Sea Level Rise Causes, Impacts, and Solution

The sea, a vast and powerful force, has captivated humanity for millennia. But our planet's oceans are not static; they are in a constant state of flux. Sea level, the average height of the ocean's surface, has risen and fallen throughout Earth's history, leaving its mark on the land and its inhabitants. Understanding these changes is crucial, for they hold the key to our planet's past and future. Sea level changes can be global, affecting coastlines worldwide, or local, impacting specific regions. A rise in sea level can reshape continents, inundate low-lying areas, and alter ecosystems. Conversely, a fall can expose land bridges, create new coastal plains, and trigger shifts in plant and animal life. Throughout geological time, sea levels have fluctuated dramatically. During glacial periods, vast ice sheets locked up enormous volumes of water, causing sea levels to plummet. Conversely, interglacial periods, like the one we are currently experiencing, witness the melting of these ice sheets, leading to a rise in sea levels. These natural fluctuations have shaped our planet for millions of years. However, the rate of sea level rise we are witnessing today is unprecedented in human history. This rapid change is primarily driven by human activities, making it imperative to understand its causes and consequences. causes : The IPCC projections include estimates of contributions from: Ocean thermal expansion Glacier mass loss Greenland and Antarctic ice sheet surface mass balance (net change from the addition of mass through precipitation and loss through melting) and dynamic processes such as collapse of ice shelves Changes in land water storage (dams and ground water storage) Impact of sea level rise : coastal flooding intensity and frequency is increasing , earlier it was 1 in every 100 years now 1 in every 10 years. land size is decreasing due to sea level rise ; low-lying coastal areas are submerged; coral islands are (average height is 5 m or below) , will be lost if this rise of sea level continues . already many islands are being lost. submerged landforms : rias, fiords/fjords, submerged valleys, parallel islands to the coast (darmintia coast of croatia). some densely populated coastal cities are on threat of submergence and lost such as jakarta, manilla, Guangzhou, mumbai,etc-- coastal soils and water bodies are becoming saline. coral reef ecosystem : threats and challenges in the forms of coral bleaching, coral deaths, microfossil planktons such as foraminifera and diatoms sinking Higher projected storm surge and inundation levels. Landward recession or erosion of sandy shorelines. Depending on the rate and scale of sea level rise, the environmental, social and economic consequences or shoreline recession within low lying inter-tidal areas, in particular, may be significant in the medium to long term. Salt water intrusion and landward advance of tidal limits within estuaries. This may have significant implications in the medium to long term for freshwater and salt water ecosystems and development margins, particularly building structures and foundation systems within close proximity to the shoreline. Existing coastal gravity drainage, stormwater infrastructure and sewerage systems may become compromised over time as mean sea level rises. Sea level rise will influence the entrance opening regimes for intermittently closed and open lakes and lagoons and alter catchment flood behaviour over time. The level of protection provided by seawalls and other hard engineering structures will decrease over time due to increasing threat form larger storm surges and inundation at higher projected water levels. according to the study by 2100, the global population potentially exposed to episodic coastal flooding will increase from 128 -171 million to 176-287 million. the value of global assets exposed to these episodes is projected to be between $6000-$9000 billion, 12-20 %of the global GDP. GLOBALLY, 68% area that is prone to coastal flooding over 32% can be attributed to regional sea level rise by 2100. mitigation and adaptation measures against sea level rise :-- Hierarchy of Adaptation Options Avoid the risk. Identify future ‘no build areas’ and use planning tools to prevent new development in areas at risk now or in the future. Undertake a planned or managed retreat from the risk. Withdraw, relocate or abandon assets that are at risk and allow ecosystems to retreat landward as sea levels rise. Accommodate for the risk. Continue to use the land but accommodate changes by building in piles growing salt tolerant crops or converting from agriculture to aquaculture. Protect from the risk. Use hard structure (sea walls) or soft solutions (dunes and vegetation) to protect land from the sea.