Global temperature change is the number one extreme risk to economic growth and asset returns for investors, a new ranking by the Thinking Ahead Institute has suggested.
A global trade collapse is the number two extreme risk listed in the index, driven by a rise in protectionism and other geopolitical developments over the last six years.
Cyber warfare completes the top three risks, with the prospect of a weaponised internet thought to be increasingly possible as the world becomes more connected.
Tim Hodgson, head of the Thinking Ahead Group, said that extreme events are much more likely than previously thought in a complex world, even if they are hard to imagine.
"We believe that the world is subject to fundamental changes, whether environmental or political, which will alter power balances," he continued.
"Global temperature change becomes the highest ranked risk due to our assessment of higher likelihood coupled with significant impact - in the extreme, this would mean mass extinction."
Extreme risks are described as "events that are very unlikely to occur but that could have a significant impact on economic growth and asset returns should they happen".
Biodiversity collapse and abandonment of fiat money enter the top 15 risks for the first time, while deflation, terrorism and an insurance crisis drop out.
The Thinking Ahead Institute - established by Willis Towers Watson in 2015 - said there are three main hedging strategies available to investors, one of which is holding cash.
It highlighted how cash has held its real value through episodes of inflation and deflation over long historical periods, although there is no guarantee this will remain so in the future.
The researchers also said that investors should look to hold derivatives and a negatively-correlated asset, but warned that no asset will work against all possible bad outcomes.
"Our extreme risks ranking has seen the emergence of a general trend with financial risks falling down the rankings and non-financial extreme risks growing in significance," Hodgson said.
"To navigate through this complex world, we suggest investors need to be open-minded, avoid concentrated risks, be sensitive to early warning signs, constantly adapt and always prepare for the worst."