Rising of the Sea Levels - Essay Example

Introduction Effects of Rising Sea Levels Bodies of water hold ecological and economic values, and are thus centers of commerce and population. When coastal cities and communities were still being established, its members chose areas that are closer to water mass for easier access to food and access between communities. Such connections are of primary importance especially before when aircrafts are non-existent. Rising sea levels threaten these seaside communities that are already well-established after staying there for so long. Flooding and erosion caused by increasing sea levels may result to loss of life or damage to property. In addition, increasing sea levels decreases the land mass available for agriculture, wildlife and housing. Global sea level rise is an international issue, especially because poor countries are ill-prepared against the effects of rising sea levels. The large populations of low-lying seaside areas of Bangladesh, Vietnam, India and China are at risk of being displaced from their habitats. Massive relocation is almost impossible in island nations such as the Philippines, Indonesia and Vanuatu because they do not have enough elevated areas to transfer the displaced residences to. Freshwater supply is also endangered as the saltwater is being pushed to freshwater basins (Climate Institute). Increase in sea levels has another indirect path to which it can cause rising sea levels. When melted ice runs off to the ocean, the water mass’ surface temperature decreases, this makes the natural overturning of water, from the ocean floor to the top, harder. In addition, the relatively fresh surface of the ocean does not sink on a much denser ocean bottom. Thus, every time the sun rises, the relatively less salty surface of the ocean evaporates more quickly, leaving the salts behind. In the long run, the density of the ocean steadily increases (Climate Instiute). Causes of Rising Sea Levels Because of the implications of rising sea levels, detecting it and identifying their causes become of utmost importance. Various studies, no matter how different they are in terms of measuring approaches, have agreed that sea levels are rising in various bodies of water. Historically, global sea levels was approximated to be increase by 1 mm/yr prior to 1930s. From 1930s to 1950s, the rise went as much as 2.5 mm/yr, before decreasing to 2 mm/yr between 1950s and 1980s (Church et al., 2008). The eustatic or global sea level rise refers to the collective change in the mass of all the Earth’s oceans due to the melting of the glaciers (Ericson et al., 2006). 1. Melting of ice Many misjudge that the melting itself contributes to the rising sea levels, but one must remember that the ice sheets are already floating on the ocean, and it would not change the mass of the ocean even if it melted. The melting instead leads to a reduction in surface reflectivity, causing a greater absorption of solar radiation. As energy is absorbed, the water is warmed, causing the excitation of the water molecules and subsequent expansion of its mass (Climate Institute). 2. Thermal expansion The effects of thermal expansion can also be observed immediately after volcanic eruptions, in which cooling of the surface causes subsequent decrease in SLR (Edwards, 2008). Thermal expansion, together with melting of the ice, can be direct effects of global warming, which in turn is brought about by the increasing amount of greenhouse gases suspended in the atmosphere (Church and Gregory, 2000). Measurement discrepancies of SLR Despite similar conclusions of studies on sea level changes, certain discrepancies of the values of SLR have been reported. First, regional variability is a recognized phenomenon. Oscillating patterns of acceleration and deceleration can be observed from European and North American waters, while in some other areas, this pattern is not evident. These differences are concluded to be caused by inherent differences in atmospheric and ocean circulation patterns. The pattern recognized to have obvious effects are El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO). At a lesser extent, North Atlantic Oscillation (NAO) also causes SLR (Lombard et al., 2005). Second, because there is an obvious link between global warming and sea levels, the unpredictable progress of global warming makes it harder for its effects in sea levels, among others, to be predicted (Climate Institute). Aside from natural variations, current SLR measurements are still sensitive to choice of measurement protocols and data analysis programs used (Edwards, 2008). For example, one research presents SLR via a decadal change, while another assess it from year to year. Obviously, comparison between the two will be impossible. When presented with data sets from two different places, comparison will be inconclusive. It is thus futile to compare two studies obtained using different statistical methods or modes of SLR measurements, despite obtaining monumental findings from doing so. Because of such discrepancies, projection of the future rises in sea levels becomes complex. Different simulating programs have been created to better estimate future values of sea levels. However, models currently simulating during the past 20th century have underestimated data. Despite continued advances in the field, one cannot deny that simulators have limitations, and may not come up with the actual values. For one, no simulator has been able to account for the dynamic movement of ice sheets in the increase in sea levels. However, once such phenomena have been well understood and elucidated, it is likely that further improvements can be seen (Climate Institute). Diatoms Because it is mainly composed of silica instead of the structurally weaker carbonate, diatoms are commonly used for paleogeographical studies (.Wyss, et al., 2000). Hoylake The town of Hoylake is primarily a residential area located within Merseyside, England. As of 2001, the total population is more than 5,000. Because of its proximity to a water mass, the community enjoys sailing. Results References Church, J, J. M. Gregory Changes in sea-level, 2000, In: Houghton, J. T., Y. Ding, D. J. Griggs, M. Noguer, P. J. van der Linden, X. Dai, K. Maskell, C. A. Johnson (Eds.) Climate Change 2001: the Scientific Basis. Contribution of Working Group 1 to the Third Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press, Cambridge. Church, J. A., N. J. White, T. Aarup, W. S. Wilson, P. L. Woodworth, C. M. Domingues, J. R. Hunter, and K. Lambeck Understanding global sea levels: past, present and future, 2008, Sustainability Science, Vol. 3, pp. 1-167. Edwards, R Sea levels: science and society, 2008, Progress in Physical Geography, Vol. 32, pp. 557-574. Ericson, J. P., C. J. Vorosmarty, S. L. Dingman, L. G. Ward, and M. Meybeck Effective sea-level rise and deltas: causes of change and human dimension implications, 2006, Global and Planetary Change, Vol. 50, pp. 63-82. Lombard, A., A. Cazenave, P. Le Traon, M. Ishii Contribution of thermal expansion to present-day sea-level change revisited, 2005, Global and Planetary Change, Vol. 47, pp. 1-16. Wyss, W, S. Yim, and J. Li. Diatom preservation in an inner continental shelf borehole from the south china sea, 2000, Journal of Asian Earth Science, Vol. 18, pp. 471-488. Read More