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Research reveals more people died from hot or cold weather conditions than COVID-19 in parts of UK

Image shows a woman sat outside experiencing heatstroke

Press release issued: 23 May 2024

Research has highlighted how weather extremes worsened by climate change are now a major national public health threat.

The study, led by the University of Bristol and published today in Nature Communications, showed how the death toll from temperature hazards overtook the number of deaths from COVID-19 in the South West region of England, when the UK was in the throes of the pandemic.

Lead author Dr Eunice Lo, Research Fellow in Climate Change and Health at the University’s Cabot Institute for the Environment and Elizabeth Blackwell Institute for Health Research, said: “The statistics are stark and illustrate how high the health burden of adverse weather is in the UK in the current climate. I anticipated higher levels of mortality than normal as the country was also experiencing a record heatwave during the peak of the pandemic, but the extent of the increases are surprising and concerning.”

The researchers sprang into action after Sir Patrick Vallance, the UK Government’s former Chief Scientific Adviser, highlighted at COP26 that the climate crisis was a far bigger problem than COVID-19, which would prove more fatal without immediate changes.

Their findings clearly evidence such claims with analysis revealing temperature-related mortality exceeded COVID-19 mortality by 8% in South West England between 2020 and 2022. Temperature-related deaths were also just a quarter less than deaths from COVID-19 in London and not far from a third less (58%) in East Midlands over the same period.

Dr Lo said: “The pandemic rightfully generated huge media attention with the spotlight on daily briefings announcing the latest death toll and public health interventions. Although many, and in some parts of the country more, people were dying from high and low temperatures, this largely went under the radar.

“Ironically the record temperatures, topping 40 degrees, were associated with positive news of people enjoying the sunshine which perhaps reflects a general lack of awareness about how harmful excess heat can be.”

The research highlighted how the coinciding crises presented by COVID-19 coupled with a heatwave or conversely an extreme cold snap put health services under unprecedented pressure, potentially increasing avoidable loss of life.

Findings showed combined excess deaths from extreme temperatures and COVID-19 between 2020 and 2022 were at least twice as high than the previous decade, depending on the region.

Dr Lo said: “The figures strongly demonstrate how negative consequences compound when there are co-occurring major health and weather-related events. For instance, extreme cold during the outbreak of an unexpected disease puts massive strain on hospital bed availability. This research therefore underscores how the UK must be more robustly prepared for such eventualities, which are likely to coincide more often in future with the growing spectre of a changing climate and other global health threats.”

Sir Patrick Vallance discussed whether it was possible to compare the relative health impacts of COVID-19 and climate change with Profs Phil Taylor, Pro Vice-Chancellor for Research and Enterprise and Dann Mitchell, Professor of Climate Science at the University of Bristol at COP26, hosted by Glasgow in 2021.

Prof Mitchell and Dr Lo set to analysing relevant statistics to better understand the comparative health repercussions. They wrote to Sir Patrick sharing the findings and were invited to present them at the Natural History Museum.

Co-author Prof Dann Mitchell said: “Climate change is not just an environmental issue; it is a constant, underlying stressor that magnifies the impacts of other global crises, including pandemics, wars, and economic instability. Our research highlights that during the peak of the COVID-19 pandemic, the compound effects of extreme temperatures led to significant mortality burdens in the UK.

“This was likely much larger in other, less developed countries. Our evidence illustrates how climate change can intersect with and exacerbates other crises, creating a multiplier effect that can strain health systems, destabilise economies, and heighten social tensions. To mitigate these compounded risks, it is imperative to integrate climate resilience into global health, economic, and security policies.”


‘Compound mortality impacts from extreme temperatures and COVID-19 pandemic’ by Y.T. Eunice Lo, Dann Mitchell, and Antonio Gasparrini in Nature Communications

Further information

About the Cabot Institute for the Environment

The Cabot Institute for the Environment works with academics, students, and research partners, as well as local and international communities, governments and individuals, to help solve the biggest global environmental challenges. Its mission is to provide knowledge, evidence, education, and solutions that protect our environment and identify better ways to live within our changing planet.

About Elizabeth Blackwell Institute  

The Elizabeth Blackwell Institute drives innovation in research to improve health for all. It nurtures interdisciplinary research to address the complex health challenges facing us today. 

The institute focuses on: 

  • Supporting the next generation of health researchers
  • Connecting people to develop interdisciplinary research
  • Including everyone in research so the research can benefit all.

Elizabeth Blackwell Institute for health research and the Cabot Institute for the Environment, at the University of Bristol, are working together to improve our knowledge of the impacts of climate change on our health. The Climate Change and Health research programme brings together experts from different fields of science to understand and address the complex and interwoven areas of climate and health. Together we can find solutions for a healthier future…for us and the planet.

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