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Marine Cloud Brightening


The concept of marine cloud brightening is gaining prominence recently as a tactic for addressing extreme ocean heat and as a way to reduce coral bleaching and safeguard marine ecosystems.


GS III: Science and Technology

Dimensions of the Article:

  1. About Marine Cloud Brightening
  2. Challenges and Risks Associated with MCB
  3. What is Coral Bleaching?
  4. Conclusion

About Marine Cloud Brightening:

  • The concept of marine cloud brightening (MCB) was introduced by British cloud physicist John Latham in 1990. It aims to combat global warming by modifying the Earth’s energy balance.
  • Latham’s calculations suggested that by brightening clouds over specific ocean regions, it might be possible to offset the warming effects resulting from a doubling of pre-industrial atmospheric carbon dioxide.
Mechanism of Marine Cloud Brightening:
  • In regions of clean maritime air, clouds predominantly form from sulfates and sea salt crystals, which are relatively scarce. This leads to the creation of larger cloud droplets with lower light reflectivity.
  • MCB seeks to enhance the reflectivity (albedo) of marine clouds, making them whiter and brighter.
  • It involves the use of water cannons or specialized vessels to release fine sea water droplets into the atmosphere.
  • As these droplets evaporate, they leave behind salt particles that act as cloud condensation nuclei, promoting the formation of denser and brighter clouds.
Potential Benefits:
  • MCB holds the potential to reduce sea surface temperatures in specific areas, potentially mitigating the frequency and severity of coral bleaching events.
  • This technology could offer a lifeline for coral reefs, aiding in their survival and recovery while the world transitions away from fossil fuels.
  • Researchers are investigating the feasibility of implementing MCB for the Great Barrier Reef through modeling studies and small-scale experiments.
  • The Great Barrier Reef, a UNESCO World Heritage Site, has been highly susceptible to coral bleaching, experiencing numerous bleaching events in recent years.

Challenges and Risks Associated with MCB:

  • Marine cloud brightening (MCB) involves the large-scale spraying of seawater into the atmosphere at significant altitudes, which poses engineering challenges in terms of designing, funding, maintaining, and operating the spraying mechanisms.
  • Modifications in cloud patterns and precipitation patterns caused by MCB may influence regional climate and hydrological cycles, potentially resulting in unintended consequences such as droughts or floods.
  • MCB raises ethical concerns regarding human intervention in natural processes, and questions surrounding governance and decision-making related to its implementation.
  • There is a risk that MCB could lead to complacency among policymakers and the public, potentially reducing their commitment to mitigating greenhouse gas emissions and adapting to climate change through other means.

What is Coral Bleaching?

  • Coral bleaching is a phenomenon characterized by the loss of color in corals, which are typically vibrant and colorful. It occurs due to stress, often induced by elevated sea temperatures.
  • Coral bleaching takes place when corals expel the symbiotic algae residing within their tissues. These algae provide nutrients and color to the corals.
  • Coral bleaching weakens the corals, rendering them more vulnerable to diseases and potentially leading to their death if the stressful conditions persist.


  • Marine Cloud Brightening (MCB) is still in its early stages of research and development, necessitating further studies to assess its feasibility, effectiveness, impacts, risks, and governance.
  • It’s crucial to understand that MCB is not a standalone solution but a potential complementary measure to help coral reefs cope with extreme heat stress in the short term.
  • MCB should be incorporated into a comprehensive approach that encompasses conservation, restoration, adaptation, and innovation, aimed at protecting coral reefs from the adverse effects of climate change.

-Source: The Hindu

February 2024