In December, 2018, NOAA/ESRL reported global carbon dioxide at 409.36 ppm, or 2.83 ppm above December, 2017. That annual change was the highest since those associated with the 2015-2016 El Nino, when the world experienced increases above 3 ppm for 12 consecutive months.
This month continues the unbroken CO2 concentration rise observed at Mauna Loa since 1959, then globally since 1980.
Five and Ten Year Increases
When December, 2018 is compared to 2013, global carbon dioxide has increased 12.71 ppm, the highest five year change since July, 2017 when we experienced a five year increase of 13.09 ppm.
The last three months have experienced a decadal change above 23 ppm, with December having the highest at 23.32 ppm. The five and ten year rates continue trends which reflect ever increasing global emissions at increasing rates of change.
The world is on track to pass 410 ppm in 2019. It is possible this will be reached in February, quite probable in March, and almost certain in April, 2019. It is also probable that the global concentration will exceed 411 ppm in April or May 2019, given historical changes of 2+ ppm between December and April/May in recent previous years.
Of greater concern is reaching 10 ppm increases in shorter times. If we pass 410 ppm in March, 2019, it will be only 48 months after passing 400 ppm in March, 2015. To increase from 320 to 330 ppm took 12 years (May 1960 to May 1972). We are now blowing through these 10 ppm milestones in 1/3 the time.
The Future Trend?
If we stabilize carbon dioxide concentration increases for each future 10 ppm at 48 months, the planet will experience a doubling of CO2 compared to pre-industrial by 2080 and over 610 ppm by 2100. However, given that emissions are not slowing, combined with potential environmental system feedbacks, we may reach 560 ppm sooner, with less ability to influence the trend with decreasing emissions. More on this in another post.