On Tuesday, Climate Central released a major new study and an online map showing that sea level rise and coastal flooding could affect hundreds of millions more people in the next 30 years than previously understood by the research community and global institutions. It has been covered by news media around the world.
Assessments based on improved elevation data show that without existing, augmented or new coastal defenses, land currently home to 300 million people is at risk of flooding at least annually by 2050, and land home to 150 million could be permanently below the high tide line. By the end of the century, the tideline could climb above land now occupied by 200 million people. Asia faces the greatest threats by far. (Because high-quality lidar-based elevation data are already available for the United States, our previous maps and analyses remain a better source there.)
These findings are based on merely mid-range sea-level projections and on CoastalDEM®, a new, peer-reviewed elevation dataset developed by Climate Central using sophisticated machine learning techniques that correct for systematic errors in the principal elevation dataset used until now for international assessment of coastal flood risks. CoastalDEM-based estimates of the global population occupying land at risk across a wide range of scenarios are three times or more greater than those produced using older data.
For us at Climate Central, these findings have been more than three years in the making. Here are some resources to learn and do more:
- Our peer-reviewed scientific paper in Nature Communications, covering multiple sea-level scenarios
- Our interactive world map (note: continue to use Risk Zone Map for the U.S.)
- Our new report, Flooded Future, with findings by year and country
- CoastalDEM® data are available for download and free for noncommercial use
The dangers of sea level rise are far greater than previously thought — and so are the benefits of cutting climate pollution and preparing for higher seas.
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