Have carbon emissions peaked?

Global anthropogenic carbon emissions grew only slightly in 2014 and 2015, and only a small increase is expected for 2016, according to an analysis released 14 November during the United Nations Framework Convention on Climate Change in Marrakech , Morocco. The total rise of less than 1% for those three years contrasts with a 2.3% average annual increase in emissions seen between 2003 and 2013. And the slowdown happened despite a global economic growth rate of around 3% a year.

“This third year of almost no growth in emissions is unprecedented at a time of strong economic growth,” said analysis lead author Corinne Le Quéré (University of East Anglia, UK) in a statement. “This is a great help for tackling climate change, but it is not enough. Global emissions now need to decrease rapidly, not just stop growing.” Whether emissions growth will recur in the next few years depends on whether energy and climate policies from Marrakech take hold, added report coauthor Glen Peters from the Center for International Climate and Environmental Research–Oslo in Norway.

Despite the progress in curbing emissions, humans still emitted a record 36.3 gigatons of carbon dioxide in 2015, a 60% increase from 1990. And the concentration of CO₂ in the atmosphere continues to rise at record or near-record levels. The unrelenting increase is due to the recent strong El Niño event, which led to high temperatures and dry conditions that diminished the amount of CO₂ absorbed by trees, Le Quéré said. The recent onset of La Niña should slow the rate of CO₂ buildup.

The report says that 2016 will be the first full year in which global CO₂ concentration will be measured at or above 400 ppm. The preindustrial concentration was 277 ppm.

China is by far the world’s largest carbon emitter, accounting for 29% of the world’s annual output. But the surge in Chinese emissions that began around 2000 topped off in 2013, and output has since declined slightly as coal use decreased, the report shows. The US, which produces 15% of global emissions, saw a 2.6% falloff in 2015, and a further 1.7% decline is expected this year. That decrease is also due to less coal combustion, the report says.

The European Union’s carbon emissions, which make up 10% of the global total, increased 1.4% last year to end a decline that began in the mid 2000s. And India’s emissions, 6% of the total, jumped 5% in 2015.

On a per capita basis, the US remained by far the biggest emitter in 2015, at 16.8 metric tons of CO₂ per person per year. China is second at 7.5 tons per person annually, followed by the EU at 7 tons and India at 1.7 tons.