A skull above planet Earth
An international commission of experts for the journal The Lancet has identified 17 major threats to human health through 2100. Two of them, the malicious use of artificial intelligence and nuclear conflict followed by global famine, are singled out as capable of leading to the complete extinction of humanity. The probability of such outcomes is currently estimated as low, but the experts argue they cannot be ignored. The other 15 threats could each cost more than 1 billion years of healthy life by the end of the century, and according to the authors, that damage can be prevented with the right policies.
What you need to know
- The Lancet commission, led by Christopher Murray of the University of Washington, ranked 17 health threats for the period 2025–2100.
- Malicious AI use, including AI-assisted bioweapon development, and nuclear war followed by global famine are the two threats placed at the top as potential extinction risks, though their probability is estimated as low.
- Obesity, poor diet and physical inactivity form the largest preventable threat: the gap between the best and worst scenarios is 23.1 billion years of healthy life by 2100.
- Under the baseline forecast, all diseases and injuries combined will cost humanity about 246 billion years of healthy life between 2025 and 2100.
Who produced the assessment and what it measured
The large-scale study involved dozens of scientists led by Christopher Murray, a physician and health economist at the University of Washington. The team estimated how much health loss humanity could prevent between 2025 and 2100. Their headline conclusion is encouraging: the coming crises are enormous in scale, but societies still have the time and the tools to bring them under control.
The two scenarios that could end humanity
At the top of the commission’s risk pyramid sit two threats that could call the survival of the human species into question before the end of the century:
- Malicious use of artificial intelligence, including the use of neural networks to develop new types of biological weapons.
- Nuclear conflict and the global famine that would follow from the resulting climate changes.
The likelihood of either scenario is currently assessed as low. The other threats also require attention, but these two stand apart.
What was left off the list
Several familiar doomsday scenarios did not make the final ranking. The researchers excluded a major asteroid impact and a supervolcano eruption because the probability of either event in the 21st century is negligible. They also set aside so-called “mirror life”, synthetic organisms built from mirror-image molecules. The technology does not yet exist, so it is too early to put numbers on its potential harm.
How the commission compared very different disasters
To compare threats as different as wars and unhealthy habits, the researchers used a metric called DALY (disability-adjusted life year). One DALY equals one lost year of healthy life. It combines years lost to premature death with years lived with illness or disability.
To make the figures easier to grasp, the authors translated them into a familiar benchmark: 1 billion lost years of healthy life is roughly equivalent to the damage caused by two COVID-19 pandemics. Under the commission’s baseline forecast, all diseases and injuries combined will take about 246 billion years of healthy life from humanity between 2025 and 2100, comparable to around 500 COVID-19 pandemics.
Fifteen more threats that can be prevented
Directly below the extinction-level risks in the pyramid are 15 large-scale dangers. Each could cost the world’s population more than 1 billion years of healthy life by the end of the century, but this damage can be prevented with the right government policies.
The list spans medical, environmental and social problems:
- obesity, poor diet and physical inactivity;
- low educational attainment and income inequality;
- air pollution and climate change;
- high blood pressure, smoking and alcohol misuse;
- antimicrobial resistance and naturally occurring pandemics;
- child undernutrition, declining mental health and unhealthy ageing;
- conventional armed conflict and the withdrawal of international financial assistance for health.
Infections and parasites are not going away either, and drug-resistant microbes combined with cuts to health funding are making them harder to fight.
Obesity and education top the preventable risks
The largest preventable threat of the century is obesity together with high body mass index, poor diet and lack of physical activity. The difference between the best- and worst-case scenarios by 2100 amounts to 23.1 billion years of healthy life, the equivalent of roughly 46 COVID-19 pandemics.
A doctor consults a woman at a desk, with vegetables and a stethoscope nearby
Next come low educational attainment and income inequality. Accessible, high-quality education works in two ways. At the individual level, educated people tend to pay closer attention to their health, notice warning signs earlier and are less likely to let chronic conditions go untreated. At the global level, rising literacy slows excessive population growth in the poorest regions.
Why the numbers cannot simply be added up
The authors stress that the figures for individual threats should not simply be summed. Many problems are closely intertwined in the same people: poverty, for example, often leads to poor nutrition, high blood pressure and harsh living conditions.
What the commission recommends
To prepare for the crises of the 21st century, the commission proposed three steps for governments:
- Restructure health systems to cope with future threats.
- Sharply increase investment in breakthrough medical and climate technologies.
- Create an international system for continuous monitoring of global risks.
