Two Dozen U.S. Cities Are At Risk Of Disappearing Underwater: Study 

According to a study published in the leading scientific journal, Nature, at least 24 coastal cities in the U.S. are at risk of significant flooding by the year 2050. The study, led by Virginia Tech researchers, compiles data obtained through satellite measurements of sinking land, also referred to as subsidence. Virginia Tech has released a detailed map showcasing forecasts of sea-level rise and tide patterns.

500,000 Americans Will Potentially Be Impacted

For the study, researchers thoroughly assessed the potential risk for flooding for 32 cities that are located around the Pacific, Atlantic, and Gulf coasts.

The study forecasts that as many as 500,000 Americans may potentially be impacted. At least one in 35 private properties is likely to be impacted by flood damage within the next three decades.

People Don’t Often Recognize the Severity of The Issue

It is often hard for people to grasp the imminent danger that U.S. coastline cities are facing.

Leonard Ohenhen, a grad student and the lead author of the study, said, “One of the challenges we have with communicating the issue of sea-level rise and land subsidence broadly is it often seems like a long-term problem, like something whose impacts will only manifest at the end of the century, which many people may not care about.”

Not Too Far Into The Future

Explaining the projected timelines for the study’s findings, Ohenhen said, “What we’ve done here is focused the picture on the short term, just 26 years from now.”

Virginia Tech released a study in early March revealing that 24 out of the 32 cities studied are experiencing a subsidence rate of over 2 millimeters every 18 months. This rate of subsidence is significant, especially when considered alongside the gradually rising sea levels.

Akin to Being On A Sinking Boat

Ohenhen provided the analogy of a sinking boat to explain the gravity of the situation. Ohenhen said, “Imagine you are in that boat with a steady leak, slowly causing the boat to sink. That leak symbolizes sea-level rise or broadly flooding.”

Ohenhen added, “What would happen if it also starts raining? Even a minor rainfall or drizzle would cause the boat to sink more quickly than you thought it would.”

The 32 Coastline Cities Collectively Have 131 Flood Control Structures

The 32 cities that were part of the study collectively have 131 flood control structures. Half of these structures are situated along the California coast.

Conversely, the Atlantic Coast appears to be a lot more vulnerable considering the fact that only three out of 11 highlighted cities have levees or floodwalls.

Not Enough Measures Have Been Taken Along the Atlantic Coast

Ohenhen said, “When we looked at it across the board, we found that there is a general unappreciation for flood protection, particularly on the Atlantic coast.”

Ohenhen added, “And even the levees there often protect less than 10 percent of the city, compared to other cities on the Pacific or Gulf coasts where up to 70 percent is protected.”

Miami Can Go Underwater

Miami is among the list of cities that are at the highest risk of disappearing underwater.

In South Florida alone, around 80,000 homes are at risk of disappearing underwater. This puts approximately 122,000 residents in jeopardy. The potential damage is estimated to be around $31 billion.

The Additional Challenges of Racial and Socioeconomic Factors

Some of the coastal cities, particularly those around the Gulf coast, are likely to face additional challenges due to racial and socioeconomic factors.

Cities like New Orleans (LA) and Port Arthur (TX), have racial minorities living there and also properties with values below the median. Hence, these cities are likely to be disproportionately impacted whenever flooding happens.

The Goal Is To Help People Make Informed Decisions

Talking about the results of the study, associate professor Manoochehr Shirzaei said,” The whole purpose of this paper is to provide data to support decisions.”

Shirzaei added, “It’s likely nobody has received the entire picture until this study, which creates probably the first comprehensive picture of what’s happen in the not-too-distant future.”

Rising Sea Levels

The study, published in Nature, says, “The sea level along the US coastlines is projected to rise by 0.25–0.3 m by 2050, increasing the probability of more destructive flooding and inundation in major cities.”

The report further elaborates, “However, these impacts may be exacerbated by coastal subsidence—the sinking of coastal land areas—a factor that is often underrepresented in coastal-management policies and long-term urban planning.”

The Consequences of Climate Change

The study also emphasizes the importance of understanding the consequences of climate change across the globe. It says, “The widespread consequences of global climate change stress human communities and ecosystems worldwide.”

The study adds, “Climate change is already causing an increase in the frequency and intensity of heatwaves, hurricanes and wildfires and severely affecting the world’s freshwater resources through sea-level rise (SLR), more frequent droughts and changes in precipitation and evapotranspiration and these effects will almost certainly grow in the future.”

The Goal Is To Help Cities Plan and Adapt Better

According to Nicholls, a climate adaptation professor, “This study demonstrates that we can now measure vertical land motion at a sufficient scale to create a useful climate service that supports planning and management decisions on flooding.”

Nicholls added, “This approach has the potential to be applied in any city around the world, really supporting adaptation.”

Previous Forecasts Hadn’t Taken Into Account The Rate At Which The Cities Are Sinking

While prior flood forecasts evaluated the rise in sea levels, they hadn’t taken into account the highly alarming rate at which many U.S. coastline cities are sinking.

Ohenhen  pointed out, “The omission of subsidence in previous flood estimates can largely be attributed to its gradual nature, which often escapes immediate notice.”

No Reasons to Continue Making Excuses

Shirzaei emphasized that the goal of the study is to help people take preemptive measures and not be caught totally by surprise when the flooding happens.

Shirzaei said, “Very often, we hear, ‘Oh, we didn’t know about land subsidence’ or, ‘We didn’t know about that other factor,’ but this study will take away those excuses from everybody.”