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Earth Science

Hunga Tonga Eruption Put Over 50 Billion Kilograms of Water Into Stratosphere (arstechnica.com) 47

An anonymous reader quotes a report from Ars Technica: In January this year, an undersea volcano in Tonga produced a massive eruption, the largest so far this century. The mixing of hot volcanic material and cool ocean water created an explosion that sent an atmospheric shockwave across the planet and triggered a tsunami that devastated local communities and reached as far as Japan. The only part of the crater's rim that extended above water was reduced in size and separated into two islands. A plume of material was blasted straight through the stratosphere and into the mesosphere, over 50 km above the Earth's surface. We've taken a good look at a number of past volcanic eruptions and studied how they influence the climate. But those eruptions (most notably that of Mount Pinatubo) all came from volcanoes on land. Hunga Tonga may be the largest eruption we've ever documented that took place under water, and the eruption plume contained unusual amounts of water vapor -- so much of it that it actually got in the way of satellite observations at some wavelengths. Now, researchers have used weather balloon data to reconstruct the plume and follow its progress during two circuits around the globe.

Your vocabulary word of the day is radiosonde, which is a small instrument package and transmitter that can be carried into the atmosphere by a weather balloon. There are networks of sites where radiosondes are launched as part of weather forecasting services; the most relevant ones for Hunga Tonga are in Fiji and Eastern Australia. A balloon from Fiji was the first to take instruments into the eruption plume, doing so less than 24 hours after Hunga Tonga exploded. That radiosonde saw increasing levels of water as it climbed through the stratosphere from 19 to 28 kilometers of altitude. The water levels had reached the highest yet measured at the top of that range when the balloon burst, bringing an end to the measurements. But shortly after, the plume started showing up along the east coast of Australia, which again registered very high levels of water vapor. Again, water reached to 28 km in altitude but gradually settled to lower heights over the next 24 hours.

The striking thing was how much of it there was. Compared to normal background levels of stratospheric water vapor, these radiosondes were registering 580 times as much water even two days after the eruption, after the plume had some time to spread out. There was so much there that it still stood out as the plume drifted over South America. The researchers were able to track it for a total of six weeks, following it as it spread out while circling the Earth twice. Using some of these readings, the researchers estimated the total volume of the water vapor plume and then used the levels of water present to come up with a total amount of water put into the stratosphere by the eruption. They came up with 50 billion kilograms. And that's a low estimate, because, as mentioned above, there was still water above the altitudes where some of the measurements stopped.
The recent findings appear in a new study published in the journal Science.
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Hunga Tonga Eruption Put Over 50 Billion Kilograms of Water Into Stratosphere

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  • by jenningsthecat ( 1525947 ) on Saturday September 24, 2022 @08:59AM (#62910287)

    I just looked for the first time and apparently it's a controversial subject - but I always just assumed that melting glaciers would lead to increased seismic activity. So I'm wondering if, along with all the other shit that comes with AGW, we'll also be dealing with additional earthquakes and changes in volcanic activity.

    • I always just assumed that melting glaciers would lead to increased seismic activity. So I'm wondering if, along with all the other shit that comes with AGW, we'll also be dealing with additional earthquakes and changes in volcanic activity.

      AFAICT it is generally believed that the weight of water being added unevenly to land masses (around their perimeters, natch) is highly likely to increase seismic activity — the weight of water during monsoons affects seismicity, for example — and some quakes over about magnitude 6 are believed to have been responsible for volcanic activity.

    • Perhaps. But there aren't a lot of glaciers anywhere near Tonga.

  • by Opportunist ( 166417 ) on Saturday September 24, 2022 @09:02AM (#62910291)

    So ... 50 Million tons?

    Or 50 megatonnes?

    You do know we are allowed to use derivates of SI units to make it more readable?

    Oh, you were going for the shock value. Ok, never mind, carry on.

  • by fronobulax ( 1833910 ) on Saturday September 24, 2022 @09:50AM (#62910343)
    I think I must have seen this as a preprint a month or two ago... My pondering on the paper included: Since H20 is one of the most effective greenhouse molecules, what changes could this have made to the general climate since the first of the year? Since we have never really understood this as an issue, I don't know how climate models could account for it, but an increase this large should have had some effect on the outcomes, or do the models go ahead and forecast without taking another potential variable into account?
    • I think I must have seen this as a preprint a month or two ago... My pondering on the paper included: Since H20 is one of the most effective greenhouse molecules, what changes could this have made to the general climate since the first of the year? Since we have never really understood this as an issue, I don't know how climate models could account for it, but an increase this large should have had some effect on the outcomes, or do the models go ahead and forecast without taking another potential variable into account?

