The rise of robots and deadly viruses are among the threats that could wipe out swathes of humanity - but governments are failing to prepare properly for them, a new report warns.
Catastrophic climate change, nuclear war and natural disasters such as super volcanoes and asteroids could also pose a deadly risk to mankind, researchers said.
It may sound like the stuff of sci-fi films, but experts said these apocalyptic threats are more likely than many realise.
The report Global Catastrophic Risks, compiled by a team from Oxford University, the Global Challenges Foundation and the Global Priorities Project, ranks dangers that could wipe out 10 per cent or more of the human population.
It warns that while most generations never experience a catastrophe, they are far from fanciful, as the bouts of plague and the 1918 Spanish flu that wiped out millions illustrated.
Sebastian Farquhar, director at the Global Priorities Project, told the Press Association: "There are some things that are on the horizon, things that probably won't happen in any one year but could happen, which could completely reshape our world and do so in a really devastating and disastrous way.
"History teaches us that many of these things are more likely than we intuitively think.
"Many of these risks are changing and growing as technologies change and grow and reshape our world. But there are also things we can do about the risks."
In the next five years asteroids, super volcanic eruptions and unknown risks are ranked as the biggest threat to humanity.
In the longer term, the rise of artificial intelligence (AI) has been listed alongside catastrophic climate change, nuclear war and pandemics as a threat to humanity.
The biggest long term threat to civilisation is natural and engineered pandemics and nuclear war, according to the report.
Strides have been taken to cut the number of nuclear weapons in the world, but the rise of synthetic biology could open the door to the creation of "off the shelf" deadly viruses.
While the danger of a potent form of avian flu mutating and rapidly infecting humans could also kill many millions, researchers said.
Mr Farquhar said that while there is no evidence to suggest that in the "very near term" militant groups such as Islamic State (IS) will be able to manufacture their own viruses, this could be a future threat.
The report calls for the international community to improve planning for pandemics and health systems, investigate the possible risks of AI and biotechnology and continue to cut the number of nuclear weapons.
Mr Farquhar said ameliorating these risks "definitely requires international co-ordination".
He said: "What is really important to remember is that many of these risks don't stop at the borders and wait patiently for their passports to be checked, they are truly global in nature.
"This is not the sort of thing where one country can say 'Oh well we are prepared and the rest of the world can fend for itself'. That is one of the things we saw with the Ebola crisis - how this thing spilled over national borders."
