California’s primary source of water is at risk because the sea level is gradually rising and will begin to contaminate the Sacramento-San Joaquin River Delta estuary with ocean water. The Sea level is predicted to rise 3 to 7 feet by 2100, depending on how fast Antarctic and Greenland ice melts. A 3-foot rise in sea level would inundate the Delta estuary west of Route 5. A larger catastrophe is also looming because any one of several known potential glacier collapses would significantly exceed current sea level rise predictions.