Sandy beaches are of great importance for people who live close to it as they consider it their home and source of living, and also for people who visit them from time to time to enjoy the beauty and silence of nature. But, these soft sands are now suffering from successive blows that change their features and threaten their existence.
As the world's coastlines become more vulnerable to erosion, flooding and storms due to climate change, humans have tried to protect them. But, the results were opposite to what was expected, as the third of the world's sandy beaches have become "hard" due to human-made infrastructure and structures, according to a recent study.
Grey infrastructure and coastal hardening
The term “grey infrastructure” refers to hard structures built by humans such as levees, dikes, harbors, or roads to protect coastlines from erosion and flooding.
Although these solid structures seem to be a good means of defense against climate phenomena, they make the beaches lose their natural ability to adapt to rising sea levels, and hinder the return of the sandy coastline, causing the phenomenon of coastal hardening.
The study, recently published in the journal “Nature”, showed that 33% of sandy beaches worldwide are currently suffering from “coastal hardening,” based on geospatial data derived from satellite images.
Most affected coasts
The study identified the five regions most affected by the phenomenon of coastal hardening worldwide, with an explanation of the percentage of sandy coasts covered by hard structures in each region. These are:
1- Bay of Bengal is currently covered by structures for about 84% of its coastline.
2- Western and Central European coasts (68%).
3- Mediterranean coasts (65%).
4- Western North American coasts (61%). 5- East Asia (50%).
The study also found that the proportion of coastal populations living within 100 km of the coast in the Bay of Bengal and the Mediterranean Sea is estimated at more than 50-75% of the total population, which underscores the urgent need for coastal protection and management.
Future risks
Due to the phenomenon of coastal hardening, the coasts lose their natural ability to adapt to future sea level rise, making them more vulnerable to severe erosion, with a large area of sandy beaches expected to be lost as the coastline recedes in the coming decades.
The study cites a number of examples of the erosion of a complete sandy beach in front of several solid structures, such as what happened in front of the sea barrier that was built on the Pacific coast in Santa Cruz County, California, USA, due to the effect of waves.
Also along the coast of Oahu, one of the largest islands in the US state of Hawaii, a gradual loss of beach in front of the sea wall has been documented.
The study, conducted by the Department of Water Engineering and Management at the University of Twente in the Netherlands, estimated the potential losses of sandy beaches in the future.
Based on the projections of the IPCC’s Sixth Assessment Report, which assumes that carbon emissions continue at the current rate, the world is likely to lose 21% of its sandy coastline (42,080 km) by the end of the 21st century.
Social and economic dimensions
Currently, about 10% of the world's population lives in low-lying coastal areas, a figure that is expected to reach 11.6% by 2050. And, as infrastructure and coastal protection measures are gradually developed, hard shorelines will increase and lead to significant social and economic impacts on the population.
The study results also show that most of the threatened sandy beaches are located within high and above middle-income countries, which are concentrated in eastern North America, northern South America, the Mediterranean coasts, the Bay of Bengal, West Africa, and Southeast Asia.
The researchers explain that the link between hard sandy beach losses and the economy reflects that high-income countries may have the resources to invest in coastal strengthening and maintenance structures, which, the results show, could lead to unintended consequences and greater beach losses in the future.
Finally, climate change is causing sea levels to rise, and coastal areas are increasingly at risk. Although these extreme weather events occur all the time, human activities are making them more severe and dangerous.
In order to protect coastal areas from erosion and flooding, without resorting to hard structures,
The study suggests eliminating carbon emissions to confront climate change and to reduce pressure on beaches, by adopting natural solutions, such as restoring sand dunes, wetlands and mangroves, and paying attention to neutral urban planning.
