A recent study has revealed a troubling connection between mangrove dieback in the Maldives and two major factors: rising sea levels and the extreme phases of the Indian Ocean Dipole (IOD). This highlights the far-reaching effects of oceanic climate phenomena on ecosystems and coastal communities.
What is the Indian Ocean Dipole (IOD)?
The Indian Ocean Dipole (IOD) is a climate phenomenon characterized by the difference in sea surface temperatures (SSTs) between the eastern and western regions of the Indian Ocean. This phenomenon plays a critical role in shaping weather patterns, not just in the Indian Ocean region but also globally.
Phases of IOD
Positive Phase
Warm waters accumulate in the western Indian Ocean, while cold deep waters surface in the eastern Indian Ocean.
Impact:
Increased rainfall along the coastal regions of Africa.
Drought conditions in Australia due to lower temperatures and reduced moisture in the eastern regions.
Negative Phase
Warmer waters shift to the eastern Indian Ocean, cooling the western region.
Impact:
Heavy rains in Australia.
Drier conditions and reduced rainfall in the African coast.
Effects of IOD
Associated sea-level changes often amplify the risks of coastal flooding.
Contributes to extreme weather events like cyclones, prolonged droughts, and floods.
Why in News?
Recent research links the IOD with mangrove dieback in the Maldives, exacerbated by:
Rising Sea Levels: Accelerated inundation of coastal zones.
Extreme IOD Events: Increased frequency and intensity, leading to irregular weather patterns that stress coastal vegetation.
Importance of IOD for India
Monsoon Dynamics
Positive IOD often strengthens the Indian Monsoon, bringing enhanced rainfall.
Negative IOD can weaken the monsoon, potentially leading to droughts in India.
Agricultural Impacts
IOD significantly affects crop yields, especially in rainfed areas.
Fisheries and Marine Ecosystems
Changes in water temperature disrupt marine biodiversity and fisheries.
Disaster Preparedness
Understanding IOD patterns helps in early warning systems for floods and droughts, enabling better disaster management.
Way Forward
Research and Monitoring: Strengthen observational networks to monitor IOD phases and sea-level changes.
Mangrove Restoration: Undertake coastal afforestation and mangrove conservation projects to mitigate rising sea levels.
Global Cooperation: Collaborate internationally to address the effects of climate phenomena on vulnerable ecosystems.
Practice Question
Consider the following statements about the Indian Ocean Dipole (IOD):
The IOD is based on the temperature difference between the eastern and western Indian Ocean.
A positive IOD phase leads to droughts in Australia and heavy rains along the African coast.
Sea-level changes associated with IOD have no impact on coastal flooding.
Which of the statements given above is/are correct?
(a) 1 and 2 only
(b) 1 and 3 only
(c) 2 and 3 only
(d) 1, 2, and 3
Answer: (a) 1 and 2 only
Explanation:
Statement 1 is correct; the IOD is determined by the sea surface temperature difference between the eastern and western Indian Ocean.
Statement 2 is correct; the positive phase of IOD brings heavy rains to coastal Africa and droughts in Australia.
Statement 3 is incorrect; sea-level changes associated with IOD significantly increase the threat of coastal flooding.
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