Satellites watch as Bali’s Mount Agung volcano propels ash and gas into the atmosphere, threatening climate cooling

By Tom Yulsman | November 29, 2017 12:55 pm

An animation of satellite images shows Mount Agung in Bali, Indonesia erupting. The images were acquired by Himawari-8, a Japanese weather satellite, between 12:00 UTC on Nov. 26th and 8:00 UTC on Nov. 27th.  (Note: When the animation page comes up, make sure to click on ‘play’ there. Source: SLIDER BY RAMMB/CIRA @ CSU)

With magma boiling at its peak and swelling its body from within, Mount Agung in Bali, Indonesia has awakened from more than a half century of slumber.

Agung has been rumbling since August. Now it is propelling ash thousands of feet into the atmosphere, prompting evacuations of thousands of people from the danger zone around it and causing authorities to halt flights in and out of Bali’s international airport. (Flights have resumed today to allow stranded travelers to get out.)

Dramatic views of the eruption have been captured by photographers on the ground. And now you can watch what it looks like to satellites in orbit.

I created the animation above using a cool, public website called “Satellite Loop Interactive Data Explorer in Real-time,” or SLIDER. It consists of images acquired by the Himawari-8 weather satellite between 12:00 UTC on Nov. 26th and 8:00 UTC on Nov. 27th. Click on it and then make sure to press play on the animation page that comes up. (You may have to be patient for the animation to fully load.)

The animation begins at night. Watch for flickering blue pixels. My guess is that the satellite sensor is detecting flashes from erupting lava. Another possible explanation is that lightning is occurring in clouds billowing up from the volcano. There are also fainter bluish emissions that are likely indicative of ash plumes.

As day turns to night, watch for brownish plumes of ash spewing from the summit of Agung.

Sulphur dioxide plumes from the eruption of Mount Agung in Bali, Indonesia

Data from NASA’s Aura satellite show the high sulfur dioxide (SO2) concentrations associated with the volcanic eruption of Mount Agung in eastern Bali, Indonesia, on Monday, November 27, 2017. (Source: NOAA/NASA)

Ash isn’t the only thing Agung is propelling into the atmosphere. The volcano also has been emitting large amounts of sulfur dioxide. While invisible to our eyes, satellite sensors can detect the SO2 — a gas that can harm people and also alter the climate.

Sulfur dioxide spewed into the atmosphere by a volcano like Agung reacts with water to produce sulfuric acid aerosols. If an eruption is powerful enough to propel these aerosols into the stratosphere, they can cool the global climate by reflecting sunlight back into space — and they can stay there for a number years.


Global mean surface temperatures from Berkeley Earth (black dots), major volcanoes (shaded areas), and estimated temperatures based on human and natural radiative forcing (red) with a 1963-size Agung eruption in mid-2017 (blue). The baseline period is 1961-90. (This graphic was created by Carbon Brief for an analysis of Agung’s potential climate impact.)

Mount Agung last erupted massively in 1963. That natural disaster killed more than 1,000 people. It also had an appreciable climate impact, reducing the global average temperature by about 0.1 degree C. Should the current activity at Agung lead to an eruption of that magnitude, global temperatures could drop by 0.1 to 0.2 degrees C, according to data scientist Zeke Hausfather, writing in an analysis at the Carbon Brief website.

The time-lapse above shows a massive phreatic eruption from Agung on Nov. 25th. Phreatic eruptions occur when water comes into contact with lava or other intensely hot material, causing an explosion of steam, water, ash, and rocks.

As big and bad as the Nov. 25th eruption looks, it is nothing like the one in 1963. So is Agung definitely headed for something like that?

Unfortunately, there was very limited monitoring of the precursors to the 1963 eruption, according to Tracy K.P. Gregg, a geologist at the State University of New York at Buffalo. And as she puts it in an excellent science backgrounder at The Conversation:

We don’t yet know if Agung volcano is currently giving us two weeks, two months or two years (or more) of warning because we don’t know precisely what it did before its 1963 eruption.

