Our rapidly warming climate has numerous operational implications for the NHS. As well as mounting pressure to lower its carbon emissions, the health service needs to adapt to the inevitable effects of climate change on patient need and staff wellbeing.

According to the Met Office, 2025 was the warmest year on record. The World Health Organisation says climate change is now the leading threat to global health and it also threatens to disrupt the NHS’s ability to deliver high quality care.

There is evidence that climate change is already starting to affect people’s health. In summer 2018, for example, a fire on Saddleworth Moors led to a surge in people ringing emergency services with breathing difficulties. And during the 40°C heatwave in 2022, there were approximately 3,000 excess deaths among people over 65 in England.

In the coming years, there will be changing patterns of infectious diseases, with higher temperatures increasing the risk of diseases like Dengue Fever, Lyme disease and West Nile fever, through mosquitoes, sand flies and ticks. Worsening air pollution also means a higher risk of respiratory and cardiovascular illnesses.

The UK government’s 2023 report on the health impact of climate change predicts that, without efforts to adapt and decarbonise, heat-related deaths will increase nearly six-fold by the 2050s. And experts warn there will be an increased risk of PTSD, depression and anxiety due to more frequent and severe flooding.

But the impacts of climate change won’t fall evenly across the population, says Chris Naylor, senior fellow in health policy at The Kings Fund. “People in lower income areas already with worse health outcomes will be disproportionately affected,” he says. Experts also warn that the impact of climate change will fall disproportionately on children, people with disabilities, the homeless, and those in prison or social care settings.

According to the government’s climate risk assessment, flooding and heatwaves will increase the risk of operational disruption in the NHS. This includes interruptions to critical services such as water, energy, transport and the supply chain, as well as physical damage to NHS buildings requiring temporary closures.

Heatwaves and hotter summers will bring many more challenges for NHS staff, says Neil Cartwright, NHS England’s Greener NHS programme manager in the North East and Yorkshire.

As an example, he points to the failure of two data centres during the 2022 heatwave which resulted in Guy’s and St Thomas’ hospitals losing access to their clinical IT system. During the same heatwave, a survey of critical care clinicians reported that almost a fifth of UK hospitals had to cancel operations because operating theatres were too hot.

“There’s a potential staff welfare issue with colleagues working in intolerable heat in wards and clinics that are getting hotter and hotter,” explains Cartwright. “The 2022 heatwave, where we saw temperatures over 40C, pushed the UK into national emergency territory. For the first time in recorded history, we had a red heat warning and a Level 4 Health Alert issued simultaneously. If temperatures like that had persisted for a week, the health impacts and disruption to essential services would have escalated rapidly.”

The NHS is responsible for 5-6% of the UK’s carbon footprint.  This includes emissions from buildings, anaesthetic gases, supply chains, commissioned health services and travel.

“The biggest chunk of the NHS’s carbon footprint is medicines,” says Naylor. “Producing them is an energy intensive process.” But, he adds, if the NHS can reduce the £300 million worth of medicines wasted every year, it could save money as well as carbon.

In England, the NHS has a legally binding commitment to reach net zero by 2040 for its direct carbon emissions, and by 2045 for the emissions it influences. NHS England says NHS carbon emissions fell by 14% between 2020 and 2025—the equivalent of one million fewer people flying from London to New York.

In trying to reduce emissions, many NHS trusts have run campaigns to reduce waste and unnecessary interventions. In 2020, a multidisciplinary team at Charing Cross Hospital achieved a 25% decrease in cannulation during emergency attendances in one year, reducing emissions by 19 tonnes of CO2 equivalent. And Great Ormond Street Hospital launched ‘The Gloves Are Off’ campaign, which led to 36,600 fewer disposable gloves being used every week.

On a national scale, NHS England set targets in 2020 to reduce the use of desflurane, an anaesthetic gas with a huge carbon footprint. It was fully decommissioned in routine surgical practice in 2024.  

“The NHS targets are ambitious,” says Tom Hardie, senior fellow at The Health Foundation. “With the wider supply chain, this is very complex, but there are ways this can be done.”

NHS England’s Net Zero supplier roadmap is the key initiative for reducing supply chain emissions, setting out the steps suppliers need to take to align with NHS targets. From 2030, suppliers who can’t verify their progress through carbon emission reporting will be excluded from NHS contracts.

Last year, NHS England published a Climate Adaptation Framework to help NHS organisations identify and address relevant climate risks. “Some NHS trusts are starting to assess heat, flooding and wider climate risks, largely because they have dedicated staff capacity to do it and because foresighted leaders are choosing to prioritise the work,” says Cartwright.

“What worries me is that this is not yet happening consistently across the wider health and care system, despite the UK Climate Change Committee warning that the UK is not adequately prepared for the effects of climate [change],” he adds.

It’s also important to focus on preventative, community-based healthcare, experts say, as acute hospitals have been found to have the biggest environmental impact.

“Anything that involves intervening early and avoiding hospitalisation can reduce the need for carbon-intensive hospital care,” Naylor says. Initiatives such as patient empowerment and lean, efficient care pathways, can bring clinical and financial as well as environmental benefits, he explains.

The issue of sustainability needs to also be integrated and aligned with other system priorities, such as those set out in the NHS Ten Year Plan, says the Health Foundation’s Tom Hardie.

The foundation advises that in shifting from analogue to digital healthcare, NHS organisations should follow ‘green digital’ principles, including lean approaches to digital product design, energy use and data storage, as well as adopting ‘circular economy’ approaches.

But, crucially, Hardie argues, senior leaders need to build sustainability into strategies so that it becomes “business-as-usual” rather than a “do on lunch break” project driven by a few passionate people. “It starts from the top, with boards of NHS provider organisations taking sustainability seriously, putting it into strategy, and setting out clear actions,” he says. //