Thanks to Nature, a Large Atmospheric Sulfur Dioxide Experiment is Now Underway in the Pacific

Last June, WIRED magazine wrote an in depth article that asked:

Can a Million Tons of Sulfur Dioxide Combat Climate Change?

The question arose from research from research at Lawrence Livermore National Laboratory near San Francisco, by Lowell Wood, a protégé of the brilliant and controversial hydrogen bomb inventor Edward Teller. The idea was simple:  Inject sulfur dioxide into the stratosphere to reflect a portion of the sun’s rays back into space, thus cooling the planet. It also seemed to be within the realm of possibility to some.

Here is how it works:

Graphic and text below adapted from Wired magazine article

1. Make sulfur dioxide

A million tons of sulfur dioxide would be needed to begin the cooling process. Luckily SO2, a byproduct of coal-burning power plants, is a common industrial chemical.

2. Inject it into the stratosphere

Load the sulfur dioxide into aircraft — converted 747s, military fighters, or even large balloons — and carry it up to the stratosphere. This will cost about $1 billion a year.

3. Wait for the chemical reaction

In a series of reactions, sulfur dioxide combines with other molecules in the atmosphere, ultimately forming sulfuric acid. This H2SO4 binds to water to form aerosol droplets that absorb and reflect back into space 1 to 3 percent of the sun’s rays. (The particles also contribute to the depletion of the ozone layer, but scientists are researching alternate chemicals.)

4. Let the planet cool

Results will be quick, especially over the Arctic.

And just a few days ago, over a million tons of sulfur dioxide (SO2) was in fact injected into the atmosphere over the Pacific Ocean, here is a satellite sounder derived image of the cloud that has been released:

Source: AVO

The Terra/MODIS satellite snapped a nice image of the release, notice the obvious brown trail as the plume becomes airborne over the Pacific ocean:


Source: NASA

Here is a photo of where the experiment took place:

The Kasatochi volcano as seen from space, and location map below:

Thanks to a posting on another wordpress blog called “eruptions” we have this insight from Dr. Simon Carn from the University of Maryland in Baltimore:

The August 7-8 eruption of Kasatochi volcano (Aleutian Islands)produced a very large stratospheric SO2 cloud – possibly the largest since the August 1991 eruption of Hudson (Chile). Preliminary SO2 mass calculations using Ozone Monitoring Instrument (OMI) data suggest a total SO2 burden of ~1.5 Tg. This figure will be revised in the coming weeks but is more likely to go up than down. The SO2 cloud has drifted over a large area of North America and is now (August 14) reaching Europe.

With the released SO2 at ~ 1.5 Tg (Teragrams, a unit of mass approximately equal to one megaton) this is actually 50% more than mass in the experiment proposed by Wood and Teller.

For those wishing to follow the plume, NOAA offers a website that tracks SO2 in the atmosphere here. You can also keep tabs on the eruption and plume at the Alaska Volcano Observatory.

With this eruption coming on the heels of a short term global cooling trend that we’ve seen in the last 18 months, it will be interesting to see if this real-world experiment being performed by nature will add to the trend we’ve already seen.

Click for a larger image

Reference: UAH lower troposphere data

This type of “experiment” has already been seen before in recent times, as the Wired article mentions:

Pinatubo’s eruption didn’t just unleash huge mud slides and lava flows; it also fired an ash stream 22 miles into the air, injecting 20 million tons of sulfur dioxide into the stratosphere. Over the following months, a massive haze gradually dispersed across the globe. Meanwhile, the sulfur dioxide component underwent chemical reactions to form a particulate known as sulfate aerosol (in essence, droplets of water and sulfuric acid), which absorbs sunlight and reflects some of it back into space.

The climatic effect of this volcanic eruption was rapid, dramatic, and planetary in scale. In a year, the global average temperature declined by half a degree Celsius, and researchers observed less summer melt atop the Greenland ice sheet.

