BOSTON – On a sunny summer's day at historic Christopher Columbus Park on Boston's waterfront, it's hard to picture the dormant fury of the Atlantic Ocean as it laps softly at the creaking docks.

But one day, according to the city’s climate projections,a massive storm driven by unusually high winds and high tides will pour water over the park's grassy rise and inundate the arbors where grape vines trail and newlyweds pose for photos. The waters will rush across the brick pavers onto Atlantic Avenue and flow toward historic Faneuil Hall and Quincy Market, where generations of tourists have learned about the Boston Tea Party. The floodwaters will threaten nearby Old North Church, where Paul Revere's ride kicked off, and lap at the edges of Bunker Hill.

High tides and strong storms already regularly inundate the area, but this storm would be different. It's a vision that keeps Boston Mayor Marty Walsh up at night.

That's why Walsh is preparing to have the city spend billions of dollars over the next decade to try to blunt the effects of climate change on the city, including armoring Columbus Park and gently raising it to provide a buffer against the worst of what the Atlantic can throw.

The plans to harden Columbus Park and large portions of the city's 47 miles of shoreline are part of a massive but generally uncoordinated local-level effort across the country to fight the changes that will accompany the Earth as it continues warming.

Frustrated by what they see as the Trump administration's decision to de-emphasize the danger posed by climate change, local government officials, nonprofit leaders and university researchers are busily forging ahead with limited resources in a piecemeal approach they say is better than nothing. They're hardening buildings, digging bigger storm drains and changing zoning laws to keep homes from being built in low-lying areas prone to flooding.

While many cities and states are also trying to reduce emissions of greenhouse gases to slow global warming, these more concrete efforts are aimed at mitigating the actual impacts of climate change, which many elected officials say is politically easier to tackle.

“Climate change is real and it’s impacting our city right now,” said Walsh. “We just can’t back down from the threat regardless of what’s happening in Washington, D.C. I would love to have a strong federal partner. We don’t have that right now. But that doesn’t mean we stop.”

An exhaustive federal report issued last month warned that climate change could, under a worst-case scenario, deliver a 10 percent hit to the nation's GDP by the end of the century. The 1,600-page National Climate Assessment details the climate and economic impacts U.S. residents will see if drastic action is not taken to address climate change.

President Donald Trump downplayed the report's findings, complaining that the United States is already very "clean" and that other countries aren't addressing climate change.

“I’ve seen it. I’ve read some of it. It’s fine," Trump told reporters at the time. Speaking about the potential economic impacts, Trump said, “I don’t believe it.”

Broad scientific consensus says the Earth's climate is warming, and that humans are accelerating that process though the burning of fossil fuels. Climate change threatens the health and well-being of the American people by causing increasing extreme weather, changes to air quality, the spread of new diseases by insects and pests, and changes to the availability of food and water, the NCA researchers said.

The report says the changing climate poses a cascading series of linked risks, like storms destroying aging bridges and roads, which will then make it harder to move food and fuel around the country, and droughts making it harder for power plants across the West to safely generate electricity due to a lack of required cooling water. Meanwhile, larger insect populations in northern areas could bring more Lyme, West Nile and Zika infections to areas that were once free of them.

"Earth’s climate is now changing faster than at any point in the history of modern civilization, primarily as a result of human activities," the report concluded.

Experts say the devastating and unusually powerful hurricanes that have struck the East Coast over the past decade have done more than any politician could to raise awareness of just how much risk the nation faces. Heavy flooding in Texas, warming ocean waters in the Pacific Northwest and New England, and eroding islands in Alaska are adding even more weight. Scientists for years have been warning that ocean levels are rising, and that storms will become more violent.

"The number of people having that conversation is larger today than it ever has been in the past,” said Mark Misczak, who a longtime emergency manager who spent the bulk of his career as a Federal Emergency Management Agency leader under multiple presidents. "The disasters, as terrible as it sounds, provide an opportunity to re-envision how things function and to consider that resiliency."

Across the country, communities large and small are drawing on university experts and nonprofit scientists to help chart their course, which they say must be laid down to prepare for future climate-related disasters.

Some of the efforts are small, like Denver's decision to create a list of air-conditioned facilities where residents can take refuge during heat waves. Others are more ambitious: In Alaska, officials are preparing to relocate several native villages in danger of being washed away by seas that no longer freeze solid for months at a time. Many more fall into the middle, like the decision by Florida Keys officials to raise up portions of their low-lying roads to serve as flood barriers, or efforts by Austin, Texas, to reduce water consumption in anticipation of droughts in.

"It's really simple: This isn't a political issue. The changes we are seeing firsthand are affecting our communities, our economies, affecting ways of life that have existed for millennia," said Michael LeVine of the nonprofit Ocean Conservancy, which has worked on climate change issues in Alaska. "We simply don't have a choice. It is incumbent on us as Alaskans to work together. We are past the point of fighting about who did what, who caused what, or what the political consequences might be. Our way of life depends on adapting to the changes that are happening."

