Global 1-km Gridded Age-Stratified Population Projections (SSP2, 2021–2100)

We implement the approach of Falchetta et al. (2024) [1] to produce global, 1-km, gridded, age-stratified population projections under the SSP2 scenario. Age strata start at 0–4 years and then advance in 5-year intervals up to 80+. Projections are generated at 5-year steps for 2025–2100 and, combined with the WorldPop 2020 1-km age-structured baseline, are linearly interpolated to obtain year-by-year projections from 2021 to 2100. The dataset is approximately 4.4 TB and is distributed as .tar-compressed files. After extraction, filenames follow the convention SSP2_[age-span]_[year]_1km.nc. The dataset is freely accessible via Purdue Fortress long-term archive through Globus (link). After clicking the link, users may be prompted to log in with a Purdue institutional Globus account. You can switch to your institutional account, or log in via a personal Globus ID, Gmail, GitHub handle, or ORCID ID. Alternatively, the dataset can be accessed by searching for the universally unique identifier (UUID)—"10ca372d-e0ae-4f93-a955-bf010918b4e0" in Globus. We couple these projections with empirically derived, age-specific heat-compensability limits [2–4] to estimate future exposure to uncompensable heat stress under global warming. The related manuscript, Age-related vulnerability greatly amplifies the risk of uncompensable heat, has been submitted to Nature; we will update the citation when available (preprint forthcoming). Please refer to Falchetta et al. (2024) and our manuscript for full methodological details and validation. References:[1] Falchetta G, De Cian E, Sue Wing I, Carr D. Global projections of heat exposure of older adults. Nat Commun. 2024 May 14;15(1):3678.[2] Tony Wolf S, Cottle RM, Fisher KG, Vecellio DJ, Larry Kenney W. Heat stress vulnerability and critical environmental limits for older adults. Commun Earth Environ. 2023 Dec 18;4(1):486.[3] Wolf ST, Cottle RM, Vecellio DJ, Kenney WL. Critical environmental limits for young, healthy adults (PSU HEAT Project). Journal of Applied Physiology. 2022 Feb 1;132(2):327–33.[4] Cottle RM, Fisher KG, Leach OK, Wolf ST, Kenney WL. Critical environmental core temperature limits and heart rate thresholds across the adult age span (PSU HEAT Project). Journal of Applied Physiology. 2024 July 1;137(1):145–53.