As a coastal city, Boston is pretty well attuned to the threat of rising seas. Just a few years ago, we got an unwelcome preview of what’s to come when back-to-back storms washed out the city’s waterfront parks, inundated the MBTA’s Aquarium station, and forced firefighters to patrol downtown streets by boat.

But the climate threat in these parts isn’t just about more frequent flooding. It’s also about extreme heat. And that could pose an even greater threat.

Heat already kills more people in the United States than flooding, tornadoes, hurricanes, or cold. And the latest projections for the region are worrisome. A recent study led by University of Massachusetts Boston researchers found that even if the world does an especially good job of curbing carbon emissions, we can expect that, by the end of the century, the area will have about 20 days per year with temperatures above 90 degrees, up from about eight to 10 days now.

And in a high carbon emissions scenario, we can expect a stunning 80 days per year with temperatures above 90 degrees.

The impact would be significant. Soaring temperatures would be a boon to pests, pathogens, and invasive species — and a blow to the region’s cranberry and maple syrup industries. In Boston, one study found, the heat-induced mortality rate is expected to triple over the next three decades.

The city government gets good marks for planning. In April, Mayor Michelle Wu released a 351-page heat resilience plan, with detailed analyses of which parts of the city get hottest (Chinatown, the South End, South Boston, and parts of Dorchester and Roxbury), data on the distribution of trees and public parks (there are fewer of these cooling elements in the poorest stretches of the city), and a sketch of some strategies the city might pursue to mitigate rising temperatures.

To start, then, the city needs to execute on its nascent plans. Mariama White-Hammond, Boston’s energetic chief of environment, energy, and open space, says the city is in preliminary talks with the MBTA about providing more shade at Silver Line bus stops. Officials are also discussing how to build more tree cover into street overhauls, beginning with a big Blue Hill Avenue project. And the city, she told the editorial board, is finalizing a contract with an outside vendor to create “cool roofs” — painting flat, dark roofs white, sharply cutting the heat they absorb. The goal is to install 10 such roofs in high-heat neighborhoods this summer.

But there is much more to be done.

One of the most important tasks for the city and other municipalities in the region is creating comprehensive early warning systems that alert citizens by text message and social media to coming heat waves — providing basic information on symptoms of heat exposure (nausea, dizziness, muscle cramps, confusion) and offering resources for staying cool and hydrated.

The city or state should also follow the lead of Seville, Spain, and start naming and categorizing heat waves, the way hurricanes are already named and categorized. That would raise the profile of these often deadly events and give the public some sense of their expected severity.

The city will also have to make sure its 311 information line is fully prepared to field inquiries during heat waves as they become more frequent and longer lasting. Last year, Multnomah County, Ore., faced sharp criticism after its 211 line fumbled calls during an extreme heat event that left at least 116 Oregonians dead.

There are a number of other policy changes that the city should consider.

Cars generate quite a bit of heat, and closing certain streets when temperatures spike could make a difference. The city could also offer incentives for developers who incorporate green roofs and other cooling measures into their plans — allowing them, for instance, to build more units than the zoning code would otherwise allow.

The city will also need to figure out how to lure the elderly and other vulnerable populations to its underutilized cooling centers. White-Hammond says the city is thinking about “hot bingo,” among other activities. That’s a good start.

New infrastructure is going to be required in Boston and other urban centers too — more trees, more fountains, heat-resistant pavements and coatings. And it all costs money.

Here, the state has an important role to play.

Three years ago, Governor Charlie Baker proposed a real estate transfer tax that would have poured more than $1 billion into climate resilience measures over the course of a decade. The bill went nowhere, but now advocates are calling for an even larger tax that would funnel money into both climate resilience and affordable housing. The Legislature should get behind it.

The state should also establish strong protections for construction workers, landscapers, and others who work outdoors, ensuring they don’t have to work in the sun when the heat is extreme.

The temperature is rising, just as surely as the tide. And the city, the region, and the state must be prepared.

Editorials represent the views of the Boston Globe Editorial Board. Follow us on Twitter at @GlobeOpinion.

Work at Boston Globe Media