Millions more people the world over will be at risk of coastal flooding from climate-driven sea-level rise later this century.
That’s the conclusion of new research conducted by Climate Central, a US-based non-profit news organisation.
It finds that 190 million people will be living in areas that are projected to be below high-tide lines come 2100.
Today, the group calculates roughly 110 million are presently occupying these lands, protected by walls, levees, and other coastal defences.
The future at-risk total assumes only moderate global warming and therefore limited ocean encroachment.
Climate Central’s investigations, published in the journal Nature Communications, have sought to correct the biases in the elevation datasets previously used to work out how far inland coastlines will be inundated.
When this new CoastalDEM is used in tandem with population statistics and the latest forecasts for sea level rise, it becomes apparent that many more people are entering a precarious future.
The improved elevation data finds that even with moderate reductions in greenhouse gas emissions, six Asian countries (China, Bangladesh, India, Vietnam, Indonesia, and Thailand), where 237 million people live today, could face annual coastal flooding threats by 2050. That’s roughly 183 million more than assessments based on prevailing elevation data.
Under a pessimistic future of continued high emissions, CoastalDEM suggests up to 630 million people live today on land that is projected to have annual flood events by 2100.
For 2050, this number is 340 million, up from the estimated 250 million people who already live in this predicament.
In general, the CoastalDEM-derived estimates of the global population at risk from coastal flooding are three times greater than the values produced using just the shuttle information.
“We estimate one billion people now occupy land less than 10m above current high tide lines, including 250 million below 1m,” the team tells Nature Communications.
BBC