Carbon dioxide, the primary greenhouse gas (GhG) responsible for global warming, has become more plentiful in the Earth's atmosphere and saw an increase of 2.87 parts per million in 2018.
This reading at NOAA's Mauna Loa Observatory represents the fourth largest increase in the agency's 60 years of record-keeping. On Jan. 1, 2018, the average concentration of atmospheric CO2 measured 407.05 parts per million (ppm). On Jan. 1, 2019, the average measured 409.92 ppm.
NOAA pointed out that three of the four highest annual increases on record occurred during the last four years or from 2015 to 2018.
The record, however, belongs to 2016. Atmospheric CO2 concentrations in 2016 jumped 3.01 parts per million. The second highest goes to 2015, which saw an increase of 2.98 parts per million. Last year's increase ranks slightly behind 1998's growth of 2.93 parts per million.
But in April 2018, for the first time, CO2 concentration averaged above the 410 parts per million mark for an entire month. Scientists regularly measure the abundance of CO2 in atmospheric samples collected at the Mauna Loa Observatory.
"At a time when there's all this talk about how we should be decreasing CO2 emissions, the amount of CO2 we're putting into the atmosphere is clearly accelerating," said Pieter Tans, a senior scientist with NOAA's global monitoring division. "It's no coincidence that the last four years also had the highest CO2 emissions on record."
Climate scientists agree human sources of CO2 are to blame for the rising concentration of this GHG in the atmosphere.
"Today's rise of CO2 is dominated by human activities," said Tans. "It's not from natural causes."
The United States witnessed is again emitting more CO2 thanks to the anti-climate change policies of the Trump administration. U.S. CO2 emissions rose 3.4 percent in 2018 after leveling-off in the years before Trump came into office, said the Rhodium Group.
