Beaches Disappearing under Climate Change

March 2, 2020

Guardian:

Almost half of the world’s sandy beaches will have retreated significantly by the end of the century as a result of climate-driven coastal flooding and human interference, according to new research.

The sand erosion will endanger wildlife and could inflict a heavy toll on coastal settlements that will no longer have buffer zones to protect them from rising sea levels and storm surges. In addition, measures by governments to mitigate against the damage are predicted to become increasingly expensive and in some cases unsustainable.

In 30 years, erosion will have destroyed 36,097km (22,430 miles) or 13.6% of sandy coastlines identified from satellite images by scientists for the Joint Research Centre (JRC) of the European commission. They predict the situation will worsen in the second half of the century, washing away a further 95,061km or 25.7% of Earth’s beaches.

These estimates are far from the most catastrophic; they rely on an optimistic forecast of international action to fight climate breakdown, a scenario known as RCP4.5. In this scenario of reduced ice-cap melting and lower thermal expansion of water, oceans will only have risen by 50cm by 2100.

However, if the world continues to emit carbon at its current rate, sea levels will rise by an estimated 80cm, according to the Intergovernmental Panel on Climate Change. If this happens, a total of 131,745km of beaches, or 13% of the planet’s ice-free coastline, will go under water.

Around the globe, the average shoreline retreat will be 86.4 metres in the RCP4.5 scenario or 128.1 metres in the high-carbon scenario, though amounts will vary significantly between locations. Flatter or wilder coastlines will be more affected than those where waterfronts are steeper, or those artificially maintained as part of coastal development.

In the best-case scenario, the UK will lose 1,531km or 27.7% of its sandy coast, and 2,415km (43.7%) in the worst case. Australia (14,849km lost) and Canada (14,425km) are predicted to be the worst-affected countries, followed by Chile (6,659km), Mexico (5,488km), China (5,440km) and the US (5,530km). The Gambia and Guinea-Bissau have short coastlines, but both are predicted to lose more than 60% of theirs.

“The length of threatened seashores incorporates locations that will be submerged by more than 100 metres, assuming there are no physical limits to potential retreat,” said Michalis Vousdoukas, an oceanographer at the JRC and lead author of the study, published in the journal Nature Climate Change. “Our 100-metre threshold is conservative since most beaches’ width is below 50 metres, especially near human settlements and in small islands, such as the Caribbean and the Mediterranean.”

Large beaches will narrow by 100-200 metres on Atlantic and Pacific coasts and the Australian side of the Indian Ocean, wiping out more than 60% of sand deposits in a number of developing countries that are economically fragile and heavily dependent on coastal tourism.

But swift action to limit emissions and fight climate breakdown could help reduce the impact, experts say. “Moderate emissions mitigation could prevent 17% of the shoreline retreat in 2050 and 40% in 2100, thus preserving on average 42 metres of sand between land and sea,” Vousdoukas said.

22 Responses to “Beaches Disappearing under Climate Change”

  1. rhymeswithgoalie Says:

    The Texas coast, for one, has been suffering a deficit of beach sand due to the damming of rivers. (Paraphrasing one geology professor: One of the primary functions of rivers is to erode high land and move it to the sea. One of the primary functions of dams is to capture sediment and prevent it from moving to the sea.)

    Another problem in the last few years is sand piracy. Sea and river sands are stolen from unprotected beaches to be resold to construction companies and resort beaches.

  2. tootallken Says:

    I was thinking about the loss of beaches the other day, but I don’t think they get used for frac sand. Here’s a primer on frac sand. https://geology.com/articles/frac-sand/

    Most frac sand comes from the midwest because the high quartz content. I live near some oil and gas fields in Colorado and long sand trains regularly arrive all the way from Minnesota and Wisconsin. You can always recognize them because they have short covered hopper cars and lots of locomotives–the stuff is heavy!

