A new study from the University of Oxford has found that climate change is responsible for at least 1,700 heat-related deaths in Zürich since 1969. The research, titled 'Refining methods for attributing health impacts to climate change: a heat-mortality case study in Zürich,' was conducted by Dr Rupert Stuart-Smith and colleagues at the Smith School of Enterprise and the Environment.
The study highlights that while extreme heatwaves are often linked to higher mortality rates, many deaths occur on milder days when temperatures exceed local health thresholds. According to Dr Stuart-Smith, "We find that heat-related deaths were already occurring as a result of climate change as early as 1969, but that the numbers of heat-related deaths have increased substantially over time, and despite improvements in our resilience to heat."
Since 2004, measures such as improved access to cooling systems, better healthcare services, and increased public awareness have prevented about 700 deaths. However, the overall number of fatalities continues to rise due to increasing global temperatures. Dr Stuart-Smith stated: "Our results point to the potential effectiveness of climate adaptation measures. However, more people are dying than ever before because of climate change which is pushing temperatures ever higher. The best way to avoid these deaths in future remains rapid and sustained emission reductions, delivered by quickly moving away from fossil fuels and animal agriculture."
The research also found that focusing solely on heatwaves does not capture the full impact of human-induced climate change on mortality rates. "Analyses that focus on heatwaves alone do not capture the full effect of human-induced climate change on heat-related deaths," said Dr Stuart-Smith.
Additionally, emissions from six major investor- and state-owned companies worldwide were linked with at least one additional death per summer in Zürich since 2004. The authors suggest similar outcomes would likely be observed elsewhere.
A preprint version of this study was referenced by the European Court of Human Rights (ECtHR) during its decision in KlimaSeniorinnen v Switzerland. It supported the court's finding that adaptation measures alone are not enough; reducing emissions is necessary for Switzerland to meet its obligations under the European Convention on Human Rights.
The full study can be read in Climatic Change.