Volcanic afterglow: Skies bathed in an explosion of colours

Six months on from the Hunga Tonga-Hunga Ha’apai volcanic eruption, skies in the Southern Hemisphere have been bathed in colour.

A spectacular show of colours has filled the skies of Antarctica, Australia and New Zealand.

This is said to be from a spike in aerosols (including ash, CO2, sulphur and water vapour) that were shot up into the stratosphere following the Hunga Tonga-Hunga Ha’apai eruption, evident in satellite lidar.

It also produced the highest ash plume ever recorded by satellites.

Although the eruption was in January 2022, the particles have circulated for months after and spread thousands of km across the southern hemisphere.

During this time of year, the southern hemisphere are enduring the depths of their winter. In Antarctica, the sun doesn't rise at all between mid-April until the end of August, and they are left in perpetual darkness.

However, the presence of these particles has lit the sky in an unusual array of pinks and purples, by bending and scattering the light as the sun nears the horizon.

Volcanic eruptions can have profound impacts on weather and climate by injecting volcanic material into the stratosphere.

The excessive water vapour in the stratosphere is expected to persist for years, and could lead to surface warming. This is because water vapour is a greenhouse gas, absorbing and emitting radiation.

Water vapour also holds more moisture, so as the climate warms, more surface evaporation occurs, increasing atmospheric moisture, further enhancing the greenhouse effect.