Pink Skies Seen Over Antarctica May Be Explained by Tonga Volcano Eruption

The skies above Antarctica are burning a fiery pink, which is thought to be as a result of the Hunga Tonga volcano eruption in January 2022.

Similar hues have dazzled other regions in the Southern Hemisphere during July, including New Zealand and Australia. Antarctica is in a state of near-constant twilight in July, as it is just past the midwinter in the Southern Hemisphere, so Antarctic scientists see these sunset-like colors at about midday.

The scientists in Antarctica communicated with New Zealand's National Institute of Water and Atmospherics (NIWA) after they started experiencing the same skies. According to NIWA, their shared phenomenon was due to the remnants of the enormous plume of ejecta produced when the Hunga Tonga-Hunga Ha'apai volcano erupted in the South Pacific earlier this year.

pink winter sky
Stock image of a winter landscape with pink sunset clouds. The skies above Antarctica are glowing pink thanks to the afterglow of the Hunga Tonga volcanic eruption in January. iStock / Getty Images Plus

The underwater volcano erupted on January 15, exploding with approximately 100,000 times more energy than the Hiroshima nuclear bomb, sending out a pressure wave that circled the globe multiple times, and producing an enormous plume of ash, sulfur dioxide and steam that reached over 30 miles high.

Aerosols, including sulfur dioxide, from the plume of gas and ash released by the volcano have dispersed around the world, aided by the immensely powerful and record-breaking atmospheric waves produced by the eruption blast. The aerosols were measured to be present in the atmosphere around 10 to 15 miles above Antarctica currently, and were not present before the eruption.

"Usually when you see a sunrise or sunset, it is the clouds that morph into the most vibrant colors, however, when stratospheric aerosols are present after a volcanic eruption, they scatter and bend the light as the sun dips or rises past the horizon, creating a glow in the sky with hues of blue, purple, and violet," Nava Fedaeff, a NIWA forecaster, said in a statement.

These colorful twilights are known as volcanic "afterglows," with the amount of haze and aerosol in the air determining the colors.

The aerosols and fine dust particles low in the atmosphere backscatter red wavelengths of light. After sunset, alpenglow is an afterglow caused by the illumination of atmospheric particles by sunlight as it gets refracted and scattered through the Earth's atmosphere. Blue light is scattered, leaving the pink and red hues of the remaining sunlight.

A similar phenomenon occurred after the 1883 eruption of the volcano Krakatoa, with burning sunsets being seen across the world: it is even thought that perhaps the intense red background in the famous Edvard Munch painting The Scream was caused by the volcano.

"Nature never fails to put on a show in Antarctica, and it can be beautiful or destructive", said Antarctica New Zealand's Chief Science Advisor Jordy Hendrikx in a statement.

"These photographs capture the awe it inspires, and how connected our planet is. Antarctica is some 5000km [3100 miles] from New Zealand, some 7000km from Tonga, but we share our skies."