Climate and health: health and care systems’ preparedness for the changing climate

Jenny Chapman; Sabina Musiał

Overview

Climate change has, to date, led to average global temperatures rising 1.5°C above pre-industrial levels.[1] This has increased the frequency, scale and intensity of extreme weather events, such as heatwaves and floods.[2] Impacts are being felt by humans, non-human species, water and food systems and ecosystems around the world.[2]

Climate change has been recognised as “the biggest health threat facing humanity” by the World Health Organisation,[3] and “a major threat to human health and wellbeing in the UK” by the UK Health Security Agency.[4]

The Climate Change Committee’s 2025 report assessed preparedness of health and care systems to the impacts of climate change. It found implementation was “insufficient”, and policies and plans were “limited”.[5]

Climate-related impacts on human health are expected to cost more in the future.[6] For example, heat-related mortality in England costs an estimated £6.8 billion per year, with this predicted to increase to £14.7 billion per year by 2050.[7]

Health impacts of climate change are unevenly distributed between and within countries.[8] The impact of climate change can depend on urbanisation, where heat stress is more likely, and proximity to the coast, where sea-level rise affects communities.[2] This can affect the preparedness of health and care systems.

At the population level, social deprivation, pre-existing health conditions and age affect vulnerability to climate change in the UK.[9] Climate change may worsen existing health inequalities, with ethnic minorities and disabled people more likely to be adversely impacted.[9]

Health and care services need to be prepared for the direct and indirect effects of climate change on physical mental health.[7]

Heatwaves and wildfires negatively affect air quality, which can lead to and exacerbate respiratory illnesses, such as asthma (PN 717). There is evidence that some mental health conditions, such as bipolar disorders, are worsened by poor air quality.[10] Experiencing wildfires and their consequences, such as the destruction of homes, can affect mental health.[11]

Elderly populations, very young children and people with chronic illness are most at risk from extreme heat (PN 723) and cold.[12] An ageing population means an increasing proportion of people in the UK will be vulnerable to extreme temperatures.[5]

Health and care services need to be prepared for new threats, such as vector-borne diseases being seen in the UK that have previously not been encountered.[8] For example, Aedes albopictus, a species of mosquito that can transmit dengue and Zika, was detected in southern England in 2016. [13]

Extreme rainfall can lead to flooding. This can lead to drowning and prevent people reaching health and care services..[9]10% of hospitals in the UK are at risk of flooding.[14]

Indirect health impacts of climate change include malnutrition, due to disruption of food production.[15] Harvests may be lost due to drought, which can affect livelihoods, lead to stress and disrupt the distribution, availability and cost of healthy foods.[16]

Mental health can also be affected by an awareness of climate change, which can lead to depression and feelings of worry and helplessness, known as ‘climate anxiety’.[17] 75% of adults in Great Britain report being concerned about the impact of climate change.[18]

Some aspects of UK health and care infrastructure and services are not resilient to climate change impacts, such as extreme heat.[19] For example, a heatwave in London in 2022 led to temperatures over 40°C. The heat caused two data centres to stop working at Guy’s Hospital and St Thomas’ Hospital, which led to treatment delays.[20]

Approaches to addressing climate change can be classed as adaptation or mitigation.[21]

Adaptation involves reducing vulnerability to current and future changes in the climate. In the context of health and care, this could include educating communities about how to cope during heatwaves and building flood defences to protect homes near rivers.[21]

Mitigation involves reducing greenhouse gas emissions to limit future climate change. Examples include renewable energy and low-emission transport.[21]

Increasing preparedness to climate change requires both mitigation and adaptation efforts.[21] As “nearly all of the modelled scenarios considered by the Intergovernmental Panel on Climate Change” predict further warming, adaptation is essential for health and care systems.[22]

Adaptation measures are location-dependent, and could lessen health impacts in lower warming scenarios, increasing health and care services’ preparedness.[8] Health-related adaptation may involve physical infrastructure, such as shelters, and psychological measures, such as education campaigns.[23]

