Heat, Health, and Habitats: Analyzing the Intersecting Risks of Climate and Demographic Shifts in Austrian Districts

TL;DR

The paper analyzes how heat exposure and population aging combine to affect mortality across Austrian districts, using a district-week panel (2015–2022) with fixed effects. It shows that each additional heat day raises weekly deaths per 1,000 inhabitants by about $0.004$ ($2.4\%$) and that vulnerability is amplified in districts with more residents aged $65+$, while greenness in residential areas measurably mitigates this effect. Forecasts for 2050 under multiple climate scenarios indicate a broad shift toward higher heat-age vulnerability across nearly all districts, though local greening can reduce mortality risks. The work highlights the potential of municipal greening initiatives as a practical adaptation strategy amidst unavoidable climate and demographic trends.

Abstract

The impact of hot weather on health outcomes of a population is mediated by a variety of factors, including its age profile and local green infrastructure. The combination of warming due to climate change and demographic aging suggests that heat-related health outcomes will deteriorate in the coming decades. Here, we measure the relationship between weekly all-cause mortality and heat days in Austrian districts using a panel dataset covering $2015-2022$. An additional day reaching $30$ degrees is associated with a $2.4\%$ increase in mortality per $1000$ inhabitants during summer. This association is roughly doubled in districts with a two standard deviation above average share of the population over $65$. Using forecasts of hot days (RCP) and demographics in $2050$, we observe that districts will have elderly populations and hot days $2-5$ standard deviations above the current mean in just $25$ years. This predicts a drastic increase in heat-related mortality. At the same time, district green scores, measured using $10\times 10$ meter resolution satellite images of residential areas, significantly moderate the relationship between heat and mortality. Thus, although local policies likely cannot reverse warming or demographic trends, they can take measures to mediate the health consequences of these growing risks, which are highly heterogeneous across regions, even in Austria.

Figures (4)

• Figure 1: The marginal effects of additional heat days on mortality in Austrian districts, conditioned on the share of the population above $65$. The marginal impact of an additional heat day on mortality is significantly larger in districts with an older population. Estimates are derived from Model $2$ in Table \ref{['tab:elderly_regs']}, and we report $90\%$ confidence intervals derived from robust standard errors.
• Figure 2: Comparing the greenness of two Austrian municipalities in $2020$, on the left, Eichgraben from Niederösterreich, and on the right, Neudörfl from Burgenland. Both have similar total areas, residential areas, and similar population sizes. However, regarding the greenness of the municipalities using the RGS, Eichgraben has the highest RGS score of all municipalities, while Neudörfl is in the bottom $30\%$ of municipalities ranked by RGS.
• Figure 3: In this figure, we compare the change of the heat-age vulnerability of Austrian districts using mean data over the last $5$ years for the current situation and forecast data for $2050$ under the RCP $4.5$ and RCP $8.5$ scenario.
• Figure 4: In this plot, we made the shift in the number of yearly heat days and the change in population share over $65$ years visible by comparing the mean heat-age vulnerability over the last $5$ years from $2018$ to $2022$ (dots) vs. the projected heat-age vulnerability in $2050$ under the RCP $8.5$ scenario (stars).