A $20 billion plan to gird New York with levees, flood gates and other defenses is a bold stroke from a mayor who saw the city through Superstorm Sandy and has championed preparedness for global warming. But the future of Mayor Michael Bloomberg’s sweeping proposals will largely rest with his successor.

The slate of projects Bloomberg outlined Tuesday marks one of the biggest, most ambitious plans ever for defending a major U.S. city from the rising seas and severe weather that climate change is expected to bring. Recommendations range from installing removable flood walls in lower Manhattan to restoring marshes in Jamaica Bay in Queens, and from flood-proofing homes to setting repair timeframe standards for phone and Internet service providers.

With less than seven months left in office, Bloomberg said his administration plans to start on projects such as fortifying beaches and to begin designing others and lining up money, but he acknowledged much of the work would extend beyond his term.

“It’s up to you,” he told a crowd of officials and others at the Brooklyn Navy Yard, “to hold the next administration accountable for getting it done.”

With that said, the ideas face an uncertain political landscape amid the bevy of candidates seeking Bloomberg’s job, including at least one who suggests the proposals may be needlessly expensive. It also remains to be seen what kind of support – financial and otherwise – they might get from the federal government and other entities, not to mention from New Yorkers themselves.

Several mayoral candidates praised the mayor for thinking big, and Democrat Sal Albanese, Republican George McDonald and GOP front-runner Joe Lhota said they were inclined to pursue its major projects. Democratic front-runner Christine Quinn, who heads a City Council that is making its own proposals, called Bloomberg’s report “a roadmap for future mayors.”

Others raised some caveats.

Democrat Bill de Blasio, the city’s elected public advocate, praised the all-encompassing approach but said officials need to ensure the plan does enough to help the poor and doesn’t rely too much on uncertain federal support.

And Republican John Catsimatidis, who has questioned whether the effects of climate change are overstated, wondered in a statement whether the city could spend considerably less and still get adequate protection.

“The $19.5 billion price tag is a huge amount of money,” said the billionaire candidate, whose businesses include oil, real estate and grocery stores.

Bloomberg said the city and federal money already allocated for Sandy relief would provide $10 billion for the project, and the city believes it could get at least $5 billion more from the federal government. Other options include a small surcharge on homeowners’ insurance, around $1 a month for a homeowner who pays a $1,000 premium a year, according to a 400-page city report on the plan.

Environmentalists, real estate interests and local officials hailed the plan as far-reaching and comprehensive. “The mayor has rightly decided to face the future,” Natural Resources Defense Council Executive Director Peter Lehner wrote in a blog post. The proposals would dwarf the estimated $12 billion that the Army Corps of Engineers has spent so far to improve the New Orleans area’s floodwalls, gates and levees since Hurricane Katrina in 2005.

In lower Manhattan, a removable system of posts and slats could be deployed to form temporary flood walls rising from ground level along the waterfront. The height would depend on the ground elevation and potential surge. The approach is used along some Midwestern rivers and in the Netherlands, city officials said.

Projects also include a 15-to-20-foot levee to guard part of Staten Island, building dunes in the Rockaways, building barrier systems of levees and gates to bar one creek from carrying floodwaters inland, and possibly creating a levee and a sizeable new “Seaport City” development in lower Manhattan.

Bloomberg acknowledged some projects could block water views and otherwise prove controversial. But “if we’re going to save lives and protect the lives of communities, we’re going to have to live with some of the new realities,” he said.

After Sandy, at least some New Yorkers are ready for it, Staten Island Borough President James Molinaro said.

“The constituents that I talk to would take a 15-foot wall tomorrow,” he said.

The plan doesn’t call for moving people out of coastal communities. And it dismisses building major sea barriers with gates and levees, an idea some researchers and residents have promoted but Bloomberg has long called impractical.

That wasn’t welcome news to Julie Menin, who chaired a lower Manhattan community board that called for a study of the idea in 2010. “It is something that we think needs to happen,” Menin, who is now running for Manhattan borough president, said Tuesday.