Fossil Fuel CO₂ Emissions for the OCO2 Model Intercomparison Project (MIP)

These are fossil CO₂ fluxes updated through November 2025 for atmospheric CO₂ modeling. They were constructed primarily to be used for the OCO2 Model Intercomparison Project (MIP).

• For 2000-2023, they're based on ODIAC 2024, which in turn uses BP's energy use statistics for 2022 and 2023.
• ODIAC monthly emissions have been disaggregated to hourly using the TIMES emission factors for day of week and time of day (https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2012JD018196).
• For 2024 onwards, ODIAC's 2023 emissions have been scaled by the ratio of that month to 2023 emissions reported by Carbon Monitor, downloaded on February 23, 2026 from https://carbonmonitor.org/.
  • ODIAC does not have sectoral decomposition to the degree provided by Carbon Monitor, so total ODIAC emissions for each region have been scaled by the total emission change between 2023 and each extended year reported by Carbon Monitor, i.e., power, ground transport, etc. have not been separately scaled.
  • Carbon Monitor data are daily, but ODIAC emissions are monthly. So Carbon Monitor data have been aggregated to monthly totals before deriving scaling factors between 2023 and the extended years.
  • Carbon Monitor reports international aviation emissions by country of origin, while ODIAC reports aviation emissions on a grid. Since there is no way to derive the points of emission for Carbon Monitor aviation emissions , all Carbon Monitor international aviation was aggregated to create a single number for each month, then  that number was used to scale ODIAC's bunker fuel for each month in 2024-2025.
  • CarbonMonitor data used for deriving 2024 and later emissions are now included in this dataset for convenience as netcdf files (converted from original CSV files).
• Hourly global totals are given in the files as a check, in case you want to verify your units and file reading.

These files can be downloaded from the browser, or from the command line following guides such as this.