How to Think About Risk
The Micromort
- A micromortⓘ is a one-in-a-million chance of death — a concept developed to help people compare risks on the same scale[?:howard-micromort-1984]
- Humans are bad at judging risk intuitively — we overestimate rare dramatic events and underestimate common ones
- The numbers below give approximate micromorts per activity to help calibrate your intuition
Why This Matters
- People fear flying but happily ride motorcycles, despite motorcycles being far more dangerous per mile
- Understanding relative risk helps you make better decisions about safety precautions
- Risk is unavoidable — the goal is informed choice, not zero risk
Transport
Per Trip or Per Mile
- Motorcycling is roughly 28 times more dangerous per mile than driving a car[?:nhtsa-motorcycle-2023] — a review found the ratio may be as high as 34 times[?:motorcycle-risk-review-2009]
- Driving a car: ~1 micromort per 250 miles
- Motorcycling: ~1 micromort per 6-10 miles
- Cycling: ~1 micromort per 20 miles
- Walking: ~1 micromort per 17 miles
- Flying (commercial): ~1 micromort per 10,000 miles
What Stands Out
- Commercial flying is extraordinarily safe — you'd need to fly every day for thousands of years to accumulate serious risk
- Motorcycling is the highest-risk common transport — even with a helmet, the risk per mile is enormous
- Short car trips feel safe but add up — the average person accumulates about 4 micromorts per year just from driving
Warning: Motorcycling is roughly 30 times more dangerous per mile than driving. Helmets reduce death risk by about 37% but cannot overcome the fundamental lack of crash protection.
Adventure and Sport
Per Participation
- Base jumping: ~430 micromorts per jump
- Skydiving: ~8-10 micromorts per jump
- Hang gliding: ~8 micromorts per flight
- Scuba diving: ~5-10 micromorts per dive
- Rock climbing: ~3 micromorts per climb
- Horse riding: ~0.5-1 micromort per ride
- Bungee jumping: ~0.5-2 micromorts per jump
- Marathon running: ~7 micromorts per race
Mountaineering
- Climbing Mount Everest: ~38,000 micromorts per attempt (about 1 in 26 chance of death)
- Himalayan mountaineering generally: ~12,000 micromorts per expedition
- The Matterhorn: ~2,840 micromorts per ascent
- These are among the most dangerous recreational activities humans undertake
Context
- A single base jump is roughly as risky as driving 100,000 miles
- Recreational scuba diving with proper training is far safer than most people assume
- Horse riding injuries are more common than many extreme sports — riders just don't think of it as dangerous
Medical
Surgery and Anaesthesia
- General anaesthesia (healthy adult): ~1-5 micromorts per hour
- Hip replacement surgery: ~100 micromorts
- Heart bypass surgery: ~16,000 micromorts
- Childbirth (developed country): ~80-120 micromorts
For Comparison
- A healthy person undergoing minor surgery faces roughly the same risk as a 250-mile car journey
- Major heart surgery carries risk comparable to a Himalayan expedition
- Modern medicine has made many procedures remarkably safe — but no surgery is risk-free
Everyday Life
Background Risk
- Simply being alive carries a daily risk that increases with age
- A 20-year-old faces about 1 micromort per day from all causes
- A 60-year-old faces about 30 micromorts per day
- By 90, it's about 500 micromorts per day
Lifestyle Choices
- Smoking 1.4 cigarettes: ~1 micromort (from long-term cancer/heart disease risk)
- Drinking 0.5 litres of wine: ~1 micromort
- Living 2 days in New York or Boston (air pollution): ~1 micromort
- Eating 100 charcoal-grilled steaks: ~1 micromort
Animals
The Deadliest Animals Are Small
- Mosquitoes kill roughly 725,000 people per year — more than any other animal by a huge margin[?:who-vector-borne-diseases-2024]
- Snakes kill 81,000-138,000 people per year[?:who-snakebite-2023]
- Dogs (via rabies) kill ~30,000-59,000 per year, almost entirely in countries without widespread rabies vaccination
- Sharks kill about 5-10 people per year worldwide
Sharks vs Reality
- A global analysis of shark attack data found roughly 60-70 unprovoked attacks per year worldwide, with only 5-10 fatalities[?:shark-attacks-trends-2019]
- Your chance of dying from a shark attack on any given ocean swim is roughly 1 in 4 million
- You are far more likely to drown than be bitten by a shark
- Surfers and boarders account for about 42% of shark bites, swimmers about 39%
Myth: Sharks are one of the most dangerous animals
Reality: Sharks kill fewer than 10 people per year globally. Mosquitoes kill over 700,000. You are more likely to die from a bee sting, a dog, or even a falling vending machine than from a shark attack.
