Climate change is mainly caused by the burning of fossil fuels (oil, gas and coal). This releases carbon dioxide and other greenhouse gases into the atmosphere, trapping heat and leading to:
- increasing land and air temperatures
- more frequent and severe extreme weather events
- melting ice sheets and glaciers
- warming oceans and rising sea levels
- loss of biodiversity and degradation of ecosystems
These can trigger tipping points and multiplier effects where small shifts can suddenly lead to irreversible changes, and one problem can make another worse. For example, heat can increase air pollution, which in turn amplifies health risks.
The changing climate is already impacting the UK population’s health:
- Heatwaves caused 10,781 excess deaths in England between 2020–24. (1)
- An estimated 30,000 deaths per year in the UK are attributed to air pollution – this compares to just over 1600 road casualties in the UK in 2024. (2, 3)
- Adverse mental health impacts associated with flooding, including depression, anxiety and PTSD (4)
- Vector borne diseases – such as dengue fever, malaria and Lyme disease – are highly climate sensitive and have increasing impacts in the UK. (4)
Without action, the changing climate will worsen health outcomes
‘Heat-related deaths – with no additional adaptation and limited global decarbonisation – could increase nearly 6-fold from a 2007 to 2018 baseline average estimate of 1,602 deaths per year, to 10,889 in the 2050s.’
UK Health Security Agency – Health effects of climate change in the UK: 2023 report
Some groups are more vulnerable than others and climate change risks exacerbating health inequalities:
- Older people
- Infants and children
- People with existing health conditions and disabilities
- Coastal and low-lying populations
- People experiencing homelessness
- Pregnant women and pregnant people
- People in densely populated areas
Climate-related events like food insecurity and flooding affect low-income groups the most as they often lack the resources to adapt or recover, deepening health inequalities.
The NHS is currently unprepared to respond to climate change and ensure service delivery is maintained during adverse weather:
- Around 90% of hospitals in England are at risk of overheating. (5)
- In 2024, 25.5% of healthcare facilities in England were at risk of flooding – projected to rise to 31.5% by 2040–60. (6)
- Service disruption is already happening – data system failure at Guy’s and St Thomas’ NHS Foundation Trust during a 2022 heatwave.
