Geography Optional Answer Writing Day-16 Synopsis. As per the scheme of this
Question no.1 and 2 are left for the aspirants to work upon.
Q.3) State the concept of sea level change. What are the causes for sea level changes and its impact on biodiversity? (20 marks)
Seg level change or Eustatic movement involves the worldwide movement of sea level resulting from changes in the total volume of liquid seawater and the capacity of the ocean basins.
Worldwide (eustatic) Sea level major causes.
a) Climate changes resulting in growth of continent ice sheets – will cause global sea level to drop.
b) Climatic changes resulting in melting of continental ice sheets — will cause global sea levels to rise.
c) Global warming will heat the upper several hundred meters of ocean water causing a thermal expansion of the water and global sea level rise.
d) Periods of increased plate tectonic activity the mid-ocean ridges will cause the volume of the ridges to Increase, thereby displacing ocean water sea level to rise.
In the present context the third category i.e sea level rise due to Global warming has been widely discussed and debated because of the anthropogenic in nature.
The causes for the sea level rise (third category) are as follows
Due to global warming – warming air temperatures contributed to half of the increase. A warmer ocean causes sea level rise in two ways. First, warm water takes up more space. About half of the sea level rise in the past century is because of this effect.
Warmer temperatures melt the ice sheets covering Greenland and the polar ice caps. Over the winter, snowfall rebuilds the ice. But shorter winters mean less time for water to evaporate and turn into snow. As a result, more water stays in the ocean and the glaciers aren’t rebuilt. At the same time, more water enters the ocean from the melting ice.
As with mountain glaciers, increased heat is causing the massive ice sheets that cover Greenland and Antarctica to melt more quickly. Scientists also believe that meltwater from above and seawater from below is seeping beneath Greenland’s ice sheets, effectively lubricating ice streams and causing them to move more quickly into the sea.
Impact on biodiversity
When sea levels rise as rapidly as they have been, even a small increase can have devastating effects on coastal habitats farther inland, it can cause destructive erosion, wetland flooding, aquifer and agricultural soil contamination with salt, and lost habitat for fish, birds, and plants.
Rising seas and increasingly dangerous storm surges threaten to submerge and erode their habitat and make the groundwater more saline — killing coastal plant communities and ruining drinking water.
The mangrove forest of India facing threat due to the increased sea level.
The corals which in habit in shallow water are under threat due to seal level rise. The coral reefs are the habitat for the diverse species of ocean. Loss of corals is the loss of rainforest of oceans.
The sea level rise putting more number of species in the critically endangered list. And hence the governments all over the world should educate all the stakeholders and implement relevant policies so as to reduce the global warming and thereby sea level rise.
Q.4) Explain the role of International Tribunal for the Law of the Sea in the context of disputes in South China Sea and Indian Ocean. (15 marks)
The International Tribunal for the Law of the Sea is an independent judicial body established by the United Nations Convention on the Law of the Sea to adjudicate disputes arising out of the interpretation and application of the Convention. The Tribunal is composed of 21 independent members, elected from among persons enjoying the highest reputation for fairness and integrity and of recognized competence in the field of the law of the sea.
The South China Sea disputes involve both island and maritime claims among several sovereign states within the region, namely Brunei, the People’s Republic of China (PRC), Republic of China (Taiwan), Malaysia, Indonesia, the Philippines, and Vietnam.
A verdict issued by a Tribunal set up under the United Nations Convention on the Law of the Seas (UNCLOS) has ruled that there was no evidence that China had exercised exclusive control over the waters and resources of the South China Sea (SCS), and therefore had no legal basis to claim historic rights to sea areas within the so-called ‘Nine-Dash Line’.
Second, it noted that while small groups of fishermen had used the rocky outcrops of the sea, collectively called the Spratly Islands, none of them were capable of sustaining a stable community and thus could not claim an exclusive economic zone (EEZ).
Third, that some of the areas were in fact within the Philippines EEZ and China had violated their rights by interfering with Filipino fishermen and oil exploration teams.
Fourth, that Beijing’s artificial island programme had violated UNCLOS obligations on protecting the environment.
The disputes in Indian Ocean range from fisherman’s issues to the settlement of maritime boundaries.
India’s Maritime dispute with Pakistan – India’s maritime dispute with Pakistan involves the demarcation of boundary along Sir Creek. sir Creek will further provide the reference point for demarcation of maritime boundary.
Sir Creek is a tidal estuary which exist on the border of India and Pakistan (Gujarat state and Sind Province). The land boundary between the countries upto Western Terminus were fixed by UN Tribunal, but it left the boundary from thereon undemarcated. This has become a conflicting issue between the two countries.
The issues with Sri lanka are being dealt by bilateral agreements and hence no role for the International Tribunal for the Law of the Sea to interfere.
Q.5) It had been said that climate change is making it harder to monitor marine pollution. Elucidate (15 marks)
Answer
Most environmental pollution in oceans and seas is caused by much smaller incidents that are often invisible, persistent, and far more difficult to track.
Biomarkers of exposure provide a tool to identify pollution events early on, often at levels that are not detectable by conventional methods. Loosely defined as measurable effects (endpoints) in organisms, providing evidence of exposure to pollutants, biomarkers lead to establishing the cause and giving the necessary data to inform any policy decisions that need to be taken.
The latest Intergovernmental Panel on Climate Change (IPCC) reports on climate change show that the upper 75 metres of the world’s oceans have been warming at a rate of 0.11°C per decade since at least 1971 and the uptake of CO2 caused by human pollution has depressed pH (acidity level) by -0.0014 to -0.0024 per year, and is predicted to continue.
Effects of climate change
First of all, commonly used organisms may no longer be available, as they migrate further north in search of cooler water. And they may then be replaced by invasive species from warmer waters that are not be as sensitive to pollution and therefore not as useful as biomarker organisms.
Changing migratory patterns may increase the transport of contaminants in the bodies of organisms in significant quantities to other, previously clean locations, in some cases even becoming more important than wind or water-driven methods.
Second, the fate and behaviour of contaminants in the environment, particularly their persistence, their ability to be taken up by organisms and how they behave once absorbed, is strongly driven by environmental factors such as salinity, pH and temperature – and these are all subject to change under climate change scenarios. This means, organisms may be more or less susceptible to pollutants; the degree of change will depend on the specific pollutants and the organism species involved.
Last of all, organisms unable to migrate will experience increased stress owing to changes in temperature, salinity and pH which may mean they may no longer be sensitive enough for the biomarker task.
The evidence for climate change driven by pollution caused by humans is overwhelming and it is clear it is affecting the marine environment.
As a result, some commonly used biomarker species and endpoints may need to be re-evaluated and adapted for this changing environment if they are to be used in future as early warning systems for pollution.