Scientists Plan "Artificial Volcano" Climate Experiment 292
First time accepted submitter tonyt3 writes "Scientists plan on conducting an unusual climate experiment at a Norfolk airfield next month. They plan to spray water into the air about 20 km high to mimic volcanic particles, hoping that their findings could lead to a solution to global warming. From the article: 'Pouring 10 million tonnes of material into the stratosphere each using 10 to 20 giant balloons could achieve a 2C global drop in temperature, the scientists believe. Sulphate emissions from the Mount Pinatubo eruption in the Philippines in June 1991 reduced world temperature by 0.5C for two years.'"
Re:Not much air (Score:4, Informative)
Okay, TFA (I know, I know) says 20km.
Re:Not much air (Score:4, Informative)
The water is just for the test (Score:5, Informative)
This is just a first test of the technology. If they were really going to use this for climate engineering, they'd use "clay, salts or metallic oxides suspended in liquid" (according to TFA) to reflect some sunlight back into space before it hits the earth.
As you can imagine, just figuring out whether you can pump millions of kilograms of stuff 1,000 meters into the air (not 1,000 km, as the submitter wrote) is an open question. Their ultimate goal is to get it 20 km up. For the first test, you use what's cheap: water.
The water itself is a greenhouse gas, but water molecules condense and fall as rain. It quickly returns to the existing equilibrium. The goal is to put up particles that would stay there for a while. Unlike water, they don't condense and fall out as quickly.
Before it fell, the water would reduce sunlight a bit. Water vapor is a greenhouse gas, but water in clouds isn't vapor; it's condensed droplets. Those droplets can reflect light; that's why cloudy days are dark. The goal isn't to produce water clouds, which would only be temporary and would be too much darkening. The goal is to put up enough particulates to get a slight reduction of incident light without having to continually pump new particles into the atmosphere.
(Note: I'm not crazy about geoengineering as a solution to climate change, but the experiment is still interesting.)
Climate physics fail. (Score:5, Informative)
Argh, blargh. I really hate it when people are so sure about completely wrong science, especially as their aggressive misinformation is being exploited by civilizational sociopaths.
I am usually nice on the internet, but this will be an exception.
Slashdot posters usually have some knowledge of Newtonian mechanics 101 and will rightly laugh at those who don't believe in say, conservation of momentum.
Well, this is the same level of blunder, so here goes the explanation, as nice as I can make it without wanting to strangle internet ignoramuses.
Yes, water is a greenhouse gas, and yes every climate scientist since 1900 or whatever has known this, and there has never been any conspiracy to "suppress" this, especially given that the water cycle is at the core of every weather and climate model and observational data set.
And human "emissions" of water are completely and totally irrelevant (say like the post above) because the planet is in statistical equilibrium with those very large sources of water known as "oceans". Water, namely vapor and clouds, are *feedbacks* with timescales of two weeks, vs dozens to thousands of years for carbon dioxide. For example, if you magically took all the water out of the atmosphere, how long would it take to get back to normal? A few weeks. If you magically saturated the atmosphere completely with water, how long would it take to get back to normal? A few weeks. If you magically took all the CO2 out of the atmosphere, how long would it take to get back to normal? Many, many millions of years.
The amount of water in the atmosphere is determined in large measure, by,what---yes the temperature! Hotter air absorbs more water, and yes, the water vapor will add its own greenhouse effect. The water vapor amplifies global warming which was induced by the excess of long-lived greenhouse gases like CO2 (and others) introduced by human activity. (Clouds are less certain---they may go both ways for heating/cooling in various cases, this is a complex area of current study---but the base level effect of vapor {clear, humid air} is undisputed and significant)
The scientists who have been studying this for decades know what they're talking about.
Re:Isn't water vapor a greenhouse gas? (Score:5, Informative)
It's also generally accepted that these are not independent, since increases in CO2, CH4, and O3 increase the temperature, which increases the water vapor: "The average residence time of a water molecule in the atmosphere is only about nine days, compared to years or centuries for other greenhouse gases such as CH4 and CO2. Thus, water vapor responds to and amplifies effects of the other greenhouse gases."
(2) "and that the amount generated by human activity is further less than 10% of that CO2."
The CO2 in the atmosphere has increased from 270-280 ppm a century ago to 390 ppm today (and it was down to 180 ppm in the last ice age). 390/280 = 40% increase. And, before you say that not all the 110 ppm increase is due to human activity, I submit this graph showing that CO2 levels over the past 600,000 years have never been above 300 ppm until the 20th century ( http://static-www.icr.org/i/articles/af/does_carbon_dioxide_fig3new.jpg [icr.org] )
You know: I'd think there was a lot more to climate change denial if the facts presented by climate deniers weren't almost always wrong.
I would be interested to know, though, how they think this would lower the temperature - for example: if water vapor at different elevations have different effects.
Re:Evidence? (Score:3, Informative)
Yes. The animals and birds and glaciers don't respond to human biases, and what they're doing is clear indication of warming.
The denialists are getting worse---they started out saying "there's no warming" (after the 1990's volcano had some temporary cooling), and then when the warming got clear, they said "well we don't know that people are responsible" (after all it could be magic fairys who just happen to change infrared emissivity of the atmosphere in exactly the way predicted by liberal-infected chemistry professors say that greenhouse gases do, when of course they don't, because in the atmosphere they're special and closer to heaven and don't have the same vibrational modes that they do in the lab). And now they're going back to denying that there's warming at all?
Re:Isn't water vapor a greenhouse gas? (Score:5, Informative)
The Sun provides the incoming energy. Without the greenhouse gases in the atmosphere blocking some of the outgoing IR radiation the average temperature on the surface of the Earth would be around 0F (-17.7C) instead of 58F.
Re:Isn't water vapor a greenhouse gas? (Score:4, Informative)
Nonsense. Models predict no discernible change over the last ten years. Besides, I think our Anonymous Cowards run quite enough.
Re:Not much air (Score:5, Informative)
Water is much more potent than CO2, but it does not cause climate forcing (in the sane temperature range, anyway). I.e. water vapor exists in the equilibrium condition - put more some additional vapor into the air and it will quite soon (hours to days) condense into water. So the more water you put into the atmosphere - the harder it'll going to rain down a few days after.
CO2 doesn't work that way. If you put it into the atmosphere - it just stays there (modulo CO2 sinks). It's not an equilibrium system (well, it is, but with very large reaction times) - more CO2 in the atmosphere will just give you more CO2 in the atmosphere.
Now, stratospheric water is yet another thing. It'll exist a a very fine snow ice particles (I won't call it 'snow' for the don't look like it) and in fact have the opposite effect - they reflect sunlight back into space. The greenhouse effect of stratospheric gases is mostly irrelevant, because 'stratosphere' is just another name for 'almost a hard vacuum'. AND stratosphere doesn't mix a lot with troposphere, so these ice particles are going to persist for a fair amount of time (probably months).