For a while it looked as if the world might be turning the corner.
But after a three-year stall in their growth, human-caused carbon-dioxide emissions have not, in fact, peaked, an international team of scientists announced this morning.
In 2017, global emissions of CO2 from fossil fuels and industry will once again rise by 2 percent, the scientists project, to a record 37 billion metric tons. Those emissions had increased by only a quarter of a percent from 2014 to 2016. Changes in land use, such as deforestation, will add around 4 billion metric tons of CO2 in 2017, bringing the global emissions total to an estimated 41 billion metric tons.
The resurgence tightens the time constraint on the world’s efforts to keep global warming from exceeding 2 degrees Celsius (3.6 degrees Fahrenheit)—a cap scientists increasingly believe is important to ward off climate change’s most catastrophic effects.
“What’s driving, really, the global trend is this pick-up in China,” says Corinne Le Quéré of the University of East Anglia, and the lead author of one of several new emissions studies released today. An unexpected rise in coal-burning in China—due in part to a summer drought that diminished the country’s rivers and its generation of hydropower—was the biggest contributor to the global surge in emissions.
But China’s shift didn’t happen in a vacuum. Its emissions rose just as the United States and European Union each saw their emissions decrease more slowly than expected.
In the U.S., higher natural gas prices led to a slight rise in coal burning, for the first time in five years, while oil use also increased. As a result, emissions that had been declining about 1.2 percent a year dropped less than half a percent. In the E.U., emissions dropped less than a quarter percent after a decade of annual declines topping 2 percent a year.
On the other hand, India’s emissions, which had been steadily rising about 6 percent a year, as the country industrializes and rapidly brings electricity to rural areas, are projected to increase by only 2 percent in 2017. That good news is also troubling, because it’s almost certain not to last.
With five of the hottest years on record all having come just since 2010, the big question is whether the renewed emissions growth is a one-time slip or the new normal.
“It’s hard to say whether 2017 is a hiccup on the way to a trajectory that eventually peaks and goes downward—or if it’s about returning to high growth,” Le Quéré says.