Global sea level rise has centrally featured in most debates in recent times, although it is not entirely a new phenomenon. The water level has been rising over the years, but marked changes were witnessed in the twentieth century. “The increase in the sea level in the twentieth century alone was over half times much more than that of the preceding years combined” (Nicholls and Cazenave 1517).
This is expected to be even more accelerated in the twenty-first century owing to the effects of global warming. Climatic change monitors have issued a foresight arguing that sea levels around the world would increase by up to approximately 60 centimeters by the year 2100 (Nicholls and Cazenave 1517).
However, the recent documented accelerated decline of polar ice sheets indicates that this increase could yet be higher than these projections (Nicholls and Cazenave 1517). The primary risk factors for this projected rate of increase in sea level include ocean warming and acidity as a result of global warming, as well as the melting of glaciers.
The rate of the twenty-first-century sea level rise has become a subject of heated debate and intense controversy. Both proponents and opponents of global warming as a cause of an increase in sea level would be on a constant upward trend. What they differ on is the numerical values of this rise.
Additionally, they all attribute two main factors with this contemporary rapid increase of sea levels. These include thermal expansion of seawater and the addition of large volumes of water into the seas by the melting of terrestrial glaciers and underground water reservoirs (Nicholls and Cazenave 1517).
Justification of global warming as the primary cause of sea level rise can be found in the fact that massive increases in thermal expansion over the last 50 years of the twentieth century caused a significantly huge increase in water level. Thermal expansion alone caused approximately 25 percent increase in sea level since 1960, and about 50 percent if you consider only 1993 to 2003 (Nicholls and Cazenave 1517).
Additionally, global glaciers and ice caps have been observed to be retreating over the last few decades. This has facilitated sea level rise by increasing seawater volume causing the oceans to expand beyond their traditional banks. Studies indicate that melting of glaciers alone has contributed up to 30 percent of the worlds sea level between the years 1993 and 2009 (Miller and Douglas 409).
Human activities and changes in water storage as a result of natural climatic shifts are thought to contribute less than 10 percent of the current sea level changes (Nicholls and Cazenave 1517). Ironically, human activities that involve the intensive building of dams along rivers can lower the sea level by approximately -0.5 mm/year (Nicholls and Cazenave 1517).
When not mitigated, sea level has detrimental effects on the oceans, especially on water aquifers and land. For instance, salt water invasion of surface water has been documented in the short-term (Nicholls and Cazenave 1517). Long term effects are more detrimental and include increased erosion of the coastal lands and saltwater invasion of groundwater (Williams 184).
This essentially means that all sources of fresh drinking water are invaded with salts and other sea elements that can be toxic to humans and animals alike. Unless something is done, this ‘poisoning’ of water reservoirs and aquifers will continue causing poor health and fatalities.
Works Cited
Miller, Lynn, and Charles Douglas. “Mass and volume contributions to 20th century global sea level rise.” Nature 428. 6981(2004):.406–409. Print.
Nicholls, R. Jones, and Allison Cazenave. “Sea-Level Rise and Its Impact on Coastal Zones.” Science 18(2010): 1517-1520. Print.
Williams, Jeffress. “Sea-Level Rise Implications for Coastal Regions.” Journal of Coastal Research 63. 63(2013): 184 – 196. Print.