The 2015 Lancet Commission on Health and Climate Change highlighted that action against climate change was possibly “the greatest global health opportunity of the 21st century”.

How does climate change impact health?

 Temperature-related deaths and illnesses – High temperatures have substantial adverse effects on mortality and morbidity. In a study published in the Journal of Epidemiology and Community Health, researchers forecast the number of annual preventable deaths caused by hotter weather to increase by 257 percent over the next 40 years, in the UK. The elderly population are at highest risk, as was evident from the large proportion of elderly people from the 70,000 victims of the 2003 European heat wave. With an ageing population, the UK has a lot to be concerned about.

Air quality – Increasing concentrations of CO2 in the air stimulate growth of plants that release aeroallergens, which compromise our respiratory and cardiovascular systems. Also, ground-level ozone (O3) pollution is predicted to increase, which has been linked to acute respiratory symptoms and premature deaths. Wildfires are becoming increasingly common, resulting in harmful fine particles and ozone precursors released into our air. Greater pollen concentrations and prolonged pollen seasons can instigate allergic sensitization and asthma attacks.

Vector-borne diseases – Extreme temperatures and changing precipitation patterns affect the seasonality, distribution and occurrence of vector-borne diseases. Changes in temperature will alter distribution and abundance of mosquitoes; human exposure to infectious bites may be worsened, therefore we should not rule out possible re-establishment of indigenous malaria in the UK. It is difficult to say how the abundance of ticks will be affected in the UK, but it is likely that the risk of human exposure to these will increase due to changing uses of land for agricultural and recreational purposes. Emergence of new vector-borne pathogens would mean that we will have to take greater personal protective measures.

Water-related illness – The UK has good water and sanitation infrastructure and management, however, rising temperatures could promote growth of harmful algae, which produce freshwater- and marine-toxins. Whether or not this translates inro waterborne illnesses will be dependent on human behaviour and social determinants. The UK has seen a rise in occurrence of flooding, causing damage to water infrastructure systems; exposure to pathogens and chemicals in drinking water could occur where treatment barriers break down.

Food safety and nutrition – Increasing concentrations of CO2 fuel growth and carbohydrate production in some plants, but can also reduce the levels of protein and important minerals in several crops of common consumption, including wheat, rice, and potatoes. Inevitably, this would have harmful implications for human nutrition. Climate change also renders food vulnerable to certain new pathogens and toxins, possibly translating to foodborne illnesses. Additionally, there will greater likelihood of chemical contaminants in the food chain; higher sea surface temperatures result in higher levels of mercury in seafood.

UV radiation – The depleting ozone layer is allowing more and more ultraviolet rays to penetrate to the earth’s surface, resulting in more cases of skin cancer. Epidemiological studies have also demonstrated a correlation between cortical cataract incidence and UV exposure.

Mental health and wellbeing – Weather-related disasters can have severe mental health consequences, including post-traumatic stress disorder, depression and anxiety. People relying on the natural environment for sustenance and livelihood are at higher risk for negative mental health outcomes. Mental illness often goes hand in hand with physical illness.

Is it too late?

Not yet. Global health could be vastly improved if nations worked together to limit the currently escalating changes in our climate.

Is climate change the biggest threat to global health? Possibly. Thus far, few resources have been allocated to research on health impacts of climate changes and consequently, few countries have conducted reviews of this growing crisis. The World Health Organisation has stated that surveillance for climate-sensitive diseases needs to be prioritised, which will facilitate understanding of relationships between climate and disease.

While we wait for decision makers to take action, we could be take our health into our own hands. For more information on simple changes that can be implemented into our daily lives to make a global impact, please visit:


Zainab graduated from University College London with a degree in Biomedical Sciences. She has a keen interest in Global Health, particularly in providing women and girls with equal access to healthcare.

The opinions expressed by Bloggers and those providing comments are theirs alone, and do not reflect the opinions of the Selfless. Selfless is not responsible for the accuracy of any of the information supplied by Bloggers.


Is climate change the single biggest threat to human health?

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