  3. redskylite Says:

    “Where we now see water, our farming land used to be, it was very big, nearly three hours’ walking distance. We all lost our farmland to the sea.”

    https://www.reuters.com/article/us-climate-change-myanmar-erosion/rising-sea-levels-put-myanmars-villages-on-frontline-of-climate-change-idUSKCN20L040


  4. The sand lost by these beaches is not lost to the world. It has to go somewhere. There might be new beaches elsewhere.

    • redskylite Says:

      Unfortunately seldom we read about new beaches appearing, unless they are man made, it seems much more common for the eroded beach sand to be lost out at sea.

      Littoral Cell

      A littoral cell is a distinct area of the coastline where sand enters the ocean, flows down the coast, and then is removed from the system. Permanent loss of sand occurs at the end of the littoral cell when it flows into a submarine canyon or, less frequently, when it accumulates on shore as part of a sand dune. The amount of sand available to beaches is the amount of sand flowing into the littoral cell minus the amount flowing out. If this sand budget is altered, beaches can narrow or even disappear.

      • redskylite Says:

        “Sea level rise is inevitable, but how bad it will be is still not certain. Replenishing the most endangered beaches by pumping sand onto them – a process called “coastal nourishment” – could cost USD$65–220 billion in total, but that’s still less than one-fifth of the economic cost of taking no action at all on sea level rise. It could reduce land loss by up to 14%, lower the number of people that might be forced to migrate by up to 68%, and shrink the cost of forced migration by up to 85% by 2100.”

        http://theconversation.com/half-of-worlds-sandy-beaches-could-disappear-due-to-sea-level-rise-by-2100-132688

        • Gingerbaker Says:

          Could there be a more stupid way to spend climate funds? Hard to imagine.

          • dumboldguy Says:

            What’s even harder to imagine is that much of this sand pumping is meant to protect the second “homes at the beach” of the rich folk—-who only use them for part of the year (the part where they’re not at their winter homes in the ski areas or in the Caribbean).

        • rhymeswithgoalie Says:

          Some communities along the Atlantic coast spend a lot of money replacing sand lost to a storm, then a couple of years later they lose that, too.

          Hurricane Matthew (Cat 5 in 2016) crawled offshore along the coast, sparing many communities from landfall storm surges, but eating their beaches with prolonged rough surf.

    • smurfix Says:

      Not if it’s just washed off the coast and spread on the sea bed. Also the sea level is rising …

  5. redskylite Says:

    “That includes developing “nature-based” solutions, including restoring wetlands and creating oyster beds that can buffer the effects of sea level rise. It also references managed retreat, a lightening rod in climate change dialogues in San Diego. Gold said consideration of managed retreat should focus more on public infrastructure, such as the Coaster train or Port of San Diego, instead of private property.

    Another target proposes an “infrastructure resiliency plan focused on state roads, railroads, wastewater treatment plants, water supply facilities, ports and power plants by 2023.”

    “What can we do to ensure that the port, which is an economic engine for San Diego, is protected,” he said. “So we’re trying to reframe that dialogue. Managed retreat is a tool of last resort.”

    The plan also aims to minimize ecological effects of ocean warming by “protecting, restoring or recreating” 10,000 acres of coastal wetlands by 2025. And it calls for updating water quality rules to combat ocean acidification and low ocean oxygen, reduce sewage discharge to the ocean, and increase water reuse.”

  6. dumboldguy Says:

    An excellent book about the stupidity that rules along America’s coasts, with particular emphasis on the mistakes made in New Jersey.

    THE GEOGRAPHY OF RISK: EPIC STORMS, RISING SEAS, AND THE COST OF AMERICA’S COASTS by Gilbert M. Gaul, Sarah Crichton Books, 2019

  7. smurfix Says:

    What’s the time between these images?

    • dumboldguy Says:

      There are many sets of “before and after” images like these from many parts of the country’s coasts. Most of them have been taken only a few days apart—before and after a major storm—-that’s what makes them so notable—-how vividly they show the power of the ocean and its ability to wash away large quantities of sand almost overnight.


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