An interesting passage in the article on SO2 injection suggests:

Until large-scale experiments are funded, the only way to explore the potential consequences is through computer simulations. By turning down the virtual sun or cranking up the digital carbon, we can create any planetary future we want.

It looks like nature has stepped up and eliminated that need for computer simulation.

Based on Carn’s estimate, when the data is all in on Kasatochi, it will likely be about 10 times less than Pinatubo in total mass of SO2 ejected. But we’ll watch, measure, and see what this smaller event does for our global climate. Unfortunately, most any global cooling we see in the next couple of years, no matter what the true cause of it is, will probably be labeled as “volcanically induced” due to this event.

h/t to Philip_B for comments that lead to this article’s creation

UPDATE: 8/19/08 10:20 AM PST There has some been some questions in comments as to whether or not the plume reached stratospheric levels. This press release from USGS notes that the plume has reached more than 35,000 feet altitude, which would put the plume into the lower stratosphere.


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This is the kind of thing I’ve been afraid of for some time. They go and do something radical, like this, or the iron in the oceans, and cause the already falling temps worldwide to crash further.


This must be emphasized to AGW-crazed politicians. If you want to cool the Earth, just reduce sunlight. 1993 is the coldest year on record for Nebraska, thanks quite a bit to Pinatubo ash. This will, of course, have more immediate and meaningful effects than cutting CO2 emissions. They should dump all of it in the stratosphere over the Arctic if everyone is so freaked out about the sea ice. The benefits are, of course, nil. Colder is worse than warmer, but we may have no choice but to push this as much as possible. Of course, the watermelons will hate it because it encourages an end to sacrifice.

Patrick Henry

Perhaps this eases the pressure on GISS to prop the temperature data up for August?
REPLY: No, but it does mean that most any cooling we see in the next couple of years, no matter what the true cause of it, will be labeled automatically as “volcanic induced”. – Anthony

Mr B

Anyone remember the shrieking over acid rain? How is this different/better?
“Acid rain is a serious environmental problem that affects large parts of the United States and Canada. Acid rain is particularly damaging to lakes, streams, and forests and the plants and animals that live in these ecosystems.”
Does this latest “solution” mean the measures to decrease SO2 emissions were a “bad thing” and a waste of time and money? Why scrub the coal emissions? Why low sulfur diesel?
Next you’ll tell me CO2 is actually good for the environment……….

[…] Watts – Watts Up With That? 17 August, 2008 AGW Proponents Seek “Endless […]


Great, Let’s replace plant growing CO2 with Acid Rain?????
Sounds like a stupid idea to me!!!!!


“Opps” left out:
“At least until someone can define the manmade CO2 impacts mean anything”.


This was presented in a conference several years ago on technologies that dealt with CO2 issues. I remember Lowell Wood was received rather poorly by many environmentalists in the audience. Yet if there were truly a run-away warming event, this is the solution you would want. Not that I believe there will be a run-away warming event…

In the 70s they wanted to cover the polar ice caps with carbon black.


The unmitigated arrogance astounds me.

deadwood (22:48:40) : “The unmitigated arrogance astounds me.”
Aargh… Doggone pigheaded nature… Never will wait around for peer review…

John D.

“The Arrogance of Humanism” by David Ehrenfeld should be required reading by all scientists, students, and politicians; regardless of “chosen side”.
I need a beer.


deadwood (22:48:40) I’ll drink to that!!!
I’m not a Climate Scientist, but I have spent the last 7 years researching this subject and until some intelligent & honest, scientific experts in this world can reach some sort of an agreement on the “REAL” effects/problems of man’s quantified impact on the World Climate (HOT or Cold), let’s cease this foolishness and see where Nature is taking us. If we find Nature is again taking us into another long term HOT or COLD phase as it has in the past, we will then be required to find a solution or go the way of the Unicorn! Right now it is obvious we cannot predict the weather for the next 15 days with an acceptable degree or accuracy. IMHO!!

