Table of Contents
Introduction
The concept of sea level rise is one that has become popular in the modern world, especially in the wake of different catastrophic disasters that have hit different parts of the world through coastal wetlands flooding. Currently, sea level rise is a concept that is being followed keenly in the scientific realm, having been largely attributed to the various modern day catastrophes such as storms and hurricanes. The rise in sea level is defined as the increment of the levels of water in the oceans and seas of the world (Church and White, 602). The idea of how water levels in the oceans and seas are rising in an age where rain has become increasingly scanty is causing confusion among many. Additionally, the issue of how the rise in sea levels is a concept that is associated with climate change and global warming also becomes ambiguous. Naturally, it would be expected that as climate change causes a decrease in the amount of rain the world receives, the levels of waters in the various world water bodies would continue to decrease. However, on the very contrary, as the climate change continues to trigger global warming, the water levels in the world seas and oceans continue to rise (Weissenberger and Chouinard, 27). This contradiction can be explained by the investigation of how the concept of sea level rise is associated with climate change. The other issue at the core of the discussion on sea level rise is related to how the rise in sea level is measured, and the specific tools that are used to measure this change. Therefore, this discussion focuses on the inquiry of how the concept of sea level rise is associated with climate change and coastal wetlands flooding, as well as defining the tools used to measure the rise in sea level, and how the tools have changed over time.
Climate Change and Sea Level Rise
The rise in sea level is often attributed to climate change. In the recent decades, the conversation around climate change and global warming has remained dominant in the public forums, with concerns over the disastrous impacts of climate change remaining the major concern. Nevertheless, there are two fundamental causes of the rise in sea levels, which occasion coastal flooding and the flooding of the coastal wetlands, namely sea water thermal expansion and the melting ice sheets (Douglas, Kearney and Leatherman, 7).
Sea water thermal expansion
When water in the world seas warms, it expands to occupy more space (Barrow, Wigley, and Warrick, 36). The concept of climate change and global warming provides that the world is increasingly receiving high temperatures from the sun, as the world continues to suffer from desertification occasioned by deforestation. The increasing decline of the forest and other natural vegetation all over the world means reduced use of the sun previously consumed by the forestry trees and vegetation for photosynthesis. Therefore, in the absence of forests and natural vegetation cover, the sun rays and waves are currently heating directly at the water bodies, causing the water in the seas and oceans to become increasingly warm (Church and White, 589). Additionally, the increase in the levels of greenhouse gases has continued to corrode and deplete the ozone layer, increasing the intensity of the sun heat waves that reach the surface of the earth (Weissenberger and Chouinard, 42). The combination of these factors causes an increment in the heat content within the global seas and oceans, which in turn causes warming and expansion of the waters therein. The continued warming of the water means that the process of thermal expansion takes place, causing the water to expand its levels. The expansion of water as it warms causes the sea water level to rise beyond the initial levels, resulting in the rise of the water levels in seas and oceans (Douglas, Kearney and Leatherman, 15). For example, a mere rise in the global temperatures by one degree Celsius in the next 2,000 years will occasion a significant rise in the global sea levels by 2.3 meters (Levermann, Clark, Marzeion, et al., 47). Therefore, the sea and ocean thermal expansion arising from climate change and global warming is a major source of the recorded high rise in the sea levels.
The ocean thermal expansion continues to be a major factor accounting for the rise in the seas levels, especially as the concept of climate change and global warming continue to impact the world. For example, according to the available sea level rise data from NASA, the change in sea height water level variations since 1993 has been drastic, with the sea levels rising from the initial 0 millimeters to about 3.2 millimeters per year as by December 2017 (NASA, n.p.). This increase in the annual sea levels of water is significant, compared to the historical rises in sea levels, where for example, the world only recorded an annual average increment of 1.8 millimeters between 1961 and 2003 (Dasgupta and Craig Meisner, 12). The increase in the sea water levels in the past few decades has been also high, compared to the historical estimations of the global rise in sea levels 0.1-0.2 millimeters per year over the past 3,000 years, (Dasgupta and Craig Meisner, 12). It is estimated that in the 21st century, the rise in sea levels will continue to be significantly high than the historical trends, while it is also estimated that the incremental rise in the sea levels will continue for centuries.
Nevertheless, the rise in sea levels arising from the thermal expansion effect is different for the different seas of the world. The outcome is that the rise in the ocean and sea heat content causes water levels to rise differently in different seas and oceans of the world, with some rising quickly above the global average, while other rise slowly (Weissenberger and Chouinard, 26). There are several factors that inform the extent of the rise in sea levels either above or below the global average, which include the geographical specific factors such as the tectonic effects, water currents, tides, storms, among other such sea and ocean water associated factors (Church and White, 597).
Melting of ice sheets and icebergs
The second mechanism through which sea level rise occurs is through the melting of floating ice shelves and glaciers, which is also occasioned by climate change and global warming (Barrow, Wigley, and Warrick, 54). The world has registered serious climate and global warming changes, which impacts on the temperature levels both in the atmosphere and land. The continued increase in the temperatures of the land has a subsequent impact on the water levels in the world seas and oceans. When the land temperatures rise, the major stores of the land ice such as the ice glaciers, icebergs and the ice sheets are all impacted by the temperatures, causing the melting of the stored ice (Weissenberger and Chouinard, 41). Once the ice from the land ice stores is melted, it becomes water that flows directly into the oceans and seas of the world, thus occasioning a rise in the water levels within these water bodies. Therefore, the melting of the land ice storage is causing sea level rise through practically increasing the volumes of water in the oceans and seas, once the ice glaciers have been melted into water (Lindsey, n.p.). While thermal expansion of the oceans and seas is a major cause of rise in the seal levels, the melting of land ice stores is an even serious cause of the sea level rise, accounting for about 68% of the total water sea level rise recorded between 1993 and 2008 (NASA, n.p.).
