Addressing threats to future global health-what is the right timeframe?

Our decisions today can support or threaten future human health. Insofar as we protect the planet or invest in fruitful research on pandemic countermeasures, we promote future wellbeing and health, sometimes at the present generation's expense. As we warm the planet, accelerate antibiotic resistance, or consume finite natural resources, we might serve present-day wellbeing or health at the expense of future generations. To decide which such trade-offs are legitimate or advisable, we need to know how to balance the health interests of future generations against each other and against our own. Should concerns for future health be confined to the 21st century as per the stated mission of the Lancet Commission on 21st century global threats to health? If not, how far into the future should they extend, and why? Population ethics is a branch of ethics that considers future populations' wellbeing. This Review, a part of the Lancet Commission on 21st century global threats to health, applies general insights from population ethics to future populations' health, and shows why that application is more complex than meets the eye.