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Test Paper

Q 64- Evaluate the impact of global warming on the coral life system of the world with examples. (250 words)

  •   Paper & Topic: GS I à Geography

 

  • Model Answer:

 

  • Introduction:

 

  • A coral reef is an underwater ecosystem characterized by reef-building corals.
  • Reefs are formed of colonies of coral polyps held together by calcium carbonate.
  • Most coral reefs are built from stony corals, whose polyps cluster in groups.
  • Most reefs grow best in warm, shallow, clear, sunny water.
  • They occupy less than 0.1% of the world’s ocean area, yet they provide a home for at least 25% of all marine species.
  • Hence, they are also known as “rainforests of the ocean”.
  • The increase in greenhouse gases in the atmosphere due to human activities causes global warming or climate change.
  • Global warming has increased substantially over the past couple of decades that have led to warming of oceans.
  • This warming has affected the ocean inhabitants including corals.

 

  • Body:

 

  • Threats faced due to global warming:

 

  • According to UNESCO, the coral reefs in all 29 reef-containing World Heritage sites would cease to exist by the end of this century if we continue to emit greenhouse gases under a business-as-usual scenario.
  • A team of Indian researchers has warned that rising sea temperatures due to climate change could put these wondrous underwater systems under peril.
  • Their study, which analysed data of sea surface temperatures since 1982, has found that three mass bleaching events occurred in 1998, 2010 and 2016, impacting five major Indian coral reef regions — in Andaman, Nicobar, Lakshadweep, Gulf of Mannar and Gulf of Kutch.
  • According to Global coral reef monitoring network, 19% of world corals are already dead.
  • The main cause behind it is Global warming.
  • Between 2014-17, 50% of Great Barrier reef bleached
  • Cyclones responsible for 48% of coral loss in Australia between 1985-2012
  • Marine Heat wave was major cause of bleaching in GBR in 2017
  • Japan’s largest reef Okinawa witnessed death of 75% corals due to bleaching
  • In Maldives, 60% corals suffered bleaching in 2016 Impact of Global warming on Coral Reefs

 

  • Coral Bleaching:
  • When corals are stressed by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae living in their tissues, causing them to turn completely white.
  • For instance, Great Barrier Reef: Over 2016 and 2017, Great Barrier Reef suffered back-toback bleaching, leaving half of the shallow water corals dead. One-third of the 3,863 reefs that make up the Great Barrier Reef went through a catastrophic die-off.

 

  • Infectious diseases:
  • rising sea temperatures also causes diseases among coral systems due to rise of bacteria such as viborio shiloi.

 

  • Algal blooms:
  • Changes in precipitation result in increased runoff of freshwater, sediment, and land-based pollutants contribute to algal blooms and cause murky water conditions that reduce light.

 

  • Hampers marine ecosystem:
  • Changes in coral ecosystem also affect the species that depend on them, such as the fish and invertebrates that rely on live coral for food, shelter, or recruitment habitat.

 

  • Solar irradiation:
  • global warming results in changes in local weather patterns.
  • With decreased cloud cover, the sunlight penetrates more into water increasing stress among corals.

 

  • Ocean Acidification:
  • Due to increased CO2 levels in atmosphere, oceans absorb more CO2.
  • This increases the acidity levels in water and inhibits the corals ability to build calcareous skeletons that are vital for their survival.
  • Ocean acidification, or increased CO2 levels has reduced calcification rates in reef-building and reef associated organisms, causing their skeletons to become weaker and growth to be impaired

 

  • Rise of nutrients:
  • Increased temperatures raise the activity of photosynthesis resulting in increased amounts of nutrients in water.
  • This promotes population of organisms that compete with corals for growth.

 

  • Increased instances of Natural disasters:
  • Coral reefs act as key barrier to guard against incoming storms and mitigate the damage done by surging seas.

 

  • Global warming is associated with increases frequency of natural disasters.
  • And this threatens the survival of corals.

 

  • Affects food chain:
  • It is also expected that there will be a gradual decrease in the quantity of marine plants such as phytoplankton in warmer waters, effectively reducing the amount of nutrients available to animals further along the food chain.

 

  • Loss of livelihoods:
  • Countries in Southeast Asia such as Indonesia, Thailand and Philippines would bear the brunt of the damage, as it will reduce the fish stock rapidly.

 

  • Economic Impact:
  • Both fishing and tourism will be hit hard. Many communities in Queensland had to look for alternate livelihoods due to coral bleaching and loss of ocean ecosystem.

 

  • Way forward:

 

  • Limiting global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C, in line with the Paris Agreement on climate change, provides the only chance for the survival of coral reefs globally.
  • Other measures alone, such as addressing local pollution and destructive fishing practices, cannot save coral reefs without stabilised greenhouse gas emissions.
  • Reinforcing commitments to the Paris Agreement must be mirrored in all other global agreements such as the Sustainable Development Goals. l.
  • Economic systems need to rapidly move to the low greenhouse gas emission scenario to enable global temperature decrease.
  • A move away from current economic thinking should include the benefits provided by coral reefs, which are currently not taken into account in mainstream business and finance.
  • Therefore, sustaining and restoring coral reefs should be treated as an asset, and long-term investments should be made for their preservation.
  • Investments should also include support for research at the frontiers of biology, such as genetic selection of heat-resistant corals that can withstand rising global temperatures.

 

  • Conclusion:

 

  • There also needs to be a transformation of mainstream economic systems and a move towards circular economic practices.
  • These are highlighted in SDG 8 (inclusive and sustainable economic growth) and SDG 12 (sustainable consumption and production patterns).
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