Heat Exposure and Mortality in Aotearoa New Zealand: A Time-Stratified Case-Crossover Study

Siyi Lu, Ilan Noy and Daithi Stone

No 12549, CESifo Working Paper Series from CESifo

Abstract: Extreme heat is increasing in frequency and intensity, with disproportionate risks for clinically and socially vulnerable groups. This paper identifies the relationship between acute heat and mortality in Aotearoa New Zealand. To estimate same-day heat-mortality associations, we link weather-station observation data to national administrative mortality records for all deceased individuals. Both wet bulb globe temperature (WBGT) and air temperature (daily mean, maximum, minimum) were used to estimate same-day effects using time-stratified case-crossover models with month×weekday strata for four samples: all-cause or only non-injury mortality, and full year or only warm season mortality. We additionally examine discrete exposure bins, distributed lag non-linear curves (lags 0–7), and heterogeneity by location, sex, and age. Across daily summaries, the mean series of both variables yields the largest effect: over the full year, all-cause mortality rises by 0.44% per +1 °C for WBGT (mean) versus 0.39% per +1 °C for Temperature (mean). Similar results are identified for non-injury mortality. Warm season effects are larger: all-cause mortality increases by about 0.57% per 1 °C in mean WBGT, versus 0.51% per 1 °C in mean air temperature. Across samples, WBGT estimates are generally larger than temperature-only measures. A simple scaling using average death counts suggests that a uniform +1 °C increase in mean WBGT would correspond to approximately 140 additional all-cause deaths and 110 non-injury deaths per year, and about 85 and 70 extra deaths per warm season, respectively.

Keywords: extreme heat; Wet-Bulb temperature; mortality risk; time-stratified case-crossover (search for similar items in EconPapers)
JEL-codes: I10 Q54 (search for similar items in EconPapers)
Date: 2026
New Economics Papers: this item is included in nep-hea
References: Add references at CitEc
Citations:

Downloads: (external link)
https://www.ifo.de/DocDL/cesifo1_wp12549.pdf (application/pdf)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:ces:ceswps:_12549

Access Statistics for this paper

More papers in CESifo Working Paper Series from CESifo Contact information at EDIRC.
Bibliographic data for series maintained by Klaus Wohlrabe ().