CO2 Budget Model Update Through 2022: Humans Keep Emitting, Nature Keeps Removing

by Roy Spencer, Apr 14, 2023 in WUWT

This is an update of my CO2 budget model that explains yearly Mauna Loa atmospheric CO2 concentrations since 1959 with three main processes:

  1. an anthropogenic source term, primarily from burning of fossil fuels
  2. a constant yearly CO2 sink (removal) rate of 2.05% of the atmospheric “excess” over 295 ppm
  3. an ENSO term that increases atmospheric CO2 during El Nino years and decreases it during La Nina years

The CO2 Budget Model

I described the CO2 budget model here. The most important new insight gained was that the model showed that the CO2 sink rate has not been declining as has been claimed by carbon cycle modelers after one adjusts for the history of El Nino and La Nina activity.

If the sink rate was really declining, that means the climate system is becoming less able to remove “excess” CO2 from the atmosphere, and future climate change will be (of course) worse than we thought. But I showed the declining sink rate was just an artifact of the history of El Nino and La Nina activity, as shown in the following figure (updated through 2022).