Carbon dioxide levels highest in 3 million years
The concentration of carbon dioxide in the atmosphere hit 415.39 parts per million (ppm) over the weekend — the highest level seen in some 3 million years, before humans existed, according to scientists at the Mauna Loa Observatory in Hawaii. CO2 levels are now rising 3 ppm each year, up from an average 2.5 ppm over the last decade.
On May 14, the daily concentration of carbon dioxide in the atmosphere hit the highest level ever recorded in human history, at 415 parts per million.
The last time the Earth experienced a comparable concentration of CO2 was between three million and five million years ago, according to experts from the World Meteorological Organisation.
The globally-averaged carbon dioxide concentration reached 407.8 parts per million in 2018, up from the 405.5 parts per million in 2017. Based on current emissions, scientists estimate CO2 levels could hit 500 ppm in as little as 30 years.
CO2 – which is emitted when we burn fossil fuels like coal, oil and natural gas – is a greenhouse gas which traps heat in the earth’s atmosphere, contributing to the global temperature increases which drives climate change.
Carbon dioxide is not the only gas on the rise. Methane is the second most important long-lived greenhouse gas. According to the WMO, atmospheric methane reached a new high of about 1869 parts per billion (ppb) in 2018 and is now 259 percent of the pre-industrial level. Levels of nitrous oxide are 123 percent of pre-industrial levels. The rise of all three gases shows we are in deep trouble.
It’s estimated that about 60 percent of methane emissions come from human activities, such as from landfills, cattle breeding and certain types of agriculture, while the other 40 percent comes from natural sources.
Nitrous oxide, which is emitted from agricultural and industrial activities, is the third-most potent greenhouse gas and depletes the ozone layer that shields the planet from the sun’s ultraviolet radiation.
Atmospheric concentrations of nitrous oxide — a chemical compound commonly known as laughing gas — in 2018 reached an average of 331.1 parts per billion, which was a 123 percent increase over pre-industrial levels.
The WMO report was released ahead of the United Nations Framework Convention on Climate Change conference, which is being held Dec. 2 to 13 in Madrid.
