Which cities are most at risk as sea levels rise?
The obvious answer would appear to be, those nearest the coast. Strangely, however, sea level is not constant across the planet. Factors as diverse as sea currents, winds, the rise and fall of land masses, and the effects of gravity all contribute to variations in the height of the oceans. In effect, some oceans actually slope, meaning that sea levels differ around the world.
Now, a French scientist has created a model of sea level increases which takes these factors into account. Mahe Perrette of the Institute for Climate Impact Research in Potsdam, Germany, has projected the different rises in sea level across the world by 2100.
With the world’s average sea level rise predicted to be between 30 and 106 centimeters data from Perrette’s research and other studies suggests some key danger-spots:
- Tokyo. The Greater Tokyo Area is home to a staggering 35 million people. Sea levels here are predicted to rise by 45% more than the global average.
- Sydney. The iconic Sydney Opera House is only four meters above an inlet of the Pacific Ocean whose level is set to rise significantly.
- New York-Newark. The Jersey coast, Staten Island, the western part of Long Island, and southern Manhattan are all deemed high risk areas according to the US Geological Survey.
- Shanghai. With currently 2.3 million inhabitants deemed to be vulnerable, China’s economic powerhouse has an elevation of only four meters above a rapidly-rising sea.
- Kolkata. Like several cities on this list, Kolkata’s location on a river delta adds significantly to its risk of flooding. The population living on the southern side of the vast Indian city are particularly vulnerable.
- Miami. An OECD study described Miami’s $461 billion of real estate assets as the world’s most financially expensive risk area for coastal flooding.
- Ho Chi Minh City. Arguably the least-developed city on this list, Vietnam’s southern metropolis is likely to experience greater loss of life than more modern cities, adding to the tragedy for the former Saigon.
- Mumbai. The vastness and density of Mumbai’s population and its regular monsoons are likely to make future sea level rises especially disruptive.
- Guangzhou. As cities tend to be warmer than their surrounding countryside, the warm air rising from them can produce heavier local rain falls. This fact, added to Guangzou’s vulnerable position on the Pearl River Delta, makes China’s third city a higher-than average flood risk.
- New Orleans. The city is currently eight feet below sea level. Need we say more?
Flood defences are expensive. How they should be funded goes beyond the realm of personal lifestyle choices. It’s ultimately a political question. If Perrette’s predictions are correct, cities need answers soon.