Abstract
Global sea levels have fluctuated during the earth’s long history, falling during the ice ages and rising during periods of global warming. The most recent ice age occurred more than 10,000 years ago. Over the last few decades, we have experienced global warming, which has been aggravated by the effects of global warming resulting into excess gases that trap heat in the atmosphere. Records on rise in sea level for the last 100 years indicate an average rise of one to two inches every 25 years and the figure is increasing. The rising sea level will have significant impacts by reducing living space any country. The main factor that escalates the threat of current rising sea levels compared to earlier one is the global increase in the activities of human and their preference for developing and living in coastal areas.
Introduction
New research suggest that the rise in sea-level is occurring much faster than anticipated by scientist exposing millions of Americans to the destructive effects of floods produced by rising sea levels. Satellite measurements records over the last two decades indicating that sea level have been rising 60 percent faster than the computer projections submitted by United Nation’s Intergovernmental Panel on Climate (Florida State University, 2009). The rapid rise in sea levels will force authorities to take measures to protect populations living in low-lying area such has Los Angeles, New York City, and Florida, or face the consequences of destructive combination of storm surges in addition to rising sea-level (Goldenberg, 2012). In addition, scientists reported that the rising sea level have already doubled the risk of historic flooding across the entire area of the United States. According to a recent research published in January in Environmental Research Letters, it estimated the rate of rise in sea level at 3.2mm a year, compared to IPCC estimate of 2mm a year (Kettle, 2012). A rise in sea level has significant impact on people around the world because it can reduce living space for any country.
Discussion
A slight increase in sea level can have devastating effects on the coastal habitats. As seawater reaches further inland, it occupies the surrounding land resulting into less land. The surging seawater can cause destructive effects such as flooding of wetlands, erosion, contamination of agricultural soils and aquifers, and loss of habitat to wildlife. Rising sea level has the potential impact on the habitats of species including birds, fish, and plants. A slight rose in sea level can displace many animals and plants from their habits.
The increase in melting of glacier after the ice age rapidly increased the sea levels. However, over the past few decades, the sea level of the United States has risen by 25 to 30 centimeters relative to land (University of Copenhagen, 2009). Global warming resulting from increases in greenhouse gases is melting glacier and making ocean water to warm and expand thermally. This results into increased volume of the ocean, which raises its surface level. Warming of seawaters can result into suitable habitats for temperate-sensitive species to shift to such areas. Some areas have even experienced migration among both warm and cold fish and other marine species. Changes in weather conditions such as warmer springs have led to early nesting for some birds species on the East Coast of the United States.
Global warming has also resulted into decline in duration and intensity of sea ice in the Arctic. This has resulted into decline in the availability of ice algae, which survive in the nutrient rich pockets in ice. These algae constitute the main source of nutrient to zooplankton, which are also eaten by marine mammals including seals (Graversen, et al., 2012). Decline in sea ice will have a significant impact on sea life, which also constitutes a major source of nutrient to millions of people in the United States. It could also result into increase in runoff and flooding. Additionally, warmer temperatures could lead to further runoffs as snow in the mountains melt. The increased runoff and flooding could threaten the health and quality of coastal waters. Some regions including Chesapeake Bay and Gulf of Mexico are already experiencing “dead zones”.
Rising sea level results in pressure on available land. However, the world population is increasing at a faster rate than land reclamation. Many millions of people live in areas prone to flooding. Rising sea level would force them to abandon their homes and relocate to higher grounds as low-lying lands could be submerged completely. Currently, there are no policies in place to control birth with the exception of China (Loáiciga, Pingel & Garcia, 2012). People will put pressure on the available high grounds because the rate of land reclamation will be lower than the speed of population growth. The rising sea levels will reduce the size of dry land as the population increases. This will result into pressure on the available natural resource thereby causing environmental degradation.
