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Water Vapor Causing Climate Warming
karvind writes "According to BBC, new studies suggest that water vapor rather than carbon dioxide in the atmosphere is the main reason why Europe's climate is warming. The scientists say that rising temperatures caused by greenhouse gases are increasing humidity, which in turn amplifies the temperature rise. This is potentially a positive feedback mechanism which could increase the impact of greenhouse gases such as CO2. Even though 2005 will probably be warmest year, climatologists still differ in opinion"
Scientists promptly advised everyone to:
1. Stop drinking water
2. Stop breathing
3. Stop taking showers (note: this doesn't apply to some countries such as France and Mexico)
Warming starts with CO2 and other greenhouse gases. Warmer climate means more evaporated water in the atmosphere. Guess what? Water vapor is also a greenhouse gas. So climate gets warmer. Lather. Rinse. Repeat.
This isn't a story that undermines or changes the prevailing scientific view. This may allow some fine tuning of the models. Some skeptics had argued with the results of the models because they didn't believe the contribution of water vapor. This may force them to reevaluate their view. (Yeah right).
Assuming this your post wasn't completely tongue-in-cheek...
So, in order to "mine" the water vapor out of the atmosphere, you would need some way of condensing the vapor. Any sort of heat exchanger would work, but the laws of thermodynamics dictate that, in the end, you would just be heating the atmosphere up more than accomplishing anything else. This does assume that the control volume for the system is the earth itself, and you're not using space as your 'cold reservoir'--doing that gets into all sort of pesky heat transfer issues as space is rather non conductive. There is something to be said for radiation, but it would only really be effective if shielded from the sun. Anyway, since the most likely mediums for heat rejection would probably be either the atmosphere (you lose), the ocean (you lose again), or the terrestrial bits of the earth (you lose still), all you would be doing it heating the atmosphere up more and putting more water vapor into the atmosphere in the long run.
If your toast does not accquire any kind of royalty, please do not contact us. We can't help you.
(Hopefully) before this ends up in a big pissing match over whether or not global warming is real, I'd like to lay down some ideas.
Our climate changes- it has for billions of years and it will for billions of more years.
Our climate is *incredibly* complex, so accurate prediction either way is nigh impossible (and I think it's arrogant to imply we know enough about our climate to even try to control it).
Global warming *is* happening, but factually only in the sense that our planet has been getting warmer- the debate is over whether or not man is to blame. Keep in mind, we just came out of an ice age several thousand years ago, so global warming is basically a given until we enter the next ice age.
There is NO consensus on whether or not man-made global warming is happening- anyone who claims to have "climatologist" friends who say it most definitely is or isn't real and that all the real scientists agree are just pulling stuff out of their ass (and it's pretty obvious, too, so don't even try to do it).
Not everyone who believes global warming is caused by man is a crazy hippy and not everyone who believes it isn't caused by man is some money-grubbing republican. It's that kind of black and white approach to this and other topics, both by the people and especially the media, that has trivialized the issue at hand.
Please try to keep this in mind.
-Moses
I'm just curious how many scientists have looked at the possibility that the earth warms and cools in cycles,
Yes. All of them. Find an atmospheric science textbook. It's in there.
and there's really not anything we can do to affect it, or stop it.
You're asking whether atmospheric scientists, people who study the atmosphere and its behavior, think that the manner in which earth's chaotic, multi-factored atmosphere behaves over time is fixed, unchanging, and can never be effected by anything.
No, none of them think that. The cycles themselves, which are quite erratic, demonstrate that changes can happen: For one thing, the cycles obviously happen for some kind of reason. For another thing, the cycles to which you refer haven't always happened. Further back in the past the climate's cycles operated differently.
The way in which the atmospheric cycles have operated for the last 2 billion years or so-- long stable periods followed by slowly increasing, then sudden and dramtic shifts-- suggest not that climate is some preplanned externally determined thing, caused by the hand of God moving a knob on a thermostat somewhere. What they suggest is the idea of the earth's atmospheric state having a number of equilibrium points, and we are moving back and forth between those equilibrium points. This is exactly what the article slashdot links here is about-- feedback mechanisms. The idea is that as you move further away from a stable equilibrium point, positive feedback mechanisms come into play which move you further and further away from that equilibrium point, and negative feedback mechanisms which were keeping you stable at that equilibrium point shut down. Once you nudge things away from the place where they were, the more the mean temperature rises the more the mean temperature is inspired to rise further, and the more the CO2 concentration rises the more the CO2 concentration is naturally inspired to rise even further. The lesson to take away here isn't to blame the cycles; the cycles themselves need that nudge to start. The lesson to take away is, you don't want to nudge the atmosphere out of that stable state, because once you start it may be too late to nudge it back.
Irritable, left-wing and possibly humorous bumper stickers and t-shirts
There seem to be a few things missing in this discussion:
s .1896.climate.pdf
1. The fact that most of the warming associated
with global warming is directly forced by water
vapor is well established, going back at least
as far as Arrhenius's 1895 paper often credited
with "discovering" global warming.
(original paper at:
http://geosci.uchicago.edu/~archer/PS134/arrheniu
)
i.e. this result is CONSISTENT with our understanding
of global warming.
2. Increases in atmospheric water vapor are tightly tied
to temperature. The saturation specific humidity
(the amount of water air will hold) increases
exponentially with temperature (an implication of the
Clasius-Claperyon relationship). Thus when you increase the
temperature of the atmosphere by dT (by, for example, adding
some CO2), more water vapor evaporates into the atmosphere,
amplifying the warming.
3. This effect, known as the water vapor feedback, has been in
our climate models from the beginning (at least as far back
as 1895), and produces results consitent with observations.
4. The cited Geophysical Research Letters paper uses observations
to estimate the strength of the water vapor feedback and
finds that it is strong (even stronger than most models
predict). It is also a step in the process
of understanding climate change on a regional level.
Z