Washington, Dec. 6 -- After several years of little growth, global emissions of heat-trapping carbon dioxide experienced their largest jump in seven years, discouraging scientists.

World carbon dioxide emissions are estimated to have risen 2.7 percent from 2017 to 2018, according to three studies released Wednesday from the Global Carbon Project, an international scientific collaboration of academics, governments and industry that tracks greenhouse gas emissions. The calculations, announced during negotiations to put the 2015 Paris climate accord into effect, puts some of the landmark agreement's goals nearly out of reach, scientists said.

"This is terrible news," said Andrew Jones, co-director of Climate Interactive, which models green...