Washington is announcing a goal of retrofitting or removing all of its flood-prone buildings by 2050, the first major U.S. city to set such a policy.

The proposal is part of a broader plan to protect Washington, which is home to 700,000 people and the headquarters of most federal agencies, from climate change and other threats. That plan, called “Resilient DC” and released Monday, sets a range of goals for coping with increasingly severe floods and heat waves, the major climate stresses projected for the city, which sits at the junction of the Anacostia and Potomac Rivers.

“Confronting climate change means setting bold goals for the future,” Washington Mayor Muriel Bowser said in a statement. She said the resilience plan “builds on our reputation as a leader in the response to a changing climate.”

The plan would apply to all buildings, including homes, businesses and hospitals. The District says it also wants to include federal government buildings, though it has limited authority over them. The proposal envisions “a mix of regulations, incentives and outreach” to address each building.

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The initiative comes as cities around the country face a growing toll from climate change. The Congressional Budget Office recently projected that hurricanes and storms will consume 0.3 percent of the nation’s GDP, while bond rating agencies warn that ignoring extreme weather will hurt cities’ credit ratings. In response, cities are looking at everything from new types of private disaster insurance to gigantic coastal-protection projects.

Washington’s proposal marks a new approach to that problem. The plan includes tougher building codes for new buildings, constructing new flood-resistant infrastructure and helping residents understand the climate risk they face. But retrofitting or moving the structures that already exist in flood plains may be the plan’s most aggressive proposal, measured by the cost and amount of change it could entail.

“It’s not going to be cost-effective for every building to say, here’s how we’re going to flood-proof it,” Kevin Bush, Washington’s chief resilience officer and the lead author of the strategy, said in a phone interview. “In some cases, we’re going to have to figure out how to do managed retreat and relocation.”

Bush said the plan is to first project which buildings will be at “significant” risk in 2050, and then sharing that information with the owners.

“I want to be very inclusive with the process to determine appropriate levels of risk,” Bush said. “The scenarios we use and level of risk we accept can’t be decided unilaterally.”

It’s too early to know how much the effort might cost, or who would pay for it, Bush said. The goal at this point “is putting that line in the sand, so that we can organize around it, and then come up with the tools that we need.”

Being resilient to climate change requires addressing the buildings that already exist in high-risk areas, according to Bush.

“I can’t think of another city that has articulated this,” he said. Simply focusing on tougher standards for new or renovated buildings “is not going to get you where you need to be.”

A challenge for the plan may be the number of federal government buildings in Washington, over which the city has less authority. The headquarters of at least seven federal agencies are located within the 100-year flood plain, according to documents obtained by Bloomberg News in 2017 through a public-records request.

Included on that list are the main offices of the Environmental Protection Agency, the Internal Revenue Service and the Justice Department. Also in the floodplain is the Trump International Hotel, which President Donald Trump’s company has leased from the U.S. General Services Administration.

“Obviously we’re not going to be able to have the same set of requirements on the federal government as we would on private property,” Bush said. “That doesn’t mean we can’t work with them, and come up with tools from a D.C. perspective that they can use.”

Another challenge, Bush said, is finding new homes in the city for the residents whose houses can’t affordably be retrofitted. The problem is that Washington, like other places around the country, is facing both a housing shortage and climate change at the same time.

“Those two big changes are in conflict with each other,” he said, noting that the city’s resilience plan also addresses both affordable housing and income inequality. “You can’t seriously address climate change without also understanding what we need to do to grow more inclusively.”