A new research conducted by Climate Central, a US-based non-profit news organization, has conclude that later this century, millions more people will be put at risk because of coastal flooding due to rising sea levels driven by climate change.
The research also noted that areas that are projected to be below high-tide lines come 2100 will have about 190 million people lining there.
Currently about 110 million are presently occupying these lands, according ot the calculation of the group, which are now protected by walls, levees, and other coastal defences which prevent flooding.
The future at-risk total assumes only moderate global warming and therefore limited ocean encroachment.
The biases in the elevation datasets that have been used earlier to calculate the extent to which ocean inundation will happen for inland coastlines is sought to be corrected in the investigations by the Climate Central’, the report of which has been published in the journal Nature Communications.
Inputs from a space shuttle mission have delivered the most famous of these datasets.
Heights across the globe were mapped by a radar instrument in 2000 fitted atop the Endeavour orbiter. The resultant 3D model of the Earth is now one of the most used Earth observation datasets in history.
But that model suffers from biases because the images make the land look higher than it really is in some places, claimed the Climate Central team, of Scott Kulp and Benjamin Strauss. This issue is particularly acute in geographic locations that are covered in thick vegetation such as forests. This is because the radar tends to see the tree canopy and not the actual ground.
A computer was trained by Kulp and Strauss to make corrections to the shuttle’s digital elevation model (DEM) based on the data taken by more modern, higher-resolution information from airborne lidar (laser) instruments for this study.
Population statistics and the latest forecasts for sea level rise are used along with this new CoastalDEM which has made it apparently clear that a much greater number of people are at risk of ocean flooding in the future.
The difference between estimates based solely on the shuttle legacy data and the reworked elevations are illustrated in an interactive map produced by the team.
And it’s possible to see on this map how circumstances change depending on how well the world manages to constrain climate warming, which is pushing up ocean levels by heating the seas and melting ice stored in Antarctica and Greenland.
According to the study, currently up to 630 million people live on land where there is a projection of annual flood events by 2100. That number is 340 million for a projection till 2050 compared to earlier estimates of 250 million people.
“We estimate one billion people now occupy land less than 10m above current high tide lines, including 250 million below 1m,” the team told Nature Communications.
(Adapted from BBC.com)