The Intersection Between Climate Change and Cancer

By Laura Kalitsis – Publications Project Manager

Laura explores the nexus between climate change and cancer and the necessary solutions to protect the health of humans and the planet.

Climate change is a pressing global threat, marked by rising global temperatures, shifting climatic patterns, and an increase in the frequency and severity of extreme weather events. These climatic changes have significant adverse effects on human health and well-being, impacting individuals through various exposure pathways, often exacerbating existing vulnerabilities and systemic inequities. These health impacts include injuries, fatalities, mental health consequences, heat-related illnesses, respiratory conditions, cardiovascular diseases, foodborne and waterborne diseases, vector-borne diseases, and social disruptions caused by conflict, forced migration, and displacement.

However, when discussing the connection between climate change and health, the specific intersection between climate change and cancer often receives less attention. This article aims to draw attention to this intersection and highlight how addressing climate change can serve as a form of cancer prevention and control. It will elucidate the mechanisms through which climate change may affect cancer risk, incidence, and care and discuss how climate change mitigation and adaptation strategies can be beneficial for human health.

The Impact of Climate Change on Cancer

Air Pollution and Lung Cancer

Lung cancer is the leading cause of cancer-related deaths globally, responsible for 2.2 million new cancer cases and 1.9 million cancer-related deaths in 2017. While tobacco consumption remains the primary cause of lung cancer, air pollution is increasingly becoming a significant threat that also contributes to climate change. Activities like fossil fuel combustion, extensive vehicle use, land management, and urban development release pollutants into the atmosphere, degrading air quality. Air pollutants are now recognised as carcinogenic, with approximately 43% of global lung cancer deaths attributed to air pollution. Carcinogenic pollutants include sulphur dioxide, nitrogen dioxide, ozone, particulate matter (PM¹⁰ and PM^2.5), as well as substances like formaldehyde, benzene, and polyaromatic hydrocarbons that adhere to PM^2.5. Additionally, climate change can worsen air quality by increasing the risk of bushfires, which produce smoke containing high concentrations of PM^2.5 and carcinogenic compounds. 

Ultraviolet Radiation and Skin Cancer

Ultraviolet radiation is a well-established cause of skin cancer, particularly melanoma. Depletion of the ozone layer, partly due to the use of ozone-depleting substances, has likely increased ultraviolet radiation exposure and skin cancer incidence. Whilst the Montreal Protocol introduced in the 1980s has prevented further ozone layer depletion, progress is slow in restoring the ultraviolet radiation absorption abilities of the ozone layer. Moreover, as temperatures rise, human behaviours will likely change, affecting ultraviolet radiation exposure. Warmer temperatures may lead to more outdoor activities and the wearing of less protective clothing and therefore, increased ultraviolet radiation exposure, however, excessively high temperatures could have the opposite effect as more people seek shelter indoors. Thus, it is evident that interactions between climate change, ultraviolet radiation exposure, and skin cancer are complex and challenging to predict.

Food Production, Nutrition, and Cancer

Climate change negatively impacts agricultural production and the quality of food available globally. Warming temperatures, droughts, storms, and sea-level rise affect food production and crop yields. Elevated ambient carbon dioxide levels reduce the protein and micronutrient content in staple grain crops, potentially putting communities at risk of inadequate nutrition. Ocean acidification and rising sea temperatures may reduce aquaculture productivity, leading to decreased fish consumption and a reduction in omega-3 fatty acids, which offer protection against some cancers. The exact impacts of climate change on nutrition and diet-related cancers are challenging to quantify. However, research predicts that climate-related changes in food production and reduced fruit and vegetable consumption could lead to 534,000 climate-related deaths globally by 2050, including deaths due to cancer caused by changes in food production and reduced fruit and vegetable intake.

Disruptions to Cancer Care

Cancer care is a complex and integrated system that encompasses various healthcare delivery services. Any disruption to healthcare delivery services can jeopardise cancer care, leading to adverse impacts on patient outcomes and survivorship. Extreme weather events and disasters, including bushfires, storms, and floods, can damage healthcare infrastructure, reduce the availability and access to cancer diagnosis and treatment services, lead to staff shortages, and disrupt power, transport, supply chains, and communications. Disruptions to cancer care can result in delayed treatment, poorer prognoses, and adverse mental health impacts on patients. With climate change increasing the frequency and severity of extreme weather events, ensuring the continuity of cancer care is vital.

What are the Solutions?

Climate Change Mitigation

Efforts to reduce carbon emissions are crucial to mitigate climate change and protect human health. Decreasing the use of carbon-emitting transportation, such as road vehicles, and promoting modes of active transport, like walking and cycling, can reduce air pollution, lower exposure to harmful components of air pollution, and prevent health issues like lung and respiratory cancer, respiratory infections, and asthma. Encouraging active transport also promotes physical activity and healthy lifestyles, which can aid in preventing cancer and risk factors associated with cancer. 

The healthcare sector’s contribution to carbon emissions cannot be overlooked when addressing emissions reduction. Hospitals and the pharmaceutical industry are major sources of emissions within the healthcare sector. Implementing solutions like the use of renewable energy sources, improving energy efficiency, prioritising low-carbon pharmaceuticals, and minimising medical and food waste can help reduce emissions from cancer care. Furthermore, telehealth and fewer in-person visits can decrease emissions associated with patient travel.

Climate Change Adaptation

Adaptation measures should be implemented to reduce exposure to carcinogens that are produced or intensified by climate change. For example, public health education and awareness campaigns can promote sun safety and protection against ultraviolet radiation. Additionally, in communities prone to bushfires, centralised clean-air shelters can reduce exposure to smoke and poor air quality. Moreover, healthcare systems must be strengthened to ensure that they can provide continuous cancer care, adapt to changes in disease burden, and address the underlying social determinants of cancer that will be exacerbated in a changing climate.