January 2018 continued record-breaking growth of CO2 in the atmosphere
6 February, 2018
2 February 2018 (RealClimate) – Based on NOAA’s ESRL “Trends in Atmospheric Carbon Dioxide” data, in particular “Mauna Loa CO2 monthly mean data”.
January 2018 continues the record-breaking growth of CO2 in the atmosphere.
Current estimates for the January monthly mean are ~408 ppm – another Record-Making High for January has been set (once the final figures are published.)
408 ppm is +1.18 higher than last month (December 2017), and is +1.87 above the previous record high for January of 406.13 ppm (January 2017).
408 ppm is +22.45 higher than a decade ago when CO2 was only 385.52 ppm in January 2008.
This indicates an average growth rate of +2.25 ppm per year for the month of January.
This means that the 2017-2018 growth rate of +1.87/yr is -0.38 (or 16.9%) below the January average. This is not a significant deviation from the long term trend.
In fact, it represents a recent short-term annual Growth Rate of +2.67 PPM for January in the last 3 years, which is significantly higher than the decadal growth rate of +2.25 per year (above).
The lowest increase of CO2 from one month to the next is typically January to February. On average February is only 0.86 ppm higher than January.
This means that next month’s Average Mean is likely to be about 409 ppm – still a new Record High for February. Therefore Record Weekly Mean averages near or above 410 ppm may occur this month.
The all-time Record Weekly Mean is 410.36 ppm in May, 2017. The only Month CO2 concentration has been above 410 ppm for millions and millions of years.
January’s 408 ppm is the 4th highest Monthly Mean CO2 PPM in the instrumental record – behind April-May-June 2017.
January 2018 is the 8th time the Monthly Mean CO2 PPM has been above 407 ppm.
January 2018 is the 14th time the Monthly Mean CO2 PPM has been above 405 ppm.
2015 was the last time the January Monthly Mean CO2 PPM Reading was below 400 ppm. [By RealClimate commenter, “Thomas”. –Des]