
UNKNOWN EFFECTS. In this photo provided by New Zealand’s Ministry of
Foreign Affairs and Trade, the Hunga Tonga-Hunga Ha’apai volcano erupts
near Tonga in the South Pacific Ocean on January 14, 2015. The volcano
shot millions of tons of water vapor high up into the atmosphere,
according to a study published in the journal Science. (AP
Photo/New Zealand’s Ministry of Foreign Affairs and Trade)

This satellite image made by the Japanese weather satellite
Himawari-8 shows the eruption of the Hunga Tonga-Hunga Ha’apai undersea
volcano near Tonga on January 15, 2022. The volcano shot millions of
tons of water vapor high up into the atmosphere, according to a study
published on September 22, 2022 in the journal Science.
Researchers estimate the event raised the amount of water in the
stratosphere — the second layer of the atmosphere, above the range where
humans live and breathe — by around 5%. (Japan Meteorology Agency via
AP)
From The Asian Reporter, V32, #10 (October 3, 2022), pages 10
& 14.
Tonga volcano blast was unusual, could even warm the
Earth
By Maddie Burakoff
AP Science Writer
NEW YORK — When an undersea volcano erupted in Tonga in January, its
watery blast was huge and unusual — and scientists are still trying to
understand its impacts.
The volcano, known as Hunga Tonga-Hunga Ha’apai, shot millions of
tons of water vapor high up into the atmosphere, according to a study
published in the journal Science.
The researchers estimate the eruption raised the amount of water in
the stratosphere — the second layer of the atmosphere, above the range
where humans live and breathe — by around 5%.
Now, scientists are trying to figure out how all that water could
affect the atmosphere, and whether it might warm Earth’s surface over
the next few years.
"This was a once-in-a-lifetime event," said lead author Holger Voemel,
a scientist at the National Center for Atmospheric Research in Colorado.
Big eruptions usually cool the planet. Most volcanoes send up large
amounts of sulfur, which blocks the sun’s rays, explained Matthew Toohey,
a climate researcher at the University of Saskatchewan who was not
involved in the study.
The Tongan blast was much soggier: The eruption started under the
ocean, so it shot up a plume with much more water than usual. And since
water vapor acts as a heat-trapping greenhouse gas, the eruption will
probably raise temperatures instead of lowering them, Toohey said.
It’s unclear just how much warming could be in store.
Karen Rosenlof, a climate scientist at the National Oceanic and
Atmospheric Administration who was not involved with the study, said she
expects the effects to be minimal and temporary.
"This amount of increase might warm the surface a small amount for a
short amount of time," Rosenlof said in an e-mail.
The water vapor will stick around the upper atmosphere for a few
years before making its way into the lower atmosphere, Toohey said. In
the meantime, the extra water might also speed up ozone loss in the
atmosphere, Rosenlof added.
But it’s hard for scientists to say for sure, because they’ve never
seen an eruption like this one.
The stratosphere stretches from around 7.5 miles to 31 miles above
Earth and is usually very dry, Voemel explained.
Voemel’s team estimated the volcano’s plume using a network of
instruments suspended from weather balloons. Usually, these tools can’t
even measure water levels in the stratosphere because the amounts are so
low, Voemel said.
Another research group monitored the blast using an instrument on a
NASA satellite. In their study, published earlier this summer, they
estimated the eruption to be even bigger, adding around 150 million
metric tons of water vapor to the stratosphere — three times as much as
Voemel’s study found.
Voemel acknowledged that the satellite imaging might have observed
parts of the plume that the balloon instruments could not catch, making
its estimate higher.
Either way, he said, the Tongan blast was unlike anything seen in
recent history, and studying its aftermath may hold new insights into
our atmosphere.
The Associated Press Health and Science Department receives support
from the Howard Hughes Medical Institute’s Department of Science
Education. The AP is solely responsible for all content.
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