[LINK] O/t: Climate change temperature related deaths

[Stephen Loosley]

Heat disproportionately kills young people:

Evidence from wet-bulb temperature in Mexico

By Andrew J. Wilson
Science Advances 6 Dec 2024 Vol 10, Issue 49
https://www.science.org/doi/10.1126/sciadv.adq3367

Abstract

Recent studies project that temperature-related mortality will be the 
largest source of damage from climate change, with particular concern 
for the elderly whom it is believed bear the largest heat-related 
mortality risk.

We study heat and mortality in Mexico, a country that exhibits a unique 
combination of universal mortality microdata and among the most extreme 
levels of humid heat.

Combining detailed measurements of wet-bulb temperature with 
age-specific mortality data, we find that younger people who are 
particularly vulnerable to heat:

People under 35 years old account for 75% of recent heat-related deaths 
and 87% of heat-related lost life years, while those 50 and older 
account for 96% of cold-related deaths and 80% of cold-related lost life 
years.

We develop high-resolution projections of humid heat and associated 
mortality and find that under the end-of-century emissions scenario, 
temperature-related deaths shift from older to younger people.

Deaths among under-35-year-olds increase 32% while decreasing by 33% 
among other age groups.

INTRODUCTION

Historically, temperature exposure has caused a large number of 
premature deaths.

Heat-related mortality is expected to increase under climate change.

As the evidence base has grown, multiple studies have found that the 
elderly are especially vulnerable to heat. Furthermore, many other 
studies have expressed particular concern for joint heat and humidity 
extremes, given the importance of perspiration for human thermoregulation.

In this study, we explore the relationship between humid heat and 
mortality in Mexico, a country that exhibits a unique combination of 
rich, age-specific, universal mortality microdata and among the most 
extreme historical humid heat exposures.

We find that historically, the majority of heat-related mortality in 
Mexico has been concentrated among younger people: 75% of heat-related 
deaths and 87% of heat-related lost life years occur among those under 
35 years old.

By contrast, the vast majority of cold-related mortality is concentrated 
among older people: 98% of cold-related deaths and 90% of cold-related 
lost life years occur among those over 35, with the majority of 
cold-related deaths occurring among individuals older than 70 years.

We then develop projections of humid heat and associated outcomes to 
assess the future implications of these findings. As in other studies, 
we find that climate change is expected to increase heat-related 
mortality while decreasing cold-related mortality.

However, we uncover an important source of future climate-driven 
inequality: The disproportionate impact of heat and cold across age 
groups reallocates the temperature-related mortality burden from the 
elderly (who are more affected by cold) to the young (who are more 
affected by heat).

This has important implications for understanding the distributional 
impacts of climate change and for developing effective policies to adapt 
to these impacts. (snip)

Discussion (snip)

.. Last, our conclusions further underscore the importance of ethical 
choices around monetizing the cost of premature deaths. We find that 
climate change is expected to shift the mortality burden away from older 
individuals (more affected by cold) to younger individuals (more 
affected by heat).

Thus, the choice of whether to value life years, where premature deaths 
among younger individuals are considered more costly than premature 
deaths among old individuals, or to value all premature deaths the same 
becomes especially important.

Although we do not take a stance on this difficult ethical choice, our 
findings further emphasize the importance of this debate for evaluations 
of the impact of climate change, given that we are finding that climate 
change is expected to shift the temperature-related mortality burden 
toward the young.


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