Rising Sea Levels
Rising sea levels threaten to wash away entire nations
It is projected that global warming will cause sea levels to rise by as much as 5 mm per year over the next 100 years. Rising sea levels threaten entire nations on low-lying islands in the Pacific and Indian Oceans.
As temperatures rise, seas will absorb more heat from the atmosphere, causing them to expand and rise. Ice sheets, such as those in Greenland and on Antarctica, and land glaciers will also continue to melt and further increase the level of the seas.
According to the Intergovernmental Panel on Climate Change(IPCC), by 2080 sea level could rise from 9 to 48 cm in a ‘Low Emissions Scenario’ and from 16 to 69 cm in a ‘High Emissions Scenario’.
Several Pacific island states are threatened with total disappearance and 2 uninhabited islands in the Kiribati chain have already disappeared due to sea level rise.
The people of Funafti in Tuvalu and on Kiribati island are lobbying to find new homes: salt water intrusion has made groundwater undrinkable and these islands are suffering increasing impacts from hurricanes and heavy seas. In the village of Saoluafata in Samoa, villagers have noticed that their coastline has retreated by as much as 50 metres in the last decade. Many of these people have had to move further inland as a result.
Coastal areas around the world will also be threatened by rising sea levels. This will not only affect agricultural areas around the coast but also cities – 13 of the 15 largest cities in the world are on coastal plains. The IPCC confirms that sea level rise is already affecting coastal ecosystems, including coral reefs, mangroves and salt-marshes.
A third of the Blackwater National Wildlife Refuge marshland on Chesapeake Bay, United States, has disappeared since 1938 and the rest of the marsh, which provides winter habitat for many waterfowl species, is expected to be flooded within 25 years. While half the existing loss is thought to be due to extraction from aquifers, the remainder is believed to be due to sea level rise.
In Waccasassa Bay State Preserve in Florida, researchers concluded that cabbage palms and other trees are falling victim to saltwater exposure tied to global sea level rise, exacerbated by drought and a reduction of freshwater flow. Rising seas are said to have flooded 7,500 ha of mangroves in the Sundarbans National Park of Bangladesh, although sea-level rise is aggravated by subsidence in the delta.
In Vietnam, mangroves are reported to be undergoing species change because of increased salt intrusion, including those in Dao Bach Long Vi, a proposed marine protected area.
The Great Rann of Kutch in Gujarat is one of the remotest places in India: the vast area of seasonal salt lakes supports huge populations of flamingos and is the only remaining habitat for 2,000 Indian wild asses. The area is likely to become inundated by the sea, thus destroying the habitat and threatening the Wild Ass Sanctuary and the Kachchh Desert Sanctuary.