentially requires zero emissions in the second half of the century is astonishing. The agreement specifies that:

Parties aim to reach global peaking of greenhouse gas emissions as soon as possible, recognizing that peaking will take longer for developing country Parties, and to undertake rapid reductions thereafter in accordance with best available science, so as to achieve a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of this century.

Carbon neutrality by 2050 is a truly transformational goal; by some calculations, the United States will have to reduce emissions by 80 percent in the next thirty-five years to meet its commitments.The deal is, in part, the result of the extraordinary growth—in scale, sophistication, and effectiveness—of the climate movement worldwide, as well as the rapid rise of new energy technologies. (It is also, less happily, the result of many climate-driven disasters.) The climate movement was ineffective and fragmentary a decade ago; what it will be a decade hence is impossible to know but crucial to our fate. A document can help shape the future, but it cannot determine it.

Al Gore was a prominent figure at the conference, and it’s hard not to daydream of an alternative history in which the coup of 2000 didn’t put Bush Junior in the White House for eight years of blood and oil. But once you go down that road, you might as well go back to the late Seventies, when Exxon knew everything we really needed to know about the scale and urgency of climate change and decided to suppress the truth for the sake of profits. The mainstream U.S. media for decades largely underreported or, playing along with the likes of Exxon’s disinformation campaigns, misreported as a controversy the reality of climate change. Building public engagement in the United States has been made profoundly more difficult because of this dereliction of duty. Even this month, the New York Times buried much of its climate-conference coverage while giving a prominent podium to Trump’s verbal eruptions. In ten thousand years, what we do about the climate right now will matter. (The mock trial of ExxonMobil, with Bill McKibben and Naomi Klein as prosecutors, was one of the high points of the 300-ring circus that was Paris during the talks; the American media could be seen as an unindicted co-conspirator.)

Documents are not revolutions, any more than marriage contracts are marriages, but this one gives us something to hold governments to in the future—and in the present, with the nearly 200 national plans for carbon-emissions reduction that are supposed to be ratcheted up regularly. (“Each Party’s successive nationally determined contribution will represent a progression beyond the Party’s then current nationally determined contribution and reflect its highest possible ambition.”) The agreement is revolutionary for acknowledging what so many have said over these past two weeks in Paris: The age of fossil fuel must end.

The transformation is already underway. Bloomberg News reported this week that the Stowe Global Coal Index, which tracks the stock performance of more than two dozen major coal producers, is down 59 percent this year. MarketWatch recently ran a story titled “Five reasons crude-oil prices are facing an ugly death spiral,” which included this line: “The historic climate-change deal reached in Paris can be another nail in the coffin for future demand for fossil fuels, analysts at Morgan Stanley said in a note Monday.” Elsewhere those Morgan Stanley analysts used the phrase “left in the ground” in quotes, a paraphrase of the activist slogan “keep it in the ground.”

From now on all of our actions—how we produce and consume, farm and build and travel—will have to be viewed with their cumulative impact in mind. If we make this conceptual shift, it will be more than a revolution in energy; it will be a revolution in consciousness and worldview.