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The world is on its way to record-high carbon emissions in 2017, after three straight years in which human-caused emissions appeared to be leveling off, new research shows.
The projected 2 percent increase in emissions this year adds urgency to the UN climate talks this week in Bonn, where 197 countries are negotiating how to implement the 2015 Paris climate agreement to slow global warming.
"There's not much time left to cut emissions and keep warming below 2 degrees Celsius, let alone 1.5 degrees," said Corinne Le Quéré, director of the Tyndall Centre for Climate Change Research at the University of East Anglia, who led the emissions research presented Monday in Bonn. The aim of the Paris Agreement is to keep global temperature rise to well below 2 degrees Celsius over pre-industrial times. For that to happen, studies have shown that emissions must peak within the next decade and then decline to net zero.
The new figures may be disappointing after hopeful speculation that emissions were already peaking, but not entirely unexpected.
China's Coal Bump
The region with the biggest projected surge in 2017 emissions—about 3.5 percent—is China, where coal consumption increased, according to the study.
Le Quéré said the increase in Chinese emissions can be partly attributed to a long dry spell that cut the amount of water available for hydropower, meaning more coal was burned. The Chinese drought hasn't directly been linked to climate change, but it is an example of a possible reinforcing feedback in the climate energy cycle, she said.
The research suggests U.S. coal consumption is also up slightly this year, but it projects that overall emissions from the U.S.—currently the No. 2 emitter behind China—will drop by 0.4 percent, due in part to a shift to natural gas and renewable energy.
India's emissions, meanwhile, are projected to grow by about 2 percent—down from over 6 percent growth per year during the last decade. Emissions are projected to decrease in 22 other countries with growing economies representing 20 percent of global emissions.
"Our expectations had always been that emissions would grow, but perhaps not as steeply as this," Le Quéré said. "What the countries have said they were going to do in Paris is that emissions will continue to grow by about 1 percent per year until about 2030. But that's not in line with limiting the global temperature increase to less than 2 degrees Celsius. That's why we have to increase our ambition for greenhouse gas cuts."
'A Red Flashing Light on the Dashboard'
It would be a mistake to think that a 2 percent increase is not a big deal, said Colorado State University climate scientist Scott Denning.
"It's somewhat tempting to be complacent and say emissions have flattened out, but having them flatten out at that level is not going to help us," Denning said. "We've got to cut emissions by half in the next decade, and by half again in the next two decades, as well. The fact that it's going up is like a red flashing light on the dashboard."
A 2 percent global increase would be a jump from previous years. A 0.7 percent increase was reported in 2014, no increase in 2015, and 0.2 percent in 2016. Despite the leveling off of emissions from fossil fuels and other human sources during those years, research shows that increased carbon emissions from tropical forests linked to El Niño, a cyclical warming of the equatorial Pacific, continued to drive atmospheric concentrations of CO2 and global temperatures up.
Overall, human-caused carbon emissions have grown at an average annual rate of 3.5 percent since 2000, but at a slower pace of 1.8 percent between 2006 and 2015, according to the Global Carbon Project.
"This shows how totally urgent it is to decrease emissions as fast as we can," said Pieter Tans, an atmospheric scientist with NOAA's Earth System Research Laboratory, whose research on monitoring and verification of emissions was also presented Monday.
Tans urged world leaders to forge ahead with emissions cuts, despite the Trump administration's efforts to roll back U.S. climate policies and promote fossil fuels.
"Show the U.S. what you can do," he said, "as the rest of the world goes ahead and leaves the U.S. behind in the 19th century."
He explained his frustration: "I'm not just a scientist. I'm a citizen, and I'm worried about the direction we're going. I have kids and grandkids. I want them to have a good life, and things don't look good currently."
A New 'World Scientists' Warning to Humanity'
On Monday, the journal BioScience published a letter signed by more than 15,000 scientists from around the world that looks back at the human response to climate change and other environmental challenges in the 25 years since another large group of scientists published the 1992 "World Scientists' Warning to Humanity."
"Since 1992, with the exception of stabilizing the stratospheric ozone layer, humanity has failed to make sufficient progress in generally solving these foreseen environmental challenges, and alarmingly, most of them are getting far worse," the authors of the new letter write. "Especially troubling is the current trajectory of potentially catastrophic climate change due to rising GHGs (greenhouse gases) from burning fossil fuels, deforestation, and agricultural production—particularly from farming ruminants for meat consumption."
The original letter had warned about the need to move away from fossil fuels and cut greenhouse gas emissions that are warming the planet. The new letter notes, among other trends, that 10 of the hottest years in 136 years of records have occured since 1998.