UNESCO’s State of Ocean Report 2024 | 13 Jun 2024

Source: DTE

Why in News?

Recently, the UNESCO State of Ocean Report 2024 highlighted the need for enhanced oceanographic research and data collection to address escalating ocean crises, including warming, acidification, deoxygenation and rising sea levels.

What are the Key Findings of the State of Ocean Report 2024?

• Inadequate Data and Research: The report identifies a critical gap in data and research on accelerating ocean warming.
  • There is an urgent need for regular data to monitor ocean warming and its impacts, supporting the challenge for healthy and resilient oceans.
• Ocean Warming: The upper 2,000 meters of oceans warmed at a rate of about 0.32 Watt/m² from 1960 to 2023, which has accelerated to 0.66 Watt/m² in the past two decades.
  • This warming trend is expected to continue, causing irreversible changes over the centennial to millennial timescale.
• Earth Energy Imbalance (EEI): Increased greenhouse gas emissions from human activities has resulted in the increased uptake of the EEI by oceans.
  • EEI is the balance between incoming energy from the Sun and outgoing energy from the Earth.
  • About 90 % of the EEI is being absorbed by oceans, resulting in a cumulative increase in ocean heat content (OHC) in the upper 2,000 m of the water column. 
    • OHC is the total amount of heat stored by oceans.
  • This warming may prevent ocean layer mixing, potentially reducing oxygenated deep waters and leading to deoxygenation.
    • Deoxygenation can have long-term negative impacts on the health of coastal and large marine ecosystems and coastal communities.
• Ocean Acidification: There has been a mean global increase in ocean acidification in all ocean basins and seas.
  • The open ocean has been experiencing a continuous decline in pH (increase in acidic levels), with an average global surface ocean pH decline of 0.017-0.027 pH units per decade since the late 1980s.
    • Coastal waters can turn acidic due to natural processes, such as freshwater influx, biological activity, temperature change and climate patterns like El Nino Southern Oscillation (ENSO).
    • Human activities like nutrient input from agricultural and industrial activities also influence the chemistry of coastal areas.
  • However, limited long-term observations, particularly in coastal areas, hinder a complete understanding of this phenomenon.
• Continuation of Sea Level Rise: The global mean sea level from 1993 to 2023 increased at a rate of about 3.4 mm/yr.

  • The world will have to improve the space-based and in situ observing systems for monitoring sea level rise at global, regional, and coastal scales. 

• Marine Carbon Dioxide Removal (mCDR): The report acknowledges the growing interest in mCDR technologies aimed at capturing and storing atmospheric carbon dioxide.

  • Examples like altering the chemical composition of seawater so that oceans absorb more carbon dioxide from the atmosphere or adding nutrients such as iron to encourage the growth of microscopic plankton that can sink to the seafloor and be stored for centuries or longer.
  • There has been an increased interest in mCDR technologies with the growing number of start-ups developing mCDR techniques, alongside funding by the United States and the European Union for mCDR research announced in 2023.
  • There has been some challenges like the limited use of mCDR and how they will interact with the ocean carbon cycle, possibly causing unintended consequences such as threat to marine life in the long term.

What are the Impacts of the Global Warming on the Indian Ocean?

• Cyclones and Marine Heatwaves: The Indian Ocean is warming faster than other oceans, with the potential for irreversible changes like cyclones and heatwaves.
  • The Indian Ocean plays a significant role in the formation of monsoons and pre-monsoon cyclones that bring rain and pose threats to South Asia, East Africa, and West Asia.
  • The North Indian Ocean doesn't generate as many cyclones as the Pacific or Atlantic Ocean, but their numbers and rapid intensification have been growing making them the deadliest storms by mortality.
    • For example, the 2019 Cyclone Fani in Odisha, India, caused widespread destruction with its high winds and storm surge.
  • Marine heatwaves are becoming more frequent and intense, causing coral bleaching and harming marine life. 
    • For instance, a 2010 marine heatwave in the Indian Ocean caused widespread coral bleaching in the Lakshadweep Islands.
• Altered Ocean Circulation and Marine Life: Warming can weaken upwelling, a process that brings cooler, nutrient-rich waters to the surface. This can harm fish populations that depend on these nutrients.
  • For example, a decline in upwelling in the Arabian Sea can negatively impact the sardine fishery.
  • As the ocean absorbs more carbon dioxide, it becomes more acidic, harming organisms with calcium carbonate shells and skeletons, such as coral reefs and shellfish. 
    • The Great Barrier Reef in Australia is already experiencing significant damage due to ocean acidification, and similar threats are faced by coral reefs in the Indian Ocean.
  • Warmer water holds less oxygen. Increased stratification due to warming can prevent deep ocean mixing, leading to oxygen depletion in deeper layers. This can create dead zones where marine life cannot survive.
• Human Populations at Risk: Disrupted fisheries, cyclones, and droughts all threaten food security for millions of people who depend on the Indian Ocean for their livelihood.
  • Rising sea levels due to global warming threaten coastal communities with inundation and erosion. Low-lying areas in India, such as Mumbai and Kolkata, are particularly vulnerable.
  • Tourism and recreation industries that rely on healthy coral reefs and beaches will be negatively impacted by bleaching and coastal degradation.

Way Forward

• Developing and utilising real-time weather forecasts and cyclone warnings to coastal communities.
  • For example, India should aim to enhance the capabilities of the Indian National Centre for Ocean Information Services (INCOIS) for more accurate and timely predictions.
• Several geo-engineering techniques like stratopheric aerosol injection, marine cloud brightening etc can be utilised on a large scale to tackle the issue of oceanic warming.
• Promotion of sustainable coastal development practices building seawalls and leevees that minimise damage to infrastructure and communities during extreme weather events.
  • For example, the Odisha government's initiative to plant casuarina trees along the coast proved effective in mitigating the impact of Cyclone Fani.
• Conducting public awareness campaigns and regular evacuation drills to educate coastal communities about cyclone risks and evacuation procedures.
• Establishing marine protected areas to conserve coral reefs and other fragile ecosystems.
• Collaboration of international efforts to address climate change and limit global warming will ultimately benefit the Indian Ocean.

Conclusion

Overall, the UNESCO report highlights critical knowledge gaps and the need for improved data collection to understand and address the multiple threats facing oceans across the globe. It also explores potential solutions like mCDR and coastal habitat restoration, emphasising the need for further research to address associated uncertainties.