Researchers had previously analysed satellite images showing shoreline change from 1984 to 2016. They found that a quarter of sandy beaches worldwide had already eroded at a rate of more than 0.5m per year, shedding over 28,000 sq kilometers of land to the sea. The rate at which sea levels are rising is accelerating by about 0.1mm per year each year; but it is said that the sea level rise won’t be even across the globe.
Sandy beaches occupy more than one-third of the global coastline and of all the different types of beaches, sandy beaches are the most heavily used by people. Many coastal areas have been built on for industry, housing and tourist resorts, this has taken place in Sri Lanka too. The build-up of concrete structures at the landward fringe of sandy beaches has created an abrupt barrier to coastal retreat, preventing beaches from moving inland as sea levels rise; thus sandy stretches of coastline are at risk of being eroded and washed away entirely.
Soft sandy beaches are continuously moved by waves and currents – depleting them in certain areas and depositing them in others. This transport of sand is normal is a natural phenomena that has been disturbed by human interference in many countries; with combined force of higher sea levels and stronger storms spell extinction for many beaches.
For humans are actively accelerating coastal erosion by removing sand from beaches in enormous quantities and at much faster rates than it can be naturally renewed. Gravel and sand is extracted from rivers and on beaches for use in construction – and at a faster rate than fossil fuel extraction in some areas. Refer to Environmental Toll on Sri Lanka due to uncontrolled sand mining @ https://northernbreeze.blog/2020/03/08/hidden-environmental-toll-on-sri-lankan-due-to-uncontrolled-sand-mining/
Further, coastal ecosystems that bind and trap sediment, like mangrove swamps, are also being destroyed. The world lost almost 10,000 sq km of these habitats between 1996 and 2016; in Sri Lanka the destruction of mangrove increased during the war-zone areas. But conservation measures are visible at present, especially along south coast areas of Jaffna peninsula @https://northernbreeze.blog/2020/02/10/mangrove-conservation-visible-along-south-coast-areas-of-jaffna-peninsula/
Coastal nourishment would have to be done with careful attention to the local environment can just reduce the rate at which we are consuming sand and burning fossil fuels. Such coastal nourishment could reduce land loss and lower the number of people that might be forced to migrate and shrink the cost of forced migration.Further with the moderate emission mitigation policy the global emissions could reduce the landward retreat of shorelines and this would save more sandy beaches around the world. Thus expanding and protecting coastal habitats the said terrible predictions might never come.
According to a new study, published in Nature Climate Change, up to half of the world’s sandy beaches are at risk of disappearing by the end of this century if no action is taken to limit greenhouse gas emissions. Even with a better outcome from action on climate change, where global emissions peak around 2040, over one-third of the world’s beaches would be lost by 2100. With the ice at the poles already melting as ocean and air temperatures keep rising causing ice on land to slide into the ocean; displaces ocean water to cause sea level to rise. The sea level will rise everywhere on Earth, depending on local factors including tectonic effects and subsidence of the land, tides, currents and storms. Thus sea level rises can influence human populations considerably in coastal and island regions.
In this context, the new Colombo Port City span on 269 hectares, (2.69 sq kilometers) of reclaimed land with 65 million cubic meters of sand from the sea. It is currently the single largest private-sector development project in Sri Lanka, set to boost the economy alongside existing development plans; with state-of-the-art living, working, public and recreational spaces.
Climate change is a serious concern, with sea levels rising as the ice caps melt, while hurricanes and storms also contribute to the destruction of low-lying coastal areas. Estimates vary, of course, but it’s predicted that sea levels could rise over a meter in thirty years, and while that might seem like nothing, it would make a huge difference to many coastal cities, that include the Port City of Colombo. For rising sea levels are predicted to cause ‘chronic and disruptive flooding’, enough constant flooding to make parts of the city permanently uninhabitable in another few decades,
Northern Breeze 