The Greener NHS, Net Zero, Sustainability and Climate Change: The Complete Guide for Medicine Interviews

The Greener NHS is the programme taking the health service to net zero. The NHS produces around 4 to 5 per cent of the country's carbon footprint, with targets of 2040 for the emissions it controls directly and 2045 for its wider footprint. Medicine interviews use it to test whether you can connect climate change to patient care.

I'm Dr Akash Gandhi, an NHS GP, and I've prepared students for medicine interviews at TheUKCATPeople since 2012. Sustainability is a growing interview topic, and the questions are practical: why it matters to a doctor, cutting pollution in a hospital, and what you could do as a student. Our medicine interview hot topics guide covers the other current topics.

What is the Greener NHS?

The Greener NHS is the national programme responsible for cutting the health service's carbon emissions and getting it to net zero. It works with trusts, staff and suppliers on energy, buildings, travel, medicines and procurement, and every NHS trust and integrated care board has to publish its own Green Plan. The key facts:

• First in the world: the NHS committed to net zero in October 2020, the first national health system anywhere to do so.
• The size of the problem: the NHS produces around 4 to 5 per cent of the country's carbon footprint and roughly 30 to 40 per cent of public sector emissions.
• Two targets: 2040 for the emissions the NHS controls directly and 2045 for the wider footprint it can only influence, which includes everything it buys.
• Written into law: the Health and Care Act 2022 placed a legal duty on every NHS organisation in England to have regard to the UK's net zero and environmental targets, the first health system to put net zero into law.
• Green Plans: every trust and integrated care board publishes a board-approved Green Plan. The refreshed plans for 2025 to 2028 were due by 31 July 2025.
• Where it is run from: inside NHS England, which is being folded into the Department of Health and Social Care. The targets belong to the NHS as a whole, and how the NHS is organised is a separate topic.

A useful way to picture it: a hospital is a small town, with heating, kitchens, a transport system and a supply chain, running 24 hours a day. Everything a town emits, a hospital emits too.

Key Takeaway: The Greener NHS has two deadlines, 2040 and 2045, it is written into the Health and Care Act 2022, and most of the emissions it chases sit in what the NHS buys.

What are the NHS net zero targets?

There are two targets, and the difference between them is the thing to know. Net zero by 2040 covers the NHS Carbon Footprint, the emissions the NHS controls directly, such as buildings, fleet and anaesthetic gases. Net zero by 2045 covers the NHS Carbon Footprint Plus, which adds everything the NHS can only influence, including its supply chain.

Both run from a 1990 baseline, and progress between them has been uneven. Direct emissions are down 68 per cent since 1990, and 14 per cent in the last five years, while the wider footprint is broadly where it was in 2019.

Measured per hospital admission the wider footprint has fallen 7 per cent, so the NHS is doing more care at a lower carbon cost. The 2045 target is still harder because the NHS controls it least.

The NHS can change the heating in its own hospitals, but it can only ask a drug company to change how a medicine is made, which is why the procurement rules below matter so much.

Key Takeaway: Say both dates, 2040 and 2045, and say what each covers: the NHS's own emissions first, then everything it buys.

Why does the NHS have a carbon footprint?

The NHS has a carbon footprint because delivering care uses energy, buildings, vehicles, gases and an enormous quantity of manufactured goods. Treating illness produces emissions, and those emissions go on to cause illness in their turn, through air pollution and heat, so a health service has a clinical reason to cut them.

A good deal of the footprint turns out to be waste. The example: at Hull Women and Children's Hospital, staff found the pipes carrying nitrous oxide, the gas and air used in labour, were leaking almost all of it into the atmosphere before it reached a patient.

Disconnecting the valves until the gas was needed cut monthly emissions from 395 tonnes of carbon dioxide equivalent to 43, with no change to anyone’s pain relief.

Key Takeaway: The NHS is roughly a twentieth of the country's carbon footprint, and a surprising share of that is waste it can stop without touching patient care.

Where do NHS emissions come from?

Most NHS emissions come from the things the NHS buys, and only about a tenth come from the buildings it runs. The table below is most of what you need, and the first row is the one that changes an answer.

Personal travel by staff, patients and visitors, most of it by car, is several times bigger than the NHS fleet, which is one reason telemedicine and artificial intelligence in the NHS are sustainability questions as well as safety ones.

The supply chain row is where nearly all of the policy sits. The NHS buys over 600,000 products from around 80,000 suppliers, so its strongest lever is being a customer big enough to change what it will buy.

• Net zero is scored in the tender: since April 2022 every new NHS procurement carries a 10 per cent weighting for net zero and social value.
• Carbon reduction plans are mandatory: required from April 2023 for contracts above £5 million a year, and for all new procurements from April 2024.
• Single use is being designed out: the Design for Life roadmap commits the NHS to a circular system for medical technology by 2045, so devices are built to be reused, repaired or recycled.

