The short answer
No UK government source says whether a nuclear war would end the world, and scientists don't agree on how bad the global effects would be. A 2025 US National Academies report found large uncertainties at every step. A 2022 study in Nature Food modelled smoke from burning cities cooling the climate and cutting harvests, and estimated that a large US-Russia war could lead to more than 5 billion deaths from hunger. These are research estimates, not predictions. For a UK home, the useful steps are the ones the government already asks for: food, water, a radio and a plan.
The short answer
Nobody can honestly say yes or no. No UK government page answers this question. The scientists who study it say a large nuclear war could cause serious harm around the world, far from where bombs fall. They also say they are not sure how serious, and they disagree with each other.
This page sets out what has been published, who said it, and how sure they are. Then it covers what this means for a UK home. We do not predict war or give odds.
What scientists have published
| Source | Type | What it says |
|---|---|---|
| US National Academies (June 2025) | Expert review, ordered by the US Congress | Looked at effects over weeks to decades, from small regional wars to large wars between major powers. Found "major uncertainties and data gaps" at every stage. Did not include radioactive fallout |
| Xia and others, Nature Food (August 2022) | Primary research, computer models | Modelled 6 wars. Smoke from burning cities cools the climate and cuts harvests. Estimated more than 2 billion deaths from an India-Pakistan war and more than 5 billion from a US-Russia war |
| UN Scientific Panel (set up December 2024) | 21 independent experts | Studying climate, environment, radiation, health, farming and economies after a nuclear war. Report due in 2027 |
| National Risk Register 2026 | UK government | Publishes one nuclear scenario: a limited war between two other states. Lists economic disruption and supply chain problems for the UK. Says nothing about global cooling |
How "nuclear winter" works, in plain words
The idea dates from the 1980s. Large fires in cities could send soot very high into the sky, above the weather. Up there it could stay for years, block sunlight and cool the ground. Cooler, darker seasons mean smaller harvests.
The 2022 Nature Food study says that if more than 5 million tonnes of soot reached that height, there would be mass food shortages in almost all countries. In its smallest scenario, world food calories fell by 7% within five years. In its largest, a US-Russia war, the University of Colorado says calories fell by about 90% three to four years later. Its maps show northern countries, "including Canada and much of Europe", among the worst affected.
How sure are scientists?
Not very, and they say so.
- The National Academies report found big gaps in what is known at each step: how many weapons are used, how fires burn, how high the smoke rises, and how farms and trade respond. It asks US agencies to compare their climate models to narrow this down.
- According to Arms Control Today, the report found that studies mostly agree a lot of soot high in the sky would cause major cooling. They disagree about whether that much soot would actually get that high.
- The same article says scientists at universities tend to expect severe climate effects, while some at US weapons laboratories think severe effects are less likely. That is the article's view, not a finding of the report.
- The Nature Food authors say their models don't yet include ozone loss and stronger ultraviolet light.
So the honest summary is: serious global harm is possible, the size is uncertain, and the end of all human life is not what these sources describe.
What it means for a UK home
The main risk for most UK households, in the research, is not the blast. It's what happens to food, trade and prices across the world. The UK government's own scenario points the same way: it lists economic disruption and supply chain problems, even when the UK isn't involved.
No home kit protects against a global famine. But some steps help with smaller shocks, like price rises, shortages or a few weeks of disruption:
- Start with the Be Ready list. 3 days of water (3 litres per person per day) and food that keeps without a fridge or cooking. Our emergency supplies calculator works out amounts.
- Grow it to two weeks, slowly. Add an extra item to your normal shop. See two weeks of supplies.
- Rotate it. Eat the oldest first and replace it. Be Ready suggests checking dates every six months. See stock rotation.
- Keep a manual tin opener and an FM radio. Official news would come by radio if other services fail.
- Know the basic radiation advice. Go in, stay in, tune in. See our radiation emergency guide.
Don't buy large amounts of food you won't eat.
If this topic is worrying you
Reading about this can be upsetting. It's normal to feel scared. It can help to limit how often you check the news and to focus on a few practical steps. Our post on coping with worry about war has more ideas. If worry is affecting your sleep or daily life, talk to your GP.
