GENEVA, 24 October (BelTA - Xinhua) - Globally averaged concentration of carbon dioxide (CO2)in the atmosphere reached the symbolic milestone of 400 parts per million for the first time in 2015 and surged again to new records in 2016 on the back of the powerful El Nino event, according to a report released by the World Meteorological Organization(WMO) here on Monday.
WMO released its annual "Greenhouse Gas Bulletin" ahead of the United Nations climate change negotiations in Marrakech, Morocco, to be held from November 7 to 18, providing a scientific base for decision-making.
The report said CO2 levels had previously reached the 400 ppm barrier for certain months of the year and in certain locations but never before on a global average basis for the entire year. Monitoring systems predict that CO2 concentrations will stay above 400 ppm for the whole of 2016 and not dip below that level for many generations.
The growth spurt in CO2 was fueled by the El Nino event, which started in 2015 and had a strong impact well into 2016. This triggered droughts in tropical regions and reduced the capacity of "sinks" like forests, vegetation and the oceans to absorb CO2.
These sinks currently absorb about half of CO2 emissions but there is a risk that they may become saturated, which would increase the fraction of emitted carbon dioxide staying in the atmosphere, according to the report.
"The year 2015 ushered in a new era of optimism and climate action with the Paris climate change agreement. But it will also make history as marking a new era of climate change reality with record high greenhouse gas concentrations,"said WMO Secretary-General Petteri Taalas."The El Nino event has disappeared. Climate change has not."
The report highlighted there was a 37 percent increase in radiative forcing - the warming effect on our climate - because of long-lived greenhouse gases such as carbon dioxide, methane and nitrous oxide (N2O) from industrial, agricultural and domestic activities between 1990 and 2015.
In 2015, globally averaged CO2 levels were 144 percent of pre-industrial levels. In 2015, global annual average concentration of CO2 concentrations reached 400.0 ppm. The increase of CO2 from 2014 to 2015 was larger than the previous year and the average over the previous 10 years.
