Soot thrown into the atmosphere would block out the sun, causing crops to fail and people to go hungry.
Vladimir Putin's aggressive nuclear strategy threatens to unpick decades of careful negotiation.
This year saw nuclear weapons tested, stockpiles renewed, and disasters remembered.
The global nuclear non-proliferation regime depends on American leadership. What if Donald Trump loses interest?
In early December, the nations of the world are poised to take an historic step on nuclear weapons. Yet Australia sticks out like a sore thumb among Asia-Pacific nations in arguing against change.
Donald Trump will soon have command of thousands of nuclear weapons. This presents a new and unknown threat to global security - and an urgent incentive for all states to ban nuclear weapons.
In the summer of 1946, the U.S. government detonated the first of many atomic bomb tests in the Marshall Islands. Seventy years of radiation exposure later, residents are still fighting for justice.