BOSTON MAYOR MARTY WALSH on Wednesday laid out an expansive plan for public projects to combat the impacts of climate change in Boston, a city whose vulnerability has been exposed in recent storms and tidal surges.

“It’s a system not of barricades but of beaches – and parks and trails and open spaces – that are elevated to block floods and enhanced to unlock opportunity,” Walsh said of the plan.

The idea is to elevate low-lying roads, build seawalls, and redevelop areas to create natural barriers, which according to Walsh will add 67 acres of greenspace to Boston’s 47-mile shoreline. The plan calls for changes affecting Charlestown, East Boston, the North End, downtown Boston, Dorchester, and South Boston.

The mayor was unable to affix a cost estimate to his plan, but said that it will require funds from the federal government, the state, private companies and from philanthropies.

“The investments you make now are the savings of tomorrow,” Walsh said.

John Cleveland, executive director of the Boston Green Ribbon Commission, a group of business and civic leaders, thinks the projects could cost up to $4 billion.

“This plan weaves a series of visions together. I think it’s exactly the right message,” Cleveland said. “There are study plans in place for the Charlestown and East Boston projects, which together could reach $1.5 billion. There need to be more studies done, and once all of the plans are in place, I think we’ll have a decent sense of the cost.”

When asked more about the funding by reporters, Walsh said that there is already a funder lined up for the project, but that he would not release any names.

Charles River Watershed Association Executive Director Emily Norton called the mayor’s plan “commendable.”

“As he notes, investing in resilience in the form of parks and wetlands brings many co-benefits to residents in terms of open space and recreational opportunities, and, we would add, water quality,” Norton said. “However this is only the beginning. Funds need to be allocated and tough decisions need to be made about development – where it happens and how. For example there are still not requirements on developers in terms of investing in resilience, there is only a voluntary checklist.”

The mayor’s speech also serves as a way to move on from the idea of building a barrier in the harbor. In the last year, there were three large-scale Boston Harbor barrier proposals suggested in the city’s Climate Ready Boston report. But a feasibility study from researchers at the University of Massachusetts Boston advised against building the multibillion-dollar wall.

“Neither barrier system appears to be cost-effective,” the report’s executive summary says. Additionally, the study assumes it would take at least 30 years for a harbor barrier to be erected.

During his speech, Walsh pointed to a recent report by the United Nations’ Intergovernmental Panel on Climate Change which found that climate change effects could be felt as soon as 2040, where the planet could be up to 2 degrees warmer, making parts of the world uninhabitable due to flooding or extreme heat.

“We don’t have to look that far for early warning signs,” Walsh said, pointing to the damaging nor’easter storms in Massachusetts last spring.

Some think the mayor isn’t moving fast enough. Deanna Moran, the director of environmental planning at the Conservation Law Foundation, says that action is necessary.

“Boston’s leadership in developing climate strategies must move from plans to specific projects that protect the City’s waterfront neighborhoods, our economy and future generations from rising seas and extreme weather,” Morgan said in a statement. “We cannot keep creating plans without meaningful action on the ground.”

Walsh promised that 10 percent of all new capital spending in Boston would be dedicated to the new resiliency projects, and added that the city has applied to the Federal Emergency Management Agency for $10 million to advance the work.

Some of the projects include redesigning East Boston’s Constitution beach to combine flood protection with expanded access, transform the parking lot at Sargent’s Wharf in the North End into a combination of open space and small-scale development and working to elevate transportation corridors like New Ellery Street along Dorchester Avenue in South Boston to create both flood protection and pedestrian connections throughout the neighborhood.

This is not the first time Walsh has promised to fight climate change. The proposed projects build off of a series of programs the city previously introduced, such as a city resilience strategy and Imagine Boston 2030. Last June, the mayor led an International Mayors Climate Summit in which he created a coalition of cities pledging to research and promote renewable energy solutions.