Is excess CO2 or excess water vapor emissions by humans more dangerous? - VeggieBoards
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#1 Old 01-03-2012, 03:03 PM
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In another thread, a poster came up with the claim that water vapor from human activities is a bigger problem than excess carbon dioxide from human activities.

This seems to be a claim often found by anthropological climate change deniers. The attribute 95% of earth's greenhouse effect to water vapor in the atmosphere (a claim that does not appear to be part of mainstream science), and imply that since water vapor contributes to far more global warming, excess carbon dioxide emissions are not a problem.

Since I was curious, I investigated.

Here's what I found:

Quote:
Here's some info on water vapor vs carbon dioxide as a greenhouse gas:

Water vapor ranges from a low of almost 0% in the atmosphere to a high of around 4%. We'll use the average of 2%, even though most of the earth's surface is ocean, which should be more humid than a desert. Carbon dioxide is around .039%. So there's about fifty times more water vapor in the earth's atmosphere than carbon dioxide. This is a low estimate, but a low estimate will err on the side of overestimating the effect of water vapor. Water vapor contributes only 35 - 85% of the greenhouse effect on earth. Carbon dioxide contributes 10 - 25% of the greenhouse gas effect. So, using 85% for water vapor, and 10% for carbon dioxide (erring on the side of overestimating water vapor's greenhouse effect), fifty times the amount of water vapor only warms the earth eight and a half times more than carbon dioxide. Which makes water vapor about one fifth as potent of a greenhouse gas as carbon dioxide. (And again, I must point out at how biased this calculation is in favor of overestimating water vapor's effect as a greenhouse gas.)

But wait. It gets worse. The lifetime of a molecule of water in the atmosphere averages nine days. The average lifespan of a molecule of excessive carbon dioxide is estimated to be decades. We'll err on the side of extremely underestimating the lifespan of excessive CO2 and say it's average lifespan is simply two and a half decades. Which means that the average excess carbon dioxide molecule lasts a thousand times as long as the average water molecule.

That would make carbon dioxide equivalent to five thousand times as much water vapor.

I've googled global water use and the first number I've found is around 10 trillion meter^3/year (rounding up). We'll assume all this evaporates and forms water vapor and ignore that at least part of global consumption is reused. A cubic meter of water weighs one metric ton. So we produce 10 trillion tonnes of water each year. In coal alone, we consume 6 billion tonnes. This, of course, through simple chemistry should make about 21 billion tonnes of carbon dioxide. 21 billion tonnes of carbon dioxide would be equivalent to 105 trillion tonnes of water vapor in terms of its global warming effect. In short, carbon dioxide from coal alone would provide ten times the effect of all global water usage, if turned directly into vapor.

Now that's strictly a back-of-the-napkin calculation. It ignores other carbon sources (petroleum, natural gas, etc). The other carbon sources would produce water as well, but considering carbon dioxide's greater potency and far greater lifespan, any carbon dioxide emission would offset any water vapor emission. There are other sources of water vapor as well that could be figured in. But ballparking it, I think it's safe to say that carbon dioxide is a far worse threat than water vapor. Carbon dioxide is far more potent of a greenhouse gas. Excess carbon dioxide has a far longer lifespan. Once those two factors are combined, excess carbon dioxide is far greater of a threat than excess water vapor.

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#2 Old 01-05-2012, 04:26 PM
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*crickets*
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#3 Old 01-05-2012, 04:35 PM
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I myself have actually been waiting to hear what responses you get to this post, but overall I am of the opinion that the planet Earth is entirely self-regulating. Regardless of anything that we humans can do to the planet, in the long-term it simply doesn't affect much. We merely displace matter and energy not destroy it, and ultimately everything will end up as it should be. Yeah I know... not the answer you were looking for.
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#4 Old 01-05-2012, 04:53 PM
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I think in geological time-frames, it's self-regulating as well.

Might be a tad uncomfortable to us beings that don't measure our life in geological scales.
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#5 Old 01-05-2012, 04:56 PM
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Yeah I know, I was simply addressing the fact that in reality, there really isn't anything we can do to 'kill' the planet.

Hope I haven't led the conversation astray.

