A new study looking at the costs of sea-level rise in coastal communities has found that Long Beach would have to spend an estimated $246.3 million in the next two decades for seawall protection.

The report released Wednesday by Center for Climate Integrity is billed as the first such study to give a dollar amount to the cost of building seawalls to protect communities against rising sea levels due to climate change. The Center for Climate Integrity is an advocacy group that supports litigation against oil and gas companies over climate change and other issues.

The study, done in partnership with an engineering firm, broke down costs by state, city, county and congressional district. Overall, it found that communities across the country would have to spend a total of more than $400 billion on seawalls and other barriers to protect against flooding by 2040.

Florida is the most impacted state with an estimated cost of $76 billion, while 23 counties are facing at least $1 billion in expenses.

California would need to build an estimated 1,785 miles of seawall throughout the state for a minimum cost of $22 billion. The Bay Area’s Solano County would be hit the hardest, with an estimated cost of $2.7 billion.

California coastal cities with big costs:

1. San Diego: $357.2 million

2. Fremont: $347.5 million

3. San Francisco: $256.4 million

4. Long Beach: $246.3 million

5. Newport Beach: $235.8 million

6. Huntington Beach: $228.9 million

7. Sea Ranch: $228.6 million

8. Imperial Beach: $211.8 million

9. Stockton: $194.1 million

10. Bodega Bay: $179.8 million

Richard Wiles, the group’s executive director, said the study took a conservative approach when measuring predicted water level rises with the costs of barrier construction. Wiles said fossil fuel companies should be held accountable for the effects of climate change.

“As things stand, taxpayers are on the hook for all of these costs,” he said.

The study notes that 14 cities and counties, including Richmond, Santa Cruz, Marin, San Mateo, Imperial Beach, Oakland and San Francisco have sued oil and gas companies for the costs associated with adapting to climate change.

The Los Angeles Region Report of California’s Fourth Climate Change Assessment, which relies on a scenario characterized by increasing greenhouse gas emissions, projects a 1- to 2-feet of sea level rise by 2050.

In Long Beach, large swaths of Naples, Belmont Shore and the Peninsula could eventually be under water with predictions that a rapidly warming ocean will rise 6 to 22 inches by 2050 and as much 6 feet by 2100.

The situation is more dire in some areas, like the Belmont Shore avenues of Bay Shore, Claremont, Pomona, which are at high risk of chronic flooding by 2030. In all, the city stands to lose as much as 8% of its property tax base in the next three decades due to lower home values in the coastal area, officials have said.

The city is working on a report that will serve as a guide for action and adaptation to climate change, beyond just sea level rise. The report is expected this fall.