Due to climate change

More heat deaths than “cold deaths” in Europe in future

While it is currently assumed that there are up to ten "cold deaths" for every heat-related death across Europe, this ratio is likely to change as temperatures rise. A research team has now estimated that under scenarios with high temperatures in European cities, deaths due to heat will dominate in the future.

The effect would be correspondingly strong in the Mediterranean region and Eastern Europe, but Austria could become a kind of "hotspot" in Central Europe.

The aim of the study, led by Pierre Masselot from the London School of Hygiene & Tropical Medicine, was to estimate the number of premature deaths caused by cold and heat across Europe as climate change progresses. By way of classification: excess mortality in connection with cold is by no means only understood as cases in which people freeze to death.

Rather, we are talking about the increase in deaths when temperatures are even slightly lower than the ideal range with a minimum mortality rate of around 20 degrees Celsius. The cooler it is, the higher the incidence of respiratory diseases and the more weakened immune systems are on average.

Higher temperatures meet an ageing population
The team estimated how various climate scenarios could affect 854 urban centers in Europe, taking into account the expected age structure of the local population. If, for example, a strong average rise in temperature occurs in an area with a relatively old population on average, the mortality caused by heat and its effects on the circulatory system increases. At the same time, the tendency towards milder winters reduces cold-related deaths.

While the now very unrealistic climate scenario with a moderate temperature increase of 1.5 degrees Celsius above pre-industrial levels towards the end of the century would result in an average excess of around 6,000 heat-related deaths per year, this figure would rise to just under 70,000 assuming a temperature increase of four degrees, the scientists write in their study. However, the range of variation in these figures is very wide: in the latter scenario, for example, the figures range from 16,000 to 136,000.

Quite a strong effect in Austria under more extreme assumptions
In their argumentation, the authors of the study rely heavily on the socio-economic pathway "SSP3-7.0" from the Intergovernmental Panel on Climate Change (IPCC) Assessment Report. This scenario assumes that greenhouse gas emissions will continue to rise in a world characterized by conflict and nationalism, leading to an increase in temperature of around four degrees at the end of the century. If this is the case and virtually no adaptation measures are taken, there would be an average of around 36,000 fewer cold-related deaths in southern Europe between 2050 and 2054. This would be offset by around 82,000 premature deaths due to heat.

Dramatic effects in Austria
If no countermeasures are taken, there would be an excess of almost 12,000 heat-related deaths in Austria during this period. This means that the negative effects in Austria, similar to Switzerland, southern Germany or Poland, are more pronounced than in other areas of Central Europe. The researchers refer to this as a "Central European hotspot".

Large regional differences
Overall, the calculations of Masselot's team are subject to many uncertainties, as several experts explained to the German Science Media Center (SMC). This can also be seen in the consistently very large fluctuation ranges in the data, which often also allow for net effects in the other direction with more moderate climate assumptions. For the authors of the study, their calculations indicate that heat-related deaths could rise relatively sharply in numerous European conurbations if the increase in temperature is not slowed down or no countermeasures, such as behavioral adaptations or structural measures such as more green spaces in cities or air conditioning systems, are taken. Northern Europe, on the other hand, could also benefit from this.

Despite the major inaccuracies in the results, the study shows "that the number of heat-related deaths in Europe will probably exceed the number of cold-related deaths in the course of this century", Barbara Schumann from Linnaeus University in Kalmar (Sweden) told the SMC. The situation in southern Europe and the large regional differences in the SSP3-7.0 pathway, which is "quite realistic" from today's perspective, are particularly worrying.