After three years of flatlining, human-generated carbon dioxide output looks set to rise again.

That’s the finding of a new study published in Nature Climate Change as part of the ongoing United Nations climate talks in Bonn, Germany. The research shows that the total atmospheric concentration of carbon dioxide will actually fall in 2017—but that’s only the result of an easing El Niño event. Meanwhile, global fossil-fuel and industrial emissions are expected to jump by 2 percent over 2016.

The bulk of that increase, says the international team of researchers that work under the banner of the Global Carbon Project, can be attributed to China and India, whose emissions look set to increase by 3.5 and 2 percent, respectively. Each country has a complex relationship with the burning of fossil fuels, and they continue to tread a fine line between keeping promises to clean up their acts and burning coal to maintain a rapid pace of development until clean energy is cheap, reliable, and pervasive.

To meet the goals of the Paris climate pact, many climate scientists agree, carbon emissions must begin to fall by 2020. That makes the new finding particularly troubling—especially if the single data point becomes a trend. “We were not particularly surprised that emissions are up again, but we were surprised at the size of the growth,” climate scientist Corinne Le Quéré of the University of East Anglia, U.K., and one of the authors of the study, told Nature. “If 2018 is as big is 2017, then I will be very discouraged.”

The news follows a recent report by the United Nations, which argued that there’s still a big gap between international government commitments to cutting emissions and the goals outlined in the Paris pact. Clearly, much yet remains to be done to soften the future impact of climate change.