Reality: Sharks kill fewer than 10 people per year globally. Mosquitoes kill over 700,000. You are more likely to die from a bee sting, a dog, or even a falling vending machine than from a shark attack.
Ticks and Lyme Disease
- A meta-analysis found global Lyme disease seroprevalence of about 14.5%, with higher rates in people reporting tick bites (18.8%)[?:lyme-seroprevalence-meta-2022]
- Lyme disease is rarely fatal but can cause long-term joint, heart, and neurological problems if untreated
- Early antibiotic treatment is highly effective — the key is recognising the symptoms
- Check for ticks after walking in long grass or woodland, especially in spring and summer
- Remove ticks promptly with fine-tipped tweezers — pull straight out, don't twist or burn
Bees, Wasps, and Stings (UK Focus)
- In the UK, bee and wasp stings kill 4-10 people per year from anaphylaxis — more than adders, sharks, and jellyfish combined
- The UK's only venomous snake (the adder) has killed 14 people in the last 100 years — the last death was in 1975
- Jellyfish stings in UK waters are painful but almost never life-threatening (unlike tropical box jellyfish)
- Weever fish stings are extremely painful but not dangerous — hot water relieves the pain
- If you have a known sting allergy, carry an adrenaline auto-injector
Perspective
- The animals people fear most (sharks, snakes, spiders) are not the ones most likely to harm them
- In temperate countries like the UK, the biggest animal-related risks are bee/wasp stings and tick-borne disease
- Globally, mosquitoes are the deadliest animal by an enormous margin — and the solution is largely bed nets and insecticide
Common Misconceptions
Myth: Flying is dangerous
Reality: Commercial aviation is the safest form of transport per mile[?:howard-micromort-1984]. The fear comes from dramatic media coverage and lack of control, not from actual risk.
Reality: Commercial aviation is the safest form of transport per mile[?:howard-micromort-1984]. The fear comes from dramatic media coverage and lack of control, not from actual risk.
Myth: Extreme sports are a death wish
Reality: Most regulated extreme sports (skydiving, bungee jumping, scuba) have well-managed risks. The danger comes from unregulated activities, poor training, or ignoring safety protocols.
Reality: Most regulated extreme sports (skydiving, bungee jumping, scuba) have well-managed risks. The danger comes from unregulated activities, poor training, or ignoring safety protocols.
Myth: If it feels safe, it is safe
Reality: Familiarity breeds complacency. Driving feels safe because you do it daily, but it's one of the most dangerous things most people regularly do.
Reality: Familiarity breeds complacency. Driving feels safe because you do it daily, but it's one of the most dangerous things most people regularly do.
Practical Takeaways
What You Can Control
- Wear a seatbelt (reduces car death risk by ~45%)
- Wear a helmet when cycling or motorcycling
- Don't drink and drive (alcohol is involved in ~30% of traffic deaths)
- Choose well-regulated operators for adventure activities
- Get proper training before high-risk activities (diving, climbing, etc.)
Perspective
- Zero risk doesn't exist — every activity has some probability of harm
- The goal isn't to avoid all risk but to understand what you're accepting
- Small consistent risks (like daily driving) often outweigh dramatic one-off risks (like a skydive)
- Making one smart choice (wearing a seatbelt, not texting while driving) can be worth more than avoiding an entire activity
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