Erosion On The Gulf Of Mexico Coast

Parts of coastal Louisiana and Mississippi could lose as much as 1 foot of elevation within 10 years according to an analysis by the National Geodetic Survey of the National Oceanic and Atmospheric Administration (NOAA). The NOAA researchers have warned that populated areas will face increased dangers from storm surges and flooding due to ongoing subsidence of coastal areas along the northern Gulf of Mexico. Coastal wetlands in Louisiana have been disappearing at the rate of 33 football fields per day (Bourne, 2004, 89). The NOAA researchers estimate that at the present rate of subsidence, 15,000 square miles of land along the southern Louisiana coast will subside to sea level or below within the next 70 years (Coastal Gulf, 2003). Shoreline in this area is sinking due to natural processes as well as the withdrawal of subsurface oil and water. In southern Louisiana, roughly 1 million acres of coastal marsh were converted to open water between 1940 and 2000, with losses accelerating over time with a quickening pace of sea level rise (Inkley et al., 2004, 8, 13). All of this makes the area especially vulnerable to hurricanes such as Katrina of 2005. --

Pacific Islands Going Under

Many Pacific Ocean islands face two problems: the sea is rising while the land itself is slowly sinking, as 65-million-year-old coral atolls reach the end of their life spans. The atolls were formed as formerly volcanic peaks sank below the ocean's surface, leaving rings of coral.

For 5 years, the government of Tuvalu has noticed many such troubling changes on its nine inhabited islands and concluded that, as one of the smallest and most low-lying countries in the world, it is destined to become among the first nations to be sunk by a combination of global warming-provoked sea level rise and slow erosion. The evidence before their own eyes, including forecasts for a rise in sea level as much as 88 centimeters during the twenty-first century by international scientists, has convinced most of Tuvalu's 10,500 inhabitants that rising seas and more frequent violent storms are certain to make life unlivable on the islands, if not for them, for their children (Barkham, 2002, 24).

Residents of the islands have been seeking higher ground, often in other countries. The number of Tuvalu's residents living in New Zealand, for example, doubled from about 900 in 1996 to 2,000 in 2001, many of them fleeing the rising seas on their home islands. A sizable Tuvaluan community has grown up in West Auckland (Gregory, 2003). The highest point on Tuvalu is only about 3 meters above sea level. "From the air," wrote Patrick Barkham in the London Guardian, "[i]ts islands are thin slashes of green against the aquamarine water. From a few miles out at sea, the nation's numerous tiny uninhabited islets look smaller than a container ship and soon slip below the horizon" (Barkham, 2002, 24).

"As the vast expanse of the Pacific Ocean creeps up on to Tuvalu's doorstep, the evacuation and shutting down of a nation has begun," Barkham wrote. "With the curtains closed against the tropical glare, the prime minister, Koloa Talake, who sits at his desk wearing flip-flops and bears a passing resemblance to Nelson Mandela," likens his task to the captain of a ship: "The skipper of the boat is always the last man to leave a sinking ship or goes down with the ship. If that happens to Tuvalu, the prime minister will be the last person to leave the island" (Barkham, 2002, 24).

Many Pacific island farmers report that their crops of swamp taro (pulaka), a staple food, are dying because of rising soil salinity (Barkham, 2002, 24). Another staple food, breadfruit (artocarpus altilis), is also threatened by saltwater inundation. The breadfruit is harvested from large evergreen trees with smooth bark and large, thick leaves which reach a height of 20 meters (about 60 feet).

INCREASING FLOODS EXPECTED IN BANGLADESH

Bangladesh, one of the poorest countries on Earth, is likely to suffer disproportionately from global warming. Cyclones there historically have killed many people; 130,000 people died in such a storm during April 1990. Less than one-fourth of Bangladesh's rural population has electricity; the country, as a whole, emits less than 0.1 percent of the world's greenhouse gases, compared to 24 percent by the United States (Huq, 2001, 1617). Bangladesh is planning to use solar energy for new energy infrastructure but lacks the money to build seawalls to fend off rising sea levels.

Saleemul Huq, chairman of the Bangladesh Centre for Advanced Studies in Dhaka and director of the Climate Change Programme of the International Institute for Environment and Development in London, said that the world community has an obligation to pay serious attention to the views of people who stand to lose the most from climate change (Huq, 2001,1617). A sea level rise of half a meter (about 20 inches) could drown about 10 percent of Bangladesh's habitable land, the home, in 2004, of roughly 6 million people.

A 1-meter water level rise would put 20 percent of the country (and 15 million people) underwater (Radford, 2004,10). In addition to sea level rise caused by warming, large parts of the Ganges Delta are subsiding because water has been withdrawn for agriculture, compounding the problem.

Venice, Italy, is Drowning

Floods have been a problem in Venice, Italy, for most of its centuries-long history, but sinking land and slowly rising seas due to global warming have worsened flooding during the late twentieth and early twenty-first centuries. Venice, which sits on top of several million wooden pillars pounded into marshy ground, has sunk by about 7.5 centimeters per century for the past 1,000 years. The rate is accelerating. Increased floods have provoked plans for movable barriers across the entrance to Venice's lagoon.

Venice has lost two-thirds of its population since 1950; the 60,000 people who still live in the city host 12 million tourists a year who make their way over planks into buildings with foundations rotted by frequent flooding.

At the Danieli, one of Venice's most luxurious hotels, tourists arrive on wooden planks raised 2 feet above the marble floors amidst a suffocating stench from the high water (Poggioli, 2002).

Waters are rising around Venice for several reasons, in addition to slowly rising seas. During the twentieth century, mudflats that once impeded the sea's advance were dredged for shipping and other forms of development. Venice is also subsiding due to the removal of water from its aquifers for human use (Nosengo, 2003, 609).

Venice residents and visitors have become accustomed to drills for "ac-qua alta," or high water. A system of sirens much like the ones that convey tornado warnings in the U.S. Midwest sounds when the water surges. Restaurants have stocked Wellington boots and moved their dining rooms upstairs. Venetian gondoliers ask their passengers to shift fore and aft—and watch their heads—as they pass under bridges during episodes of high water (Rubin, 2003). Some of the gondoliers have hacked off their boats' distinctive tailfins to clear the bridges brought closer by rising waters.

Faced with rising waters, Venice has proposed construction of massive retractable dikes in an attempt to hold the water at bay, amid considerable controversy. After 17 years of heated debate, the Venice's MOSE (Modulo Sperimentale Elettromeccanico) project will cost about US$1 billion. Some environmentalists assert that the barriers will destroy the tidal movement required to keep local lagoon waters free of pollution and thereby damage marine life. Water quality near Venice is already precarious because pollution has leached into the lagoon from industry, homes, and motor traffic. The Italian Green Party favors shaping the lagoon's entrances to reduce the effects of tides, along with raising pavements as much as a meter inside Venice. --

Was this article helpful?

0 0
Getting Started With Solar

Getting Started With Solar

Do we really want the one thing that gives us its resources unconditionally to suffer even more than it is suffering now? Nature, is a part of our being from the earliest human days. We respect Nature and it gives us its bounty, but in the recent past greedy money hungry corporations have made us all so destructive, so wasteful.

Get My Free Ebook


Responses

  • asmeret asmara
    Has coastal erosion on gulf worsened?
    8 months ago

Post a comment