Geneva, 25 November 2019 - Levels of heat-trapping greenhouse gases in the atmosphere have reached another new record high, according to the World Meteorological Organization. This continuing long-term trend means that future generations will be confronted with increasingly severe impacts of climate change, including rising temperatures, more extreme weather, water stress, sea-level rise and disruption to marine and land ecosystems.
The WMO Greenhouse Gas Bulletin showed that globally averaged concentrations of carbon dioxide (CO2) reached 407.8 parts per million in 2018, up from 405.5 parts per million (ppm) in 2017.
The increase in CO2 from 2017 to 2018 was very close to that observed from 2016 to 2017 and just above the average over the last decade. Global levels of CO2 crossed the symbolic and significant 400 parts per million benchmark in 2015.
CO2 remains in the atmosphere for centuries and in the oceans for even longer.
Concentrations of methane and nitrous oxide also surged by higher amounts than during the past decade, according to observations from the Global Atmosphere Watch network which includes stations in the remote Arctic, mountain areas and tropical islands.
Since 1990, there has been a 43% increase in total radiative forcing – the warming effect on the climate - by long-lived greenhouse gases. CO2 accounts for about 80% of this, according to figures from the US National Oceanic and Atmospheric Administration quoted in the WMO Bulletin.
“There is no sign of a slowdown, let alone a decline, in greenhouse gases concentration in the atmosphere despite all the commitments under the Paris Agreement on Climate Change,» said WMO Secretary-General Petteri Taalas. “We need to translate the commitments into action and increase the level of ambition for the sake of the future welfare of mankind,” he said.
“It is worth recalling that the last time the Earth experienced a comparable concentration of CO2 was 3-5 million years ago. Back then, the temperature was 2-3°C warmer, sea level was 10-20 meters higher than now,” said Mr. Taalas.
For further details, see a WMO Bulletin here.