Nearly 200 nations adopted the first global pact to fight climate change on Saturday, calling on the world to collectively cut and then eliminate greenhouse gas pollution but imposing no sanctions on countries that don’t.
The “Paris agreement” aims to keep global temperatures from rising another degree Celsius (1.8 Fahrenheit) between now and 2100, a key demand of poor countries ravaged by rising sea levels and other effects of climate change.
Loud applause erupted in the conference hall after French Foreign Minister Laurent Fabius gaveled the agreement. Some delegates wept and others embraced.
The agreement, South African Environment Minister Edna Molewa said, “can map a turning point to a better and safer world.”
“This is huge,” tweeted U.S. President Barack Obama. “Almost every country in the world just signed on to the #ParisAgreement on climate change — thanks to American leadership.”
In the pact, the countries commit to limiting the amount of greenhouse gases emitted by human activity to the same levels that trees, soil and oceans can absorb naturally, beginning at some point between 2050 and 2100.
In practical terms, achieving that goal means the world would have to stop emitting greenhouse gases altogether in the next half-century, scientists said. That’s because the less we pollute, the less pollution nature absorbs.
Achieving such a reduction in emissions would involve a complete transformation of how people get energy, and many activists worry that despite the pledges, countries are not ready to make such profound and costly changes.
The deal now needs to be ratified by individual governments — at least 55 countries representing at least 55 percent of global emissions — and would take effect in 2020. It is the first pact to ask all countries to join the fight against global warming, representing a sea change in U.N. talks that previously required only wealthy nations to reduce their emissions.
The deal commits countries to keeping the rise in global temperatures by the year 2100 compared with pre-industrial times “well below” 2 degrees Celsius (3.6 degrees Fahrenheit), and says they will “endeavor to limit” them even more, to 1.5 degrees Celsius. The world has already warmed by about 1 degree Celsius since pre-industrial times.
Ben Strauss, a sea level researcher at Climate Central, said limiting warming to 1.5 degrees instead of 2 degrees could potentially cut in half the projected 280 million people whose houses will eventually be submerged by rising seas.
More than 180 countries have already presented plans to limit greenhouse gas emissions— a breakthrough in itself after years of stalemate. But those pledges are not enough to achieve the goals in the accord, meaning countries will need to cut much more to meet the goal.