Every pound spent decarbonising is a pound not spent on treatment, which is the problem QALYs exist to referee, and it competes with winter pressures for capital. The next two sections show where the cheap wins are and where the expensive work is.

Key Takeaway: The supply chain is close to half the footprint, which makes procurement much the biggest lever the NHS has.

Which clinical changes cut the most carbon?

Changing anaesthetic gases and inhaler propellants has produced the fastest cuts the NHS has managed. Both are only about 3 per cent of the footprint, but a clinician can change them without rebuilding anything. Each is a small volume of gas with a very large warming effect.

• Desflurane: an anaesthetic gas roughly 2,500 times more warming than carbon dioxide. NHS England, with the Royal College of Anaesthetists and the Association of Anaesthetists, decommissioned it from routine practice from 1 April 2024. Emissions are down 98 per cent, saving up to £4 million a year, and it is still permitted in a small number of exceptional cases, such as long neurosurgical operations.
• Nitrous oxide: around 310 times more warming, and it lingers for about 150 years. The problem lies in what escapes. At one East Lancashire site, clinical use accounted for 0.26 per cent of the nitrous oxide passing through the manifold. Fixing leaks like that has cut 90,000 tonnes of emissions since 2019/20 and saves over £2.3 million a year.
• Inhalers: a pressurised metered dose inhaler fires a propellant, and the two in common use are about 1,300 and 3,350 times more warming than carbon dioxide. Dry powder inhalers have no propellant. Inhaler emissions are down 33 per cent since 2019/20, through better asthma care and device switches where they suit the patient.
• The propellant switch: on 21 July 2026 the MHRA became the first regulator anywhere to approve inhalers using the propellant HFA-152a. Same drug, same doses, and propellants of this type cut an inhaler’s footprint by at least 90 per cent.

Medicines emissions overall are down by a third in five years. In general practice, though, the change that makes the most difference is getting asthma control right, because a well controlled patient gets through far fewer reliever inhalers. Greener prescribing usually turns out to be better prescribing.

Key Takeaway: One dated example carries further than a general point, and desflurane, decommissioned in April 2024 and down 98 per cent, is the most quotable.

What is the NHS doing about plastics, travel and buildings?

Beyond the clinical quick wins, the NHS is cutting waste, moving journeys off the road and taking fossil fuels out of its buildings. These changes are slower and more expensive, and they're where most of the remaining work sits.

• Single-use plastics and waste: domestic waste sent to landfill has fallen from over 32,000 tonnes a year in 2020 to under 6,000 tonnes, and the Design for Life roadmap is pushing suppliers towards reusable and recyclable kit. Infection control sets the limits, so some items will always be single use.
• Travel: patient, staff and visitor journeys are about 13 per cent of the footprint, and care closer to home and video appointments both cut it. The NHS fleet is going electric too: one in ten of its vehicles is now zero emission, up from one in a hundred in 2021, and charging points have risen from under 1,500 to over 4,200.
• Buildings and energy: over half of the hospital estate now uses LED lighting, on-site renewable generation has more than tripled since 2020, and Great British Energy is investing £100 million in solar panels and batteries on NHS sites.

Heat decarbonisation competes with beds and staff for capital, which is why interviewers push on it. The NHS secured £370 million from the Public Sector Decarbonisation Scheme, and the 2025 Green Plan guidance asks every trust for a full heat decarbonisation plan.

The travel row also connects to the 10 Year Health Plan's shift from hospital to community care, which means fewer long car journeys to hospital sites.

Key Takeaway: Waste, travel and buildings are the slow, expensive part of net zero, and they are where the 2040 target will be won or lost.

How does climate change affect health in the UK?

Climate change makes existing illnesses more common, more severe and more unequally spread, which is why doctors call it a threat multiplier. The Lancet called it the biggest global health threat of the 21st century in 2009, and its annual Lancet Countdown report has tracked the damage since 2016, putting heat-related deaths worldwide at around 546,000 a year in 2025.

• Heat: the UK Health Security Agency estimated 1,504 heat-associated deaths in England in summer 2025, after a record 2,985 in 2022. Its interim figure for May and June 2026 alone was 2,877, so 2026 may set a new record. Older people and those with existing conditions are most at risk.
• Air pollution: the Royal College of Physicians estimated around 30,000 UK deaths linked to air pollution in 2025, at a cost of about £27 billion a year. The fossil fuels that warm the climate also drive asthma, lung disease, heart disease and stroke, so cutting them improves health now.
• Ella Adoo-Kissi-Debrah: in December 2020 a coroner recorded air pollution as a cause of death for the first time in the UK, for a nine-year-old girl from Lewisham who died of asthma in 2013 after living beside the South Circular road. The Clean Air (Human Rights) Bill, known as Ella’s Law, would make clean air a legal right. It was presented to the Commons in July 2025 and published in February 2026, but fell when the parliamentary session ended in April 2026.