Leon Brozyna

deadwood (22:48:40) — you expressed my thoughts, though I was going for presumptive arrogance.
As I read the WIRED article, I was astounded by the assumptions that are being taken for granted — that the warming that is happening is a result of mankind’s influence and that such a change is bad. They need to go back to science and dismiss the political notion of mankind changing the climate. Start with a clean slate. What are the natural forces that have warmed the climate and how long will the warming continue before the inevitable cooling kicks in?
Even in the WIRED article it is acknowledged that there are too many unknown variables. But it seems government bred scientists are really good at what they do best — creating theoretical problems with theoretical solutions that have no basis in reality other than to create a crying need for funding with which to conduct experimentation. {The article did say, Until large-scale experiments are funded…}
As for any long-term effect on climate, isn’t that more likely to come from a low latitude volcano such as Pinatubo, than from a high latitude volcano? Though this might have a limited short-term effect on NH temperatures. It should also be noted that the climate seems to have been cooling for about a year and a half already, so any effect would merely be added onto an already existing trend.

Daniel L. Taylor

Could you edit this article to clearly point out, at the beginning, that the “experiment” is not man made, but simply man observing the impact of an eruption?
The first poster made this mistake, and from the headline and article structure one could easily skim the article and not realize this. I’m sure you didn’t do it on purpose, but this kind of mistake can contribute to the already excessive amount of misinformation out there.

Some people just can’t handle reading the whole article I guess. Sure, I’ll add a note for those that don’t. Follow up – I’ve added “nature” to the title.


See the link below to follow in near-real-time the whereabouts of the SO2 plume from various satellite instruments (OMI, GOME2, SCIAMACHY).
yesterday’s (August 18) image from OMI:
More images here:
The American CALIPSO lidar instrument has frequent overpasses of various parts of the plumes, which can be helpful to determine the altitude of the plumes


Thanks for the HT, Anthony.
Latest reports (Sunday) indicate continuing SO2 emissions.
BTW, August in the SH is going to be the coldest in many years. Large cool anomalies across almost all of Australia and New Zealand. I hear S. America is the same.


If the planet is at all susceptible to runaway thermal events it will most certainly have happened before. Where is the evidence in the geological record?
I have read elsewhere that most of China’s power generating effluent ends up in this same area of the globe and over the western USA. Will this increasing output from China not impact on any SO2 measurements?


“Unfortunately, most any global cooling we see in the next couple of years, no matter what the true cause of it is, will probably be labeled as “volcanically induced” due to this event.”
And after the effects of this eruption have worn off any further cooling of the globe – natural or human induced – could well be attributed solely to the Large Atmospheric Sulfur Dioxide Experiment, which, if all going to plan, will continue and be promoted heavily.
The AGW people now need something to explain naturally declining global temperatures and from what I’ve seen to date it would not surprise me if the LASDE or some other hair-brained scheme was sold to the world’s population as the saviour of runaway GW. In this way there will be no reason why people’s negative perceptions of CO2 should change, naturally occurring causes for the earth’s cooling trend will be kept from the public, and plans to introduce carbon taxes and so on will continue unabated.
Well, that’s one possible scenario and my 2¢ worth.


I have also seen suggestions such as putting special satellites into the mesosphere or higher that reflect sunlight back into space. That might be a more manageable “solution”, if we have no choice.

F Rasmin

Perhaps this article in the Times of Malta is indicative of what could be happening in many countries with the increased price of oil. If any readers have ever been to Bankok, they will shudder at the thought!


Reading this has ruined my day, we’ve (UK) had a lousy summer already.

Maybe we’re returning to “normal” volcanic activity levels. Part of the warming over the 20th century resulted from the absence of large explosive volcanic eruptions for long periods and the low number during others.
Kasatochi is located at too high a latitude for it to have a substantial effect on global temperatures, though it might impact some of the polar amplification that’s left over from the 97/98 El Nino. Then again, polar amplification is a noticable contributor to the warming.
With Kasatochi working on the NH high latitudes and Chaiten in the SH, it will be interesting to watch.


