Scientists have drawn up a way for humanity to survive a nuclear conflict - but say it'll involve a lot of seaweed.
World leaders have been urged to get planning for a catastrophe which would follow an "abrupt sunlight reduction scenario".
Experts warn that although a nuclear would cause huge loss of life, the majority of deaths would be a result of mass starvation.
A new report by the Alliance to Feed the Earth in Disasters has drawn up a way out of such a crisis, with governments urged to be prepared.
As seaweed requires little sunlight and can resist radiation, it would be ideal for mass farming, the group said.
Asteroid impacts and huge volcanic eruptions are also among scenarios which would require similar action, The Times reports.
Scientist Juan García Martínez said: “We’re trying to promote preparedness — a culture of having institutions, government and companies prepared for a kind of global catastrophe that has been quite neglected."
Experts have said the survival of humanity would require a response in three phases.
In the first, a mass slaughter of livestock and fish could buy time while alternative food sources are found, the study published in journal Nutrients found.
After that, processing sugar from wood - which would be plentiful in dead forests - would help provide essential energy to help see people through.
The third stage would see "staple crops" such as potatoes and seaweed, established close to the equator.
These will need to be sowed rapidly, García Martínez said, with the seaweed helping provide vital nutrients.
He said that it is crucial for world leaders to get a plan together for such a catastrophic event, as it will rely on political co-operation between nations.
He said: “We believe that by being more prepared for this type of scenario, it would both reduce the likelihood and severity of a potential collapse of civilisation.”
