Why is 2023 so Hot?

What’s in today’s article?

• Why in News?
• What are Submarine Volcanoes?
• Submarine Volcano Eruption near the Pacific Nation of Tonga
• Impact of Volcanic Eruption on Climate - Why is the Tonga Volcano an Exception?

Why in News?

• As the world experiences record temperatures, scientists say an unusual culprit may be partly to blame: an underwater volcanic eruption off Tonga in the South Pacific last year.
• A massive underwater or submarine volcano erupted near the Pacific nation of Tonga in January 2022.

What are Submarine Volcanoes?

• These are volcanoes located beneath the ocean's surface and their eruptions throw rock and ash into the water, while molten lava glows beneath the surface.
• There are three ways in which they can take place -
  • Due to rift zones which are found in all of Earth’s major ocean basins.
  • Due to the collision of crustal plates.
  • Occurs as a result of a magma plume rising through the Earth’s crust overlying an area of melting in the Earth’s mantle.
• According to the NOAA, the earth's major ocean basins contain rift zones (at depths greater than 2,000 metres), also known as seafloor spreading centres or divergent plate boundaries, where crustal plates are formed.
• Therefore, around three-quarters (more than 70%) of all volcanic activity on Earth occurs as deep, underwater eruptions.
• However, the effects of these deep eruptions cannot be seen from the ocean's surface because they are hidden beneath thousands of feet of water.
• Significance of Submarine volcanoes:
  • They create unique habitats, which makes them even more interesting.
  • Seamounts, which are underwater mountains formed by volcanic activity, are biologically diverse areas.
  • Their shape aids in the deflection of food-carrying currents upward and attracts a variety of sessile fauna as well as the crustaceans and fish that feed on them.

Submarine Volcano Eruption near the Pacific Nation of Tonga:

• The Kingdom of Tonga is an archipelago located in the South Pacific Ocean (south of Samoa), about 2000 miles east of Brisbane, Australia.
• A violent eruption of an underwater volcano (in January 2022) near two small uninhabited islands of Tonga (Hunga-Ha’apai and Hunga-Tonga) has sent shock waves around half the world.
• The Hunga-Tonga-Hunga-Ha'apai volcano has erupted on a regular basis in recent decades, but this was one of the massive explosions the volcano is capable of producing roughly every 1000 years.
• There can be two theories associated with this massive volcanic eruption -Fuel-coolant (magma-cold water) interaction and Explosion of a hidden caldera.
• The eruption also caused a tsunami that swept through Tonga as well as neighbouring Fiji and Samoa.

Impact of Volcanic Eruption on Climate - Why is the Tonga Volcano an Exception?

• The June-August (2023) period was the warmest on record worldwide, with heat waves occurring from Japan to the United States.
• The 2015 Paris Agreement seeks to limit the rise in average temperatures to 1.5 degrees Celsius (2.7 Fahrenheit) above pre-industrial times to avert the worst of climate change, from floods to wildfires.
  • Temperatures are already up 1.2C (2.2F).
• Many scientists say more research into volcanoes is vital to gauge how far eruptions can briefly affect the long-term trend of global warming, driven by burning fossil fuels.
• While most big volcanic eruptions cool the planet with a sun-dimming haze, the eruption of Hunga Tonga-Hunga Ha'apai blew ~60,000 Olympic swimming pools of water into the stratosphere.
  • Water vapour is a natural greenhouse gas (GHG), trapping heat as it swirls around the globe.
  • Hence, the Tongan volcano is an exception to the rule - the first volcano in the observational record that may warm rather than cool the surface.
  • The eruption slightly increased the risk that global temperatures would temporarily breach 1.5C in at least one of the next five years.
• Some scientists say climate change might make eruptions more frequent.
  • In certain icy areas, a thaw could unleash eruptions because the weight of thick glaciers keeps a lid on some volcanoes.
  • And downpours linked to climate change could erode the sides of volcanoes.
• Volcanoes inspire 'geoengineers' to cool the planet.
  • Some scientists favour deliberately dimming sunshine as a shortcut to cool the Earth.
  • For example, a U.S. start-up recently launched balloons into the stratosphere carrying sulphur dioxide.
  • An aerosol like sulphur dioxide into the stratosphere would reflect the sun rays back upwards, shading the earth.
• However, many scientists oppose such "geoengineering", as it might disrupt weather patterns and give some nations an excuse to avoid deep cuts in emissions.

Q1) What is geoengineering?

Geoengineering, also known as climate engineering, describes a range of ways to intervene on a large scale in the Earth's natural systems - the oceans, soils and atmosphere - to directly combat climate change.

Q2) Why do volcanoes erupt?

When enough magma (melted rocks) builds up in the magma chamber, it forces its way up to the surface and erupts, often causing volcanic eruptions.

Source: Why is 2023 so hot? A rare Pacific volcano is among the suspects