This volcanic event puts to end another experiment conducted by nature, wherein we had a long period of time when the NH atmosphere was very clean. I myself assumed this ash-free period had a warming-effect, though I did not see it discussed anywhere.
I have a dim memory of reading somewhere that volcanic SO2 causes cooling in the short term, but that later on it results in warming. As I recall the discussion suggested the SO2 reacted with Ozone, reducing the amount of Ozone in the upper atmosphere, which in turn allowed more Ultraviolet Rays to hit the earth. The suggestion was that, as the atmosphere cleaned itself, the cooling effect of SO2 vanished as the SO2 vanished, and in its place was the warming effect of depleted Ozone.
Perhaps it was in a paper attempting to explain why there seems to be a correlation between major volcanic eruptions (cooling) and El Ninos (warming.)
If anyone knows more about this idea, or wishes to explain why this idea should be thrown into the trash, I’d be grateful.
(My problem is that, during this debate, I am often directed via links to long and technical papers which cross my eyes and give me migraines. I dutifully do my best to be a good citizen and stay informed, but my general impression is that the chemistry and engineering of the atmosphere is amazing, wonderful, and that anyone who thinks we are even close to understand it all is fooling themselves.) (But that is no reason to stop studying.)

Mike Bryant

Maybe it is time for an update on the NASA AIRS team? I would like to know if they are still on track. They might even be able to shed some light on this occurrence.

Frank L/Denmark

Yes, at the first glance of this article i feared that tha alarmist now has yet another excuse for the lower temperatures.
The La Nina levelled off around May, but the temperatures are still much lower than last year. And now a little late, something happends that they can use as explanation.
But still, we appear to be in for a very cold period, and never mind what, if the alarmists uses this event as explanation, they contradict earlier statements that CO2 effect is much much larger than the sun and volcanos, dont they?
Suddently alarmists would have to admit that a rising CO2 level has very little effect compared to natrual events? So maybe they have to think a little before using this event?

Anthony: Would a high latitude volcanic eruption induce a positive or negative AO? I would think there would be some influence, but which way? Low latitude volcanoes create a positive as noted in the quote that follows from the IPCC’s AR4.
Caleb: There is a short Arctic warming during winter months that shows up a couple of years after a volcanic eruption in the tropics.
Reference:“Volcanic Eruptions and Climate” by Alan Robock
Quote: “After the 1982 El Chichon and 1991 Pinatubo eruptions the tropical bands (30S–30N) warmed more than the 30N–90N band…producing an enhanced pole-to-equator temperature gradient. The resulting stronger polar vortex produces the tropospheric winter warming…”
Also, in Chapter 2 of AR4, (page 195), the IPCC describes this winter warming further: “Anomalies in the volcanic-aerosol induced global radiative heating distribution can force significant changes in atmospheric circulation, for example, perturbing the equator-to-pole heating gradient…and forcing a positive phase of the Arctic Oscillation that in turn causes a counterintuitive boreal winter warming at middle and high latitudes over Eurasia and North America…”
I haven’t found anything that says it happens after a high-latitude eruption.

Patrick Hadley

If the estimate that this volcano will be ten times less than Pinatubo in SO2 emissions is correct, then surely it is likely to have a relatively small influence on global temperatures: or is the SO2 effect logarithmic with the first 10% added having the greatest effect?


“But we’ll watch, measure, and see what this smaller event does for our global climate.”
Yes, and then we’ll compare the earth’s temperature against the control earth I have in my pocket…. 😉 Seriously, how will we know exactly what this event did, if we don’t know how things would have looked without it? Same goes for CO2 of course…..


