For the first time since people started tracking carbon dioxide in the earth’s atmosphere, the global average concentration of CO2 has surpassed 400 parts per million for an entire month.
Says Pieter Tans, lead scientist of NOAA’s Global Greenhouse Gas Reference Network, about the record carbon dioxide level:
“It was only a matter of time that we would average 400 parts per million globally. We first reported 400 ppm when all of our Arctic sites reached that value in the spring of 2012. In 2013 the record at NOAA’s Mauna Loa Observatory first crossed the 400 ppm threshold. Reaching 400 parts per million as a global average is a significant milestone.”
“This marks the fact that humans burning fossil fuels have caused global carbon dioxide concentrations to rise more than 120 parts per million since pre-industrial times. Half of that rise has occurred since 1980.”
NOAA bases its global carbon dioxide numbers on air samples taken from 40 sites around the world. The samples then ship for analysis to NOAA’s Earth System Research Laboratory in Boulder, Colorado. The lab issues monthly concentration numbers after processing these global results.
Ed Dlugokencky, the scientist who manages the global network, says that NOAA selects particular sites “because the atmosphere itself serves to average out gas concentrations that are being affected by human and natural forces. At these remote sites we get a better global average.”
The NOAA March report also prompted this prediction from Dlugokencky:
“The global average will remain above 400 ppm through May, the time of year when global carbon dioxide concentrations peak due to natural cycles on top of the persistent rising greenhouse gases. Decaying plant matter and soil organisms give off carbon dioxide gas all year long, but the dormant period in plant growth allows the respiration of carbon dioxide to dominate during those months. Carbon dioxide levels drop back down as plants begin to bloom,
using carbon dioxide for photosynthesis in late spring and summer.”
NOAA’s latest results confirm that carbon dioxide is increasing 100 times faster in the age of humans than it has in natural rises in the past. James Butler, director of NOAA’s Global Monitoring Division, adds that it would be difficult to reverse the increases of greenhouse gases which are driving increased atmospheric temperatures. “Elimination of about 80% of fossil fuel emissions would essentially stop the rise in carbon dioxide in the atmosphere, but concentrations of carbon dioxide would not start decreasing until even further reductions are made, and then it would only do so slowly.”
In an interesting sidelight, the International Energy Agency reported a few weeks ago that global emissions from fossil fuel energy use had stayed at the same levels last year as in 2013. However, despite the cackling of climate change deniers at this finding, annual variations are virtually meaningless against the total climate picture. Note that NOAA data show that carbon dioxide concentrations actually grew from 2012 to 2014 by 2.25 ppm per year, the greatest amount ever recorded over three consecutive years.