Fig 1.

Heatwave days (A) and the change per decade (B) at a spatial resolution of 0.5°×0.5° across the globe per warm season during 1990–2019. The black crosses in Fig 1A represent the 750 locations from the 43 countries or regions used in the first-stage analysis. Only grid cells with at least 1 annual death were included. For each grid cell, heatwaves were defined as at least 2 consecutive days with mean temperatures above the 95th percentile of the year-round daily mean temperatures. $\mathrm{\%}\mathrm{C}\mathrm{h}\mathrm{a}\mathrm{n}\mathrm{g}\mathrm{e}\mathrm{p}\mathrm{e}\mathrm{r}\mathrm{d}\mathrm{e}\mathrm{c}\mathrm{a}\mathrm{d}\mathrm{e}=\frac{\mathrm{C}\mathrm{h}\mathrm{a}\mathrm{n}\mathrm{g}\mathrm{e}\mathrm{p}\mathrm{e}\mathrm{r}\mathrm{d}\mathrm{e}\mathrm{c}\mathrm{a}\mathrm{d}\mathrm{e}}{Themeanvaluein1990-2019}\times 100\%$. Change per decade is calculated using a linear regression. The base layer of the world map was imported from the public domain Natural Earth project (source: https://www.naturalearthdata.com/downloads/; terms of use: www.naturalearthdata.com/about/terms-of-use/). Summarised data at the regional level are provided in S5 Table.