I agree that a big enough volcano will be used as an excuse (if necessary) by alarmists. Indeed, I asked an alarmist the other day exactly what caused the Little Ice Age and he asserted confidently that it was caused by volcanos.
The thing is, volcanos are part of the environment too. By all appearances, the world has a few major volcanos every century. If the alarmists’ predictions (on the time scale of 50 to 100 years) are made on the assumption that there will be no volcanos, then those predictions are worthless.

Christopher Elves

Are these AGW people completely bonkers? Has the belief in their hypothesis become so distorted that they’d risk utterly reckless atmospheric experiments simply to avoid the perceived ignominy of being disproved? This is just further evidence that AGW is slowly leaning more towards fundamentalist belief and further away from science: true scientists welcome contrary research as the means by which their hypotheses can be either refuted, improved or accepted. Let’s hope none of these hair-brained schemes make it beyond the drawing board.

Christopher Elves

Here’s another idea: I read yesterday that it’s estimated that termites produce more C02 than human emissions. So let’s slaughter those damned termites (keeping some specimens to restore the colonies once it’s proved that C02 actually had very little to do with climate variation). At least we’ll have a few precious years without our houses being eaten!……and let’s not even get into the Wetlands, those filthy pits of carbon pollution!……(Only joking).

bit late to blame the cold on this eruption NZ today has recorded the the biggest snow base in the history of commercial skiing in New Zealand. The snow stake at 2000m above sea level officially measures 455cm’s this morning. We are now wondering where it might all end up. Whakapapa is also entering record territory at 350cm’s, which is the most since 1994. Ok enough is enough, just blue skies now please.
also more snow on the way
charts and pics of the snow here (scroll down);
another freezing blast hitting Australia now

Alan Chappell

Frank L/Denmark
The biggest problem in the AGW debate is that the ‘Alarmists’ are as changeable as the weather.


Wow, I am sure this is going to work. This is just like Hansen predicting warming when we are in the interglacial warming cycle. It really isnt a stretch to get cooling during a cooling cycle of a solar/sunspot minimum.

Gaelan Clark

Ok, let me get this straight….all of this SO2 into the atmosphere, and we get a 1-3% reduction in incoming solar radiation, thereby reducing global temps??—–But, the sun has no effect on temps??(Ahem, or so says RC and the Team.)
And, with a ~10 year downslope on global temps, I am really inteested in learning the “NEW” argument that global cooling preceeded the actual SO2 in the atmosphere.—This is tons of fun, and so confusing my head is still spinning.


Don’t worry. These schemes for “curing” global warming (seeding the oceans/atmosphere) will never have the support of environmentalists because they do nothing to reduce man to pre-industrial living conditions.


Mea Culpa: I did in fact only skim the Wired article, I was getting ready for work. Apologies.
John D. , do a search for ‘Humanist Manifesto’. Version I was written in the ’30s, and Version III was in the early 70s, IIRC. Very enlightening, esp with regards to the education system and politicians.

Well, good timing! The cover story for the next Science News has a photo of the Mt St Helens explosion and the headline “Global Cooling.” The story is actually about a Peruvian volcano that erupted in 1600 which may have led to a three year stretch of crop failures in Russia. One third of the population died in the ensuing famine. See
The article is largely written for people who haven’t learned that “It’s not the ash, it’s the SO2” and reports that most of the SO2 came from liquid (dirty water, I assume) and not rocks.
The most useful information may be

Not only were preindustrial farming practices possibly more resilient to total agricultural failure, people then “were used to living on the margin,” Dunning says. “Everybody knew hunger … and the idea that you should plan for a bad year was ingrained in these societies.”
Today, by comparison, the world’s surplus food supply would last only about 90 days, a number that’s steadily dropping as population increases.

That may be pessimistic. Transportation will help. I’ve long claimed that a very good conservation practice would be “First, we eat all the beef.” And, in light of recent events, Russia seems to have more options than it did in the early 1600s.
Sigh. I really didn’t want a damn “stratospheric injection event” until more people figured out that it’s not the CO2 behind recent warming.

