Anthropogenic short-lived climate forcer (SLCF) and CO2 emissions

Key contacts

Summary

CEDS data is available. Emissions data are provided for SO2, NOx, BC, OC, NH3, NMVOC, CO, CO2 from 1750 - 2023. Emissions data for CH4 and N2O are provided from 1970 - 2023 (although extensions back to 1750 are available in the “supplemental” source ID).

When handling this data, solid biofuel emissions and speciated NMVOCs have the suffix “-supplemental” added to their source ID to avoid inadvertent double counting.

For documentation of the underlying data, please keep an eye on https://github.com/JGCRI/CEDS, which will be updated with more documentation soon.

This data is derived from CEDS’ aggregate emissions releases.

Full details on the dataset and all relevant links can be found on the CEDS GitHub page.

Source IDs for CMIP7 phases

The source ID that identifies the dataset to use in CMIP7 is given below.

CMIP7

For the CMIP7 phase of CMIP7, you will need data from the following source IDs:

Retrieving and only using valid data will require some care. Please make sure you read the guidance given at the start of the Summary section and process the data carefully.

This data is for use in CMIP7 production simulations. All data sets for use in CMIP7 production simulations are published with a mip_era metadata value of ‘CMIP7’. This metadata value appears both in the file’s global metadata as well as its metadata on ESGF.

If you find an issue, please create an issue on GitHub so that the identification and resolution of this issue is publicly accessible.

Testing

For the testing phase of CMIP7, you will need data from the following source IDs:

Retrieving and only using valid data will require some care. Please make sure you read the guidance given at the start of the Summary section and process the data carefully.

This data is for testing (both of the forcing data and of modelling workflows) only. Production simulations should not be started based on any data that has a mip_era value equal to ‘CMIP6Plus’. (The mip_era metadata value appears both in each file’s global attributes as well as its metadata on ESGF.)

If you have any feedback, please add it to the relevant GitHub discussion.

Recommendation for pre-industrial control

Repeat the 1850 values.

Grids and frequencies provided

CEDS emissions are provided at monthly resolution, on a 0.5 degree grid, with 50-years per data file. (A 0.1° grid for recent decades is also available.) Emissions are relatively smooth over the early portion of this time period, but annual data is supplied for consistency across the dataset. The files are in netcdf v4 (HDFv5) format with CF-compliant and ESGF-compliant metadata.

Gridded aircraft emissions are also supplied in a separate file with 25 vertical layers (using the CMIP5 historical emissions Lamarque et al. 2010, as drawn from Lee et al., as a template). Note that aircraft emissions are zero in early years, but files are provided for all years for consistency.

The gridded emissions incorporate a monthly seasonal cycle by sector drawing largely from the ECLIPSE project, Carbon Tracker, and EDGAR.

VOC speciation is provided at the 23 species resolution from EDGAR.

Variables provided

Subsequent CEDS data releases since August 2016 are in a format of one variable per data file, with the sectors included as a dimension of the variable’s data.

The sectors in the netCDF files (other than aviation) are:

Sector Description
0: AGR Non-combustion agricultural sector
1: ENE Energy transformation and extraction
2: IND Industrial combustion and processes
3: TRA Surface Transportation (Road, Rail, Other)
4: RCO Residential, commercial, and other
5: SLV Solvents
6: WST Waste disposal and handling
7: SHP International shipping (including VOCs from oil tanker loading/leakage)

Within the netCDF files the sector ids are:

sector:ids = "0: Agriculture; 1: Energy; 2: Industrial; 3: Transportation; 4: Residential, Commercial, Other; 5: Solvents production and application; 6: Waste; 7: International Shipping" ;

Supplementary Data

For use in setting aerosol size distribution and additional speciation (if desired), an auxiliary dataset providing emissions from solid biomass combustion is also provided. Note that these are a subset of emissions in the main files. These data, therefore, should NOT be added to the emissions in the main files. (Note that no data files for CO2 emissions from solid biomass are released, as CO2 emissions from CEDS are from fossil fuels only.)

