PACIFIC – The eruption of the Tonga volcano instantly vaporised 58,000 Olympic-sized swimming pools of seawater high into the atmosphere, so much that scientists say it will likely warm the Earth – temporarily.
The extraordinary undersea Hunga Tonga-Hunga Ha’apai eruption on January 15 coated Nuku’alofa in ash, and sent a sonic boom that was heard in New Zealand and rippled around the world twice.
A tsunami quickly hit Tonga, followed by surges in New Zealand, and as far away as Japan, South America – where two women reportedly died in Peru – and even in the Caribbean.
The tsunami caused millions of dollars in damage at Tutukaka Marina in Northland, where eight to 10 boats sunk and structures were damaged.
Some structures, including oyster farms, were also damaged at Whangaroa Harbour.
Scientists in the US have now used detections from a Nasa satellite to determine that the eruption also sent 146 teragrams of vaporised water into the stratosphere.
One teragram is the equivalent of a trillion grams. To get a further sense of the scale, the eruption immediately increased the amount of water vapour sitting in the stratosphere by roughly 10%.
“We’ve never seen anything like it,” Luis Millán, an atmospheric scientist at Nasa’s Jet Propulsion Laboratory in Southern California who was one of the study’s lead contributors.
“We had to carefully inspect all the measurements in the plume to make sure they were trustworthy.”
The detections made by the Microwave Limb Sounder instrument on Nasa’s Aura satellite were published in a study in Geophysical Research Letters.
Millán says the eruption released nearly four times the amount of water vapour that reached the stratosphere (located 12 to 53km about the Earth’s surface) after the 1991 Mount Pinatubo eruption in the Philippines.
Typically, powerful volcanic eruptions like Pinatubo or Krakatoa actually cool Earth’s surface temperature because the gas, dust and ash they spew reflects sunlight into space.
But water vapour sent into the atmosphere can trap heat, and the excess amount from the Tonga volcano could stay in the stratosphere for up to 10 years before it fully dissipates.
“HT-HH may be the first volcanic eruption observed to impact climate not through surface cooling caused by volcanic sulfate aerosols, but rather through surface warming caused by excess H2O radiative forcing,” the paper reads.
The warming effect of the water vapour is expected to be small and researchers don’t believe it will be enough to exacerbate the climate crisis.
