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19th March 2024 (14 Topics)

Warmer Oceans & Impact


The average global sea surface temperature (SST) — the temperature of the water at the ocean surface — for February 2024 stood at 21.06 degree Celsius, the highest ever in a dataset that goes back to 1979. The previous record of 20.98 degree Celsius was set in August 2023.

1: Dimension- Reason behind the warming oceans

  • Trapped heat: Since the beginning of the Industrial Revolution a few hundred years ago, humans have burned massive amounts of fossil fuels; cut down huge swaths of forest; and undertaken many other activities that pump heat-trapping carbon dioxide into Earth’s atmosphere. Most of the rest of the trapped heat has been absorbed into the planets’ vast oceans.
  • El Nino: The climate crisis is being compounded by the natural El Niño climate pattern.
  • Marine heat waves—defined as periods of persistent anomalously warm ocean temperatures (warmer than 90 percent of the previous observations for a given time of year)—have occurred recently in several areas.
  • Weaker-than-average windshave reduced the amount of Saharan dust in the atmosphere, which usually reduces sea temperatures by blocking some of the sun’s energy.

2: Dimension-Impact of Warm Oceans

  • Marine life: Hotter marine temperatures can have a devastating effect on marine life, and there have been multiple mass mortalities of marine animals and plants due to ocean heatwaves.
  • Displacement of species: Heatwaves can also cause damaging algal blooms, coral bleaching, the displacement of marine species – as they search for colder water – and the disruption of food chains.
  • Extreme climatic events: Increased marine temperatures can be harmful on land too, causing extreme weather, such as storms and hurricanes.
  • Vicious cycle of warming events: Less sea ice not only means possible future sea level rises, it means that there’s less ice to reflect the sun’s energy, resulting in higher sea temperatures and more frequent marine heatwaves, a vicious cycle that could have global ramifications.

There needs to be a reduction in emissions, but also more investment in nature-based solutions as well as more research into monitoring marine heatwaves. Furthermore, to ensure a stable climate and make real on the commitment of the Paris Agreement, UNEP has identified six sectors with the potential to reduce emissions enough to keep the world below the 1.5°C mark. They are: energy; industry; agriculture and food; forests and land use; transport; and buildings and cities.

Mains Practice Question

Q: What are the consequences of ocean warming? Discuss UNEP’s six-sector approach to reduce emissions enough to keep the world below the 1.5°C mark.


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