The Inundation of North American Coasts - Assignment Example

Earth Science: The Inundation of North American Coasts al Affiliation) Contents Contents 2 0. Introduction 3 1.0 Projections 3 1.2.0 Reasons for concern 4 1.3.0 Aim of the report 4 2.0. Discussion 4 2.1.0. Reasons for sea levels rise 4 2.2.0 Risk sites in North America 5 2.3.0 Mitigation 7 3.0. Conclusion 8 1.0. Introduction Inundation is a condition where dry land is covered naturally by water. There are four main causes of significant inundation. Storm surge is one of the causes and results from severe storms. Tsunamis also cause inundation; they are large waves which are generated by abrupt sea disturbance. Inland floods cause inundation when there is precipitation fall over a period of time. Shallow coastal flooding that occurs in low coastal areas during high tides also causes inundation. Global and relative sea levels rise also causes inundation. Substantial sea level rise is predicted to continue for a long term (Black & Weisel, 2010). 1.1.0 Projections It is estimated that there will be a Greenland ice sheet partial deglaciation, which could lead to increase in sea levels. The diagram below shows projections of future sea level rise changes (Pugh, D. T. 2004). 1.2.0 Reasons for concern Projected sea levels could lead to catastrophic difficulties for communities which live along the shore base. It could also lead to the displacement of such communities and make certain areas uninhabitable. The pattern of changes of sea levels is unpredictable and regions along the shore are at equal risk levels (Pugh, 2004). 1.3.0 Aim of the report There is a natural component ascribed to sea level changes in North America. An ice sheet which once covered the area led to ascending ground motion in the region. The aim of this report is to determine the cause of sea level rise in North America. It seeks to establish the areas which are vulnerable to the risks that accompany the increases in sea levels and the populations which are at risk. The report also aims at finding ways to mitigate the effects of increases in sea levels. 2.0. Discussion 2.1.0. Reasons for sea levels rise The figure above shows the future predictions of climate change. There is an isostatic adjustment in the North American shore which produces a local change in sea levels, which also changes global sea levels. There is thermal expansion of oceans which involves warming and mixing rate beneath the surface of the ocean. Melting mountain glaciers together with ice caps also contribute to rise in sea levels in North America. Melting Ice sheet are the greatest contributors to sea level rises in North America, this could allow disintegration at a much faster rate. When sea levels rise by 3 to 5-foot, there will be melting of the Greenland Ice Sheet (Black & Weisel, 2010). The melting nature of the Ice Sheet is non-linear making it hard to predict. Global warming has led to increase in sea levels in distances ranging from 0.5 to 2.0 meters. A storm surge is caused by high winds on the surface of the ocean. They are damaging especially when they occur at times of high tides. Extratropical cyclones can produce storm surge, depending on the coastline’s physical characteristics and the water shore bathymetry. Tropical cyclones cause storm surge, and the factors that determine the magnitude of the cyclone include the size, intensity and speed of the radius of maximum winds. Global warming lead to warming of waters which increase the intensity of the cyclones. Global warming causes ice sheets to melt causing the expansion of sea waters. The ocean currents make the levels of expansion to differ, temperature of the sea water and its saltiness also determine the levels of expansion. 2.2.0 Risk sites in North America Florida is the state that is more vulnerable to the effects of rising sea levels. The rise in sea levels are expected to increase by 1 to 2-feet by the time this century is at its middle and a rise of 4 to 6- feet by the time this century comes to an end. The increases in sea levels in Florida are attributed by global warming and sinkholes that are present in the area. Sinking land has been the result and it is expected to flood. Around 1.5 million Americans living in Florida are at risk of being affected by the rise in sea levels. The map below (Figure 1) shows sea levels in Florida. Figure 1 Coastal areas of Los Angeles will be destroyed more by major storms as levels of the rise are at an accelerating pace. The storms will worsen flooding and erosion of coastal areas as a result of high tides, waves which are bigger and storm surges (Pugh, 2004). By mid-century the sea levels can rise by 1.5 feet and likely to rise to 4.5 feet by the end of the century. Waste water and portable systems of water within a short distance of the high tide line are at risk of the damage that could be caused by floods. Temperatures of the area are expected to rise by averagely five degrees by the middle of this century. This could increase global warming which could eventually lead to increase in sea levels. An estimated population of about one million Americans faces risks ascribed to the effects of rises in sea levels. The map below (figure 2) shows sea levels in Los Angeles. Figure 2 Sea levels are expected to be raised by global warming along the coast of northeastern U.S. this puts New York at risk for hurricanes damage and storm surge during winter. When New York is tested on emissions from