Humans have been pumping carbon dioxide into the atmosphere for more than a century, but a recent analysis reveals that the increase over the past year has exceeded scientists’ predictions. According to a report from EarthSky, a study published in the journal Nature Climate Change reveals that 2016 will be the first year on record with atmospheric CO2 concentrations of more than 400 parts per million all year-round.

Researchers from the University of Exeter showed that El Niño, a seasonal weather pattern, is behind the record-breaking jump in CO2 levels. The scientists say that even if carbon emissions from manmade sources were discontinued entirely, the levels of the gas in the atmosphere will remain above 400 parts per million for at least one human lifetime.

According to Richard Betts, the study’s lead author, “The atmospheric carbon dioxide concentration is rising year-on-year due to human emissions, but this year is getting an extra boost due to the recent El Niño event – changes in the sea-surface temperature of the tropical Pacific Ocean. This warms and dries tropical ecosystems, reducing their uptake of carbon, and exacerbating forest fires.”

Betts explains that continued emissions have exacerbated El Niño’s effects on climate patterns, allowing for more carbon dioxide to remain in the atmosphere instead of being sequestered by natural processes. “Since human emissions are now 25 percent greater than in the last big El Niño in 1997-98,” he said, “this all adds up to a record CO2 rise this year.”

Vegetation is one of the best carbon sinks on the planet – as trees and algae around the world convert the sun’s energy into usable sugars, an enormous amount of carbon dioxide is sucked out of the air to aid the process. This is extremely gradual, however, and scientists warn that continued carbon emissions are allowing the gas to build up faster than it can be removed from the atmosphere.

A press release from the University of Exeter describing the details of the study can be found here.