Our Last Bulwark: How Effective is Climate Adaptation?

Issue

Nov 21

As headline after headline can attest, the planet continues to warm at an unprecedented rate. Although progress towards effecting positive change seems slow, a recent study shows cause for gentle optimism. Researchers at the Barcelona Institute for Global Health have investigated how Europe has been adapting to the effects of heatwaves and the associated reductions in heat-related mortality. In this article, we explore how climate adaptation has helped safeguard us against the risks of extreme heat and what this means for policymakers.

As every news cycle comes around, it would appear that with it comes some new, record-breaking heat event. Just this summer, the Guardian published a scoop on how at least 15 national temperature records have been set in 2024 alone. Earlier this year, the EU’s Copernicus Climate Change System (C3S) also announced that each of the past 12 months had, on average, consecutively surpassed 1.5ºC of warming (discussed in our previous article). This was one of the first indicators that we may, collectively, be failing in our duties as enshrined within the 2015 Paris Agreement, where national governments committed to try and keep global warming within 1.5ºC of warming and peak greenhouse gas emissions by 2025.

Whilst this should come as no particular surprise, especially to those of us tuned into climate science and environmental politics, it still makes for a challenging read knowing this will translate into yet more record-breaking heatwaves, forest fires, and droughts.

With this in mind, it’s clear that evidence is mounting that our approach as a society to mitigating climate change and limiting emissions are insufficient to keep temperatures within these self-imposed limits. Therefore, the growing perspective is that greater onus must be placed on climate adaptation in order to protect ourselves from the otherwise inevitable hotter summers, greater imbalances in the climatic system, and more frequent extreme weather events.

Yet questions remain regarding the effectiveness and suitability of current climate adaptive methods to combat the effects of climate change, particularly with regards to overheating. Can these measures truly safeguard human health?

Heatwaves and Mortality since 2000

Climate adaptation is the process by which we can adjust ecological, economic, and social factors in order to build greater climate resilience into human systems. However, it is no surprise that, having seen every new heatwave seemingly break either temperature or mortality records, it is fair to ask questions around their effectiveness - over the past decades, we have continued to suffer through annual heatwaves, with death tolls growing year by year. Therefore, with the publication of a recent study in the journal Nature, it was encouraging to see academics tackling this question head on.

Researchers at the Barcelona Institute for Global Health (ISGlobal) recently conducted a study entitled Heat-related mortality in Europe during 2023 and the role of adaptation in protecting health, whereby the team set out to assess the overall mortality rate across Europe during the multiple periods of extreme heat in 2023, which had previously been ranked as the hottest year on record. On top of this, they looked into annual heat exposure over the period 2000-23 to determine the relationship between overheating and mortality rate, in an effort to infer the effectiveness of climate adaptive measures.

Their methodology comprised applying epidemiological models to temperature and mortality records from across 823 contiguous regions from across 35 European countries, allowing them to determine both sex- and age-related excess deaths. This provided them with an estimate of 47,690 heat-related deaths during the year 2023, the majority of which occurred during the interval between May and October. This mortality corresponded to the second highest annual rate in the period 2015-23, following 2022.

The strongest influencing factor in mortality, the study found, was age; comparing the over-80 subpopulation with that in the age range 65-79, the researchers found a 768% increase in deaths in the former group. This is expected, owing to the greater vulnerability of people over 80 years old to heat-related illnesses and those, including cardiovascular issues, that can be exacerbated during periods of extreme heat.

Europe’s Ability to Adapt

Of particular interest to the work we do at Shade the UK, the second portion of ISGlobal’s research consisted of looking into temporal changes from 2000-2023 in heat-related deaths. To achieve this, the team looked into what’s known as ‘cumulative exposure-response associations’. In layperson’s terms, this refers to the number of deaths seen as a ratio to increases in temperature, meaning that if fewer deaths are seen in 2023 than 2000 at the same temperature, then the association is lower.

Generally, this measure can be used as a proxy for socioeconomic development, as well as the kinds of climate adaptive processes that are implemented as a result of this development. This allowed the team to infer the number of deaths that would have been seen should a preceding year have been exposed to the temperatures seen during the most extreme periods of heat in recent decades, namely 2023.

For the preceding periods and regions for which they had available data, across all sex- and age-related categories, the researchers were able to estimate that, if the temperatures seen during the heatwaves of 2023 were extrapolated to the period 2000-2004, the total number of deaths would have been more than 80% higher than 2015-2019, which they used as a reference period. This effect was even more marked in the 80+ population, which would have seen approximately double the number of deaths over this period.

The conclusion from this?

Using this proxy measure to infer the level of climate adaptive change that has taken place over the past 20 years, the researchers showed how present-century adaptation was able to markedly reduce the heat-related mortality burden during the summer of 2023. This safeguarding effect was substantially pronounced within elderly populations.

"Our results show how there have been societal adaptation processes to high temperatures during the present century, which have dramatically reduced the heat-related vulnerability and mortality burden of recent summers, especially among the elderly,” said Elisa Gallo, ISGlobal member and lead author on the research.

Actioning this Data

Evidently, despite the fact that temperatures across the world continue to surge, some of the measures we are implementing to combat the effects of heat have seen some degree of success.

However, it would be foolish to think that this is mission accomplished - despite having prevented huge swathes of deaths across Europe as a result of these measures, almost 50,000 annual deaths is not reason to champion our progress. This is underscored by limitations of the study itself, whereby the researchers have admitted that the use of weekly temperature measures greatly underestimates the total number of deaths; using a bias-correction methodology as a post analysis, the team was able to estimate that the true figure likely corresponds to 58,139 deaths over the course of 2023.

Moving forward, the objective for policymakers should be to utilise this data as a starting point to recognise that adaptation is not only feasible but effective.

Based on the research presented, we at Shade the UK recommend advancing the following projects in order to better defend against future extremes of heat:

Individualise the analysis: Whilst this study goes a long way to determining the positive impacts of climate adaptation in aggregate, it does not analyse the more granular effects of individual climate adaptive policies. Hence, in order to better adapt our society against future heatwaves, we need to understand those measures that are most effective and prioritise their implementation.
Tailor climate adaptive measures: In this analysis, we saw further evidence that those in more elderly age categories are most susceptible to extreme heat. Therefore, measures that disproportionately benefit the elderly must be prioritised, particularly in a climate landscape with limited resources and buy-in, to see the greatest reductions in heat-related deaths.
Localise adaptation: It was also clear that certain regions, particularly those in Southern Europe, are disproportionately impacted by extremes of heat, representing the majority of deaths. Hence, from an international perspective, measures need to be directed at those regions with the greatest level of susceptibility.

To learn more about our work at Shade the UK, please visit our website.