Governments, scientists, industry groups and environmental campaigners are meeting in Germany next week to discuss implementing a global agreement to curb climate change, despite uncertainty over how the United States will figure into the effort.
President Donald Trump announced earlier this year that the U.S. will pull out of the 2015 Paris climate accord unless his administration can secure a better deal.
Other countries have pledged to press on regardless at the Nov. 6-17 meeting in the western German city of Bonn. The 23rd Conference of the Parties (COP) will be presided over by Fiji, one of the small island nations particularly vulnerable to the effects of global warming.
Researchers say extreme weather like the events of recent months — including hurricanes in the Caribbean, heatwaves in Europe and flooding in south Asia — are going to become more frequent as a result of climate change. To prevent catastrophic consequences, they say countries must make concerted efforts to shift the global economy away from fossil fuels and to adjust to some inevitable impacts, such as rising sea levels.
"This COP is more important than most people realize," Andrew Steer, head of the World Resources Institute, a Washington-based environmental think tank, said.
Steer said a growing number of commitments from governments, as well as from major companies and cities around the world was "broadly encouraging." He noted the falling cost of renewable energy — a key technology required to help power-hungry economies kick the carbon habit.
Most of the 195 countries coming to Bonn — where the U.N. climate agency is located — appear willing to continue hammering out the details needed to make the Paris 2015 accord work, German Environment Minister Barbara Hendricks said ahead of the two-week talks.
Negotiators will try to agree on ways to measure each country's greenhouse gas emissions and to make sure everyone is playing by the same rules. Since the Paris agreement doesn't foresee sanctions for countries that fail to meet their targets, peer pressure is the main mechanism for ensuring that governments abide by their commitments and continue to increase their efforts in future.
A key issue will be the transparency of emissions reports, said Nigel Purvis, a former U.S. State Department negotiator under the Bill Clinton and George W. Bush presidencies.
The United States used to be the major force pushing for more open reporting and that will suffer because of the Trump administration's planned withdrawal from Paris, he said.
"Without U.S. leadership the deal is likely to take a little bit longer and may not be as strong," said Purvis, president of the group Climate Advisers.
Negotiators have until the end of 2018 to come up with the final rule book; it would be subject to approval at the next climate summit in Katowice, Poland.
Observers say that without the United States driving the talks — as it did in Paris when Barack Obama was in the White House — other leaders will have to fill the gap.
"The United States are not anymore the most important actor in this game of climate change," Hans Joachim Schellnhuber, director of the Potsdam Institute for Climate Impact Research, said.
"The most important actor is China, and India will soon become extremely important, as well as the European Union," Schellnhuber said.
Some are also placing their hopes in Emmanuel Macron. The French president is expected to fly in on Nov. 15 to show his support during the final phase of the talks. Macron has called for a follow-up meeting in Paris next month.
German Chancellor Angela Merkel, a veteran of past climate summits, will also put in an appearance in Bonn despite being tied up in negotiations to form a new government. The Green Party, with which she hopes to forge a coalition, has urged Merkel to set a firm date for Germany to end the use of coal-fired power plants.
Environmental campaigners are planning to highlight Germany's continued reliance on the heavily polluting source of energy with a protest at a coal mine near Bonn ahead of the talks.
Geir Moulson, Pietro De Cristofaro, Catherine Gaschka, and Seth Borenstein contributed to this report.