Greenhouse gas levels in atmosphere reach new record
The WMO Greenhouse Gas Bulletin showed that globally averaged concentrations of carbon dioxide (CO2) reached 405.5 parts per million (ppm) in 2017, up from 403.3 ppm in 2016 and 400.1 ppm in 2015. Concentrations of methane and nitrous oxide also rose, whilst there was a resurgence of a potent greenhouse gas and ozone depleting substance called CFC-11, which is regulated under an international agreement to protect the ozone layer.
Since 1990, there has been a 41% increase in total radiative forcing – the warming effect on the climate – by long-lived greenhouse gases. CO2 accounts for about 82% of the increase in radiative forcing over the past decade, according to figures from the US National Oceanic and Atmospheric Administration quoted in the WMO Bulletin. Read more from WMO