Population density

Key contacts

Summary

At present, only data for the historical period (1850-2025) is available. Data for future scenarios will be added at a later date.

Source IDs for CMIP7 phases

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

DECK

CMIP7

For the DECK simulations in the production phase of CMIP7, use data with the source ID PIK-CMIP-1-0-1

No DOIs are available for this data.

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

No data available for this phase yet.

ScenarioMIP

CMIP7

No data available for this phase yet.

Testing

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

No DOIs are available for this data.

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

Apply the 1850 value as a constant.

Grids and frequencies provided

We provide annual data (1850-2100) on a regular 0.25 (‘gn’) and 0.5 degree (‘gr’) grid. Historical files cover 1850-2025. Future scenario files cover 2022-2100, i.e. include additional historical years for convenience. Please notify the authors if you would need other resolutions for your simulations.

Variables provided

The dataset contains total population (mid-year estimate) per square kilometer of the grid cell area (pop_dens).

Uncertainty

The dataset contains many sources of uncertainty that are difficult to quantify at grid-cell level.

Data

This dataset was created by joint effort of Horizon Europe project COMPASS and project WorldPop. The data was created at high resolution (30 arc seconds, ~1 km) and upscaled to 0.25 and 0.5 degree. The following steps were followed: (1) WorldPop gridded constrained global population data for 2015-2025 were combined with FuturePop projections based on SSP v3.2 trajectories. (2) The WorldPop gridded population was extrapolated back to 1975 using Global Human Settlement Layer (3) Data were further extrapolated back to 1850 using HYDE 3.2 (4) The data were adjusted to match annual national timeseries of population: (a) 1850-1949 from a new compilation of historical population, adjusted to modern country borders made in COMPASS D3.1 (b) 1950-2023 from United Nations World Population Prospects 2024 with minor adjustments made in COMPASS D3.1. (c) 2025-2100 extrapolated from 2020 with gap-filled SSP v3.2 data, and 2024 interpolated between 2023 and 2025. (5) The population counts were converted to population density based on the size of grid-cells converted from their latitude.

Full documentation of the data will be available soon.

Revision history

PIK-CMIP-1-0-0

These datasets used an old version of WorldPop/FuturePop data. PIK-CMIP-1-0-1 uses revised WorldPop/FuturePop data hence supercedes PIK-CMIP-1-0-0. If you have started historical simulations based on PIK-CMIP-1-0-0, please restart and use the updated files. Note that even for PIK-CMIP-1-0-1, HYDE 3.2 is still used as newer data were not obtained. PIK-CMIP-1-0-1 also includes a fix to a bug discovered in the 0.25 degree resolution files in PIK-CMIP-1-0-0 thanks to @slm7826 and @vnaik60 (see #362). The 0.5 degree data was not affected by this bug.