DATE: March 13, 2019

SNIP: In the most extensive study to date on sea level rise in California, researchers say damage by the end of the century could be far more devastating than the worst earthquakes and wildfires in state history.

A team of U.S. Geological Survey scientists concluded that even a modest amount of sea level rise — often dismissed as a creeping, slow-moving disaster — could overwhelm communities when a storm hits at the same time.

The study combines sea level rise and storms for the first time, as well as wave action, cliff erosion, beach loss and other coastal threats across California. These factors have been studied extensively but rarely together in the same model.

The results are sobering. More than half a million Californians and $150 billion in property are at risk of flooding along the coast by 2100 — equivalent to 6% of the state’s GDP, the study found, and on par with Hurricane Katrina and some of the world’s costliest disasters. The number of people exposed is three times greater than previous models that considered only sea level rise.

In the USGS study, published Wednesday in the Nature journal Scientific Reports, researchers brought together a number of models that examined wave action, tides, coastal erosion and flooding in California under sea level rise scenarios ranging from 0 to 2 meters (6.6 feet). On top of these projections, they added four different storm scenarios: average daily conditions, typical annual storm, 20-year storm, and 100-year storm.

For example, with only 0.25 meters of sea level rise projected to occur by about 2040, the number of Californians exposed to flooding might not seem too significant — but add a 100-year storm, and almost seven times as many people are at risk.