For many, dealing with climate change is inherently a political issue. A December report issued by the state of Texas about the need to "future-proof" the state from worsening natural disasters never directly mentions climate change, or the role that humans have played in emitting heat-trapping carbon dioxide by burning the oil and gas Texas has long been known for.

Republican Gov. Greg Abbott, in releasing the report, said it was "impossible" for him to say whether climate change is causing the worsening disasters hitting Texas.

"We need to stop making the old mistakes in local development that expose homes and businesses to risks that only become apparent when disaster strikes," according to the report. "To paraphrase the old saying, an ounce of preparation is worth a pound of cure."

While climate change has largely broken down along partisan lines at the state and federal level, the nation's mayors have overwhelmingly put aside political parties to address the issue. A survey of mayors this year found that 57 percent of cities are planning to take climate-related actions in 2019. And dozens of the country's largest cities have committed to meeting the terms of the 2025 Paris Agreement on climate change, which Trump is withdrawing from on a national level.

"I think every mayor in the country would say it's their responsibility to do something," said James Brainard, the longtime mayor of Carmel, Indiana. "Our mayors are not sitting back. The mayors are the closest elected officials to the people and the mayors can make this happen regardless of what the federal government does."

Brainard, a Republican, said he doesn't consider climate change a political issue, but he acknowledged he sometimes has to tailor his message for different audiences. Liberal groups, for instance, love that the city replaced it's streetlights with LEDs, reducing electricity consumption and therefore the emission of greenhouse gasses. Conservative groups, he said, are usually more interested in the fact that the switch saves the city 20 percent on its electricity bill annually.

Now, Carmel is installing solar panels to generate its own electricity, which will save taxpayers money and ensure the lights are more likely to stay on if a disaster knocks out major power lines outside city boundaries.

"Everybody sees local government as the pothole in front of their house, the zoning down the street. They don't think about these global issues," Brainard said. "And I think it's the job of local leaders to explain why it's important and to lead on it."

Many local officials say the federal government should play a stronger role in increasing a cohesive strategy to combat the effects of climate change, but find themselves frustrated by Trump’s apparent willingness to dismiss scientific concerns. In absence of that leadership, they're forging ahead.

“There’s a sense from cities and states across the country that we want to be part of the solution, and that just because the federal government isn’t doing it doesn’t mean the United States isn’t,” said Sally Jewell, a former interior secretary in the Obama administration. “We’re not going to stop and wait for that (Trump administration) priority to change.”

Jewell is now working at the University of Washington as a distinguished fellow with the College of the Environment and as chair of the advisory council for EarthLab, the university's new institute dedicated to connecting researchers with people on the front lines of climate change and environmental challenges.

EarthLab offers solutions both large and small, including helping Washington state's oyster farmers deal with more acidic oceans by showing them how to adjust the PH level of the water surrounding young oysters, known as spats.

Misczak said local governments often find success when they tie climate-resiliency efforts to impacts on local businesses. And he said that while the federal government can provide leadership, it's usually a series of seemingly small decisions made at the local level that can truly make a difference: Can homes be built in floodplains? How tough is the building code? Are local emergency services designed to operate in an actual emergency? Are emergency generators sitting in basements that could get flooded, or installed atop parking garages, where they'll be better protected?

"We're getting better. But we're not doing enough yet. We're making progress. And the more we can showcase the solutions that have been effective, the more communities will consider building things that way from the start," said Misczak, who is now senior managing director at Witt O’Brien’s, an international crisis and emergency response consulting company.

Back in Boston, Walsh is trying to figure out how to get funding for the city's climate resiliency plan. Taxpayers will contribute 10 percent of all new capital funding in the city toward resilience, but the mayor knows he needs more help from businesses, and the state and federal government.

The city has already installed an approximately $100,000, 7-foot-high barrier in order to block floodwaters from the homes of 4,300 residents and at least 70 businesses in the East Boston neighborhood. The barrier across the East Boston Greenway normally lays flat across the path but can be raised during storms. Boston used to be more protected from storms and high tides by the tidal flats that surrounded the city, but those areas have either been developed on or dredged away to deepen the harbor.

Bigger solutions come with bigger price tags: Just fully protecting East Boston, home to Boston Logan International Airport, could cost the city up to $200 million. But city officials say that would ultimately prevent more than $443 million in estimated damage from a large storm. Researchers expect sea levels to rise 36 inches by 2070, leaving Boston with the likelihood of being flooded every month during the highest tide.

The city's overall climate resiliency plan has no official price tag, but Boston officials say it would pale in comparison to the damage done by a major hurricane: 2012's Superstorm Sandy did at least $32 billion in damage to New York City's streets, subway tunnels, homes and businesses, and killed at least 43 people. And that was just a single storm.

"We're not just planning for the next storm we'll face, we're planning for the storms the next generation will face," Walsh said. "Whatever the federal policy is, it's still going to be incumbent on local leaders to carry out these plans. There's no question that our environment is in trouble, and humans are responsible."