Gridding Methodology

Emissions were first estimated at the level of country, sector, and fuel. Emissions by sector were then mapped to spatial grids by country and sector (several intermediate gridded sectors were combined to form the final release sectors for CMIP7). Grid cells that contain more than one country can have portions of emissions from each country.

For recent decades, emissions were mapped to the grid level largely using the distribution of emissions from EDGAR within each country and gridding sector (usually using year-specific EDGAR grids from 1970 forward). For some sectors, the emissions distribution varies over time, while for other sectors it was held constant. For most emission species, residential combustion is the dominant source by 1850, so emissions from the RCO sector were distributed using HYDE population distributions by 1900 (with blended spatial distributions between 1900 and 1970). For other sectors the emissions distribution within each country was held fixed before 1970.

Because of the simplifying assumptions, emissions distributions, particularly in earlier years, should not be taken literally. Overall, however, anthropogenic emissions become small relative to either natural sources or mid-to-late 20th century emissions so we anticipate that these assumptions are not likely to have major impacts on global or regional modeling results.

In this release, large SO2 point sources, along with any co-emitted species, are explicitly represented

More details on the use of point sources in gridding methodology can be found here.

For more details on the gridding methodology see: Feng, L., Smith, S. J., Braun, C., Crippa, M., Gidden, M. J., Hoesly, R., Klimont, Z., van Marle, M., van den Berg, M., and van der Werf, G. R.: The generation of gridded emissions data for CMIP6, Geosci. Model Dev., 13, 461–482, https://doi.org/10.5194/gmd-13-461-2020, 2020.

For more details on the underlying emissions data see: Hoesly, R. M., Smith, S. J., Feng, L., Klimont, Z., Janssens-Maenhout, G., Pitkanen, T., Seibert, J. J., Vu, L., Andres, R. J., Bolt, R. M., Bond, T. C., Dawidowski, L., Kholod, N., Kurokawa, J.-I., Li, M., Liu, L., Lu, Z., Moura, M. C. P., O’Rourke, P. R., and Zhang, Q. (2018) Historical (1750–2014) anthropogenic emissions of reactive gases and aerosols from the Community Emissions Data System (CEDS), Geosci. Model Dev., 11, 369-408. doi: 10.5194/gmd-11-369-2018.

Uncertainty

At present, uncertainties are not quantified. Uncertainties in recent years (most recent 2-3 years) are higher due to delays in reporting data and common revision of data point in recent years (as documented here). Uncertainties farther back in time are also higher, especially the spatial distribution. However, the importance of anthropogenic emissions compared to natural sources also become less significant in these early years. In between (roughly between 1970 and 5 years before now) the uncertainties can be smaller.

Examples of working with the data

See the CEDS GitHub page. The emission harmonization team’s notebooks may also be of interest.

File formats and naming

The file formats are identical to CMIP6.

Emissions Data file name format

Bulk gridded emissions:

Gridded aircraft emissions:

Supplemental emissions Data file name format

Gridded biomass emissions:

VOC speciation grids:

There is a separate README file with further information on VOC speciation – see the CEDS project web site. Note there is a variable naming inconsistency for these file - described in the VOC README.

Revision history

CEDS-CMIP-2025-03-18-supplemental

A bug was found in gridding of data for 2022 and 2023. This does not affect any other values, so this version could still be used for piControl and historical simulations if they have already been started. If not, we recommend updating to the next version for consistency.

CEDS-CMIP-2025-03-18

A bug was found in gridding of data for 2022 and 2023. This does not affect any other values, so this version could still be used for piControl and historical simulations if they have already been started. If not, we recommend updating to the next version for consistency.

CEDS-CMIP-2024-11-25-supplemental

A number of updates have been made in CEDS-CMIP-2025-03-18*. These are significantly different from this dataset, hence it has been retracted.

CEDS-CMIP-2024-11-25

A number of updates have been made in CEDS-CMIP-2025-03-18*. These are significantly different from this dataset, hence it has been retracted.

CEDS-CMIP-2024-10-21-supplemental

A number of updates have been made in CEDS-CMIP-2025-03-18*. These are significantly different from this dataset, hence it has been retracted.