A recent study from Climate Central, published in the journal Nature Communications, suggests as many as 150 million people live on land that will be underwater at high tide by 2050, even if global warming is kept to the Paris Agreement target of 2C – a threefold increase on previous estimates. Previous estimates of flood risk were based on estimates of land elevation derived from space-based radar, which tended to overestimate elevation, mistaking building or treetops for the surface. More accurate LIDAR measurements, which rely on aeroplane observations, have been conducted in the US, Europe, and Australasia. But missing data prevented accurate topographical measurements in Asia. The researchers correct this with machine-learning techniques, obtaining a more accurate estimate of elevation, which has revealed these greater risks from flooding caused by sea-level rise. However, the study also found that 110 million people already live in zones that would be underwater by high tide – evidence that coastal barriers and adaptation can be effective, at least up to a point.
- Kulp, S.A., Strauss, B.H. New elevation data triple estimates of global vulnerability to sea-level rise and coastal flooding. Nat Commun 10, 4844 (2019) doi:10.1038/s41467-019-12808-z