Rising temperatures, melting ice, swollen seas, and increasingly erratic climatic events will cause water and food shortages that will not only bring a global health catastrophe but “trigger conflict within and between countries,” leading scientific, medical, and military experts warned at a conference in London on 17 October.

“Climate change poses an immediate, growing, and grave threat to the health and security of people in both developed and developing countries around the globe,” says a statement signed at the meeting by, among others, Michael Jay (chairman of the medical aid charity Merlin), Ian Gilmore (former president of the Royal College of Physicians), Anthony Costello (director of the Institute for Global Health at University College London), Fiona Godlee (editor in chief of the BMJ), Richard Horton (editor in chief of the Lancet), and Hege Gjessing (president of the Norwegian Medical Association).

It adds, “Mass migration will also increase, triggered by both environmental stress and conflict, thus leading to serious further security issues.”

The …