Climate change has already affected the physical and mental health of people in the United Kingdom. The country's climate is becoming warmer, with drier summers and wetter winters. Health threats due to climate change in the UK include heatwaves, floods, storms, air pollution and new infectious diseases, among others.
Extreme heat waves have contributed to thousands of deaths per summer, especially in cities. Without climate change mitigation or adaptation, heat-related deaths could increase sixfold by the 2050s, particularly affecting children, the elderly and people with pre-existing conditions. Heat events also strain healthcare systems, leading to surges in emergency visits and exposing gaps in infrastructure.
Flooding in the UK presents another major threat, currently affecting over six million people, with this number expected to rise significantly as temperatures increase. Beyond physical risks, floods have severe long-lasting mental health consequences, including post-traumatic stress disorder (PTSD). Climate change also facilitates the spread of diseases like Lyme disease and leptospirosis through warming temperatures and habitat changes that bring humans into closer contact with disease-carrying organisms.
Climate change is also affecting indoor and outdoor air quality in the UK such as contributing to longer allergy seasons in the UK and by contributing to mould growth and an increase in pollens and other pollutants, affecting respiratory and cardiovascular health. Additionally, climate disruptions to food systems reduce crop yields, increase reliance on imports, and raise food costs, disproportionately affecting low-income households and contributing to poor diets, obesity, and related illnesses. Mental health is also heavily impacted, with extreme weather and climate change anxiety driving distress, particularly among younger populations.
The UK is working toward net-zero emissions by 2050, focusing on decarbonizing energy, transport, and housing. The National Health Service (NHS) is implementing resilience measures to address climate-related health challenges, while nature-based solutions like urban greening mitigate impacts. However, health inequalities, particularly in low-income communities, exacerbate vulnerability to climate risks. Addressing these disparities is crucial to ensuring equitable health outcomes as the country confronts the growing impacts of climate change.
Changes to UK climate
The weather and climate of the United Kingdom has already been affected by human-caused climate change. The country's climate is becoming warmer, with drier summers and wetter winters. The frequency and intensity of storms, floods, droughts and heatwaves is increasing, and sea level rise is impacting coastal areas. This trend is expected to continue.
Heat events are becoming longer, more frequent and intense. Due to climate change, 2023 was the UK's second warmest year with the warmest June on record and a September heatwave.
Extreme weather
Heat The United Kingdom has experienced a significant increase in severe heat waves. Increasingly intense and prolonged heat periods can have dire health consequences. Extreme heat has already caused the death of people who would not have died without these weather events, especially in cities. In England, over the past two decades there were an increasing number of deaths due to heat-related causes. For instance, 2,985 all-cause excess deaths – meaning people who are not expected to die during this period – were recorded during the heatwaves of 2022 in England.
Without climate change mitigation or adaptation measures, heat deaths are projected to increase in the UK due to a combination of climate change and the ageing of population. The risk of heat-related death increases with age. With no additional adaptation and limited global decarbonisation, heat-related deaths could increase nearly 6-fold from an estimated average of 1,602 deaths per year in the 2007-2018 period to 10,889 deaths per year in the 2050s. It is estimated that each 1°C rise in mean temperature is associated with an 18% increased risk of heat-related illness and 35% increased risk of heat-related death.
Current knowledge regarding the number of heat-related deaths and hospital admissions for UK nations other than England is very limited. In Northern Ireland, it is estimated that there are 30 estimated heat-related deaths per year. In Scotland there are 70 estimated heat-related deaths per year. It is also assumed that impacts in southern Scotland may be similar to those observed in northern England. In Wales, there are no official reports or mortality numbers of recent heatwaves, but there are 110 estimated heat-related deaths per year. The number of deaths from heat are expected to rise in Scotland, Northern Ireland and Wales.
Although heat has a negative impact on the health of the entire population, some factors may increase the risk of adverse outcomes. People who are at an increased risk of dying from heat exposure include the elderly, young children, those who have low socioeconomic status or pre-existing diseases. People over 65 have the highest risk of death. The UK has an ageing population, which could contribute to increasing number of deaths related to heat over time.
Extended periods of heat exposure can cause an elevated risk of death from pre-existing cardiovascular (affecting the heart) and cerebrovascular diseases (affecting the brain). Extreme heat can cause a 17% increase in the risk of death due to cardiovascular disease, especially stroke and coronary heart disease. Women and over 65-year-olds are particularly vulnerable to heat-related cardiovascular disease and death. At the same time being exposed to heat does not cause the development of new cardiovascular and cerebrovascular diseases in itself.