For the wider picture, read how likely nuclear war is in 2026. We'll update this page when the UN panel reports in 2027.
What to buy
About these links: plain links to ordinary retailer pages. We may earn from some links in future; we don't now. We haven’t tested these and we don’t rank them: they are examples that were in stock when we checked. Prices change. Check what you already own first. Full kit list
Food that needs no cooking, for 3 days
Look for: Tinned meat, fish or vegetables, dried fruit and nuts: food you already eat. Check dates every six months.
Manual tin opener
Look for: Works without power. Keep it with the tins.
Bottled water
Look for: 3 litres per person per day for 3 days, for drinking. More for babies, pets and medical devices.
- Seven Oceans Emergency Drinking Water 0.5l (5-year shelf life) · EVAQ8 · £3.94 (price on 1 November 2026) Shop
Battery or wind-up FM radio
Look for: FM (Be Ready asks for FM; DAB as well is fine). Both a crank and ordinary batteries, so you have two ways to power it.
Frequently asked questions
Would a nuclear war end the world?
No official UK source answers this. Published research says a large nuclear war could cause severe global harm, mainly through smoke cooling the climate and cutting food production. But a 2025 US National Academies report found major uncertainties in how severe those effects would be. Scientists disagree, so no one can honestly give a firm answer.
What is nuclear winter?
It's the idea, first studied in the 1980s, that fires in burning cities could push soot high into the atmosphere. The soot would block sunlight and cool the Earth's surface, which would harm crops. Modern climate models still study this, but scientists disagree about how much soot would reach that height.
Could nuclear war wipe out humanity?
We didn't find a scientific body that says it would. The sources we read describe very large loss of life and food shortages, not the end of all people. The 2022 Nature Food study estimated more than 5 billion deaths from hunger after a large US-Russia war. That is a model estimate with uncertainty, not a forecast.
What does the UK government say?
The National Risk Register 2026 publishes one nuclear scenario: a limited nuclear conflict between two other states, not involving the UK. It lists effects for the UK such as economic disruption, support for British nationals, and disruption to supply chains and flights. It doesn't discuss global climate effects.
Is anyone studying this now?
Yes. In December 2024 the UN General Assembly set up an Independent Scientific Panel on the Effects of Nuclear War, with 21 experts. It is due to report to the General Assembly in 2027. We'll update this page when it does.
Sources
We opened each page on the date shown. Official advice changes: if a source says something different now, follow the source.
- National Academies of Sciences, Engineering, and Medicine: Potential Environmental Effects of Nuclear War, news release (25 June 2025) (read 1 November 2026)
- National Academies: Potential Environmental Effects of Nuclear War, report page (2025) (read 1 November 2026)
- Xia L. et al., Global food insecurity and famine from reduced crop, marine fishery and livestock production due to climate disruption from nuclear war soot injection, Nature Food (August 2022). Primary research (read 1 November 2026)
- University of Colorado Boulder: Nuclear war would cause a global famine and kill billions, study finds (15 August 2022) (read 1 November 2026)
- Arms Control Today: How Would Nuclear War Affect Climate? Scientists Are Divided (October 2025). Outside commentary (read 1 November 2026)
- UN Office for Disarmament Affairs: Independent Scientific Panel on the Effects of Nuclear War (resolution A/RES/79/238, 24 December 2024) (read 1 November 2026)
- Cabinet Office: National Risk Register 2026 (PDF), 'Nuclear miscalculation not involving the UK or its allies', page 223 (read 1 November 2026)
- GOV.UK Be Ready: be ready for emergencies (checklist) (read 1 November 2026)
Related guides
- Radiation emergency in the UK: what official advice says (go in, stay in, tune in)
- UK stockpile shopping list: the Be Ready list, aisle by aisle
- Stock rotation at home: first in, first out
- Two weeks of emergency supplies: a sensible extended plan
Free tools
- Emergency supplies calculator (water and food for your household)
- Be Ready kit: every item on the official list as a tick list
We're an independent UK site, not the government. We check guides against official sources and link to them. In an emergency call 999.
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