Tonga Volcanic Eruption and Global Climate

Tonga Volcanic Eruption and Global Climate

Subject – Environment

Context – underwater volcanic eruption occurred in Tonga in the southern Pacific Ocean January 15, 2022.

Concept –

• Volcanic eruption occurred in Tonga in the southern Pacific Ocean January 15, 2022, affect global climate.The explosion spewed plumes of gases, steam and ash into the stratosphere.
• The gases included sulphur dioxide (SO2), which is of particular interest because of its global cooling effect.
• Extreme levels of SO2 have not been recorded in the stratosphere going by the early data. The Tonga volcanic cloud contains roughly 0.4 teragram (Tg) of SO2.

1991 Mount Pinatubo explosion in the Philippines –

• According to studies, Pinatubo spewed about 15 million tonnes of sulphur dioxide into the stratosphere. The total mass of SO2 in the volcanic cloud was 20 Tg.
• Researchers recorded a 0.5 degrees Celsius (°C) drop in the average global temperature over large parts of the earth between 1992 and 1993.
• Mount Pinatubo recorded the largest SO2 cloud since 1978. It took about three weeks to spread around the world.

The Tonga event follows the Intergovernmental Panel on Climate Change report of 2021, which had suggested that an explosive volcanic eruption could occur in the 21st century.

• This eruption could lower surface temperature and precipitation globally, especially over land, for one to three years. “If such an eruption occurs, it would therefore temporarily and partially mask human-caused climate change,” the report had added.
• SO2 reacts with water to form sulphuric acid droplets, which become a part of aerosol particles. Aerosols are tiny liquid droplets suspended in the air.
• The aerosols block sunlight from reaching the Earth’s surface, causing cooling. Sulfurous aerosols, along with chlorine, contribute to the destruction of stratospheric ozone, though most of this depletion comes from man-made chemical
• The sulphuric acid-rich aerosol particles induce cooling by reflecting the incoming sunlight into space.
• The particles from Mount Pinatubo remained in the stratosphere for three-four years after the explosion, according to a study.

Pacific ring of fire

According to the US Geological Survey there are some 1,350 potentially active volcanoes around the world.

Many are located along a 40,000km (25,000-mile) arc along the Pacific known as the “Ring of Fire”, which is also where about 90 percent of all earthquakes occur.

Tonga is home to several volcanoes, all along the Ring of Fire.