None of this lands evenly across the population. The burden falls on people already at the wrong end of the social gradient, which makes climate change a health inequality question as well as an environmental one.

👉 Read More: Health Inequalities and the Marmot Review for Medicine Interviews

Key Takeaway: Say threat multiplier, then give one UK example with a date, because heat deaths in England are recent and checkable.

What does the GMC expect doctors to know about sustainability?

The GMC expects every newly qualified doctor to be able to apply the principles of sustainable healthcare to their practice. That has been written into Outcomes for Graduates, the document setting what UK medical schools must teach, since 2018, so sustainability is part of your training whichever school you go to.

• Outcomes for Graduates: outcome 25 says newly qualified doctors must be able to apply the principles, methods and knowledge of population health, the improvement of health and sustainable healthcare to medical practice, including the role of environmental hazards in ill health.
• The GMC's planetary health statement: in July 2024 the GMC published a position statement recognising the climate and ecological crisis as one of the greatest threats to health, and committing to build education for sustainable healthcare into its standards and outcomes.
• Medical schools are being graded: the Planetary Health Report Card is a student-led scheme that scores medical schools on sustainability teaching, research and campus, and most UK medical schools take part.

For an interview, this means sustainability is part of being a good doctor as the regulator defines it, alongside teamwork and consent. You don't need the outcome number, only that the GMC expects it and why.

Key Takeaway: The GMC has required sustainable healthcare in medical training since 2018, so it belongs in an answer about what makes a good doctor.

When do sustainability and patient care conflict?

They conflict whenever the greener option is worse for a particular patient, and naming that patient is what turns a slogan into an argument. Interviewers tend to push hardest here, so it's the part worth the most preparation.

• Desflurane was not withdrawn for being a bad drug: it wakes patients up faster than the alternatives. It went because safe, cheaper alternatives existed, and exceptional use is still permitted.
• Banning nitrous oxide would take pain relief away from women in labour: the savings came from stopping leaks in the pipework, and trusts kept gas and air available through cylinders attached to the machine.
• Dry powder inhalers are not right for everyone: they need a fast, deep breath in, so they can be unsuitable for young children, frail older patients and anyone having a severe attack. Devices should not be changed without consulting the patient.
• Reusable is not automatically greener: a reusable instrument has to be collected, washed, sterilised and transported, so the advantage depends on how often it is reused. Infection control sets hard limits: in 2001 England briefly required single-use instruments for tonsil surgery over a variant CJD risk, then withdrew it after surgeons reported more bleeding.
• Fewer appointments can mean missed diagnoses: a phone call saves a car journey, but some patients need to be examined in person.

Our guide to answering medical ethics interview questions sets out the pattern: name the benefit, name the patient who loses, then say what would change your mind.

Key Takeaway: Whenever you argue for a green change, name the patient it could harm and say how you'd handle that.

What can a medical student do about sustainability?

A medical student can't move 27 megatonnes, and nobody expects you to. What you can do is small and real: greener prescribing on placement, active travel, and joining the people at your medical school who already work on this.

• Greener prescribing on placement: ask why a patient is on a particular inhaler, whether their asthma control could be better, and whether an antibiotic is needed at all. Fewer unnecessary prescriptions mean less waste and less antimicrobial resistance.
• Active travel: walking or cycling to placement cuts your own emissions and matches the advice doctors give patients about exercise. Patient and staff travel is about 13 per cent of the NHS footprint.
• A sustainability group: most medical schools have a student sustainability or planetary health society, and many run the Planetary Health Report Card. Joining one gives you a project to talk about.
• The Centre for Sustainable Healthcare: an Oxford-based charity with free online networks open to students, which teaches sustainability as part of quality improvement and plants trees on hospital sites through the NHS Forest.
• Your school work: an eco committee or an EPQ on sustainable healthcare gives you something specific to describe, and your local trust's Green Plan gives you a local example.

The strongest answers on this topic come from students who have asked a real question, for example why their GP practice changed inhaler brands, and can describe the whole conversation, down to the patient who preferred to stay on the old device.

👉 Read More: Antibiotic Resistance and Antimicrobial Stewardship for Medicine Interviews

Key Takeaway: Pick one thing you've done or asked about, describe it accurately, and connect it to one national fact.

How can I talk about sustainability in my medicine interview?

Sustainability questions usually arrive in one of four forms, and the same preparation covers all of them: why it matters to a doctor, how you would reduce pollution in a healthcare setting, what you could do as a medical student, and an article on air pollution or heat to summarise and discuss.

