Globally averaged concentrations of carbon dioxide, the main man-made greenhouse gas, reached 400.0 parts per million (ppm) in the atmosphere for the first time on record and were 44 percent above levels before the Industrial Revolution, the U.N. World Meteorological Organization (WMO) said on Monday.
The relentless rise contrasts with accords by almost 200 governments to start reining in emissions, led by the Paris Agreement last year to phase out fossil fuels in favour of renewable energy in the second half of the century.
“Bad news I would say that we have exceeded this 400 ppm (parts per million) level of CO2. It was recorded as a critical, critical limit of CO2 concentration and that’s now permanent I think, independent of the seasons and independent of the hemisphere,” WMO Secretary-General Petteri Taalas told a news conference in Geneva.
An observatory at Mauna Loa in Hawaii, the main measuring station with records back to 1958, “predicts that carbon dioxide concentrations will stay above 400 ppm for the whole of 2016 and not dip below that level for many generations,” the WMO said.
“There have been some scientific studies estimating that the return back to pre-industrial levels may take tens of thousands of years and therefore it’s really urgent that we start reducing the emissions of carbon dioxide,” Taalas said.
Carbon dioxide levels will continue rising unless the world stops burning fossil fuels and starts planting trees, said WMO’s atmospheric environment research chief Oksana Tarasova.
Taalas said consequences of climate change, such as weather-related disasters, were set to continue even if emissions start to come down.
Man-made warming is blamed for causing heatwaves, downpours, droughts and rising ocean levels.
Worldwide in 2015, average levels carbon dioxide were at 400.0 ppm, up 2.3 ppm from 2014, the WMO said.
A powerful El Nino weather event, which warms the eastern Pacific Ocean, was also probably driving global rises in 2016. The El Nino is linked with more droughts and wildfires in the tropics, meaning less vegetation to absorb carbon dioxide.
A U.N. panel of climate scientists estimates that concentrations of carbon dioxide, methane and nitrous oxide are at their highest in at least 800,000 years.