Climate Change and Public Health: A Growing Intersection of Crises

In August 2023, a heatwave in southern Europe resulted in over 61,000 excess deaths, according to the Barcelona Institute for Global Health. In Nigeria, average temperatures have risen by 1.2°C since the 1960s, leading to increased malaria cases in areas where mosquitoes thrive due to prolonged rainy seasons. The connection between climate change and public health is measurable and urgent.

Heat stress exemplifies this link. A 2022 report by the World Health Organisation (WHO) noted that extreme heat events caused over 166,000 deaths annually between 1998 and 2017. This burden disproportionately affects low-income countries, where limited access to air conditioning exacerbates health risks. Dr. Chukwudi Nnadi, a climate scientist with the Nigeria Meteorological Agency, emphasised, “Climate resilience isn’t just about infrastructure. It’s about understanding local health vulnerabilities and acting on them.”

Vector-borne diseases further illustrate climate's health impacts. Rising temperatures create environments conducive to pathogen spread. The Aedes aegypti mosquito, a vector for Zika and dengue, now thrives at higher altitudes and latitudes. A 2023 study in The Lancet found that malaria transmission seasons in sub-Saharan Africa have expanded by an average of 31 days since 2000. This extension strains already limited healthcare resources.

Pollution significantly impacts health amid climate change. Wildfire smoke, intensified by prolonged dry seasons, affects millions. A recent NIST study revealed that per- and polyfluoroalkyl substances (PFAS) in firefighter gear pose cancer risks. NIST researcher Dr. Brandon Hayes stated, "The first step is measurement. Quantifying PFAS exposure informs both regulation and equipment redesign."

Water scarcity and contamination are critical issues, especially in the Global South. In March 2025, Cape Town may face its second "Day Zero" crisis within a decade. Health implications from this crisis include diarrhoeal diseases and malnutrition, particularly in rural areas. In Lagos, rising sea levels contaminate freshwater supplies. Chief Adebayo Fashola from Badagry explained, “Saltwater intrusion is already making wells unusable.” Without intervention, residents may rely on expensive tanker deliveries for water.

These challenges present opportunities. Investments in renewable energy can reduce carbon emissions and improve air quality, addressing illnesses like asthma. Electrifying medical facilities in rural areas through off-grid solar installations has shown benefits in Senegal and Kenya, creating cleaner environments for patients and staff.

Yet, the systemic challenge remains. Climate-adaptation policies often overlook public health, focusing on infrastructure instead. WHO estimates that by 2030, direct health damage costs could exceed $2 billion annually. The pressing question is not whether adaptation is affordable, but whether inaction is.

Policymakers are beginning to recognise the scope of the task. The African Union’s Health Adaptation Strategy for 2024–2030 aims to enhance early warning systems and urban planning to mitigate heat effects. However, this ambitious framework relies on sustained international financing. As of October 2023, the promised $100 billion annual commitment from developed nations for climate finance remains unfulfilled, according to the OECD.

Addressing the intersection of climate change and public health requires a shift in priorities. Tracking CO₂e or renewable capacity is insufficient. We must ask: where will the next outbreak occur, and who is uninsured against its effects? Who is most vulnerable to heatwaves, and are protective systems in place? Without addressing these issues, the most vulnerable populations will continue to bear the brunt of climate change.