Atmospheric levels of carbon dioxide have passed a critical scientific juncture from 2015 and are likely to stay above it for “generations,” a meteorological group reported Monday.
Average carbon dioxide levels in the atmosphere hit 400 parts per million for the first time in 2015, the World Meteorological Organization (WMO) reported Monday. The WMO, the climate arm of the United Nations, predicted that figure will grow significantly in 2016.
Because it takes carbon dioxide centuries to completely dissipate from the atmosphere, the group says the concentration of the globe-warming gas will remain above 400 parts per million for “generations.”
“The year 2015 ushered in a new era of optimism and climate action with the Paris climate change agreement," WMO Secretary-General Petteri Taalas said in a statement. “But it will also make history as marking a new era of climate change reality with record high greenhouse gas concentrations.”
The 400 parts per million mark is symbolic — it is the first time in millions of years that the earth has seen that figure — and practical, since some scientists have warned carbon levels need to be significantly lower to avoid the worst of climate change.
The WMO’s report concludes that carbon levels rose in 2015 due to a strong El Niño and its negative impact on ecosystems that traditionally absorb the gas.
But human activity has contributed as well. Between 1990 and 2015, the group said, there was was a 37 percent increase in the warming effect on the climate from industrial, agricultural and domestic greenhouse gas emissions.
The WMO urged quick action on the Paris climate deal, which aims to reduce carbon emissions worldwide.
“Without tackling CO2 emissions, we can not tackle climate change and keep temperature increases to below 2 degrees Celsius above the pre-industrial era,” Taalas said. “It is therefore of the utmost importance that the Paris Agreement does indeed enter into force well ahead of schedule on 4 November and that we fast-track its implementation.”