Modeling of Atmospheric Carbon Dioxide (CO₂) Concentrations as a Function of Fossil-Fuel and Land-Use Change CO₂ Emissions Coupled with Oceanic and Terrestrial Sequestration

• Main Author: John P. O’Connor
• Format: Article
• Language: English
• Published: MDPI AG 2020-05-01
• Series: Climate
• Subjects: CO2 emissions; CO2 concentrations; atmospheric fraction
• Online Access: https://www.mdpi.com/2225-1154/8/5/61

In this work, a semi-empirical relationship of carbon dioxide emissions with atmospheric CO₂ concentrations has been developed that is capable of closely replicating observations from 1751 to 2018. The analysis was completed using data from fossil-fuel-based and land-use change based CO₂ emissions, both singly and together. Evaluation of emissions data from 1750 to 1890 yields a linear CO₂ concentration component that may be attributed to the net flux from land-use changes combined with a rapidly varying component of the terrestrial sink. This linear component is then coupled across the full-time period with a CO₂ concentration calculation using fossil-fuel combustion/cement production emissions with a single, fixed fossil-fuel combustion airborne fraction [AF_FF] value that is determined by the ocean sink coupled with the remaining slowly varying component of the land sink. The analysis of the data shows that AF_FF has remained constant at 51.3% over the past 268 years. However, considering the broad range of variables including emission and sink processes influencing the climate, it may not be expected that a single value for AF_FFwould accurately reproduce the measured changes in CO₂ concentrations during the industrial era.