A recent question at Quora went like this:

Why wouldn’t humanity survive global warming?

Climate change is trumpeted as one of the most dire challenges to mankind. What is to say that, even if the globe changes irrevocably, humanity will not develop ways to survive in warmer climates? Are there challenges to our survival that we will not be able to innovate our way out of?

I answered with this:

There’s very little chance that humans will actually go extinct as any kind of short-to-medium term result of climate disruption. Humans are remarkably adaptable, and short of a scenario where Earth spirals into a Venus-style hothouse, surely humans will continue in some numbers, in some places.

However, we will definitely see many, many deaths. The World Health Organisation estimates we already have 150,000 deaths a year due to climate impacts (and a recent report by the Climate Vulnerable forum, commissioned by 20 governments, puts the figure at 400,000), and we’re still in the very early days of the curve of serious disruption. Later this century is not looking pretty at this stage.

To my mind the most serious climate threat to “humanity” as we know it is not extinction as such, but the breakdown of peaceful social structures. In the past we’ve had many local and regional conflicts over resources and land in times of stress, but these have always been specific to the pressures in a particular area. When we start having serious damage to food production, with more frequent extreme weather events and water supply disruption, we’ll start seeing conflicts over food, water and arable land in a more global and more intense way than ever before – if for no other reason than that the population pressure is so much greater now.

As a result it’s difficult for me to see a future – over the next 50-200 years – which does not involve far more warfare than the last couple of centuries, and probably the rule of the gun, without any effective national order, in some parts of the world.

Unless, miraculously, we start taking really significant steps to reduce the severity of the crisis, as opposed to the fiddling around the edges we’ve done so far.

You can see other answers and comments on this question at Quora.