Extreme Temperature Diary-Wednesday January 19th, 2021/ Main Topic: When the Volcano Blows…Will the Tonga Eruption Temporarily Cool Our Warming Climate?

The main purpose of this ongoing blog will be to track global extreme or record temperatures related to climate change. Any reports I see of ETs will be listed below the main topic of the day. I’ll refer to extreme or record temperatures as ETs (not extraterrestrials).😉

Main Topic: When the Volcano Blows…Will the Tonga Eruption Temporarily Cool Our Warming Climate?

Dear Diary. I remember back in the early 1990’s that I was just beginning to point out the global warming trend to my Weather Channel colleagues. Several harsh summers had occurred across the U.S. during the 1980’s, including the drought and heat wave of 1988, which spurred Dr. Janes Hansen to testify before Congress. All trends were pointing upwards, and I was convincing some people that climate change was indeed occurring, then Mount Pinatubo blew its top in 1991.

The eruption affected the Earth so much that we saw a global cooling trend for the next few years. Some of my ignorant friends and colleagues began to snicker behind my back, particularly when we saw some cold springs in Atlanta during the early 1990’s. These people weren’t laughing so much once the effects of soot wore off by the time the late 1990’s arrived.

When many of my current climate colleagues heard of the huge, awesome Tonga eruption, their almost immediate thoughts went to how much SO2, or radiation blocking soot, was released into the high atmosphere. At this point, large volcanic eruptions are the only natural phenomena that can temporarily put an ice pack on our warming climate. After a few days of satellite observations, we note the following:

It appears that this horrific Tonga explosion that has devastated that archipelago won’t cool 2022 much, if at all. Here is a very detailed report on the eruption as of Tuesday by my friend Matthew Capucci from the Washington Post:


Capital Weather Gang

How the Tonga volcano generated a shock wave around the world

The eruption of Hunga Tonga was among the most spectacular displays caught by a weather satellite

By Matthew Cappucci January 16, 2022 at 11:57 a.m. EST

The Hunga Tonga volcano in the southwest Pacific erupted explosively on Saturday evening local time, producing a tsunami, sending ash 100,000 feet high and generating an atmospheric shock wave that rippled around the globe. The eruption was heard in Alaska, about 5,000 miles away, while an area the size of New England was blanketed by the ashen smoke plume.

Underwater Pacific volcano sends tsunami waves to Tonga, cutting off contact with outer islands

The volcano is about 40 miles north of Tonga’s main island, Tongatapu, near the international date line. Tonga, home to 105,000 people, can be found northeast of New Zealand and southeast of Fiji.

“We have a nightmare situation of an isolated community experiencing the effects of a large volcanic ash plume producing significant volcanic lightning, as well as a tsunami,” Janine Krippner, a volcanologist at the Smithsonian Global Volcanism Program, wrote in a Twitter direct message. “Seeing that ash plume, that volcanic lightning, and that tsunami leave me feeling sick thinking about the people being impacted by this large eruption.”

In addition to the more immediate and striking atmospheric effects resulting from the volcano, some have speculated that the volcano could affect Earth’s climate. Though experts are skeptical, atmospheric scientists continue to collect more data.

Hunga Tonga, an underwater volcano, erupted in 2009 and in late 2014. Renewed eruptions ensued Dec. 21, 2021, with occasional spurts of activity during the following weeks. A particularly explosive eruption occurred Jan. 15, resulting in arguably the most remarkable and striking display of volcanic power captured by a weather satellite.

The plume towered to about 100,000 feet, roughly three times the altitude at which commercial aircraft fly. Thunderstorms flatten out at the tropopause, or top of the troposphere, the lowest level of Earth’s atmosphere, since a lid of warm air suppresses continued upward development. Hunga Tonga’s plume, however, was so buoyant that it was able to penetrate this layer and continue into the stratosphere before pockets of air and ash subsided once again. The bulge in the middle of the cloud mass where this occurs is known as the “overshooting top.”

Satellite imagery captured “gravity waves” rippling outward from where the plume punctured this ceiling-like layer in the lower atmosphere — like wavelets surrounding a stone tossed in a pond.

A prolific volcanic thunderstorm

Within six hours of the initial blast, the ash and smoke plume from Hunga Tonga covered an area larger than New England. Though night had fallen, the plume would have been thick enough to block the sun. Static discharges within the plume, which towered twice as high as Earth’s most fierce thunderstorms, yielded prolific barrages of volcanic lightning.

Lightning detection networks and satellites tallied more than 60,000 strikes in 15 minutes following the volcano’s initial blast, corresponding to nearly 70 lightning strikes per second. Few, if any, conventional thunderstorms could compare.

