As President Donald Trump backtracked Monday from his own administration’s scientific report underscoring the economic consequences of climate change, Honolulu Mayor Kirk Caldwell doubled down on the city’s commitment to adapting to the threats posed by a warming planet.

“There is no more important issue,” Caldwell said at a press conference outside Aloha Tower.

The National Climate Assessment, released Friday, highlights the financial consequences to businesses and taxpayers of not taking action on climate change. The report by 13 government agencies predicts a 10 percent hit to gross domestic product by the end of the century and billions of dollars in costs due to sea level rise, infrastructure needs and heat-related deaths.

Trump said Monday that he didn’t believe the report. But Caldwell, and numerous politicians on both sides of the isle, said it’s just another motivation to act now.

The mayor said he plans to devote his next State of the City address entirely to climate change, and was in meetings Monday morning discussing how much of the budget should go toward the issue.

Caldwell said there will be a “piecemeal” approach, driven by different communities requiring different strategies.

The mayor made it clear that Honolulu will need to be hardened in some areas. Buildings and roads will need to be raised in other parts of the city.

“It does not mean that we retreat from the urban core,” Caldwell said.

The tourism hub of Waikiki will remain in place, he said, as will other south shore areas such as burgeoning Kakaako. The mayor said moving the city landward would be prohibitively costly.

But for other parts of the island, such as the North Shore, Caldwell said there may be a need to retreat as waves and rising sea levels accelerate erosion.

“We may have to give up homes,” he said. “We may have to give up roads.”

Caldwell was joined on the pier by Honolulu Chief Resilience Officer Josh Stanbro, Honolulu Climate Change Commission Vice Chair Chip Fletcher, an author of the Hawaii and U.S.-affiliated Pacific Islands chapter of the federal report, and Honolulu Climate Change Commission member Victoria Keener, who served as the chapter’s lead.

Before, during and after the 30-minute press conference, there were signs of just how far the city and state have to go in terms of cutting Hawaii’s carbon footprint.

“People everywhere on the planet need to take action now.” — Honolulu Mayor Kirk Caldwell.

Huge shipping vessels carrying containers of goods from the mainland cruised into the harbor. A 666-foot U.S. Navy ship served as the backdrop on one side and a fossil fuel-burning power plant bookended the other side. Towering skyscrapers and hotels lined the shore and a steady stream of commercial and military planes flew overhead.

And while the state has committed to 100 percent renewable electricity by 2045, there are serious questions about how quickly the transportation sector can shift away from oil.

Hawaii tourism officials expect a record 10 million visitors next year to the islands — already home to 1.4 million residents and counting.

Caldwell said the city will continue to wean itself off fossil fuels, noting how more vehicles will be electric.

But there was less confidence in timely action in other major areas, such as airlines.  And the Honolulu rail transit project, which won’t be operational for some years still, plans to use fossil-fuel burning trains to start out.

The mayor left with a message of hope though. He noted that the city and state have committed to the goals set by the Paris climate accord and Honolulu’s climate change office that voters created in 2016.

A visitor from Guam, Steven Moylan, attended the city’s climate commission meeting Monday afternoon. He said the U.S. territory is “ground zero for climate change.”

He and his friend, a Seattle visitor, said they were encouraged by Honolulu’s work on the issue and the mere existence of commissions and agencies dedicated to it.

Fletcher said people can help by eating a more vegetarian diet, having smaller families, flying less, switching to hybrid or electric vehicles and living closer to work.

Small lifestyle changes this year, he said, followed by a little bit more in subsequent years, can help halt some of the worst effects of climate change.

“Our climate is changing,” Caldwell said. “People everywhere on the planet need to take action now.”