Did you know that Lakshadweep may not be an archipelago of 36 islands anymore? A recent study has claimed that the uninhabited island of Parali I of Bangaram atoll has disappeared due to coastal erosion. Five other biodiversity-rich islands in the atoll will soon vanish too, it claimed. If you live in a coastal city and regularly visit its beaches, you may have noticed steady changes in the coastline. Sometimes you may have found the sea to have receded and other times, it’s the beach – as if the waves have taken a bite of the sandy coast, when they retreated. This removal of beach or dune sediments or wearing away and breaking up of rocks (in the case of rocky shoreline) by wave action and tidal currents is called coastal erosion. Coastal erosion is a natural phenomenon. It shapes the coastline. What is removed from one coast is often deposited further down on another coast.Large storm-generated waves could have a more severe impact long-term loss of sediments and rocks. Geographically, this process maintains the balance of erosion and accretion (deposition). The problem arises when human activities andphenomena such as tsunami interfere with the natural rhythm and precipitate erosion. Rise in sea level caused by global warming also has its effects in accelerating the process. Anthropological effects that trigger beach erosion include the construction of artificial structures near the coast, mining of beach sand, offshore excavation or drilling and building of dams. Why does it matter? Coastal instability threatens property and puts people living in coastal regions at risk. Coastal degradation will lead to displacement of people. The fishing communities will lose their primary livelihood. Big cities will face pressure fromhuman migration. The rise in sea level will also accelerate coastal erosion to the extent of sinking islands as it has been observed in the case of Lakshadweep. It will affect coastal cropland, ecosystem and biodiversity. The rise in sea level will lead to a rise in coastal flooding events. Erosion will also affect tourism. Where solution is the problem Structures such as seawall, revetments and jetties are built to protect properties from being destroyed by erosion, but these armours only aggravate the problem. This is because they are often improperly designed, constructed andmaintained. When sea water reaches them, it bounces off them with more energy than a wave washing back off a normal sand beach. More sand is carried offshore, leading to beach loss. When the structures are built to stop erosionat specific places the adjacent coast is left to erode. Points to remember * Coastal erosion and accretion are natural processes. They become a problem when exacerbated by human activities, natural disasters or sea-level rise. * Erosion is widespread in the coastal zones of Asia and other countries in the Indian Ocean. * Population growth and unmanaged economic development along the coast compound the issue. * Understanding the key processes of coastal dynamics and altering human activities accordingly along the coast is crucial. * Coastal forest and trees provide some protection and their clearance has increased the vulnerability of coasts. * Presence of vegetation will improve slope stability, and diminish the amount of wave energy moving onshore. * India’s coastline is 8,414 km long. The eastern and western coastline have a greater differentiation in terms of economic activities, population, industry and infrastructure. * Forty five % of the country’s coastline faces erosion, according to a study published in 2015. It took into account satellite data of over 15 years.