• Why does sustainability matter to a doctor? Because climate change and air pollution make people ill, the NHS is a large emitter, and the GMC expects doctors to practise sustainably.
• How would you reduce pollution in a healthcare setting? Start with procurement and travel, the biggest levers, then anaesthetic gases and inhalers, then waste and energy.
• What could you do as a medical student? Greener prescribing on placement, active travel, a sustainability group and your local Green Plan.
• Summarise this article: find the main claim, the evidence and who is affected, then give your view with one fact of your own.

Then give your answer a clear shape:

1. Answer the question in one sentence. Give your position before the detail.
2. Anchor it in one fact you can defend. The two target dates, the supply chain share, or the heat deaths figure.
3. Add one example, ideally your own. Something you saw, asked about or read in a Green Plan.
4. Name the tension. Say who could be harmed by the green option, and what would change your view.

Here's what interviewers are listening for:

• Whether you have read past the headline: recycling is real, but most of the emissions are in the supply chain.
• Whether patients come first: a green argument that ignores a patient is a warning sign.
• Whether you can hold two goods in tension: cost, carbon and care all matter at once.

How to handle an article station on air pollution

Some interviews hand you a short article, often on air pollution, heat or inhalers, with a few minutes to read it before you discuss it. Read it twice: first for the main claim and the evidence behind it, then for who is affected and what the article leaves out.

Then summarise it in three or four sentences, say whether you find it convincing and why, and add one fact of your own, such as the 2020 coroner's ruling. Interviewers are checking that you read carefully and can form a view, so keep the summary short and accurate.

The lowest carbon consultation is the one that never happens, which is why the sugar tax and the obesity crisis have a climate dimension too.

Answers like this are worth saying out loud before the day, which is what our medicine interview tutoring sessions are for.

Key Takeaway: One specific observation from your own experience, plus one national fact, covers all four forms of the question.

Example interview questions on sustainability and the greener NHS

You are unlikely to be asked any of these word for word, and you do not need a prepared answer to each one. Use them to check your understanding: if you could speak for a minute on most of them, you know this topic well enough for whatever the interviewer actually asks.

Questions to get you thinking

1. Why does sustainability matter to a doctor?
2. What is the Greener NHS, and when is the NHS aiming to reach net zero?
3. Where do most NHS emissions actually come from?
4. How would you reduce pollution in a hospital or GP surgery?
5. What could you do about sustainability as a medical student?
6. You are on work experience and notice a lot of single-use plastic being thrown away. What would you do?

Harder questions to stretch you

1. How does climate change affect health in the UK, and who is harmed first?
2. Should the NHS be spending money on cutting carbon when waiting lists are this long?
3. Is it ever right to change a patient’s inhaler for environmental reasons?
4. Here is a newspaper article about air pollution and children’s asthma. Summarise it and tell us what you think.

Model answer: "Why does sustainability matter to a doctor?"

I think it matters for three reasons. The first is that climate change is already making people ill here. The UK Health Security Agency estimated 1,504 heat-related deaths in England in summer 2025, and its interim figure for May and June 2026 alone was higher.

Air pollution is linked to around 30,000 deaths a year, and in 2020 a coroner recorded it as a cause of death for a nine-year-old girl, Ella Adoo-Kissi-Debrah.

The second is that the NHS is part of the problem. It produces around 4 to 5 per cent of the country’s carbon footprint, and has committed to net zero by 2040 for the emissions it controls and 2045 for everything it buys.

The third is that some of the changes are better medicine anyway. On work experience I asked why a patient had moved to a dry powder inhaler, and the answer was that her asthma was better controlled on it, with lower carbon as a bonus.

So I would see sustainability as part of good care, with the patient in front of me coming first. If a greener option were worse for that patient, I would say so and look for another way.

Why this answer works:

• It answers first: the position arrives in the opening sentence, then the reasons follow in order.
• It uses dated, checkable facts: the 2025 and 2026 heat figures, the 2020 coroner’s ruling and the two target dates.
• It is personal: one real conversation from work experience does more than a list of policies.
• It names the tension: the patient comes first, and the candidate says what happens when green and safe pull apart.

Key Takeaway: Three reasons, one fact for each, and the patient first, spoken in about a minute: that shape fits almost any version of the question.

What is the one line to take into the room?

The NHS is about 4 to 5 per cent of the country's carbon footprint, most of that sits in what it buys, and climate change is already a health problem in the UK, which is why the GMC expects every doctor to practise sustainably.

Related topics: the Lord Darzi review for the state of the NHS, and the NHS Long Term Workforce Plan for staffing.

Key Takeaway: The fastest wins so far, anaesthetic gases and inhaler propellants, worked by changing the product and keeping the patient.