September 26, 2023

General Studies Paper 3


  • The Arctic Ocean could be ice-free in summer by the 2030s, even if we do a good job of reducing emissions between now and then. That’s the worrying conclusion of a new study in Nature Communications.

The background

  • Predictions of an ice-free Arctic Ocean have a long and complicated history, and the 2030s is sooner than most scientists had thought possible.
  • The Arctic has been experiencing climate heating faster than any other part of the planet.
  • As it is at the frontline of climate change, the eyes of many scientists and local indigenous people have been on the sea ice that covers much of the Arctic Ocean in winter.
  • This thin film of frozen seawater expands and contracts with the seasons, reaching a minimum area in September each year.
  • The ice which remains at the end of summer is called multiyear sea ice and is considerably thicker than its seasonal counterpart. It acts as barrier to the transfer of both moisture and heat between the ocean and atmosphere.
  • Over the past 40 years this multiyear sea ice has shrunk from around 7 million sq. km to 4 million.
  • That is a loss equivalent to roughly the size of India or 12 UKs. In other words, it’s a big signal, one of the most stark and dramatic signs of fundamental change to the climate system anywhere in the world.

Blue Ocean Event (BOE)

  • A Blue Ocean Event (BOE) is probably something you’ve never heard of, but in just a few years it will be the biggest story that everyone is talking about.
  • A BOE is when the Arctic Ocean changes from being covered in ice year-round and reflecting most of the sunlight that impacts it back into space to being mostly ice-free blue water for a period of time during the warm season (May through October), which will cause it to absorb most of the sunlight that impacts it.
  • Once a BOE occurs during a warm season, the Arctic Ocean water will refreeze during the following cold season.
  • However, since the water will be slightly warmer each year, longer Blue Ocean Events are expected with each passing warm season, causing extensive impacts to the global climate and human habitat.
  • Blue water, which is dark, absorbs more sunlight than white ice, due to the fact that darker colors naturally absorb more sunlight than lighter colors, a phenomenon known as the “albedo effect.”
  • One problem with predicting when this might occur is that sea ice is notoriously difficult to model because it is influenced by both atmospheric and oceanic circulation as well as the flow of heat between these two parts of the climate system.

The Consequences

  • There is still plenty of uncertainty around the exact date – about 20 years or so– because of natural chaotic fluctuations in the climate system. But compared to previous research, the new study still brings forward the most likely timing of a blue ocean event by about a decade.
  • Arctic sea ice is an important component of the climate system. As it dramatically reduces the amount of sunlight absorbed by the ocean, removing this ice is predicted to further accelerate warming, through a process known as a positive feedback.
  • This, in turn, will make the Greenland ice sheet melt faster, which is already a major contributor to-sea level rise.
  • The loss of sea ice in summer would also mean changes in atmospheric circulation and storm tracks, and fundamental shifts in ocean biological activity.

Way forward

  • In conclusion, temperatures could rise strongly by 2026, resulting in humans going extinct, making it in many respects rather futile to speculate about what will happen beyond 2026.
  • On the other hand, the right thing to do is to help avoid the worst things from happening, through comprehensive and effective action through a Climate Plan.
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