Sulphur dioxide from Caribbean volcano reaches India, WMO confirms
The sulphur dioxide (SO2) emissions from a volcanic eruption in the Caribbean reached India April 16, 2021 sparking fear of increased pollution levels in the northern parts of the country and acid rain. Sulphur dioxide reacts with water to form sulphuric acid which can come down with rainfall.
“Sulphur dioxide (SO2) emissions from La Soufriere volcano eruption in the Caribbean have reached all the way to India,” tweeted the World Meteorological Organisation on April 16.
Volcanic “plumes can cause aviation and air quality hazards. The injection height is needed to initialise forecast models that predict the downwind evolution of the plume,” Ralph Kahn, a climatologist at the National Aeronautics and Space Administration (NASA), said in a release on NASA’s Earth Observatory Website.
La Soufrière volcano on St Vincent Island in the West Indies started erupting on April 9 after spewing out lava into a dome and threatening to erupt since December 2020. The last time the volcano had erupted was in 1979.
“Of the 45 currently erupting volcanoes on Earth, La Soufriere is among those that worry volcanologists the most,” says NASA’s Earth Observatory website. This is because of its “explosive and erratic eruption style”.
The volcanic eruptions that occurred on April 10 were energetic enough for the plumes to be recorded at a height of 20 kilometres above the Earth’s surface by the Multi-Angle Imaging Spectro Radiometer instrument on NASA’s Terra satellite. NASA scientists have found evidence for the entry of sulphate aerosol particles (precursors for sulphuric acid) in the stratosphere, the second layer of the Earth’s atmosphere.
“The current thinking is that a volcano needs to inject at least 5 teragrams of SO2 into the stratosphere to have measurable climate impacts,” explained Simon Carn, a volcanologist at Michigan Technological University in the United States.
La Soufrière has delivered around 0.4-0.6 teragram of SO2 into the upper atmosphere which is the highest-ever recorded after satellites started observing the Earth’s atmosphere in the mid 20th century. The amount of SO2 being vented out by the volcano could increase if the eruptions continue. NASA scientists also surmise that moderate eruptions are usually far greater in number than huge eruptions and could have a greater cumulative impact.