Traditional defences may fail, and migration won’t be possible for everyone. But we may yet find more creative ways to live

We have passed the point of no return: rising seas will soon directly affect hundreds of millions of people around the planet. They will indirectly affect many millions more as transport connections, water supplies and factories in low-lying areas are lost or have to be relocated. What exactly are we facing? The latest research suggests we are likely to see a rise of a metre by the year 2100. Given how much carbon dioxide is already in the air and oceans, as much as three metres may be baked in over the 200 years or so that follow. And while that might seem like a long way off, coastal groundwater levels will rise much sooner, wrecking infrastructure and causing toxic pollution well before cities such as Miami, New York and San Francisco are permanently inundated.

Where will all those people, warehouses, water treatment plants and rail lines move to, given that the interior of large land masses will have become drier? The forced migration of hundreds of millions of people will undoubtedly lead to serious international conflict over space and basic resources like fresh water. Conflict is another word for war.