Mostly True
Sierra Club
"Our community (Tampa Bay) is one of the 10 most threatened by the sea level rise in the world."

Sierra Club on Monday, February 22nd, 2016 in a letter from Tampa Bay Group chairman Kent Bailey to Hillsborough County commissioners

Tampa Bay among top 10 regions most threatened by climate change, Sierra Club chapter says

A jet skier uses Bayshore Boulevard in Tampa after winds and storm surge flooded the street in 2004. (Tampa Bay Times photo)

The head of Tampa Bay’s Sierra Club chapter warned the Hillsborough County Commission that building more roads will only make global warming’s consequences worse for the entire region.

Chapter chairman Kent Bailey told commissioners in a Feb. 22, 2016, letter that the Sierra Club would not be supporting a proposed half-cent transportation sales tax referendum known as Go Hillsborough.

Bailey said the measure doesn’t set aside enough money to pay for expanding mass transit. He argued that adding more roads and more cars to an already congested system will only make matters worse by increasing carbon pollution.

"Our community is one of the 10 most threatened by the sea level rise in the world," Bailey wrote. He added that the Tampa Bay area will be among the first to suffer from flooding caused by climate change.

There’s no doubt the oceans are rising, and Tampa Bay will feel the effects. But is the region among the most endangered in the world? Let’s just say that we found the bay area has a lot to lose.

Flooding vs. sea level rise

There are a bunch of ways to measure how climate change will affect the world’s cities. People will be displaced, economies will be ruined, or you may end up with not enough water (or too much). These are all issues Tampa Bay faces, so buckle up.

When we asked Bailey how he came up with his ranking, he said he was referring to potential property losses, mostly in terms of real estate.

"We can move our people. But our fixed assets are a different story," he said.

He cited several sources, including a report from global-warming researchers Climate Central, and a Scientific American article that said St. Petersburg was in particular danger from sea level rise.  

He also pointed to a 2008 paper from the international Organization for Economic Cooperation and Development. The study focused on the effects of climate extremes on port cities — particularly storm surge.

Coastal flooding is different than sea level rise, but experts told us Bailey is using a fair benchmark for comparison. Vulnerability to storm surge and sea level rise often are conflated in discussions on climate change, they said.

"They are related, but not exactly the same," said Ben Strauss, vice president for sea level and climate impacts at Climate Central. In general, sea level rise can make a big impact on flooding, and will assuredly make storm surges and flooding worse in the future.

David Hastings, a marine science professor at Eckerd College in St. Petersburg, said storm surges are especially dangerous in Tampa and St. Petersburg because of the relatively shallow offshore shelf in the Gulf of Mexico. Higher sea levels will make surges even more dangerous.

But back to the OECD study: Economists examined 136 port cities and found that Tampa and St. Petersburg together were among the 10 cities with the most property at risk to wind damage and coastal flooding from storm surge. And that’s for right now, let alone after sea levels increase.

"The top 10 cities in terms of assets exposed are Miami, Greater New York, New Orleans, Osaka-Kobe, Tokyo, Amsterdam, Rotterdam, Nagoya, Tampa-St. Petersburg and Virginia Beach," the paper read. 

Those rankings could get better if steps were taken to mitigate flooding, the study said. But they could also get worse, as cities grow and gain more people. The effects of subsidence (the physical earth below the city changing or sinking, which is a major issue in Tampa Bay) and the changing climate could magnify the risk, too.

Many of the same economists revisited the rankings in a 2013 study published in the journal Nature Climate Change. Tampa-St. Petersburg came in as the seventh-most at risk of flooding.

If you’re looking for a price tag for how much Tampa Bay stands to lose, the OECD has one: In a catastrophic, once-in-100-years flood, losses to the region currently could be $49.6 billion.

University of South Florida oceanography professor Gary Mitchum noted real estate losses are only part of the story. As the oceans rise permanently, the region’s tourism-based economy will suffer extensively. Many people who can afford to simply move away probably will, but low-wage workers dependent on disappearing service industry jobs will be stuck.

Of course, the region’s property loss ranking may change some as population, planning and even geography shift. But these are from economists, considering economic impact. If we examined this another way — say, how many people will be permanently displaced by the eventual coastal floods that won’t recede — other places will have it much worse than Tampa Bay.

Even the OECD researchers said their rankings would be different by that measure. Cities in China and southeast Asian countries, like Bangladesh and Vietnam, will be much more affected that way. It’s much harder to quantify how the human toll will affect regions because you can’t easily attach a dollar amount to it.

"The social impact of this is much more complicated," Mitchum said. "The result that you get depends on how you assess it."

Our ruling

Sierra Club's Bailey said, "Our community (Tampa Bay) is one of the 10 most threatened by the sea level rise in the world."

He cited credible research that showed the region is among the most at risk of property damage from coastal flooding. He’s conflating that research with the effects of sea level rise, but several experts told us the problems are related.

It's striking that Tampa Bay is already in great danger when it comes to potential property loss, but Bailey should have been more specific. There are other ways to measure the consequences of rising oceans beyond real estate. When we consider some of these factors, other major cities could be considered worse off than Tampa Bay.

The statement is accurate but needs clarification. We rate it Mostly True.