If you want to monitor the volcano in realtime, check out this webcam:

  • OWilson

    If Global Warming is as bad as we are told, then shouldn’t the headline read, “….volcano propels ash and gas into the atmosphere, promising some relief from Global Warming”, rather than “threatening Global Cooling!”

    Or is everything Mother Nature sends our way necessarily bad?

    • nik

      It could help tip the Earth back into the next ice age, which would put an end to the ”Global Warming” bullsh!t fraud.

      • OWilson

        Looks like we are heading into a cooling period as predicted by those who pay attention to the sun’s varying energy output.

        Look at this as the preparation of an elaborate plan to explain it all away! What a co-incidence, look!

        “It wuz the Volcano that dun it!”

        Like before,

        “The ocean ate my Global Warming”

        It was “El Nino, La Nina and El Nono (pick one) :)

        They always invoke natural causes to explain away model failure, when their very models have dismissed as “debunked” the very same natural causes (Sun’s heat cycles, El Ninos, Volcanoes) as irrelevant to Global Warming.

        Go figure! :)

        • nik

          It’s my suspicion, that all this ‘global warming’ bullsh!t is just a smokescreen to blur the impending return to an ice age.
          Of course when it does finally become clear, the governments will retreat to their fallout bunkers, while the rest of the world starves. The USA has been preparing for a mass social breakdown for years, one way in particular is by militarising the police forces, which is specifically against the constitution, what’s left of it.
          If I can work out that an ice age is due, I’m sure those in government can do the same. So when the major crop growing areas like the prairies, and the steppes, get too cold, and the worlds main food growing areas fail, they’ll claim that ”we” just did too good a job of ”saving the planet”!
          Back in the 70’s scientists were asking the question, ‘Are we returning to an ice age?’ but that got quickly silenced, and was subsequently replaced with ”global warming’ which considering that the Earth and the whole solar system is in the middle of a major
          ‘galactic’ ice age, and has been for several million years, that is likely to end with the whole of Earth as a complete snowball, would be funny if it wasn’t so damn dangerous.
          Nero is said to have ‘fiddled’ while Rome burned, this lot are doing much the same, instead of finding solutions to a possible world food shortage.
          I originally took the ‘global warming’ claim at face value, until Mr Obarmy, said one thing, ”It aught to be illegal to deny global warming!”
          To me that was the same as claiming ‘heresy’ and heresy laws are not made to protect ‘god’ but to protect the free ride that priests get, and thats why I started researching for myself.

          • OWilson

            When they want to put you in jail for opposing the “official view”, you know where society is headed.

            It’s all in your history books,

            (Which they don’t teach anymore!) :)

          • nik

            The well known term, ‘history repeats’ comes to mind, and religions always follow the same pattern.
            ‘Save the planet’ is just another religious, and tax scam.

          • OWilson

            It’s more, much more than that!

            Like “women’s health”, “polution”, “education”, “religion”, all laudable causes have been co-opted by the World Leftists (socialists, communists, Islamists and other anti-Western civilization groups).

            Closer to home they have throughly politicized their own government agencies, to the point they will no longer accept duly elected representatives of the people.

            This is actually more dangerous than it appears, but has many precedents in history!

          • Mike Richardson

            Ah, more conspiracy theories. Don’t worry about rising sea levels or killer heat waves — Leftists are plotting to get you! 😂

  • Mike Richardson

    A volcano erupted, so no global warming, at least according to the expert commentary in response to this article. When they want to call b.s. on scientific facts that disagree with political ideology, you know where society is headed — just keep up with current events (or as the reality challenged declare, “fake news”).



ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

About Tom Yulsman

Tom Yulsman is Director of the Center for Environmental Journalism and a Professor of Journalism at the University of Colorado, Boulder. He also continues to work as a science and environmental journalist with more than 30 years of experience producing content for major publications. His work has appeared in the New York Times, Washington Post, Audubon, Climate Central, Columbia Journalism Review, Discover, Nieman Reports, and many other publications. He has held a variety of editorial positions over the years, including a stint as editor-in-chief of Earth magazine. Yulsman has written one book: Origins: the Quest for Our Cosmic Roots, published by the Institute of Physics in 2003.


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