The San Francisco Bay of the future will be significantly larger, rising between 4 inches to more than three feet by 2100, Will Travis told the Palo Alto City Council Thursday.

Travis, the executive director of the San Francisco Bay Conservation and Development Commission (BCDC), addressed Palo Alto leaders and a few members of the public Thursday at the invitation of outgoing Councilwoman Dena Mossar, who has served on the BCDC.

BCDC is a state agency formed in 1965 to stop the Bay from shrinking due to development built on fill. Travis recognizes the irony.

"The good news is all that Bay we lost to filling we get," Travis said. "The bad news is we have built all kinds of expensive stuff on that low lying land that is absolutely essential to life as we know it."

The grandfatherly figure with a keen sense of humor isn't planning on allowing the Bay Area to shy away from the massive challenge posed by the rising waters.

Acting on a 2006 official state climate report, the agency created a series of maps that depict the size of the Bay with an additional meter of water, a scenario Travis calls "the worst end of the best case scenario." If one of the gigantic ice sheets covering Greenland or Antarctica plops into the ocean, then the sea level will jump well over a meter almost immediately, he said.

For Palo Alto, nearly everything east of Highway 101 would be underwater, with water even stretching across the freeway to other low-lying areas. The current maps are tentative and are being refined, with revisions expected in 2008, Travis said.

"We hope the maps we produced will bring home the message that global warming isn't just a problem that's limited to penguins in Antarctica and polar bears in Alaska," Travis said.

Nothing, not even switching off all power plants and parking all cars, is capable of stopping global warming now, Travis said. During the 20th century, the Bay rose seven inches already, he said. He likened the region's position to that of the captain of the Titanic: Even though we've spotted the iceberg, we can't avoid it, Travis said.

"It's just too late, we missed our chance," Travis said.

But it's imperative to try to minimize the region's emissions by promoting high-density development amenable to public transportation, Travis said.

The Bay Area will already see a drastic increase in severe storms, wildfires and increasing Bay salinity, all critical problems that will tax the region, he said.

"We need to stop thinking about protecting the Bay and restoring the Bay to the way it was," Travis said. "Instead we need to design the Bay for the way it will be in the future. … We need to engage in proactive, adaptive management."

The region needs to come up with a plan to adapt and prepare, Travis said. As part of the plan, he proposes that BCDC's jurisdiction should be expanded to include all lands likely to be inundated within 50 years, a change that would significantly alter the powers of local government, which currently control most land use decisions. A development proposal would then need the approval from a local entity, such as the City of Palo Alto, and BCDC.

Local communities would also be tasked with identifying needed levees and proposing plans to relocate non-critical low-lying development, according to a strategy document Travis distributed Thursday. The proposed plan would also list the most critical facilities, such as the San Francisco International Airport, that need protection.

"I see planning for dealing with climate change is much like dealing with seismic safety," Travis said.

The Bay Area will need to build many levees capable of withstanding both floods and earthquakes. It needs more wetlands, which act like a giant sponge capable of mitigating floods and sucking up carbon dioxide.

And that might be doable. About $100 billion of buildings, roads and other development is threatened by the water, but the cost of protecting that could be around $5 billion, Travis said. The Association of Bay Area Governments (ABAG) is currently refining the estimates, he said.

Despite the challenges, Travis is optimistic.

"We have the good fortune to live in a region that is destined to be a world leader in climate change," he said.

The Bay Area has money, innovative people and organizations, the need to protect billions of dollars of threatened property and a tradition of being "politically courageous," Travis said.

"We have to succeed because there's too much at stake for us to fail," Travis said.