<meta http-equiv="refresh" content="0; url=https://r.sealevelrise.org/https://sealevelrise.org/states/mississippi/"/> Mississippi's Sea Level Rise - Sea Level Rise

Overview

Mississippi’s Sea Level Has Only Risen 7” Since 1978

But It’s Already Costing Over $1 Billion

The sea level around Mississippi is 7 inches higher than it was in 1978.1 This increase is mostly due to Mississippi’s sinking land, and it’s causing major issues. Coastal communities, such as the ones along the Mississippi Sound, are protected by barrier islands that are eroding from sea level rise. As this continues, communities could be threatened.2 Ocean water is overflowing more often into the streets during high tides and rain storms. This is not only dangerous for homes, cars, and city infrastructure, but it can also affect drinking water. There are already over 14,000 properties at risk from frequent tidal flooding in Mississippi.3 The state is planning over $1 billion in sea level rise solutions, which include barrier island restoration, dredging, beach renourishment, and hurricane protection.

Sea level rise is speeding up

Although the sea has only risen by 7 inches since 1978, its speed of rise has accelerated over the last ten years and it’s now rising by over 1 inch every 2 years.1 We know this because the sea level is measured every 6 minutes.4 Scientists use different equipment like satellites, floating buoys off the coast, and tidal gauges to accurately measure the local sea level as it accelerates and changes.

Created with Highcharts 6.2.0

SEA LEVEL MEASUREMENT FROM BAY WAVELAND AREA TIDE GAUGE SINCE 1950

Causes & Complications

Why Are Sea Levels Rising?

While there are multiple causes for the sea level rise in Mississippi, land sinkage is the main contributor.5 The acceleration of sea level rise erodes the shoreline and puts barrier islands at risk. This added to already sinking land can speed up the effects of sea level rise even faster. Click here to learn more about sea level rise.

How Land Sinkage Increases Sea Level Rise

Most flooding happens in the fall

King tides are unusually high tides that generally occur during a new for full moon, or when the sun, moon, and earth align. In some places, king tides are brought on by changes in the weather and ocean patterns. In places like Mississippi, king tides are typically nearly a foot and a half higher than normal tides. Add that to the 7 inches of sea level rise since 1978, and you end up with flooding even on sunny days.1

Solutions aren’t simple

Rising sea level submerges land and erodes beaches, making the streets and buildings lower to the sea. Erosion of Mississippi’s undeveloped barrier islands leaves inland communities, that are protected by those islands, exposed. This can make solving for sea level rise both complicated and urgent.2

Forecast

What's the Future of Sea Level Rise?

In the last decade, the speed at which Mississippi’s sea level is rising has increased, and is now rising by over an inch every 2 years.1 Around Bay Waveland, it took 22 years for the sea level to rise around 6 inches.1 Scientists now forecast that the sea will rise another 6 inches in just the next 15 years.6

Scientists are not certain how fast the ocean will warm and ice will melt. They expect water levels to continue to rise faster, but are not sure just how fast. Therefore scientists from the National Oceanic and Atmospheric Administration (NOAA) and the US Army Corps of Engineers (USACE) have made predictions based on ranges from low to high.

Below you can see the range of the NOAA and USACE high and intermediate forecasts for various locations around Mississippi.7 We are currently closest to the USACE high forecast, which is the darkest red line.

SLR speeding up - Mississippi English
SLR speeding up - Mississippi English
Created with Highcharts 6.2.0Dauphin Island Sea Level Rise Forecasts

Flooding

Why Are Floods More Frequent?

When the ocean rises high enough, high tides cause flooding even on sunny days. Even though the sea level has only risen by around 4 and a half inches, tidal flooding has increased by over 180% in Mississippi since 2000.8

Flooding
How sea level rise affects Mississippi

Flooding even when there’s no rain

Drainage systems are designed to channel excess rainwater from the streets and drain it into the sea. But with the pressure from rising sea levels and higher tides, seawater can get pushed into these pipes and spill out into the streets. This causes flooding even on days without rain.

Drain A
Drainage Under Normal Tidal Conditions
Drainage With King Tide / Sea Level Rise

Increased storm surge flooding

Unfortunately, slightly higher sea levels make hurricanes even more damaging. Just a few more inches of sea level rise allow a hurricane to push more water onto the land, even if the hurricane itself doesn’t make landfall.

Hurricane Katrina, 2005

Higher sea levels create a higher launching point for storm surge. These small changes in sea level rise are enough to turn what were 100-year storm surges into much more frequent events. In fact, in a third of 55 coastal sites studied throughout the US, 100-year storm surges will be 10-year or more frequent events by 2050.9

This means that in many coastal cities, if you bought a house with a 30-year mortgage today, by the time you paid off your mortgage you could be experiencing extreme 100-year storm surges ten times more frequently due to sea level rise alone. This does not include the added risk of more intense storms resulting from warmer water and a warmer atmosphere, which could further increase storm surge damage.

In 2005, Hurricane Katrina made landfall in Hancock County as a Category 3 Hurricane, and caused $32 billion in damages to the state.10 Without sea level rise, Hurricane Katrina’s estimated 28 foot storm surge would have been lower.11

Hurricane Katrina, 2005

Costs

What's at Risk in Mississippi?

There’s a lot at risk from sea level rise and flooding in Mississippi, particularly the coastal communities. As the sea level rises, it makes existing coastal flooding more severe and it erodes beaches, eventually submerging wetlands and dry land.12 Undeveloped barrier islands help protect the coastal communities that sit along the Mississippi Sound. Sea level rise can erode those islands, washing away what little protection there was.12

Beaches
Beaches

Rising seas increase the speed of beach erosion, pulling more sand from the beach into sea. Replacing the sand is possible, but expensive.

Coastal Wetlands
Coastal Wetlands

Sea level rise can disrupt coastal wetlands, which puts important ecosystems in danger, threatens habitats, and leaves communities exposed to dangerous storm surge.

Homes & Cars
Homes & Cars

Storm surges or flooding can damage the underside of your car or the first level of your home.

In Bay St. Louis, there are 1,140 residential properties already at risk from repeated tidal flooding, by 2033 that number will increase to 1,237 as sea levels rise. In Gulfport, 306 properties at risk will turn into 420 within 15 years. In Biloxi there are 568 properties at risk, which will become 806. And in Gautier, there are 714 properties at risk, which will increase to 862 by 2033. Click here to explore other coastal areas in Mississippi that are at risk at FloodiQ.com.

Mississippi is spending over $1 billion

Some cities have sufficient resources to deal with this problem while others do not. Mississippi will need solutions at the individual, local, state, and federal levels to protect its coastal communities.

USACE
USACE

The Mississippi Coastal Improvement Program,12 developed by the USACE in Hancock, Harrison and Jackson counties, has an estimated cost of $1.06 billion dollars for barrier island restoration.13

Harrison County
Harrison County

Harrison County has spent $2.9 million since 2017 for beach renourishment, including hydraulic dredging and drainage system repairs.14

Mississippi
Mississippi

Since 2009, Mississippi has received $37 million in GOMESA funding to use for coastal conservation, restoration, and hurricane protection.15

What can you do?

Individuals, mayors, legislators, governors, and Congress can work together to build protections before flooding, to build back stronger after flooding, and to create plans that future-proof our communities. Click here to see what solutions can help protect your home or what your community can do.