Adaptation finance can help communities become more resilient to hazards from climate change. For example, in Scotland, the Water Environment Fund provides financial support to restore urban rivers to encourage walking and cycling, in addition to reducing flooding.[24] This is an example of an adaptation measure that provides ‘co-benefits’ for both population health and wider society. Encouraging active travel may lead to healthier individuals, better air quality and lower greenhouse gas emissions.[25]

Other adaptation measures may result in ‘trade-offs’, where human health is improved at a cost to the environment. For example, air conditioning may protect vulnerable households from extreme heat, but increases energy consumption and releases potent greenhouse gasses.[26]

4-5% of the UK’s carbon footprint is attributable to health and care.[27] Health and care services will therefore need to adapt to support mitigation efforts:

In 2020, NHS England launched a net zero plan to decarbonise care, medicines, the supply chain, transport and hospitals by 2040.[28] In the Health and Care Act 2022, the NHS became the first health and care system to embed net zero into legislation.[29] Actions taken to reduce emissions include fixing valves on anaesthetic equipment to reduce nitrous oxide leakage.[30] Nitrous oxide, used in ‘gas and air’, is a potent greenhouse gas, and anaesthetic gases are responsible for 2% of the NHS’s carbon footprint.[30]
NHS Wales has a legally binding target to reach net zero by 2050 and aims to reduce carbon emissions by 34% by 2030.[31]
NHS Scotland aims to reach net zero by 2040, and net zero emissions from its supply chain by 2045.[32]
Targets for emissions in Northern Ireland are outlined in the Climate Change Act (Northern Ireland) 2022 which states that Northern Ireland aims to reach net zero emissions by 2050.[33]

Challenges and opportunities

Stakeholders say that:

Food and medicine supply chains are important to maintain good health. Risks to these supply chains are complex and are subject to disruption by climate change. Climate change could lead to geopolitical instability, which could also disrupt food and medicine availability.[34]
Climate adaptations need to be socially and economically sustainable, as well as environmentally sustainable.[35] This necessitates collaboration and negotiation between different sectors (PN 702, PN 408). For example, nature-based solutions to climate change include wetland restoration. Wetlands can make landscapes more resilient to flooding, but also provide habitats for insect vectors that carry disease.[8] Environmental and health stakeholders need to collaborate for wetland restoration projects to be successful.
Health and care systems need to both provide high-quality services to those in immediate need whilst considering impacts of these services on future generations.[19]

Key uncertainties/unknowns

Climate projections are uncertain as climate modelling is highly complex. Uncertainty can come from climatic ‘tipping points’ (such as permafrost thawing) and cascading impacts (such as heatwaves leading to trees dying, reducing carbon sequestration).[15] Climate risks are unlikely to occur in isolation and interactions are difficult to predict.[36] For example, a heatwave may lead to wildfires and also a period of drought. This makes it hard to plan how to adapt to future changes in the climate.[15]
There is a lack of research evidence regarding the effectiveness of different health adaptation interventions.[36] This makes it challenging to predict how adaptation measures might support health.
The evidence base for the impact of climate change on mental health is less developed than the evidence base for effects on physical health.[8]

Key questions for Parliament

How can public awareness of both the health impacts of climate change and ways to increase preparedness be improved?
How can actions to tackle challenges relating to climate and health provide co-benefits?
How can NHS infrastructure be resilient to the effects of climate change?
How can the NHS reduce its emissions and other impacts on the environment?
How can the NHS ensure it has resources to prepare for increases in demand for its services due to climate change, such as during extreme weather events?
How appropriate are the actions relating to health and care in the UK’s National Adaptation Plan and what progress has been made?
What should the UK’s role be in the implementation of global health and care adaptation and mitigation?
With inequalities between individuals and communities being a key determinant of the health impacts of climate change, how can these be addressed in adaptation and mitigation measures?
How can and should patients be involved in decisions about their treatment and care when they result in different climate impacts?