      It doesn't stay there long. But water vapor is the number one greenhouse "gas". I would guess some really short term effects, and some serious precipitation in some places.

      Modelling it? They'll possibly come up with something now that they know this can happen to this extent. I'll bet they will do a lot of looking to see just what the effects were.

      • by XXongo ( 3986865 )

        Do keep in mind that the amount of water in the atmosphere already is 13,000 cubic kilometers (ref: https://www.usgs.gov/special-t... [usgs.gov] ), or 1.3E14 metric tons. 5E7 tons sounds like a lot... but it's four ten-millionths of the water that's already there. Humidity is only a small part of the atmosphere... but there's a lot of atmosphere.

        What's different here is that this was injected into the stratosphere, whereas most of the Earth's atmospheric water is below the cold trap between the troposphere and strat

    • by hey! ( 33014 )

      I'm not sure even such a huge event as this would have any observable effect on long term climate trends, since the half life of an emitted water molecule in the atmosphere is on the order of ten days. That means a year is roughly 36 half-lives of a water molecule, so after a year you'll have 50 billion / 2^36 tons of water remaining from the eruption. That's roughly 727 kg.

    • by dryeo ( 100693 )

      Article I saw a while back claimed it would cause cooling due to clouds (or ice crystals, I forget) up there reflecting. Mostly in the southern hemisphere.

      • clouds (or ice crystals

        Sulphates and ultra-fine ash (think 2010 EyjafjallajÃkull "Icelandic ash cloud" eruption [wikipedia.org], but the fine end of that volcano's ejecta) rather than ice crystals, mostly. But their effect is largely by encouraging the nucleation and growth of ice crystals, so it's complex. Tonga is far enough south of the equator that the ejecta would largely stay in that hemisphere. In contrast, Pinatubo (1991, 15deg N) had a considerably more even distribution of effects.

        • by dryeo ( 100693 )

          That's what I would assume, the article was definitely talking about the water vapor and its affects in the stratosphere. Unluckily I can't find the article now and I doubt it was peer reviewed. It is something I've wondered so it caught my attention especially since it described the opposite affects then I expected (warming).
          As you mention it may have been the combination of vapor and fine dust for the crystals to grow on.

  • salt too, salt water is salty, how much salt got blasted up into the atmosphere too? someone smarter than me should be able to come up with a ballpark figure of how much salt got up there
    • by Etcetera ( 14711 )

      salt too, salt water is salty, how much salt got blasted up into the atmosphere too? someone smarter than me should be able to come up with a ballpark figure of how much salt got up there

      That's a great point. I'm not paying for the article print, but I do wonder if they address that at all.

    • Compared to the tonnage of salt injected into the atmosphere annually from droplets of spray generated by waves breaking all over the world, approximately one ten-thousandth of a bugger-all, expressed as a fraction.

      Oh, you'll have to correct for the waves on fresh water lakes. That's a factor of one damn-near nothingth. And waves on liquid oil seep pools.

  • I can't stop this feeling
    Deep inside of me...

  • Water vapor or ice crystals? It's important because each has different effects on light and IR transmission/reflection.

  • by doug141 ( 863552 ) on Saturday September 24, 2022 @02:05PM (#62910777)

    a cube of water 368 m on a side.

  • I need more coffee, I thought that said Honda Torhu Eruption and I started shouting kawaii! kawaii!

  • by TigerPlish ( 174064 ) on Saturday September 24, 2022 @02:34PM (#62910809)

    Wetter air holds more heat. Warmer air holds more moisture.

    The release -- by something completely out of our control -- of all that water from the Tonga eruption into the atmosphere will surely make for the kind of conditions that certain people will go gaga over, to push all sorts of crazy rules down on us.

    I expect the extra moisture and extra heat, coupled with what effects ice crystals in the higher / colder levels of the atmosphere may have will make for wetter / wilder / weirder weather for a while. How long? Who knows. Decades? Years?

