Data
Share of people born in 1960 and 2020 projected to face unprecedented lifetime exposure to heatwaves (Grant et al. 2025)
The share of the people born in 1960 and in 2020 who are projected to live through more heatwaves in their lifetime than all but 1 in 10,000 lifetimes in a pre-industrial climate, along warming pathways that reach 1.5, 2.5 or 3.5 °C by 2100, as Grant and colleagues (2025) state it for the world. It is modelled from the ISIMIP2b climate simulations, and 'unprecedented' is a statistical threshold (beyond the 99.99th percentile of pre-industrial lifetimes), not a count of deaths or of illness. The article gives one value for people born in 1960 whatever the pathway, and no world value for people born in 2020 on the 2.5 °C pathway.
Latest value
52%
World: the 177 countries the article covers, every 0.5° land grid cell, 2025 (projection). Version Nature 641, 374–379 (2025).
As published
“Under a 1.5 °C pathway, 52% of people born in 2020 will experience unprecedented lifetime exposure to heatwaves. If global warming reaches 3.5 °C by 2100, this fraction rises to 92% for heatwaves, 29% for crop failures and 14% for river floods.”
Unprecedented lifetime exposure to climate extremes by birth year (Grant et al. 2025), Abstract; Results, "Unprecedented exposure to heatwaves", second paragraph. Checked word for word against the stored copy of the document every time the data is rebuilt.
Every value
| Birth year | Warming pathway | Period | Value (%) | Status |
|---|---|---|---|---|
| Born in 1960"Unprecedented exposure to heatwaves", second paragraph: "Of the 81 million people born in 1960, on average, around 16% (13 million people) face ULE to heatwaves regardless of the scenario." The article gives this one value for the 1960 cohort on every pathway. | Warming reaching 1.5 °C by 2100"Unprecedented exposure to heatwaves", second paragraph: "Of the 81 million people born in 1960, on average, around 16% (13 million people) face ULE to heatwaves regardless of the scenario." The article gives this one value for the 1960 cohort on every pathway. | 2025 | 16 | projection |
| Born in 1960"Unprecedented exposure to heatwaves", second paragraph: "Of the 81 million people born in 1960, on average, around 16% (13 million people) face ULE to heatwaves regardless of the scenario." The article gives this one value for the 1960 cohort on every pathway. | Warming reaching 2.5 °C by 2100"Unprecedented exposure to heatwaves", second paragraph: "Of the 81 million people born in 1960, on average, around 16% (13 million people) face ULE to heatwaves regardless of the scenario." The article gives this one value for the 1960 cohort on every pathway. | 2025 | 16 | projection |
| Born in 1960"Unprecedented exposure to heatwaves", second paragraph: "Of the 81 million people born in 1960, on average, around 16% (13 million people) face ULE to heatwaves regardless of the scenario." The article gives this one value for the 1960 cohort on every pathway. | Warming reaching 3.5 °C by 2100"Unprecedented exposure to heatwaves", second paragraph: "Of the 81 million people born in 1960, on average, around 16% (13 million people) face ULE to heatwaves regardless of the scenario." The article gives this one value for the 1960 cohort on every pathway. | 2025 | 16 | projection |
| Born in 2020"Unprecedented exposure to heatwaves", second paragraph: "In a 1.5 °C pathway, CFheatwaves stabilizes for recent birth cohorts, reaching an average of 52% for the 2020 birth cohort (62 million people)." Abstract: "Under a 1.5 °C pathway, 52% of people born in 2020 will experience unprecedented lifetime exposure to heatwaves." | Warming reaching 1.5 °C by 2100"Unprecedented exposure to heatwaves", second paragraph: "In a 1.5 °C pathway, CFheatwaves stabilizes for recent birth cohorts, reaching an average of 52% for the 2020 birth cohort (62 million people)." Abstract: "Under a 1.5 °C pathway, 52% of people born in 2020 will experience unprecedented lifetime exposure to heatwaves." | 2025 | 52 | projection |
