Which cities will be underwater?

Article by Isabel Key and Mina Frost.

A third of the Netherlands has been under sea level since long before climate change was a topic [7]. You may wonder why the country isn’t flooded. This is because they built massive barriers to keep the water out [7]. But that was hard and expensive. Moreover, the barriers cover quite a short bit of coastline compared to other countries. How many countries will have to protect their cities like this as global warming gets worse?

Even if global warming is kept below 2°C, about 570 cities and 800 million people will be affected (though not permanently flooded) by 2050 [1]. About 80% of these people live in East or South Asia [1]. In contrast, the cities that will suffer the greatest economic losses from floods are those in the USA (e.g. Miami and New Orleans), Japan (e.g. Tokyo), and the Netherlands (e.g. Amsterdam) [2].

With a temperature rise of 3°C, some cities, including Miami and Shanghai, may be completely underwater [3].

Side fact: a few cities are also sinking due to the weight of their buildings and the extraction of ground water [1]. This can happen quickly, for example, Jakarta has sunk 2.5 metres in under 10 years [1], which makes them even more vulnerable to flooding.

Some cities, like those in the Netherlands, may survive by building flood defences [4]. But as crazy as it sounds, some other cities might be better off just relocating [4]. Sea level rise and storm surges are hard to predict [5] (find out why in our earlier post “Why is global warming hard to predict?”), so we need to be prepared to avoid disasters.


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