Countdown to Zero is a documentary film released in 2010 which argues that the likelihood of the use of nuclear weapons has increased since the end of the Cold War due to terrorism, nuclear proliferation, theft of nuclear materials and weapons, and other factors.
The film features interviews with leading statesmen and experts, including Tony Blair, Jimmy Carter, Mikhail Gorbachev, Robert McNamara, Pervez Musharraf, and Valerie Plame Wilson.
The idea for the film first occurred to the producers when the Nobel Peace Prize was awarded to Al Gore after the success of his documentary about global warming, An Inconvenient Truth.
Diane Weyermann of Participant Media asked Walker if she was interested in directing a film about nuclear weapons, and Walker said yes. More than 84 people were interviewed for the film. Global Zero, an international organization promoting the elimination of nuclear weapons, provided production assistance for the film.
A review in Daily Variety called the film highly creative documentary-making and concluded that the film makes a convincing argument that the human race is on borrowed time: Given the number of nuclear weapons in existence, the ease with which they can be made, the eagerness of terrorists to possess them and a worldwide cluelessness about nuclear security, it's only a matter of time before something terribly ugly happens.