Deltas sink worldwide, increasing flood risk.

• Author: Block, Ben
• Position: EYE ON EARTH - Brief article

Most of the world's major river deltas are sinking, increasing their vulnerability to severe storms and floods, new satellite studies find. Of the world's 33 major river deltas, 24 are sinking due to flood-control efforts and other human-caused changes to river systems. The study, published in the September 2009 issue of Nature Geo-science, "conservatively" estimates that the area vulnerable to flooding could increase by 50 percent worldwide.

An estimated 500 million people live on river...