Coastal Flooding and Coastal Wetlands
The concept of sea level rise is a core concept associated with coastal flooding and the flooding of wetlands. The changes in the water levels in seas and oceans means that the risks of the water bodies overflowing and flooding the surround areas are high (Church and White, 589). Additionally, the continued rise of the sea level becomes a dangerous concept as related to coastal flooding and the flooding of the coastal wetlands, when combined with the other concepts such as tectonic forces, sea storms and tides, as well as sea currents waves and land subsidence (Weissenberger and Chouinard, 14). The rise in sea level caused by both thermal expansion of the sea and melting of the ice glaciers have been contributing to roughly the same rise in the sea levels between 1970 and 2010 (Lindsey, n.p.). However, due to the significant climate change and global warming that has been recorded in the decade commencing 2010, the rise in sea level occasioned by the melting of the ice glaciers has been twice that of sea level rise caused by thermal expansion of the sea. The major hazard associated with the rise in sea level from the melting of the ice glaciers is that, it causes the practical increment in the volumes of waterin the seas and oceans, thereby making natural flooding of the coastal regions and the coastal wetlands an obvious risk (Church and White, 587). The increment in the actual amounts and volumes of water in the seas causes a mass increase in the strength of the gravity over the oceans, which then increases the risks of flowing to the coastal regions and coastal wetlands caused by the earth’s gravity forces shifts (Lindsey, n.p.).
Even a small rise in the sea levels can have a devastating effect on the coastal habitats, where the farther push of water from the seas and oceans into the mainland can occasion coastal and wetland flooding, as well as causing destructive erosions (National Geographic, n.p.). Additionally, when the storms build up in the sea and hit the land as high magnitude storms, high levels of water in the sea means bigger and more powerful storm surges, which are capable of wiping away everything on the storm’s path (National Geographic, n.p.). Under the strengths of high tides and currents in the seas and oceans, the nearby wetlands such as the low-laying coastal islands can be completely submerged by the water, where the sea levels in the oceans or seas have risen by even one foot. Therefore, the risks of continued flooding of the coastal regions and the coastal wetlands still remains high going into the future, owing to the fact that climate change and global warming are realities that the world will have to deal with for a long time into the future.
The magnitude at which the sea levels are rising across the world is alarming, considering that in a recent sea level rise observation study, it was recorded that there was a massive sea level rise of 7 centimeters in the past 25 year years (Miller, n.p.). The major problem is that the rise in the sea levels is not constant, with the continued emission of the greenhouse gases coupled with continued deforestation causing the earth’s atmospheric temperatures to increase, thus occasioning rapid melting of the ice glaciers (Miller, n.p.). The outcome is that, going into the future, the risks of strong flooding storms with devastating impacts on both the coastal regions and the coastal wetlands continue to be a reality.
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Tools Used To Measure the Rise in Seas Level
The levels of sea water shifts constantly due to factors such as currents, tides, waves and other planetary and solar orbit forces, which means that it is not possible to measure the rise in sea level using a static tools on the shores (Weissenberger and Chouinard, 18). Additionally, the presence of hills, mountains, valleys and canyons both on land and in the sea means measuring the rise in sea levels also remain a major challenge. Therefore, over the cause of history, scientists have established various tools that are used to measure the rise in sea water levels that include:
Tidal gauges
Tidal gauges remain the major historical tools that were used for measuring changes in sea levels, where these tools were planted at different harbors across the world. The tidal gauges were suspended in tide houses that had data recorders, which recorded changes in the water levels as measured by the gauge beneath (Lindsey, n.p.). Basically, the historical tidal gauges represented a rudimentary tool comprising of a measuring stick that was nailed to the harbor anchors, from which the scientists used to observe and measure changes in the sea water levels.
Satellites orbiting tools
The next advancement in the tools for measuring sea level rise saw the rise of the satellites orbiting tools that combined the satellite technology with the global mapping technology, to measure changes in sea water levels by mapping the sea water level rise (Lindsey, n.p.). The use of satellites orbiting tools was a major milestone towards enhancing the accuracy of sea level rise measurement, since the satellite measurement tools allowed for a precise estimate of the water level at the open oceans and seas (Miller, n.p.).
Sounding tube sensors
Further advancement has seen the rise of the sounding tube sensors, which apply advanced technology of sending an audio signal down the tube attached to the senor, and measuring changes in the time taken for the return signal to read (Perritano, n.p.). The use of contemporary sounding tube sensor ensures more accurate sea level rise measurement, because it calculates the water level based on other measured sea environmental factors such as the speed of the wind, water temperature and tidal heights (Perritano, n.p.).
Microwave radar water level sensors
Nevertheless, the newest tool adopted for the measurement of the rise in sea levels is the microwave radar water level sensors. These sensors are using micro electro-magnetic waves to measure the distance from a certain fixed point above the water level, to the surface depth of the water (Perritano, n.p.). This tool is more accurate in detecting changes in the sea water levels.
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