Rising Seas Are Likely to Sow Havoc Much Sooner Than Predicted - Mother Jones

Around the world, communities are bracing for sea level rise: the Netherlands is stabilizing its dikes, Senegal is relocating neighborhoods, and Indonesia is moving its entire capital city. These projects are hefty, expensive, and slow.

But they may need to pick up the pace. As new research shows, in many places, sea level rise will cause coastal flooding and other disruptions much sooner than anyone realized. It’s not that the water is rising faster; it’s that the land was lower to begin with.

The problem [with previous estimates], according to the new study by Ronald Vernimmen and Aljosja Hooijer, two data analysts working on flood risk in Southeast Asia, is that time after time, the measurements of coastal elevation that scientists feed into their models have been wildly inaccurate. In tropical forests, says Vernimmen, these misinterpretations can be off by 20 meters or more.

The scientists’ big finding is that forests and buildings along the coast have skewed radar maps, presenting planners with inaccurate elevation data. Lidar showed coastlines often lower than first realized. This has two important implications: the same amount of sea level rise will be able to reach much farther inland, and it’s going to happen a lot sooner than expected.

The risk is greatest for river deltas in tropical regions where the land is flat, the population is often high, and the data tends to be old. With two meters of sea level rise, by around the year 2150 under a high-emission scenario, the Niger Delta in West Africa and Myanmar’s Irrawaddy Delta will have five times more land underwater than the older radar-based estimates suggested. The same is true for the Chao Phraya delta, which spans metropolitan Bangkok, Thailand’s capital of 11 million.

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Mother Jones

Locations: Netherlands Senegal Indonesia Niger Delta Irrawaddy Delta Chao Phraya River West Africa Myanmar (Burma) Bangkok, Thailand Thailand 

People: Ronald Vernimmen Aljosja Hooijer 

Tags: Climate Change Ocean Sea Level 

Type: Headlines