Why Is 2023 So Hot? A Rare Pacific Volcano Is Among The Suspects

Relevance: GS1 - Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, cyclone etc. GS3 - Conservation, environmental pollution and degradation

(Source: Indian Express, 09/15/2023)

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Why in the news?

• Recently, scientists claimed that an underwater volcanic eruption off Tonga in the South Pacific in January 2022 could be the major reason for 2023 being such a hot year.
• The June-August 2023 period was the warmest on record worldwide with heat waves occurring across the world.

What is the reason for 2023 being a hot year?

• According to climate science researchers at Maynooth University, Ireland, an underwater volcanic eruption in the South Pacific Ocean was majorly responsible for the record temperatures experienced by the world in 2023.
• In January 2022, the Hunga Tonga-Hunga Ha'apai erupted, releasing the equivalent of 60,000 Olympic swimming pools of water into the stratosphere.
  • This was equivalent to more than 150 million tonnes of water vapor, i.e. nearly 10% of the 1.4 billion tonnes typically found in the stratosphere.
  • The erupted water in the form of water vapor trapped heat in the atmosphere resulting in an increase in temperature.
  • The water plume will last in the atmosphere for up to around eight years.
• The eruption also released around 500,000 tonnes of sulfur dioxide into the stratosphere.
  • Although sulfur dioxide tends to cool the planet, the mix of water and sulfur released by the eruption complicated the situation.
• The eruption altered atmospheric pressure and briefly helped clear out the fog in Seattle, U.S.A.
• According to a study by the Nature Journal, global temperatures were at risk of breaching 1.5°C in at least one of the next five years.
• Experts claimed that Hunga Tonga-Hunga Ha'apai is the first observed volcano that may warm rather than cool the surface.

Role of volcanoes in global warming

According to scientists, more research about the effect of volcanic eruptions on long-term global warming trends.

Cooling effect

• Usually, the eruption of land-based volcanoes results in a temporary dimming of sunshine due to the spread of ash until it falls back onto the earth.
• Therefore, the eruption of volcanoes usually results in a cooling effect.
  • E.g.: Pinatubo in the Philippines (1991) cut average global temperatures by about 0.5°C (0.9°F) for more than a year.
• Over the past 2,500 years, sun-dimming eruptions have occurred at the rate of twice each century according to the U.N.'s Intergovernmental Panel on Climate Change (IPCC).
  • Tambora in Indonesia (1815) led to a "year without a summer" and subsequently affected agricultural harvests across the world.
  • The Samalas in Indonesia (1257) caused famines and are believed to be one of the primary causes of the Little Ice Age, a period of unusually cool weather that lasted until the 19th century.
• There is a lack of information on how many volcanoes are located in shallow water and earlier eruptions similar to the 2022 eruption.
  • Volcanoes in shallow water can deposit erupted material in the atmosphere.
  • E.g.: Before its eruption, the Hunga Tonga-Hunga Ha'apai was about 150 meters below sea level.
• The IPCC has predicted that at least one Pinatubo-style eruption is likely to occur this century.
• However, volcanoes have had a negligible effect on the overall trend of global warming which is driven by human emissions of greenhouse gas since the Industrial Revolution.

Impact

• Eruptions are likely to become more frequent in icy areas as a result of climate change.
  • Previously the weight of thick glaciers had kept a lid on the volcanoes, which could melt as a result of climate change-induced-thaw, leading to eruptions.
  • At the end of the last Ice Age (12,000 years ago) in Iceland, the eruption rate was nearly 100 times higher than the present rate.
• Increased rainfall caused by climate change could cause erosion on the sides of volcanoes.
  • Eg: In 2018, the flanks of the Kilauea volcano in Hawaii were weakened by unusually heavy rain caused by climate change.
• Volcanic eruptions aid in the formation of new rock on the Earth’s surface.
• Atmospheric circulation patterns help eruptions in the tropics have an effect on the climate in both hemispheres by spreading the dust and pollutants erupted by the volcanoes.

Climate change control activity based on volcanoes

• It is necessary to conduct more research on the impacts of volcanoes as volcanic activity is irregular, unpredictable, and uncontrollable.
  • It would be a major challenge if several Pinatubo-style eruptions were to take place in addition to the existing threat posed by climate change.

Volcano-inspired geoengineering

• Methods to cool the planet developed by geoengineers have been inspired by volcanic eruptions.
• This includes the deliberate dimming of sunshine as a shortcut by creating a Pinatubo-like haze which can be maintained throughout the year via a fleet of special planes spraying sulfur into the stratosphere.
• In 2022, the U.S. start-up, Make Sunsets, began launching balloons into the stratosphere carrying sulphur dioxide.
• It also sells "cooling credits" at the rate of $10 per gram of sulfur which will offset the warming effect of one tonne of CO2 for a year.
  • However, CO2 can exist in the atmosphere for more than hundreds of years.
• Geoengineering has been criticized for its potential to disrupt weather patterns.
  • This could also enable countries to avoid making the necessary deep cuts in emissions.

Tonga Tonga is a Polynesian country located in the South Pacific Ocean. It is an archipelago consisting of 171 islands of which 45 are inhabited. It is bordered by Fiji, and Wallis and Futuna (France) to the northwest Samoa to the northeast New Caledonia (France) and Vanuatu to the west Niue to the east Kermadec (New Zealand) to the southwest Climate: Tonga has a tropical rainforest climate. It is a member of the Commonwealth and became a constitutional monarchy in 2010. It was visited by Captain James Cook in 1773 and came to be known as the “friendly islands” due to the friendly reception afforded to them by the locals. India and Tonga have shared a close relationship since the establishment of diplomatic ties in 1970.

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