Will we lose all our beaches underwater as sea levels rise? Won’t it take years for new beaches to form?


Will we lose all our beaches underwater as sea levels rise? Won’t it take years for new beaches to form?

In: Earth Science

Yes, but actually no. The rise will cover some current beaches. But it will take time, and much of the sand will be washed up on the new beach area. Eventually it will be so high that many miles of coastline will be underwater. Imagine the lower half of Florida underwater, so there will be much less actual beach

Yes and no. Or it’s complicated. It depends on the local geography and what humans do. Some areas will flood. Some areas will form new bays and estuaries. Take a look at how coastlines have changed in geologic time. A lot depends on what we do. We build sea walls and it changes the flow of water and sediments for large areas of coastline. We dredge rivers to make them deeper. Diapers an jetties all change the rate of sedimentation.

Your question implies that beaches as recreation are important to you.

In our lifetime “fun” beaches will remain with periodic issues of erosion, of more or less severity.

Our great-great-grandchildren will have an entirely different relationship with beach holidays.

So, yes, in the intermediate term [100 years], we are losing the typically understood holiday beach venues.

Yes, it will take millenia to re-draw the coast and establish beaches. This assumes we take explicit action to slow climate change.

If we don’t take action [and maybe if we do…the hour is late], we’re looking at inexorable Polar melt with a concomitant sea-level rise.

In this case, the loss of beach holidays is the smallest of our concerns.

You need to keep in mind that sea level rise isn’t an immediate process. The most extreme rates are currently millimeters to centimeters per year. Wave action can likely move the sand around quick enough that your favorite beach isn’t gonna be swallowed by the sea. However local geology is a massive factor in this, and the rate of inland advance depends highly on the angle of the beach.

Beaches will migrate uphill. Waves push sand up the slope, and then the draining water pulls some of it back. As the sea level increases, that’ll happen further inland than today.

And barrier islands will likewise migrate shoreward.


Don’t think so. I don’t know much about this, except I was on a beach that had moved once. You can swim out 50m and find the remains of houses and a school that were built in the 60’s. The “ruins” are mostly just foundations and septic tanks now, and it otherwise looks like a normal beach.

So if that beach was fine with conquering a human settlement I assume others can do it too.

When Hurricane Irma hit the north shore of Cuba in September 2017 – specifically the resort area of Cayo Coco and surrounding islands – the beaches were completely washed away as waves pounded inland for several hundred meters. When I went to Cayo Coco in February 2018, some of the resorts were just beginning to reopen (having been rebuilding since the previous September), and far out from the shore, massive hydrovac ships were pumping sand back to the shoreline to reestablish the beaches. Many kilometers of beaches were rebuilt with 50-100 feet+ of new waterfront sand.

I would think that as water rises slowly, and infrastructure and buildings become old, damaged, or not worth saving, that there is a lot of private and government money ready to rebuild beaches at new sea levels to maintain waterfront holiday spots whenever that time comes.

Beaches are going to be the least of your worries. Food supplies are going to get hit hard. Coastal cities will suffer catastrophic water damage. Droughts will become commonplace. Large swaths of formerly fertile if not lush areas will turn into new deserts as it becomes too hot for vegetation to survive. Fires will devastate timber and wild lands.

I’m not sure I buy the “sand will be redeposited” theories.

What happens on all of the Southern California beaches? There are houses there. The ocean rises two feet and they are either gone or protected by a sea wall.

If the houses go away, the land is usually pretty flat. You’re not going to get a bunch of people to give up their houses so the beach in the middle can have a place to restore.

If you put up a a sea wall, there’s no beach.

That’s just SoCal but there are lots of places with similar geography.

They won’t be lost. Some might look crummier because waves haven’t had enough time to level the ground further inland.

*Caveat- Natural coastline beaches won’t be lost. Beaches in front of cities and settlements definitely will be lost as some sort of seawall will be added to stop erosion, and thus stopping beach formation.

It would take thousands of years to make a noticeable difference and the beach would be made gradually with it

Many beaches have sand that’s been dredged. Some communities will be able to move more sand where it’s needed, but others won’t have the resources to do that.

No. Disease, famine, and extreme weather events will kill most of us decades before our beaches recede in any noticeable way

Beaches in urban areas that are delimited by streets with buildings and roads are probably going to disappear unless those streets are removed

You won’t have to worry. We are going into a grand solar minimum in the next few years and it will last for decades, cooling the earth.

There’s no one answer-in some cases we’ll lose beaches, in some cases the beaches will move higher than before, in some cases conservation efforts to save them will work and the original beaches will be protected. Overall though, yes, there will be a large loss of beach ecosystems as beaches do take years to form.

There is a story a read where a beach disappeared overnight due to change in currents or a storm. And then years later it reappeared when another storm or hurricane came in.

The forming of the sand takes ages but the tides and currents and storms can move sand beds very quickly.so as the oceans rise the beaches will just be pushed inland most likely.

Ideally, no, the rates are slow enough that the beaches will migrate with the change in sea level. There are situations where we humans have developed the near back-shore zone where the beaches ought to migrate if/when water rises, but the presence of human infrastructure will interfere with the natural migration. People won’t be all that complacent about beaches migrating onto their property (or later, the ocean migrating onto their property).

It is possible, likely even in many places, that the beaches will relocate laterally (like if there are rocky headlands that won’t allow sand accumulation, the sand will migrate downshore somewhere). These sorts of things already happen.

Some beaches and barrier islands will get lost and become off-shore bars rather than beaches, but how each and every situation will modify in response to changing sea level is very much dependent on the specific circumstances of the location.

So, there are plenty of sources of beach or shore erosion that are exacerbated by sea-level rise.

If you’re slowly losing land in a river estuary due to channelization, dredging, loss of silt and so on sea level rise will accelerate that. Large chunks of the gulf coast particularly Louisiana are experiencing this.

Construction of sea walls and other barriers concentrates the energy of wave action and shifts it around so the places that didn’t previously experience flooding or pounding surf now do. This is implicated in significant damage to New York and Long Island during hurricanes. New sea walls means you old flood surveys and models no longer work in dramatic ways which make planning hard.

Low lying barrier islands may no longer provide the shore with as much protection as the did previous thereby increasing erosion in places not previously prone to it. Barrier islands in the Carolinas Texas and Florida are being less effective over time.

It’s not so much that we lose beaches entirely though we do lose some, it’s more that we lose our current shoreline, the built environment that assumes the old boundaries, the habitat along our shores, and a lot of low lying islands including inhabited ones. Places like Kiribati or costal Bangladesh aren’t going to be inhabitable.