The new climate pact is more ambitous. But hopes dim for limiting warming to 1.5°C

When nations gathered in Glasgow, U.K., earlier this month for the major U.N. climate summit, “Keep 1.5 alive” was a ubiquitous mantra, repeated on protest banners and in speeches by politicians. By the end of the meeting last week, however, it was clear that the international effort to limit global warming to 1.5°C above preindustrial levels—the stretch goal set by the 2015 Paris agreement—is on life support. The Glasgow deal reached on 13 November takes important steps toward limiting warming and “still leaves the door open” to achieving the 1.5°C goal, says Sonia Seneviratne, a climate scientist at ETH Zürich. “But only slightly.”

Current commitments to curb greenhouse gas emissions—including new national pledges finalized at the summit—are more ambitious than ever, but still not enough to keep warming below 1.5°C, researchers say. Many are vague and promise results only decades from now, and the pact includes no enforcement mechanisms. Nor does it guarantee that rich nations will provide the financial help that poorer countries will need to control their emissions and cope with climate impacts.

The outcomes were disappointing, although not unexpected, for many developing and island nations that fear warming greater than 1.5°C will bring devastating harm. Still, many attendees were encouraged by signs of progress. More than 100 nations made new pledges to curb emissions that, if realized, could for the first time keep warming below 2°C. And 197 countries agreed to a host of new measures—including standards for reporting national emissions and ground rules for trading credits for carbon removal—that could promote more ambitious pledges and reveal whether countries are actually following through. Nations also agreed to return to next year’s summit, to be held in Egypt, with even stronger commitments, aimed at meeting the 1.5°C goal.

The agreement signals a “major shift” in global climate talks, from designing policy frameworks to implementing them, says Rueanna Haynes, an international climate law specialist at the Berlin-based nonprofit Climate Analytics. “It took forever, but we’re done now. … The focus is going to shift squarely into implementation,” says Haynes, who negotiated at the summit on behalf of the Alliance of Small Island States.

The talks also reflected a new level of realism about what it will take to rein in warming, says Maisa Rojas, a climate scientist at the University of Chile. This time, the agreement embraced a 2018 U.N. scientific report that concluded carbon dioxide emissions will need to drop by 45% by 2030 for the world to stay below 1.5°C of warming. “It’s great to see the science so clearly stated,” Rojas says.

The bad news, however, is that the world is not now on track to achieve such reductions. Only by halving emissions over the next 10 years and then rapidly dropping them to net zero by 2050 can the world gain a 50% chance of staying below 1.5°C, says Joeri Rogelj, a climate scientist at Imperial College London.

Such projections underscore the importance of having nations revisit and ramp up their pledges next year in Egypt, rather than in the 5 years specified in the Paris pact, commentators say. If countries waited that long to increase their ambitions, reaching the 1.5°C goal would become “basically impossible,” Seneviratne says.

Despite the difficulty of achieving the 1.5°C target, many experts were pleased the Glasgow pact retained language reinforcing its importance. Island states threatened by sea level rise—which led the charge in securing the 1.5°C target in the Paris pact—argued the goal is, for them, existential.

Still, Rogelj worries about what will happen if the 1.5°C target is declared dead. “That implies that when we miss 1.5°C, the next target is 2°C,” he says, rather than some number in between. But, “Every fraction of a degree matters,” says Nerilie Abram, a climate scientist at Australian National University. She notes that even small increases in temperature boost the risks posed by sea level rise and climate shifts. The lower goal, she and others say, should help maintain political pressure for stronger action, even if—or when—it is breached.

Developing nations did not get one big thing they wanted in Glasgow: a new “loss and damage” fund. Fund advocates argued that developed nations, having produced the vast majority of historic emissions, should help developing countries cope with the costs of climate-related extreme events, such as droughts. In the end, the pact promised only a “dialogue” on loss and damage. The issue is expected to be high on the agenda of next year’s summit, but, for the moment, “Developing countries are very angry,” says economist Sarobidy Rakotonarivo of the University of Antananarivo.

Richer nations did make some, often vague, pledges to help developing countries reduce their emissions and build the infrastructure needed to adapt to climate impacts such rising seas. But researchers say targeting that money effectively will also require funding more science, including higher resolution modeling of climate impacts and studies of the economic impacts of climate-driven extreme events.

Despite Glasgow’s mixed results, momentum for meaningful climate action is growing, believes Rebecca Willis, an environmental social scientist at Lancaster University. There is a limit to what summits can achieve, she says, because nearly 200 countries must agree to the outcomes. But she notes other players, including the energy and finance industries, keep a careful watch, and this year’s summit left them with plenty to think about. The idea of keeping fossil fuels in the ground, for example, “has gone from being a campaign slogan to being on the desk of every investment banker,” Willis says. And although the progress made in Glasgow “doesn’t go far enough, it’s not fast enough … it’s unrecognizable compared to where we were 10 years ago.” 

source: sciencemag.org