) Limiting global warming to around 1.8 degrees Celsius, instead of allowing it to reach 4.4 degrees Celsius, could prevent the loss of 1.89 billion years of healthy life to causes such as extreme heat and air pollution, according to a new LancetCommission.

Researchers said that the true burden could be even greater and that without sharp cuts to emissions, health losses would continue to compound beyond 2100, increasingly intensify other threats, such as migration, in ways not yet reflected in these numbers.

The authors of The Lancet Commission on "21st Century Global Threats to Health", launched at the World Health Summit 2026 in Berlin, Germany, examined hundreds of possible threats.

They identified 17 threats posing the greatest danger to human health and survival between 2025 and 2100. These are also the threats that can be averted through policy changes, funding decisions and innovation, they said.

The 17 interlinked "catastrophic" threats spanning diseases, social and economic conditions, environmental change, technology and conflict will shape the health of the next generation, the team added.

If current trends continue, the 17 catastrophic threats collectively could account for tens of billions of years of lost health, the analysis found.

Every country faces significant risks, even as the scale varied by threat and region. Within each country, people with limited resources and marginalised communities bear the greatest burden, compounded by existing inequalities, it said.

Nuclear conflict and the malicious use of artificial intelligence (AI) were identified as the two threats with a potential for extinction, even as their likelihood of occurring were deemed 'low'.

Accounting for both their potential impact and probability, the commission's assessment found that action to prevent nuclear conflict could avert an estimated 133 million deaths and 9.35 billion years of healthy life lost by 2100, while action to reduce the risk of malicious AI could avert an estimated 10.4 billion years of healthy life lost.

"The estimates highlight how much health loss could be avoided in each area. Some are already imposing substantial health burdens today, while others carry a real danger if they materialise. Crucially, all 17 threats are interconnected, which is why they must be addressed together, not in isolation," commission co-chair Christopher JL Murray, director of the Institute for Health Metrics and Evaluation, University of Washington, said.

"The striking finding is not only the scale of these threats, but that humanity still has the agency to act. Across all 17 catastrophic threats, the decisions made by leaders today will shape the health and wellbeing of the next generation. But delaying action will only serve to shift and increase the costs into the future," Murray added.

The other catastrophic threats to health are air pollution, antimicrobial resistance, childhood malnutrition, conventional conflict, a declining development assistance for health, high alcohol use, high blood pressure, income inequality, low educational attainment, naturally occurring pandemics, obesity, poor mental health, smoking and unhealthy ageing, the authors said.

The commission also puts forth a framework to inform action before harm becomes embedded -- create and fund threat-ready health systems, increase investment in innovation and reassess threats regularly and independently, they said.