Climate Change

Climate Change

Climate Change 150 150 Endeavour Medical

Climate Change


Climate change is the most pressing global health threat predicted to alter the lives of everyone on Earth in the next 10 to 30 years [1]. Soaring temperatures, and the vast array of environmental changes that follow, impact all of the social and economic determinants of health: drinking water, clean air, food resources and housing, amongst many others. Low to middle income countries (LMICs) are experiencing the first wave of these effects with increasingly extreme weather fronts, food and vector borne diseases, and gaps in supply chains. It is estimated that there will be an extra 250,000 deaths per year from 2030 to 2050 [1], and a 540% increase in premature deaths due to global warming [1], placing increased stress on health services.

As the sea and air temperatures rise, disease patterns are set to change, and so will the patients we expect to see in our hospitals. Moreover, hospitals will require more energy to maintain an environment suitable to care for patients in, as well as weather threatening our ability to provide care at all. The first example of this was seen in the UK in 2020, as Whipps Cross hospital in north London saw its first flood, forcing evacuation and diversion of services to nearby hospitals.

Climate Change : how the global warming affects on Health

Global temperatures have already risen by 0.6 degrees since the 1950s and there is evidence of acceleration of this, with sea levels rising an average of 10-20cm and rising sea temperatures. This causes soil degradation, loss of agricultural produce, reduced biodiversity, ecosystem breakdown, and ultimately depletion of the protective ozone layer. Human health is intimately connected with these factors as extreme weather events become more frequent with temperature rises: in the long term water resources shrink, pollution rises, and habitats favourable to vector-borne diseases grow in prevalence. People in LMICs and low-lying land are first to see these effects [2].

Extreme weather has both direct and indirect effects. Immediately, there is the disruption caused, including floods, droughts, high risk of contaminated water supplies, and loss of crops and livestock, the impact of which may be felt worldwide. Psychological impacts are complex and many-fold, including post-traumatic stress disorder, with a rising incidence of 30-40% after acute weather events [3]. Excess mortality occurs with heatwaves, especially in countries with colder climates [4]. 

The climate is intimately connected to infectious diseases, with more water pollution following floods and warmer water better for bacterial growth [5]. Rising temperatures speeds tick reproduction cycles and has been theoretically linked to increasing incidence of tick-borne encephalitis [6]. Vector-borne diseases are another example of where LMIC populations face the brunt of global warming, as associated mortality is 300 times greater than in higher income countries [7].

Healthcare’s Carbon Footprint: Time for Change

Not only must we manage the results of climate change, healthcare is also responsible for 5-10% of all emissions globally. This is predominantly due to medicines and medical equipment, but also to our use of resources.  As a single example, annually we use 1.5 million trees in GP discharge summaries in the NHS [8]. There are simple things that can be done well, and consistently, to reduce our carbon footprint, for example a shift to electronic discharge summaries and letters. This will allow us to meet the 2040 NHS net zero target and better adhere to the guiding medical principle of ‘Do No Harm’, which underscores the green agenda.

Some specialities have made more headway than others. Anaesthetics has examined the global warming potential (GWP) of the gases it uses in daily procedures [9]. With CO2 as a comparison, with a GWP of 1, the relative environmental impact of desflurane is highlighted,  with a GWP 2540 (meaning 1g of desflurane is equivalent to 2540g CO2 [10]), compared to isoflurane (GWP 510), sevoflurane (130) and nitrous oxide (265) [11]. Subsequently, there has been a shift towards total intravenous anaesthesia due to the high carbon burden of inhaled anaesthetic gases [12]. 

Similarly, nephrology acknowledges that the footprint of its speciality is also extremely high, with specific reference to haemodialysis [12]. It is estimated that in a 4-hour dialysis session 500l of water is consumed, in addition to the power needed, waste generated, and medical equipment necessary [13]. Extreme heat affects renal patients disproportionately, due to decreased renal reserve to manage dehydration, and a rise in chronic kidney disease expected to come in the next few years [13], so there is reason to invest in more environmentally-friendly options. A number of renal departments have been involved with the Green Ward competition across the UK, working on utilising wastewater from dialysis, better disposal of waste, and promoting home dialysis [14]. Grassroots changes are being seen across hospitals, but they cannot happen soon enough.