The United States’ coastal lines are heavily populated. Fifty-two percent of the US population lives in coastal watershed countries. People flock these areas due to the associated coastal and ocean activities such as offshore energy drilling, transportation of goods, fish cultivation, resource extraction, and tourism (Friedrich & Kretzinger, 2012). Coastal habitats also provide home to habitats and species that provide benefits to the natural ecosystem and the society. Human pressure on the coastal resources has resulted to several environmental impacts. For example, coastal Louisiana lost 1,900 square miles of wetlands in the past years because of human activities such as oil and water extraction that has caused the land to sink (Hagen & Bacopoulos, 2012).
Additionally, rising sea level can also increase the salinity of ground water and push salt water further upstream. The increasing sea level would make salt water to intrude further into the estuary thereby increasing salinity and moving salt front further upstream. This could make species such as gribbles, shipworms, and barnacles, which survive on a relatively high salinity to migrate further up the estuary, destroying wooden structures they come across. Additionally, increased salinity would result into dramatic increase in pollution if they were to alter flushing and mixing rates of the estuary. The problem could be escalated by the resulting loss of adjacent wetlands to encroaching salt water.
Tidal wetlands do not only act as nurseries to most species including marine fishes, but also helps in filtering dangerous pollutants carried by rivers and creeks downstream to the estuary. They also buffer the effect of floods and storms. Low tides may make productive and rich total flat inaccessible to various animals, including humans. This could also affect the deposition patterns of nutrient-bearing sediments, thus starving the entire population of living in seabed. Rising sea level also has potential public health impacts. Coastal areas are already experiencing contamination to aquifers and groundwater resources. Continued flooding creates a suitable environment that allows communicable diseases such as malaria and cholera to extend their ranges further inland. Frequent and severe storms also help increase the spread, exposure, and number of occurrences of diseases and pathogens.
Rising sea level is a threat to people living in the coastal line, as more land will be under seawater. Recent reports indicate that the sea level could rise over the next coming centuries than previously thought by scientists. They put the figures somewhere between 18 to 19 feet above current levels, as compared to about 13 to 20 feet a few years ago (Gillet-Chaulet, et al., 2012). This increase will largely come from the gradual melting of ice in Antarctica and Greenland, which have remained relatively intact since the end of the ice age, near 20,000 years ago. In addition to the rising temperatures, the effects of global warming have also contributed to the slow melting of that ancient ice, increasing the sea level by 8 inches since 1880 alone, with projections putting additional increase of 6 feet by 2100 (NRC, 2008).
That is not enough to aggravate the problem, but coupled with storm surges, rising sea level could threaten millions of coastal residents long before the end of the century. Globally, rising sea levels would put trillions of property at risk with the next decades. On the contrary, a twenty-nine feet rise in sea level would submerge hundreds of cities around the world under water, leading displacement of millions of people and destroying uncountable amount of property. For example, coastal Louisiana has experience a moderate increase by eight inches or more over the last fifty years. This is faster than double the global rate. Scientists also project the subsiding land in the Chesapeake Bay area to escalate the effects of rising sea levels, thereby increasing the risk of flooding cities, tidal wetlands, and habited islands (Boori, Amaro, & Targino, 2012). Such cases could move people from their homes relocate to other higher grounds.
On the contrary, scientists believe that the rise in sea level will not take place overnight. In reality, it takes many years to melt such large amount of ice. However, this might happen with the rapid increase in temperature that has remained relatively high over the past decades. In addition, s light rise in sea level may not reduce the living space available for countries. Many countries still have vast lands that have not been developed. They can use such land to relocate people living in the coastal regions.
Conclusion
The increasing level of seal level seems unavoidable, and scientists are warning people to plan for an increase of 2.3 feet by the end of 2050. The best strategy of people is to plan. Even as we exit the 21st century, we have never developed a solution to these problems, even with the high-tech solutions we have to other problems. Even EPA’s best solution to the problem is to advice people to “retreat and relocate,” in order to ensure a sufficient buffer zones between the edge of water and all future permanent structures. The rising sea level will eventually force many people to relocate to higher areas to evade the dangers of rising sea levels.
References:
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