Earlier this year geologists warned that North Korea's nuclear tests could trigger an eruption of the Mount Paektu volcano. New research shows just how much of a worry that is, with evidence that Paektu's last big eruption released far more sulfur than previously thought.
Paektu sits on the border between China and North Korea, making it one of the most difficult places on Earth for scientists to study. Nevertheless, it is known that a little over a thousand years ago the mountain underwent a major eruption. Research published in Science Advances suggests this released more sulfur than the fearsome explosions from Krakatau and Tambora.
Paektu's most recent eruption is thought to have occurred in 946 CE. We don't have records of the event, but an estimated 23 cubic kilometers (5.5 cubic miles) of rock was hurled into the air, along with enormous amounts of carbon dioxide and sulfur. The effects of these on the climate would have been contradictory, with the CO2 warming the world while the sulfur particles reflected sunlight and cooled us down.
The timescales of these two contributions would have been different. Sulfur washes out of the air relatively quickly, causing one or two cool years, while we are learning – to our sorrow – how long carbon dioxide sticks around.
A team led by Dr Kayla Iacovino of the US Geological Survey set out to quantify how much sulfur Paektu injected into the atmosphere. Past estimates have used what is known as the petrologic method comparing concentrations of volatile materials in the first crystals formed in the eruption and those left behind in later material. However, satellite observations of recent eruptions have found that this often underestimates how much sulfur is released.