Sea level rise, caused primarily by human-induced climate change, will pose a challenge to national parks on America’s coasts.

After months of controversy, the National Park Service last week finally released a report that said as much. To many, that’s an unenjoyable but logical statement. But in the age of Trump, getting that “human-induced” part into a government report was a hard-won battle. Though the report’s conclusions might not be shocking, its very publication is groundbreaking in an administration that has routinely denied climate change exists, let alone that it’s caused by our own actions.

Here’s why the report—both what it did and didn’t say—is important.

Some 'Reveal'-ing Background

In 2013, NPS hired University of Colorado Boulder scientist Maria Caffrey to lead a report detailing coastal parks’ vulnerability to sea level rise. The goal was to equip park managers with the latest data, but the innocuous paper turned contentious when President Trump took office in 2017.

As the investigative website Reveal first reported in April, release of the sea level report was delayed at least ten months while NPS officials combed out any mention of human-caused climate change. The revelation was a bombshell given the fact that Interior Secretary Ryan Zinke, just weeks earlier, said in a Senate hearing that censoring scientific reports was not taking place. “There is no incident, no incident at all that I know that we ever changed a comma on a document itself,” Zinke said at the time. “And I challenge you, any member, to find a document that we’ve actually changed on a report.”

Alas, the truth emerged. Documents obtained by Reveal showed such phrases as “anthropogenic climate change” being axed by NPS officials. Zinke claimed in a subsequent House hearing that he had no idea about the edits, but Democratic politicians were incensed; an inspector general investigation is pending. The censorship aligns with myriad Trump administration efforts, mostly in the Interior Department and the Environmental Protection Agency, to discredit mainstream climate science. But, at least in this instance, science won out.

“The fight probably destroyed my career with the [National Park Service],” Caffrey told Reveal, “but it will be worth it if we can uphold the truth and ensure that scientific integrity of other scientists won’t be challenged so easily in the future.”

Kiss the Coasts Goodbye

The report examined how rising oceans will affect 118 park units, and it’s clear that low-lying East Coast and Gulf of Mexico parks will be most affected. Unless efforts to curtail greenhouse gases take place, coasts outside the nation’s capital will see a 2.6-foot rise in sea levels by 2100, high enough that storm surges could flood the National Mall. Waters surrounding Wright Brothers National Memorial, on North Carolina’s Outer Banks, will see a 2.7-foot increase. At that level, a Category 2 hurricane would leave the park “almost completely flooded,” the report says. Harriet Tubman Underground Railroad, Cape Hatteras, and numerous others could see waters rise 2.5 feet. Like Wright Brothers, a Category 2 storm surge would flood pretty much all of Everglades National Park.

What the report’s predictions don’t consider, the authors note, is that much of America’s East Coast is slowly lowering into the sea, which magnifies the effect of rising waters. Using rough calculations, the authors figured that Jean Lafitte National Historical Park and Preserve, in Louisiana, could experience a relative sea level rise of nearly five feet by 2100.

Wait, It’ll Cost How Much?

National parks out west preserve scenery; back east, they mostly preserve history. Peppered in the report are historical battlefields, forts, famous-person residences, and other structures we’ve deemed important to keep intact for future generations. Flooding, of course, is incompatible with preservation.

Structures like Fort Jefferson, in Dry Tortugas National Park, sit literally at sea level. But even inland parks are threatened by storm surges if they lie along inlets or coastal rivers. This is problematic for a department that, as Zinke routinely reminds us, has a $12 billion maintenance backlog.

Failure to prepare for rising seas could be prohibitively expensive for NPS. In a report published in 2015 (back when it was safe to talk about climate change), researchers examined 40 coastal parks to see which were at risk if the sea level rose one meter. The cumulative value of roads, trails, buildings, campgrounds, and other at-risk structures surpassed $40 billion. But even before that study was published, its authors figured they had lowballed estimates. The immense damage wrought by Hurricane Sandy in 2012, they wrote, “suggests that we have been conservative in labeling an asset as high exposure. In other words, the assets identified in this study as being vulnerable are most certainly vulnerable, and the total is likely to be an underestimate.”

Zinke Could Make It All Worse

Zinke supports legislation that would tie park maintenance to energy receipts. Pending an unforeseen boom in wind and solar development, that means oil, gas, and coal receipts would fund repairs to the damage that burning oil, gas, and coal has wrought.

One might argue that slowing hydrocarbon production on public lands wouldn’t do much to stem the advance of global warming, but recent research suggests otherwise. If the federal government were to halt energy leases, one study found, U.S. carbon dioxide emissions would diminish 5 percent by 2030.

Acknowledging the human impact of climate change in this study was undeniably a win—it’s critical that government-sponsored scientists are able to report findings unvarnished by politics—but it’s probably not going to start a revolution of thought in the current administration. Drilling will continue apace. At least we now have an idea of which national parks will be underwater as a consequence.