A report from the National Research Council projects six inches of sea level rise along Southern California's coast within 20 years.
Rising seas will push cliffs back and eat into beaches — and with sediment trapped behind dams, wetlands will starve. By the end of the century, most of California from Mendocino southward will experience sea levels a meter higher than they are now.
Subsiding land contributes to that measured rise; land subsides in part because of water pumping, and gas and oil exploration.
Modeling predicts melting polar ice contributes significantly to rising seas too.
The team of researchers behind the report declined to make recommendations based on their data, but public policymakers along the west coast of the United States say they can use the information to make plans for coping with impacts to homes and businesses along the coast.
Federal agencies, Oregon, Washington and the state of California all cosponsored the research. A governor's order has directed California's state agencies to plan for sea level rise.