    Climate change fanatics will demonstrate and protest and point and shriek that we're at fault and demand all sorts of Immediate and Direct Actions, when in reality were naught more than ants to this world. If Mother Earth wants us gone, it'll happen, no matter what we puny humans do.

    Something to think about, before the entire civilized world is destroyed or massively set back with rules made with Good Intentions, but yielding Very Bad Results.

    • by XXongo ( 3986865 ) on Saturday September 24, 2022 @07:17PM (#62911223) Homepage

      Wetter air holds more heat. Warmer air holds more moisture. The release -- by something completely out of our control -- of all that water from the Tonga eruption into the atmosphere will surely make for the kind of conditions that certain people will go gaga over,

      Maybe.

      It's small compared to the amount of water already there, though.

      to push all sorts of crazy rules down on us.

      Unlikely. I can't see what sort of rules would be possible to pass on the subject of underwater volcanoes.

      I expect the extra moisture and extra heat, coupled with what effects ice crystals in the higher / colder levels of the atmosphere may have will make for wetter / wilder / weirder weather for a while.

      If the effect is measurable.

      How long? Who knows. Decades? Years?

      The article we're discussing said it was measurable by sensitive instrument for six weeks.

      Climate change fanatics will demonstrate and protest and point and shriek that we're at fault and demand all sorts of Immediate and Direct Actions,

      Huh?

      when in reality were naught more than ants to this world. If Mother Earth wants us gone, it'll happen, no matter what we puny humans do.

      Sure. But that doesn't mean we should help it along.

      Something to think about, before the entire civilized world is destroyed or massively set back with rules made with Good Intentions, but yielding Very Bad Results.

      If the climate deniers had started with "we're good with the science, but would like to point out that there will be economic consequences associated with changes in our energy supply," I'd be fine with it. But since they instead spent thirty years on a relentless attack on the science (unsuccessfully), sorry, but I don't believe that a word you say is anything other than parroting talking points fossil fuel companies have been pushing in order to protect their trillion dollar profits

      Their first campaign was to deny the science. The second was to say "well, the science may be solid but the effect isn't as bad as predicted. The current phase is "the effect is real, but doing anything would be against the libertarian ideals of the free world."

      Undoubtably the next phase will be "it's too late to do anything, so we might as well keep burning oil."

  • by Randseed ( 132501 ) on Saturday September 24, 2022 @03:13PM (#62910877)
    Global climate authorities have analyzed the situation and determined that water is likely a contributing factor to global climate change. Accordingly, authorities have contacted a group of seemingly benign aliens from the Sirius star system and invited them to vacuum up the oceans to help us. By all accounts, these human-appearing aliens do not -- I repeat do NOT -- harvest humans aboard their starships to use as a food source. Conspiracy theorists have claimed that the aliens are actually reptilian and in disguise, however the Biden administration has assured the world that this is merely "alien misinformation" spread by "MEGA (Make Earth Great Again) extremists" and has vowed to appoint a "disinformation czar" to address the situation. Several hundred Facebook and Twitter accounts have already been banned. We were unable to immediately contact any of the banned individuals, however, as they all seem to have gone on a spiritual retreat of sorts at the same time. Trial by Wombat will appear on CNN at 7pm Monday. Stay tuned.
    • seemingly benign aliens from the Sirius star system

      "seemingly" is important. They're most likely liars.

      Sirius is reckoned to be about 1/4 way through it's approximate billion-year lifetime. At the same age, The Earth was probably still in a "magma ocean" state, maybe just getting some rainfall accumulating in the deepest parts of the surface. We've got a few hundred grains of zircon from then, which show geochemical evidence compatible with the rock having been processed at least once through a meteoritic

  • Maybe we need some Vulcan Vultures.

    But seriously, man, those numbers are positively Stratospheric!

    I'll be here all week, tip your bartender.

  • I assume evaporation is the main process of the water injected to the atmosphere. The mineral salts and dead sea multicell creature precipitated back to the ocean(or sea)?
  • I ran the numbers and this figures out to 40,450.74 acre feet. A typical household consumes about 1 acre foot a year so this is enough water for a town of 150-200k for one year. While this will eventually fall back to the Earth as precipitation, it would likely be too far spread out to make much of a difference to areas in drought.
  • Water vapor is a potent greenhouse gas.

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