In response to a reader question on news of a slowdown in the rate of CO2 emissions rise, Scripps Institution of Oceanography, UC San Diego, geochemist Ralph Keeling said the following:

“Over the past year, atmospheric CO2 has risen at near record rates.  Decade by decade, the atmospheric rise rate has closely tracked the long-term growth in fossil-fuel emission.  But year by year, the rise rate has deviated from that trend, with more rapid increases some years and slower increases in others.  These fluctuations can be chalked up mainly to changes in forest growth or other processes in land ecosystems.  Most years, land ecosystems absorb some of the excess CO2 from fossil-fuel emissions, but there are large fluctuations in the absorption from year to year.  Last year was evidently a year of low land uptake, which when combined with record fossil-fuel emissions, led to the near-record increase.”