medium greenhouse gas, the area at the coast could have sea levels increases upto 1 foot (Wind, H. G. 1987).. The sea waters are salty and warm and flowing northwards and cold sea water has flow which is southwards. This causes the circulation of Atlantic Meridional which overturns causing global warming. A population of about one million Americans is at risk in the New York region in case the effects of increases in sea levels manifest. The map below (Figure 3) shows the sea levels at the shore of New York. Figure 3 2.3.0 Mitigation There are several measures that need to be taken in protection of coastlines against sea level rise threats. The first step is to confront encroaching seas through building of protective structures such as polders. Such structures reclaim inundated regions of the coastal areas and coastal defenses for instance dikes and beach nourishments. Such defenses create a provision of impediments to waters which are rising. Building of structures that are used as floods’ proof, and platforms which are floating for agriculture could help a great deal. Building of retreats is another way of mitigating the increase in sea levels (Noss, 2011). This might include sea walls building, and where no other options exist, building of floating evacuation could provide help. Global warming should also be decreased a great deal. Emissions from carbon dioxide should be cut by at least 80% by mid-century. This means that there should be more reliance on renewable and nuclear energy (Wind, 1987). Creation of alternative energy sources is not happening currently in Florida or in any other part of America. Hurricanes and severe storms in high risky areas of coastal flooding could be mitigated by dam construction and construction of floodgates which act as barriers for storm surge. They allow free passage of water but when there is a storm surge threat, the floodgates close. Housing communities with floating structures can also be used at wetlands’ edges. They are usually restrained in position by pylons which are vertical. Such wetlands can be used for the accommodation of surges and runoffs without damaging the structures, while also protecting other conventional structures. There should be conduction of shoreline assessments, suitability analysis and projections of hazardous sea levels (Blakely, 2012). There should be implementation of rolling easements or policies that support shoreline retreat. A special overlay district should be designated in areas that are prone to inundation by storm surge, levels of the sea and erosion. Unique guidelines should be established in these areas and public financing should be put into consideration since it should be on the minimum. An alongshore easement should be created for ecosystem retreat, its management and adaptation. Inundated structures should be removed and should be recreated for productive reuse. Good principles relate to waterfront design should be integrated, and new usable infrastructure should be adapted for new waterfronts. 3.0. Conclusion Inundation is a phenomenon whereby land is covered naturally by water. Inundation can be caused by several main causes. Storm surge, inland flooding, and rise in sea levels are the main causes of inundation. Melting mountain glaciers together with ice caps also contribute considerably to rise in sea levels in North America. Sea levels are predicted to rise globally by five feet by the end of the century. Increased sea levels can become catastrophic to communities living at the shore. Thermal expansion of oceans leads to increases in sea levels. Global warming also leads to increase in sea levels by big distances (Noss, 2011). Global warming leads to warming of waters which increase the intensity of cyclones. Storm surges also are caused by such tropical cyclones which are destructive to the shores. North America has risk sites which are more vulnerable to the effects of rising sea levels. Florida is one of the most risky areas. Sea levels are increasing in the area at alarming rates, and might reach a maximum of 6 feet. Coastal areas of Los Angeles are experiencing high rates of increase in sea levels. The sea levels can increase to a maximum of 4.5 feet. New York also is at risk of increased sea levels which could be increased due to global warming (Blakely, 2012). The area can have sea levels increase upto a maximum of one foot. Mitigation measures are put in place to be taken in protecting the coastlines against threats of rises in sea levels. This can be done through building of protective structures such as polders. It can also be done through building of retreats. Global warming should be decreased by cutting down carbon dioxide emissions. Other sources of energy should be used in running machines. Hurricanes and severe storms can be mitigated by the use of dams and floodgates. Good policies and principles should be developed to ensure that such mitigating measures are implemented. 4.0. References Black, B., & Weisel, G. J. (2010). Global warming. Santa Barbara, Calif.: Greenwood. Blakely, E. J. (2012). Resilient coastal city regions: planning for climate change in the United States and Australia. Cambridge, Mass.: Lincoln Institute of Land Policy. Noss, R. F. (2011). Sea level rise in Florida: an emerging ecological and social crisis. Dordrecht [u.a.: Springer. Pugh, D. T. (2004). Changing sea levels: effects of tides, weather, and climate. Cambridge, U.K.: Cambridge University Press. Read More