See how I bumped your thread there?
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#6 Old 01-05-2012, 05:12 PM
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Originally Posted by das_nut View Post

I think in geological time-frames, it's self-regulating as well.

Might be a tad uncomfortable to us beings that don't measure our life in geological scales.

Hard to say, but either way we'll either adapt or die, as countless other species have done. That doesn't mean we shouldn't try to do something about it, just that trying to decide exactly what to do is almost as hard as actually doing it once we do decide. In other words, we're probably just going to continue on our current path until we back ourselves into a corner.

"I'm not in this world to live up to your expectations and you're not in this world to live up to mine." Bruce Lee.

"On a large enough time line, the survival rate for everyone drops to zero." Chuck Palahniuk (Fight Club)

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#7 Old 01-05-2012, 05:17 PM
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The way I see it, we'll probably damage the biosphere enough to kill ourselves off... but ultimately it won't actually kill the planet in any way.
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#8 Old 01-05-2012, 05:30 PM
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Originally Posted by nomad888 View Post

In other words, we're probably just going to continue on our current path until we back ourselves into a corner.

That's my cynical take on things.
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#9 Old 01-05-2012, 05:32 PM
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That's my cynical take on things.

But then again we all know that you are a wise and intelligent man.
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#10 Old 01-05-2012, 06:01 PM
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Didn't you used to be a "anthropological climate change denier" (or at least "skeptic"), das_nut? Just wondering if you changed your mind or if I misunderstood you then/now.
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#11 Old 01-05-2012, 06:53 PM
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Originally Posted by cornsail View Post

Didn't you used to be a "anthropological climate change denier" (or at least "skeptic"), das_nut? Just wondering if you changed your mind or if I misunderstood you then/now.

I'm not an anthropological climate change denier. I tend to be rather critical of global climate models, and it personally annoys me whenever extreme weather is blamed on climate change (sometimes, extreme weather happens), as well as the doom & gloom predictions about climate change that aren't solidly backed up by our models and evidence, but that doesn't mean I'm not swayed by the evidence that mankind is changing the climate.
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#12 Old 01-08-2012, 01:01 PM
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So, no rebuttal?

I believe everything.
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#13 Old 01-08-2012, 01:10 PM
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I got nothing...I agree with everything that has already been said.

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#14 Old 01-08-2012, 01:14 PM
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I thought of a James Bond movie idea where Dr Baddie starts removing CO2 from the atmosphere, on some secret island, and holds the world to ransom, because if all the CO2 were removed, all the plants would die....

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#15 Old 01-08-2012, 01:17 PM
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Originally Posted by nogardsram View Post

So, no rebuttal?

Nope, we're all boned.

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#16 Old 01-08-2012, 01:20 PM
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Someone should come in and play devil's advocate.

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#17 Old 01-08-2012, 02:30 PM
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Where is T0mmy now? I built it, and he didn't come.
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#18 Old 01-08-2012, 03:27 PM
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Quote:
Originally Posted by das_nut View Post

Where is T0mmy now? I built it, and he didn't come.

Yeah, that's who I thought this was written for. I wanted to bump the thread so hopefully there was a rebuttal.

I believe everything.
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#19 Old 01-08-2012, 03:31 PM
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We will patiently wait...

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#20 Old 01-08-2012, 03:35 PM
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I think water vapor is like, soooo dangerous! It's all making my books soggy and my hair all frizzy!
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#21 Old 01-08-2012, 03:42 PM
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Originally Posted by das_nut View Post

Where is T0mmy now?

There's a church for Ron Paul being built in Texas, and he's shipping the floorboards.

"and I stand

upon a mountain

made of weak and useless men"

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#22 Old 01-17-2012, 08:00 PM
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Sorry, my classes started and I had to deal with scheduling, I've had my online time put aside for a while (you'll notice I will not be on these boards much for a few months).

I don't believe I made the claim you claimed I claimed. I simply posted a facetious post in regards to how dangerous water vapor is, because there's a big hullabaloo over carbon. Granted, I understand there to be no real concerns over water vapor, but I don't think the sarcasm translated very well to das_nut, who took me seriously and made this thread.
In the end if he believes the federal government needs to impose taxes on us due to a carbon scare then I simply disagree.

