Understanding the Indian Ocean

Recently, the Indian Ocean has been under a lot of attention due to its rapid warming and the outsized influence on other oceans. 

Indian Ocean Warming Accelerates

• Importance of Understanding Climate Change Response
  • Exploring the Indian Ocean helps us grasp how oceans react to climate change and increasing greenhouse gases.
  • Insights from studying this ocean contribute to strategies for mitigating and adapting to climate change worldwide.

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About Indian Ocean

Indian Ocean is the Third-largest ocean, covering 70,560,000 km², about 20% of Earth’s water surface.

• Borders: Asia (north), Africa (west), Australia (east), Southern Ocean or Antarctica (south).
• Major regional  seas: Andaman Sea, Arabian Sea, Bay of Bengal, Laccadive Sea.

• Naming: Named after India, previously known as the Eastern Ocean.
• Average depth: 3,741 meters; located entirely in the Eastern Hemisphere.
  • Bordered by land on three sides, resembling an embayed ocean centered on the Indian Peninsula.
• Strategic significance: Its maritime route manages world’s container traffic and helps India in its  external trade. 
  • The region is also rich in mineral deposits and energy reserves, which make it a major area for  trade. 

Ecological Diversity and Tourism

• Rich in biodiversity: coral reefs, mangroves, seagrass beds.
• Significant tuna catch; home to endangered species.
• Attracts tourists with dolphins, whales, beaches, and coral reefs from Lakshadweep to the Andaman-Nicobar Islands and Reunion Island.

Unique Features of the Indian Ocean

• Northern Boundaries: The Asian landmass closes off the northern boundary, with small connections to the Persian Gulf and Red Sea.
• Southern Boundaries: The southern Indian Ocean connects to the Pacific and Southern Oceans through two oceanic tunnels.
  • First Tunnel: The Indonesian seas allow the Pacific Ocean to transfer up to 20 million cubic meters of water per second into the eastern Indian Ocean. 
    • This water, known as the Indonesian Throughflow, carries heat and affects circulation, temperature, and salinity in the Indian Ocean.
  • Second Tunnel: Connects the Indian Ocean to the Southern Ocean with two-way traffic. Colder, saltier waters flow from the Southern Ocean into the Indian Ocean below 1 km depth.

Heat Dynamics and Influence

• Water mix: Due to the closed northern boundary, the waters mix upward and with Pacific waters, then exit south.
  • The mix of heat and water in the Indian Ocean significantly influences global ocean heat uptake.
  • Impact of Global warming: It adds extra heat from the Pacific, while cold water from the Southern Ocean is less cold, causing the Indian Ocean to warm rapidly.
    • This rapid warming leads to heatwaves and extreme rainfall over the Indian subcontinent, posing threats to corals and fisheries.
    • Changes in wind circulation due to the warming Indian Ocean affect the Pacific’s ability to absorb heat, impacting global warming rates.

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Impact on Global Climate, North Atlantic Heat Sink

Heat Absorption Mechanism

• In the North Atlantic, surface waters become dense and sink deep into the ocean, carrying heat with them.

Impact of Global Warming

• Due to global warming, the sinking of water in the North Atlantic is slowing down, causing reduced heat escape from the surface. 
• Surprisingly, the warming of the Indian Ocean is actually speeding up the sinking of heat in the North Atlantic, affecting global warming directly, ultimately helping to moderate its effects.