Climate change and human health

Climate change impacts human health in a multitude of ways, but climate action also has the potential to address these issues through holistic and cross-cutting approaches

The nexus between climate change and human health is increasingly entering national and global climate processes and conversations. Climate change is not just an environmental and economic issue but also poses an important challenge for public health that affects millions of people worldwide in multi-faceted ways.

On the one hand, the impacts of extreme weather events, slow-onset disasters, and long-term climatic changes—such as rising day- and nighttime temperatures—seriously threaten human health in a multitude of ways, including physical, mental, as well as psychosocial health. On the other hand, climate actions and investments into climate change adaptation, mitigation, loss and damage, or a just transition have the potential to positively impact health and enhance the overall resilience and effectiveness of the health sector by mobilising additional resources, expertise, and capacities.

Health and climate change: A critical nexus

As stated with very high confidence in the Sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR6), “climate change has adversely affected physical health of people globally and mental health of people in the assessed regions.” These adverse effects include extreme heat events and heat stress; climate-related increases in food-, water-, and vector-borne diseases; the emergence of human and animal diseases (including zoonoses) in new areas; exposure to wildfire smoke and atmospheric dust; disruption of health services; mental health impacts and trauma from disasters and their consequences; and anxiety and stress, “particularly for children, adolescents, elderly, and those with underlying health conditions.”

The report outlines that “climate change and related extreme events will significantly increase ill health and premature deaths” in the near- to long-term. In urban settings, “climate change has caused impacts on human health, [such as] hot extremes including heatwaves, [...] aggravated air pollution, [...] and limited functioning of key infrastructure,” mostly concentrated amongst informal settlements and other economically and socially marginalised urban residents. Furthermore, there is a connection between climate impacts on food systems which result in food or nutritional insecurity and downstream health impacts of rural households, farmers, and vulnerable groups or communities.

Human mobility is another area that highlights the intersection between climate change and health. In cases of climate-related migration (either temporary or permanent) and displacement, adverse health impacts can include non-hygienic lodgings (such as hostels, boarding houses, and shelters) and insufficient sanitary facilities; heightened exposure to water- and vector-borne diseases; unhealthy eating habits and limited food access resulting in poor nutritional status, underweight, anaemia, gastritis, or micronutrient deficiencies; occupational injuries, heavy workloads, and sleep deprivation; alcohol and substance abuse; lack of continuity of treatment for chronic and non-communicable diseases (such as diabetes, heart diseases etc.); lack of knowledge about health; lack of family support; and vulnerability to a number of psychological, psychosocial, sexual, and reproductive issues, including loneliness, sadness, anxiety, depression, stress, PTSD, STDs, and mood and behavioural disorders.

Health in the global climate policy process

The outcome of last year’s meeting of the Conference of the Parties to the United Nations Framework Convention on Climate Change (UNFCCC COP28) acknowledges that countries around the world should respect, promote, and consider their obligations on, inter alia, a healthy and sustainable environment as well as the right to health. This inclusion of health in the outcome text and the Global Stocktake calls attention to an emerging nexus and the need for holistic approaches that understand the health implications of climate change and bring together health and climate change experts, practitioners, and stakeholders.

In particular, health has been highlighted in the workstreams on loss and damage as well as under adaptation and the new framework for the Global Goal on Adaptation (the UAE Framework for Global Climate Resilience), which includes health as one of its seven thematic targets for 2023: “Attaining resilience against climate change related health impacts, promoting climate-resilient health services, and significantly reducing climate-related morbidity and mortality, particularly in the most vulnerable communities.” Currently, there is a two-year work programme focused on developing indicators for this target (as well as the other targets of the Framework), which provides a space to further explore and identify key interlinkages and entry points.

Climate change disrupts healthcare delivery through damaged infrastructure, supply chain interruptions, and increased disease burdens. Climate-adaptive and resilient health systems could include aspects such as the integration of climate considerations into public health planning; improved surveillance and early warning for climate-sensitive diseases; disaster-resilient health infrastructure; improved emergency response capacities; public awareness on climate-related health impacts; climate-specific training for healthcare workers; a steady supply of essential medicines; or healthcare facilities running on renewable energy.

To effectively address the health impacts of climate change, financial resources are crucial. Investments need to be scaled up to build resilient healthcare systems, develop early warning systems, and fund research on climate-related health issues. Innovative financing mechanisms, such as climate bonds and public-private partnerships, could also help to mobilise additional funds, build capacities, and transfer key technologies for a more climate-smart and climate-resilient healthcare sector.

Looking ahead

The nexus of climate change and health is complex and multifaceted, and the understanding of it often remains limited despite an emerging conversation. Addressing the impacts of climate change on human health systems will require comprehensive and holistic approaches that break down siloes to coordinate between sectors, mobilise resources, and invest in adaptive and climate-resilient healthcare systems that can safeguard public health in a changing climate.

(The writer works as Director: Research and Knowledge Management at SLYCAN Trust, a non-profit think tank based in Sri Lanka. His work focuses on climate change, adaptation, resilience, ecosystem conservation, just transition, human mobility, and a range of related issues. He holds a Master’s degree in Education from the University of Cologne, Germany and is a regular contributor to several international and local media outlets.)