Extreme heat could also cause a 14% increase in the risk of dying for people with diabetes. Heatwaves lasting for 3 or more consecutive days are also associated with a 6% increase in the risk of the development or worsening of a broad range of mental health conditions.
Although taking medications (particularly those influencing body's heat regulation and the stability of the cardiovascular system) are potential risk factors for heat-related death, their exact impact is not known.
In addition, heat events are causing significant disruption to the National Health Service (NHS). There is a significant increase in A&E attendances due to heat stroke during heat periods. At the same time experts are uncertain about the exact impact of heat on the number of hospital admissions. Emergency admissions between 2001 and 2012 increased because of extreme heat, especially among older and socioeconomically deprived groups. In Greater London between 1994 and 2000 there were heat-related increases in emergency admissions for respiratory and kidney diseases, in children under 5, and for respiratory diseases in over 75-year-olds. At the same time this happened without an overall increase in hospital admissions perhaps due to bed capacity. The substantial increase in the number of deaths without a comparable increase in hospital admissions might be explained by rapid deterioration that prevents vulnerable individuals from asking for help or getting to a hospital before dying.
Information regarding how heat impacts people who are already in medical facilities (inpatients) is limited. For instance, the heat events in 2020 caused significant increases in hospital deaths, but the underlying causes and risk factors for these excess deaths remain unknown. Competing priorities, inappropriate facilities and equipment to cope with heat may all contribute to excess deaths in NHS hospitals.
Different regions in the UK can be impacted by heat to a different degree. Regional differences might be due to differences in day and night-time temperatures, other environmental conditions, or population characteristics.
The natural and built environment influences the temperature experienced indoors and outdoors. In Greater London in 2007-2016 temperatures were higher in neighbourhoods with lower levels of urban vegetation and with higher levels of income deprivation, social housing, and non-native English speakers. The number of heat-related deaths increased by about 3% for each 1°C increase in temperature. Vegetation cover afforded the largest reduction in the risk of heat-related death. Based on heatwaves in the West Midlands in 2003-2006, it is estimated that reflective "cool" roofs could significantly reduce temperatures by 0.3°C (about 23% of the urban heat island effect).
Besides changes in the environment, individual protective behaviours can also reduce the health consequences of heat. These behaviours include using fans, drinking water, immersing feet and hands in cold water. However, recent public health messages about risk and protective behaviours may not be reaching the most heat-vulnerable people. During the level 3 heat-health alert in England in 2017 most heat-vulnerable did not consider themselves at risk and were unaware of protective behaviours. Only 25% reported changing their behaviour in response to hot weather-related health advice. Many vulnerable adults were more concerned about the effects of the ultra-violet radiation on the skin than the health effects of hot temperatures.
Older people, men, lower income groups and those with lower education levels might be less likely to adopt personal protective behaviours. A survey by the British Red Cross in 2023 reported that the public acknowledges that many people lack information about their risk and are unprepared to cope with heat events, particularly those who are likely to be the most vulnerable.
Based on a 2022 survey, rising UK temperatures are the biggest impact of climate change that most British adults expect to experience by 2030. Furthermore, 62% of adults in the UK are concerned about the impact of heat events on themselves.
In the future the vulnerability of the British population to heat will depend on the ability to implement strategies for effective, sustainable, and equitable adaptation, which requires behaviour change by policy makers, service providers and individuals. The ageing population and the increasing prevalence of chronic diseases, particularly multimorbidity, will exacerbate the impact of climate change, making people more vulnerable to extreme temperatures. Therefore, public health policies and behaviour change interventions that promote healthy ageing and reduce risk factors for chronic diseases might improve heat resilience of the UK population.
Floods Flooding represents one of the most serious impacts of climate change in the UK, particularly for England. Currently more than 6 million people are at risk of flooding due to where they live. This is expected to rise 61% by 2050 with a modest warming of climate (2°C). If temperatures rise more (4°C), 118% more people will be threatened by flooding. Climate change has increased the intensity of storms in the UK, making them more likely to produce heavy rainfall. These extreme weather events create more damaging floods.
Besides threatening physical health, experiencing flooding also has a negative impact on mental health. More than a third of people who experienced flooding in England in 2013/14 had post-traumatic stress disorder a year after, while around 20-25% developed anxiety disorders or depression. For many, the psychological symptoms persisted for years after the floods.
Wildfires Wildfires refer to an uncontrolled fire of vegetation where a decision is required whether to suppress it. The UK has two fire seasons: spring and mid-late summer. Climate change is expected to significantly increase the number of days with a very high risk of wildfires, especially in the summer season.
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