| Born in 2020 | Warming reaching 2.5 °C by 2100 | 2025 | none (Grant et al. (2025) state no world share for people born in 2020 on the 2.5 °C pathway: the text gives the 1.5 °C and 3.5 °C values only, and Fig. 2a draws the 2.5 °C value as a box plot, which is not read.) | projection |
| Born in 2020"Unprecedented exposure to heatwaves", second paragraph: "Comparatively, CFheatwaves of the 2020 birth cohort is almost doubled in a 3.5 °C pathway, reaching 92%." Abstract: "If global warming reaches 3.5 °C by 2100, this fraction rises to 92% for heatwaves, 29% for crop failures and 14% for river floods." | Warming reaching 3.5 °C by 2100"Unprecedented exposure to heatwaves", second paragraph: "Comparatively, CFheatwaves of the 2020 birth cohort is almost doubled in a 3.5 °C pathway, reaching 92%." Abstract: "If global warming reaches 3.5 °C by 2100, this fraction rises to 92% for heatwaves, 29% for crop failures and 14% for river floods." | 2025 | 92 | projection |
Where it comes from
- Producer
- Luke Grant, Inne Vanderkelen, Lukas Gudmundsson, Erich Fischer, Sonia I. Seneviratne and Wim Thiery (Vrije Universiteit Brussel, Environment and Climate Change Canada, KU Leuven, Royal Meteorological Institute of Belgium and ETH Zurich); published in Nature (Springer Nature) · Unprecedented lifetime exposure to climate extremes by birth year (Grant et al. 2025)
- Version
- Nature 641, 374–379 (2025)
- Fetched
- 2026-10-12 (automatically), 112,126 bytes
- Fingerprint
- sha256 4224ab518159b19d8ca09c2cdc673d6e34ccb24d674c8df6bcca0a53c341ad3c
- Copies
- No Wayback copy recorded yet.Our copy of the exact file
- Cite the producer
- Grant, L., Vanderkelen, I., Gudmundsson, L. et al. Global emergence of unprecedented lifetime exposure to climate extremes. Nature 641, 374–379 (2025). https://doi.org/10.1038/s41586-025-08907-1
What was done to it
Read the article's JATS XML from Europe PMC (sha256 4224ab518159…), checked its DOI and its CC BY 4.0 licence statement, and found in its text the 3 Results sentences and 2 abstract sentences that state the values, and 10 sentences of the Methods and Discussion that the scope relies on.
Code: pipeline/src/envdash/transforms/impacts/grant_2025.py · code sha256 c45a84e85fa0f1d3… · inputs 4224ab518159…
Published 5 world shares exactly as the Results text prints them, each read from the words that state it inside its checked sentence: 16% for people born in 1960, which the article gives 'regardless of the scenario' and which is therefore shown under each of the three pathways, and 52% (1.5 °C) and 92% (3.5 °C) for people born in 2020. The abstract states 52% and 92% again; each was checked to print the same number.
Code: pipeline/src/envdash/transforms/impacts/grant_2025.py · code sha256 c45a84e85fa0f1d3… · inputs 4224ab518159…
Published people born in 2020 on the 2.5 °C pathway as missing, because the text states no world share for it. Nothing was read from a figure or computed, and the numbers of people in the same sentences (13, 62 and 111 million) are not published.
Code: pipeline/src/envdash/transforms/impacts/grant_2025.py · code sha256 c45a84e85fa0f1d3… · inputs 4224ab518159…
What it covers
- Geography
- World: the 177 countries the article covers, every 0.5° land grid cell
- Baseline
- Pre-industrial control climate (lifetimes resampled from pre-industrial simulations); warming levels relative to 1850–1900
- Basis
- Projected (modelled) lifetime exposure. A heatwave is a 3-day extreme heat event expected about once a century in a pre-industrial climate, from four bias-adjusted CMIP5 climate models (ISIMIP2b). A birth cohort in a grid cell faces unprecedented lifetime exposure when its lifetime count passes the 99.99th percentile of pre-industrial lifetimes there; the whole cohort of that cell is then counted. Lifetimes use each country's average life expectancy, with no migration and no adaptation (such as air conditioning). Pathways are constructed from AR6 scenarios; the 1.5 °C pathway peaks at 1.57 °C. The period is the year of publication; each value covers the cohort's whole lifetime.
- Unit
- percent of the people born that year (%)