The concentration of carbon dioxide in the atmosphere is increasing more than expected due to less-efficient use of fossil fuels, and carbon sinks that are absorbing less carbon, according to research published in the Proceedings of the National Academy of Sciences. Overall, “atmospheric carbon dioxide growth has increased 35 percent faster than expected since 2000,” said the British Antarctic Survey, a group involved in the research. The report said that changes in carbon levels “characterize a carbon cycle that is generating stronger-than-expected and sooner-than-expected climate forcing.” In lay terms, that means many climate models may be off the mark since only the most gloomy have forecasted less-efficient carbon sinks in the present. The effect of the weakening sinks alone could translate into an increase in the global average temperature of 2.7 degrees Fahrenheit by 2100, according to study coauthor Corinne Le Quere. Le Quere said it’s not clear precisely where the sinks are weakening, except in the Southern Ocean. A separate study of the North Atlantic Ocean to be published in the Journal of Geophysical Research next month also suggests the world’s oceans may be sequestering far less carbon dioxide than previously thought.