German Chancellor Angela Merkel, right, talks to Fiji prime minister and COP president Frank Bainimarama, second right, and Timoci Naulusala, a child from Fiji, with Patricia Espinosa, executive secretary of the United Nations Framework Convention on Climate Change, left, and French President Emmanuel Macron. Credit:AP It is, in effect, a giant bet on the power of peer pressure — with the future of the planet at stake. And no one yet knows how that bet will pan out. The Trump administration's vow to withdraw the United States from the Paris agreement by 2020 has made that peer pressure dynamic more complicated. While State Department officials still attended this year's talks and helped shape rules around how countries will report their progress on emissions, the world's richest nation is no longer seeking to lead the fight against climate change. Virtually everyone at the Bonn conference acknowledged that the world's nations are still failing to prevent drastic global warming in the decades ahead. "We need more action, more ambition, and we need it now," said Patricia Espinosa, the UN climate chief. Under the Paris agreement, nearly every country submitted a voluntary pledge for constraining its emissions. Yet those pledges are modest: even with them, the world is still on course to warm at least 3 degrees Celsius this century, an outcome that carries far greater risks of destabilising ice sheets in Greenland and Antarctica, drastic sea-level rise and more extreme heat waves and droughts.

A coal-burning power plant steams in Gelsenkirchen, Germany while the 23rd UN Conference of the Parties (COP) climate talks end in Bonn, Germany. Credit:AP So, at Bonn, diplomats focused on ways to encourage countries to ratchet up their ambitions. Next year, world leaders will meet for a formal dialogue to assess how their efforts stack up against the goal of limiting global warming to "well below" 2 degrees Celsius. They plan to discuss which domestic climate policies are working and which ones aren't, and then try to figure out which countries can step up the pace of their emissions cuts. Ultimately, countries plan to submit newer, stronger climate pledges to the United Nations by 2020. Negotiators sought this year to write a "rule book" that will govern this process, laying out guidelines for how emissions from each country should be measured or how financial aid from rich countries to poor ones should be tracked. Most of the hard decisions about what this rule book should look like were put off until next year. The biggest unknown is whether this whole process will translate into meaningful further action to cut emissions. At Bonn, there were a few signs peer pressure is working and that some countries are indeed feeling compelled to take stronger action. Leaders from the European Union, which is currently on pace to fall short of its 2030 emissions goals, said they would push to enact new legislation on increasing clean energy and efficiency. "The level of ambition from the European Union has been questioned," said Miguel Arias Canete, Europe's commissioner for climate change. "We understand the concerns."

And elsewhere, long-standing divisions among nations reasserted themselves. Throughout the talks, China argued that the Paris agreement rule book should hold developed nations to higher standards than developing countries. In past climate talks, the United States had taken the lead in pushing back against this notion, but with the Trump administration stepping back from the Paris agreement, US influence in this area was weaker. These disagreements may only be partly resolved at future climate talks. Andrew Deutz, an expert on international negotiations at the Nature Conservancy, argued that one of the most important climate developments of the year actually happened outside of the Bonn meeting — when the Chinese government announced that it would expand its domestic market for electric vehicles to 7 million cars by 2025, a move spurred in part by Chinese concerns over air pollution in cities. Experts say national climate policies will be shaped far more by domestic considerations than by international pressure. But, Deutz added, these talks can be useful for "creating a forum where everyone has confidence in what everyone else is doing. That sort of mutual confidence can be enabling." Still, there is the question of pace. During the second week of talks, climate scientists gave a presentation to the conference on the vast task ahead of them. To stay below 2 degrees Celsius of warming, global emissions would likely have to peak in the next few years and then be cut by half every decade all the way down to zero by mid-century. The scale of that transition is staggering. Virtually every coal plant around the world would need to be phased out or outfitted with carbon capture technology within decades. Electric vehicles would need to be the primary mode of transportation, and the world's power grids would need to be virtually emissions-free. Technology that barely exists today to suck carbon dioxide out of the atmosphere may need to be deployed on a huge scale.

Loading That presentation came on the heels of a news conference by a different set of scientists, who announced that current industrial emissions of greenhouse gases have not yet peaked — instead, they are likely to rise again in 2017, driven in part by a rebound in coal use in China. New York Times