Fear is simply the consequence of the acceptance of ignorance; reject ignorance and accept knowledge-- with knowledge all fears are relinquished and the light of truth within shines through to guide your path.
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#23 Old 01-17-2012, 10:03 PM
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The sarcasm doesn't translate because there are global warming skeptics who argue that water vapor is a bigger greenhouse gas.

In short, your comment fell under a variant of Poe's Law.
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#24 Old 01-17-2012, 10:50 PM
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Originally Posted by t0mmy View Post

Sorry, my classes started and I had to deal with scheduling, I've had my online time put aside for a while (you'll notice I will not be on these boards much for a few months).

I don't believe I made the claim you claimed I claimed. I simply posted a facetious post in regards to how dangerous water vapor is, because there's a big hullabaloo over carbon. Granted, I understand there to be no real concerns over water vapor, but I don't think the sarcasm translated very well to das_nut, who took me seriously and made this thread.
In the end if he believes the federal government needs to impose taxes on us due to a carbon scare then I simply disagree.

Your sarcasm went on and on and at no point did you ever address the real issue of CO2, instead pretending like saying that water vapor was a real threat was an acceptable way to respond, as if they are even comparable, let along equivalent.
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#25 Old 01-17-2012, 10:56 PM
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I think the term is anthropogenic. And we're not doomed, but things are certainly going to be different. They already are; people just don't think it's really happening to them.
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#26 Old 01-18-2012, 12:24 PM
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A shame, but I had a good chuckle over it though :^]

Fear is simply the consequence of the acceptance of ignorance; reject ignorance and accept knowledge-- with knowledge all fears are relinquished and the light of truth within shines through to guide your path.
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#27 Old 01-18-2012, 01:55 PM
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I can bring some atmospheric physics to this discussion. The effect of water vapour on the greenhouse scenario can not be compared to the way carbon dioxide influences it.
Things like atmospheric to surface saturation ratios make it a false analogy. On earth, our temperature is cold enough to allow for a limit on the atmospheric saturation of water vapour. The main variable in influencing the amount of water vapour in the atmosphere is surface ocean temperature- itself influenced by the amount of evaporation from water in surface ocean into water vapour becoming atmospheric water vapour.
In short, humans really have little effect on water vapours contribution to global warming.
Shoving 400~ million years worth of stored carbon back into the atmosphere in an amount that out-weights natural processes by far does affect the climate, no matter what scientifically illiterate anthropogenic climate change deniers will want you to think.
Methane is probably more potent, as to avoid the "point of no return" scenario, the thermodynamic properties of methane allows for higher re-radiating of infrared(= about 23 times more heat than co2) than carbon, with a much shorter lifespan, meaning methane = higher warming effect over a shorter period, whereas carbon overall allows for more heat energy re-radiating but evened out over a longer time span.
It's most definite from a scientifically educated point of view that our water vapour contributions should be discounted. IF we were on Venus, a planet which receives about twice as much solar energy to its surface then it probably would be a worry. Too late for Venus though :P
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#28 Old 01-18-2012, 02:05 PM
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A shame, but I had a good chuckle over it though :^]

But the last laugh is on us, it seems. After all, having to present a red-herring as your rebuttal tends to weaken your argument.
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#29 Old 01-20-2012, 12:22 AM
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It wasn't an argument, it would have had premises to support a conclusion.
A big hint would have been me asking if the sarcasm detector was delivered yet X^]

Fear is simply the consequence of the acceptance of ignorance; reject ignorance and accept knowledge-- with knowledge all fears are relinquished and the light of truth within shines through to guide your path.
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#30 Old 01-20-2012, 05:50 AM
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It wasn't an argument, it would have had premises to support a conclusion.
A big hint would have been me asking if the sarcasm detector was delivered yet X^]

Your premise was that the idea of taxing CO2 emissions is ridiculous. Also recall you said "I accept your resignation of argument" with regard to the issue. So calling it a non-argument with no premises seems disingenuous.

The implication of your sarcasm was that water vapor is an equivalent or greater threat than CO2 (or equivalent in the sense of neither being a threat) and that arguments in favor of a carbon tax would also support taxing water. The OP provides evidence that these things are not the case.
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