How climate change disrupts cancer services and threatens progress

Climate change threatens past and future progress in cancer control. Dr Leticia Nogueira of the American Cancer Society explains how, with substantial overlap between climate and cancer hazards, the cancer community is well-positioned to act on both.

In the past decades, we have made substantial strides in cancer prevention, treatment, and care. Through advances in cancer prevention, early detection, treatment, and survivorship care, we substantially reduced the cancer burden worldwide. Now, this amazing progress, as well as the potential for future progress, are all endangered by the greatest threat to human health of our time.

Climate change threatens each step of the cancer control continuum, and its effects are already measurable – no future projections needed.

The most visible way in which climate change impacts cancer control is through disruptions in access to cancer care. During extreme weather events (e.g., floods, hurricanes, wildfires) access to healthcare facilities is frequently impeded due to impassible roads or evacuation orders.

Facilities may also lose power, shift towards prioritising emergency services, and change staff assignments, all of which can result in oncology care appointments being cancelled. Among patients diagnosed with aggressive tumors, even short disruptions in access to radiation therapy, for example, can result in worse mortality.

Extreme weather events have been around forever, which is how communities have been able to develop disaster preparedness plans. With climate change, however, extreme weather events are behaving differently.

As a result, communities and healthcare systems are impacted by increasingly unpredictable circumstances, which complicate disaster preparedness and response efforts. For example, warmer air holds more water vapor, which increases the water capacity of storms, resulting in catastrophic rainfall. The far-reaching consequences of anomalous downpours and subsequent floods was seen around the globe in 2024.

Further, access to cancer care can be disrupted even when disaster strikes far from where cancer care is being delivered due to disruptions in the medical supply chain. Institutions shaping advances in cancer research and quality of care have an important role to play in improving our ability to better protect the health and safety of cancer patients during disasters, which is currently feeble.

In the absence of evidence-based climate adaptation strategies and guidelines, cancer patients and healthcare professionals will continue to struggle with the same issues over and over again when disaster strikes.

For example, Hurricane Maria damaged an intravenous (IV) bag factory in Puerto Rico in 2017, causing shortages of this essential medical supply and consequently, interruptions in non-emergent care, which happened again in 2024 when Hurricane Helene damaged an IV bag factory in Tennessee.

While disruptions in access to cancer care are striking and capture media attention, they are far from being the only way climate change jeopardizes cancer control. Cancer diagnosis and treatment have several well-known detrimental consequences to one’s physical, mental, and financial well-being, all of which can increase vulnerability to climate hazards among people who have diagnosed with cancer. There are three factors which contribute to our vulnerability to climate hazards: exposure, sensitivity, and adaptive capacity.

Some health consequences of a growing tumours (e.g., organ damage, fatigue) and/or side-effects of cancer treatment can increase our sensitivity to climate hazards, which is defined as the degree to which climate hazards impact humans. For example, some chemotherapy drugs impact thermoregulation (i.e., our ability to regulate our body temperature), placing cancer patients at higher risk during heatwaves.

Moreover, the physical, psychological, and financial consequences of cancer diagnosis and treatment interact with the multitude of hazards produced by climate-driven disasters, compounding climate vulnerability.

For example, more intense wildfires increase exposure to air contaminated with smoke, as well as water and soil contaminated with byproducts of burned infrastructure and household items, which can persist long after the smoke clears. Wildfire hazards also include the stress associated with potentially having to evacuate, which is especially difficult for people recovering from surgery, who frequently have limited mobility.

A recent study found patients recovering from lung cancer surgery are especially vulnerable to the hazards of wildfires, which are becoming more frequent and intense with climate change. The mental health consequences of a cancer diagnosis can be compounded during climate-driven disasters, which also impact the mental health of healthcare professionals.

Cancer diagnosis and treatment can also have financial consequences resulting from increased healthcare costs and changes in employment that are commonplace after a cancer diagnosis. Financial hardship can hinder our ability to follow evacuation orders, stockpile food, or improve housing infrastructure (e.g., use air conditioning, flood-proof the house, install special air-filters during wildfires). Together, strategies used to cope with climate hazards are called “adaptive capacity”, and people with fewer financial resources, such as cancer patients experiencing financial hardship, frequently have lower adaptive capacity.

Consequently, climate change can exacerbate existing cancer disparities. When climate-driven extreme weather events hit communities with lower adaptive capacity, who lack the financial resources to cope with climate hazards, it’s a recipe for a disaster. As demonstrated by recent climate-driven extreme weather events, however, such as the 2023 heatwaves, wildfires, and flooding events in Europe and North America, nobody is safe from climate change.

To no one’s surprise, communities that have been impacted first and worst by climate hazards are also the communities developing innovative solutions with climate and health co-benefits. When you are closer to the problem, you are closer to the solution. For example, after Hurricane Maria destroyed the electrical grid in Puerto Rico, residents have been leading efforts in establishing microgrids, a group of interconnected energy resources which are controlled locally.

When powered with clean energy sources, microgrids have climate mitigation benefits by reducing greenhouse gas emissions. Microgrids can also have climate adaptation benefits. First, microgrids can improve community resilience to power outages by reducing demand on the main electrical grid, which reduces the risk of outages. Second, microgrids improve community resilience through providing backup power when outages do occur.

Puerto Rico residents’ experiences with power outages in the aftermath of Hurricane Maria also illustrate the pitfalls of current reliance on diesel-powered emergency generators. Because diesel has to be transported, diesel-powered emergency generators are susceptible to disaster-driven disruptions in the supply chain.

In contrast, clean energy sources generated and managed onsite can be storm-proofed and are not impacted by supply-chain disruption. Importantly, this solution also has health benefits: with fewer generators burning diesel, fewer community members are exposed to toxic diesel pollution.

Climate solutions with health co-benefits are especially relevant for all of us committed to reducing the burden of cancer worldwide. Contradictory to our commitment to first do no harm, the healthcare system is one of the top emission-intensive industries in the world. There are several solutions already available for reducing the environmental impact of institutions engaged in research and cancer care, including feasible and readily available alternatives to use of anaesthetic gases and single-use plastics.

Some climate solutions with health co-benefits have always made financial sense, while others come with high upfront costs and longer time to return on investments. Shutting off light, cooling, and heating systems when facilities are closed (e.g. weekends, holidays) is an example of the former, while installing clean energy sources onsite is an example of the latter.

Now, with increased financial incentives from governments for implementation of sustainable solutions (e.g., US Inflation Reduction Act, EU Net Zero Industry Act), short-term cost barriers can no longer be used to justify delaying implementation of these solutions.

Which brings us to the final and most fundamental connection between climate change and cancer. The same human activities fuelling climate change also undermine cancer control efforts. The same air pollution driving the greenhouse effect also increases lung cancer risk.

Plastic production is emission-intensive and communities living near petrochemical extraction, processing, transportation, and waste management sites are exposed to carcinogens frequently used in plastic production. Industrialised food production, a major source of global emissions, also creates health hazards at each step, from exposure to pesticides to consumption of ultra-processed foods.

With so much overlap between human activities worsening climate change and the cancer burden, to care about cancer control is to care about climate change. Moreover, with so much overlap between climate and cancer control solutions, the cancer community is well-positioned to act swiftly. Each one of us has an opportunity to start making a difference today. Later is too late.