David Segesta

Changing the earth’s reflectivity may be a good way to regulate its temperature. But hopefully there is a better way to do it than dumping tons of SO2 into the atmosphere. That’s some pretty nasty stuff.
BTW How does this work? That brown cloud looks like it would absorb sunlight rather than reflect it.
REPLY: Part of the cloud is ash.

Mr B (22:09:31) :
“Anyone remember the shrieking over acid rain? How is this different/better?”
The key word is stratosphere. If you look at the temperature profile at (be sure to click on the image to see the annotated version), the temperature rises through the stratosphere. This makes it very hard for moist air from the Earth’s surface to reach the stratosphere and wash out the SO2.
Acid rain develops in the troposphere and washes out in only days or weeks. SO2 in the stratosphere remains for years and turns into an aerosol that reflects sunlight and produces a couple years of cooling. Eventually it does settle out and normal temperatures return.
This eruption may be much more significant than the volcano in Chile a few months ago.

retired engineer

How dare the volcano do this without filing an Environmental Impact Statement?!? Call out the lawyers!
Slightly more seroiusly, if SO2 is common, resulting from coal combustion, what of the 1.3GT of coal burned each year in China? Does the smoke not get high enough to create the same effect? LASDE in progress?
Global Warming, Global Cooling, Climate Change, Acid Rain, Peak Oil.. I’m gonna need a bigger score card to keep track of all these pending disasters.

One saving grace is suggested from this article on the Chilean volcane (Chaiten), see

Because Chaiten did not put a high concentration of sulfate aerosols into the atmosphere, it is unlikely to have an effect on global temperatures. But its impact is also limited by its location. Most of the volcanoes that have influenced global temperatures are located in the center of the globe near the equator. Winds in the stratosphere in the tropics quickly circulate sulfate aerosols around the globe. By contrast, stratospheric winds near the poles tend to push sulfate aerosols towards the poles and towards the surface, limiting the area influenced by the aerosols. Located in southern Chile far from the equator, Chaiten would be unlikely to influence global temperatures even if the amount of sulfur dioxide coming from the volcano were higher (unless the eruption were sustained for many months).

Kasatochi may be a little closer to the pole than Chaiten.

Anthony wrote: “REPLY: No, but it does mean that most any cooling we see in the next couple of years, no matter what the true cause of it, will be labeled automatically as “volcanic induced”. – Anthony”
Bingo! That’s exactly what will happen and NASA’a already begun the drum-beats!
Jack Koenig, Editor
The Mysterious Climate Project


Will this have a immediate (within days) effect on temperature in the Northern Hemisphere? or a slow effect (months/years)
..and if so how much ..
because if this summer is getting even worse, im driving to the mediteranian.

Bill Illis

One of the signatures of a big enough volcanic event to impact global climate is warming in the stratosphere. The three big ones in the last 50 years all left this signal.
So far, however, there is no change in stratospheric temps according to UAH’s daily sat temp measures in the upper atmosphere. Maybe too early. Maybe not big enough.
REPLY: Too early, dispersal and chemical change have yet to occur.

Patrick Henry (22:06:02) :
REPLY: No, but it does mean that most any cooling we see in the next couple of years, no matter what the true cause of it, will be labeled automatically as “volcanic induced”. – Anthony
Takes the Sun and its minimum off the hook for now…

Hoi Polloi

Why don’t they leave Nature alone? Mankind is only part of Mother Earth for a minute part and they already want to change it.
As I mentioned before why don’t accept Climate as it is and get on with your life and spend money to the 3rd world instead of crazy experiments which only purpose is to keep all them climatologists at work fer crissakes…


“Unfortunately, most any global cooling we see in the next couple of years, no matter what the true cause of it is, will probably be labeled as “volcanically induced” due to this event.”
Of course, down the road, they’ll rewrite the history to make the last 12 month’s cooling “volcanically induced”, just like the CO2-induced warming of the 20th century (for which at least half the warming occurred before the big rise in CO2).