In 2022, Hunga Tonga sent water vapour into the stratosphere, altering ozone and radiation

On 15 January 2022, an underwater volcano in the South Pacific sent an extraordinary amount of water vapour into a part of the atmosphere that is normally very dry. The Hunga Tonga-Hunga Ha'apai eruption pushed the moisture high into the stratosphere, with the plume reaching as far as about 53 kilometres above Earth. Scientists estimated that around 146 teragrams of water entered the stratosphere, equivalent to roughly 10% of the water already held there. The unusual injection did not simply fade after the eruption. The vapour spread around the globe and remained detectable through 2022 and 2023, while influencing temperatures, atmospheric circulation, ozone and the way radiation moved through the atmosphere. Later measurements showed that the added moisture's climate influence weakened as it dispersed, with most of the eruption's radiative effects close to disappearing by the end of 2023.How Hunga Tonga sent huge amounts of water vapour into the stratosphereHunga Tonga-Hunga Ha'apai was a submarine volcano, and the setting mattered. Its caldera had previously been around 150 metres below sea level, meaning enormous volumes of seawater were close to the erupting magma. According to...