Notice, too, the bull’s eye-like pattern that emerges in the lightning data. That’s the result of the aforementioned gravity waves. As the waves pass by, upward motion is locally enhanced, boosting lightning rates. In their wake, air sinks, suppressing lightning activity.

A dangerous tsunami

The blast was powerful enough to generate a tsunami of several feet in Tonga and prompted tsunami advisories across Hawaii, Alaska, British Columbia and much of North America’s West Coast, including in Washington, Oregon and California.

A four-foot spike in water levels was observed in Port San Luis, Calif., and Arena Cove, Calif., reported a 3.5-foot jump. Crescent City, Calif., got a 2.7-foot spike, and a tsunami of 2.8 feet was seen in King Cove, Alaska.

In addition to an uptick in water levels, tsunamis can produce dangerous and erratic currents. They move across oceans faster than commercial jetliners.

Tsunami waves reach West Coast as National Weather Service urges: ‘Move off the beach’

Volcano’s explosion heard in Alaska

Experts at the National Weather Service in Anchorage and the University of Alaska Fairbanks confirmed that audible booms heard in the state early Saturday morning local time originated from the volcano. That means the sound traveled more than 5,000 miles.

“Dog and I woke up suddenly at 3:30 and now I know why,” tweeted Shan Cole, a writer based in Anchorage.

That means the sound traveled close to 800 mph, and instruments confirmed that much of the noise produced did fall within the spectrum of what humans can hear. That no sound was heard in Hawaii, closer to the volcano, suggests atmospheric conditions in or near Alaska played a role in reflecting the sound to the surface.

An atmospheric shock wave

In the initial satellite imagery surrounding the volcano, it’s easy to spot a ring of white radiating rapidly outward far ahead of the volcanic plume. That’s the atmospheric shock wave.

That shock wave traveled around the world, also moving faster than the speed of sound. In Florida, for instance, it could be detected as an anomaly in air pressure shortly after 9 a.m. That’s because the wave briefly spurred a jump in air pressure, meaning the atmosphere briefly weighed more as the wave rolled through.

Daryl Herzmann of Iowa State University compiled air-pressure data from sensors across the Lower 48 to illustrate the wave rolling across the country.

Potential climate impacts

Volcanic eruptions can release enormous amounts of sulfur dioxide and aerosols that, in large enough quantities, can cool the planet and work to snuff out a La Niña pattern. Though there was initial speculation that material released by Hunga Tonga could have a similar effect, some experts were quick to point to the magnitude of its release being simply too comparatively minute.

Simon Carn, a professor at Michigan Tech, tweeted that the sulfur dioxide “columns do not appear to be extreme” so far. It would need to be five to 10 times as dense to begin to have a measurable climate impact.

Alan Robock, a professor in the Department of Environmental Sciences at Rutgers, noted that the amount of sulfur dioxide needed to cool Earth would be immense.

“Only if the eruption injects a lot of SO2 into the stratosphere, at least 1000 [kilotons, or thousands of tons] or more, will there be a climate impact,” he wrote in an email.

Satellite measurements show SO₂ quantities from the latest eruption were 400 kilotons. Robock said the eruption will “produce about 1/50 of the impact of the 1991 Pinatubo eruption,” or about 0.02 degrees (0.01 degree Celsius) average cooling.

Still, experts point to continued eruptions as something to monitor.

“We have no way of knowing when this eruption will be over,” the Smithsonian’s Krippner wrote.


A previous version of this article incorrectly referred to the Smithsonian Global Volcanism Program as the Smithsonian Global Volcano Program and incorrectly rendered Port San Luis as Port St. Luis. The article has been corrected.

Image without a caption

By Matthew Cappucci is a meteorologist for Capital Weather Gang. He earned a B.A. in atmospheric sciences from Harvard University in 2019 and has contributed to The Washington Post since he was 18. He is an avid storm chaser and adventurer, and covers all types of weather, climate science, and astronomy.  Twitter

Here are some “ET’s” from Wednesday:

Here is more climate and weather news from Wednesday:

(As usual, this will be a fluid post in which more information gets added during the day as it crosses my radar, crediting all who have put it on-line. Items will be archived on this site for posterity. In most instances click on the pictures of each tweet to see each article. The most noteworthy items will be listed first.)

Now here are some of today’s articles and notes on the horrid COVID-19 pandemic:


(If you like these posts and my work please contribute via the PayPal widget, which has recently been added to this site. Thanks in advance for any support.) 

Guy Walton “The Climate Guy”

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