What has climate change got to do with health?


London ambulance cycles make it easier to reach patients in built up areas, and have the added benefit of being lower in carbon emissions.

Dr. James Smith

I work as a public health doctor trying to protect and promote health by helping with the fight against worsening climate change.  This means I have to spend a lot of time explaining why on earth a doctor would see climate change as a health issue and why I would voluntarily move from sitting in a GP’s surgery directly helping people with their illnesses big and small to the confusing world of science and policy which is public health and why having done this I would choose to focus on an environmental problem.

I didn’t start off wanting to work on climate change. But climate change is one of those things that the more you learn about it the more important you realise it is. So much of what we expect of the future including our health depends on a stable climate.

Public health is a specialty which focuses on understanding and solving health problems at the scale of the population rather than the individual. Preventing problems before they happen is a central goal of public health, influencing those things which determine our health. This might mean trying to increase levels of physical activity or promoting healthier diets because we know these things reduce the risks of diseases such as heart disease to cancer.

But why climate change?  Well three reasons really. Firstly climate change threatens health in many ways. Understanding the health threat can help motivate much greater climate action. Secondly health is affected, potentially in a wonderfully good way, by all the changes we need to make to address climate change and thirdly the healthcare and public health system has a big environmental footprint itself.

Climate change threatens health

In 2009 the Lancet, one of the leading global medical journals published their Commission on Climate Change with the headline ‘The biggest global health threat of the 21st century’.(1) Earlier this year the Director General of the World Health Organisation described climate change as the defining issue of our time. This is from someone who has to deal with problems like Ebola and HIV.

Health is affected by climate change directly through changing weather patterns such as more heatwaves or floods. The latter particularly are associated with mental health as well as physical health risks.  In the UK if we stay on our current path heatwaves could become much more common with the UK Climate Change Committee stating that half our summers could be like 2003 by 2050.(2) Health is also affected less directly but just as seriously by changes to patterns of infectious diseases and impacts on food and water supply, economic impacts or even risk of conflict and war. Rather scarily the US military have described climate change as a ‘threat multiplier’.(3) One reason that the global impacts of climate change sit so uneasily with me as a doctor is the idea drilled into us in medical school that we should ‘first do no harm’ so when I read that children in the developing world are expected to die from malnutrition because of climate change I don’t feel happy about my contribution to this and want to change something.

Climate action benefits health

Eating less meat could be good for you and

Eating less meat. Good for us and the environment?

But the good news is that there are a multitude of potential benefits to health from making the changes we need to avoid the worst of climate change. Currently air pollution is associated with harms to health equivalent to thousands of deaths annually in the UK.(4) A large part of this is from motor vehicles so a shift to dramatically more walking, cycling and electrified public transport and cars could significantly reduce this. A change to less red and processed meat across the UK would lower rates of colorectal cancer, heart disease and diabetes and save a large amount of greenhouse gas emissions (by one estimate more than the whole carbon footprint of the NHS in England if we all ate the same low level consumed by a fifth of people already).(5) There are huge potential opportunities to create jobs and support the most deprived communities through a large scale transition to renewable energy and better insulated (and ventilated) homes. As health is closely associated with employment and poverty these could also improve health.

Recently the UK Faculty of Public Health, the professional body for public health experts in the UK, has presented a manifesto of the 12 national policy changes they recommend in anticipation of the next general election. As you might expect these include efforts to reduce smoking and alcohol abuse but perhaps surprisingly for those unaware of the above ‘co-benefits’ to health they also see climate change as a health issue and recommend tackling it by promotion of active transport (walking and cycling) and shifting to a zero carbon energy system.

The NHS has an important role

The NHS, public health and (adult) social care system in England has a carbon footprint of approximately 32 million tonnes of carbon dioxide equivalent.(6) A particularly large fraction of this is from all the medicines we use so reducing wastage of these is really important. Fortunately the NHS has recognised its impact and is working to lower its footprint, with the work led by a dedicated Sustainable Development Unit. The doctors are joining in with this by looking at how different specialties such as renal medicine and even psychiatry can reduce their footprint.

As an aside, most asthma inhalers are metered dose inhalers which use hydrofluorocarbon gas as a propellant to deliver the active ingredient. These ‘HFCs’ replaced CFCs a few years ago and are highly potent greenhouse gases giving them a very high footprint.(7) This shouldn’t stop you using your inhaler for your breathing as needed but please don’t do wasteful test squirts into the air, recycle them if the option is available locally and perhaps ask your doctor or pharmacist if there is a dry powder option which could work for you.

Not just a doctor

So being a doctor has helped me see climate change as not just an environmental issue but as a human one. In many ways this makes it far more scary. It’s no longer just about a bit more heat or rain. It’s about people’s lives, about disease, suffering and death. But I’m not just a doctor I’m also a dad and husband. It’s scary to think of this world we are creating for my children. Thankfully being a doctor has also helped me see that while the changes we need to make are big they can be really positive creating stronger healthier communities for my children to grow up in. Won’t it be great when my children have clean air to breathe?

Understanding this issue as one which is centrally about human health and wellbeing helps us rethink climate change so we see climate action as an opportunity for creating better lives for ourselves and our children. Seen in this light the future low carbon world becomes something, not to agonise over, but to rush towards optimistic in the opportunities it holds.

James Smith
Dr James Smith is a Cambridge based public health doctor who works independently to protect and improve health by fighting climate change. He has previously worked for Public Health England and the NHS Sustainable Development Unit on the issue of climate change. He can be found on Twitter @drjnsmith and has a blog at www.drjnsmith.com 


Further reading: 

 1. Costello A, Abbas M, Allen A, Ball S, Bell S, Bellamy R, et al. Managing the health effects of climate change. The Lancet. 2009;373(9676):1693-733.
2. Managing climate risks to wellbeing and the economy. Adaptation Subcommittee Report. Committee on Climate Change, 2014.
3. Quadrennial Defense Review 2014. Department of Defense United States of America, 2014.
4. The Mortality Effects of Long Term Exposure to Particulate Air Pollution in the United Kingdom. Committee on the Medical Effects of Air Pollution, 2010.
5. Aston LM, Smith JN, Powles JW. Impact of a reduced red and processed meat dietary pattern on disease risks and greenhouse gas emissions in the UK: a modelling study. BMJ Open. 2012;2(5).
6. Sustainable Development Strategy for the NHS, Public Health and Social Care. Public Health England / NHS England, 2014.
7. Hillman T, Mortimer F, Hopkinson NS. Inhaled drugs and global warming: time to shift to dry powder inhalers2013 2013-05-28 14:23:45.



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