Development of sustainable Quality Improvement Frameworks (QAFs) is making it much easier to measure the impact of everything from an appendicectomy to the running of a psychiatric ward. These QAFs inform policy-makers and heads of departments about which parts of the daily running of a hospital have the highest carbon footprint, and allow consideration of changes accordingly. The NHS supply chains are being asked to change their products to comply with the 2040 net zero target, with all suppliers expected to produce a carbon reduction plan by April 2024 [15]. These top-down changes must be matched by cultural changes within hospitals to ensure the profession as a whole complies with the green agenda. Simple changes such as minimising unnecessary glove and cannula use, low carbon transport to and from hospitals, and promotion of low meat meals for patients have been shown to make enormous savings [16]. Single-use pieces of equipment have little to evidence of superiority over their predecessors, and re-establishing sterilisation techniques is likely to provide both environmental and economical benefits [17].

Take home messages

Climate change is the biggest, most rapidly growing threat to health on Earth.

In healthcare we are faced with managing the victims of rising global temperatures but are also a major contributor. We can anticipate a wealth of changes for our patients and in the way we work due to global warming, and the best we can do is be on the front foot: being prepared to act proactively to change our practice to be as sustainable as possible as early as we can.

Are you interested in learning more about global health?

If so, why not check out our Global Health and Conservation course? Whilst you’re there, why don’t you take a look at our other expedition medicine courses too?


  1. WHO, (2021), Climate Change and health, [online] Available at: https://www.who.int/news-room/fact-sheets/detail/climate-change-and-health
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6679631/ 
  3. Solow AR. Global warming: A call for peace on climate and conflict. Nature. 2013;497:179–80.
  4. A Walinski, J Sander, G Gerlinger, V Clemens, A Meyer-Lindenberg, A Heinz, (2023), The Effects of Climate Change on Mental Health. Available via: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10154789/
  5. Bezirtzoglou C, Dekas K, Charvalos E. Climate changes, environment and infection: facts, scenarios and growing awareness from the public health community within Europe. Anaerobe. 2011;17:337–40.
  6. Zeman P, Bene C. A tick-borne encephalitis ceiling in central Europe has moved upwards during the last 30 years: possible impact of global warming? Int J Med Microbiol. 2004;293
  7. Rossati A. Global warming and its health impact. Int J Occup Environ Med 2017;8:7-20
  8. Suffolk & North East Essex Integrated Care System (2021), Can Do Health & Care, [online] Available at: https://sneeics.org.uk/resources/flipbooks/thinking-differently-together-march-2021/ 
  9. F McGain, J Muret, C Lawson, J D Sherman, (2020) Sustainability in anaesthesia and critical care, BR J Anaes. [online]. Available via: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7421303/
  10. Sulbaek Andersen M.P., Nielsen O.J., Karpichev B., Wallington T.J., Sander S.P. Atmospheric chemistry of isoflurane, desflurane, and sevoflurane: kinetics and mechanisms of reactions with chlorine atoms and OH radicals and global warming potentials. J Phys Chem A. 2011;116:5806–5820. 
  11. Sherman J., Le C., Lamers V., Eckelman M. Life cycle greenhouse gas emissions of anesthetic drugs. Anesth Analg. 2012;114:1086–1090.
  12. Barraclough KA, Agar JWM. Green nephrology. Nat Rev Nephrol. 2020;16(5):257–68.
  13. S Cheng Yeo, X Yan Ooi, T S Mun Tan, (2022), Sustainable kidney care delivery and climate change- a call to action. [online]. Available via: https://globalizationandhealth.biomedcentral.com/articles/10.1186/s12992-022-00867-9
  14. GreenTeam competition 2018, Royal Devon & Exeter hospital, Centre for Sustainable Healthcare, [online]. Available via: https://sustainablehealthcare.org.uk/sites/default/files/26th_february_ob_final_devon_green_ward_competition_evaluation_2018.pd
  15. NHS Suppliers, Greener NHS website. [accessed 20/07/23] Available via: https://www.england.nhs.uk/greenernhs/get-involved/suppliers/
  16. E Mahase, Sixty seconds on…gloves off (2019), BMJ, [online]. Available at: https://www.bmj.com/content/366/bmj.l4498.long
  17. V Pegna, S A McNally, (2021), Are single use items the biggest scam of the century?, The Bulletin of the Royal College of Surgeons of England, [online]. Available via: https://publishing.rcseng.ac.uk/doi/10.1308/rcsbull.2021.89

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