Water Vapor Causing Climate Warming 434
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"
Welcome to ten years ago (Score:5, Informative)
Accepted facts about global warming are as follows:
a)We are putting more greenhouse gases into the air than ever before.
b)Greenhouse gases trap heat.
c)The earth is getting warmer.
No one disagrees on these facts. The only legitamite disagreement is on how much warmer the earth will get, and this is because we don't know where the water vapor sits in the atmosphere. Supercomputers estimate the temperature increase will be between 1.5 and 11 degrees celcius in the next 50 years. At the low end we are seriously screwed. At the high end it is the end of civilization as we know it.
Re:Title and Summary are misleading (Score:2, Informative)
Twice as much water is produced in typical hydrocarbon reactions than CO2
C(N)H(2N+2)+[(3N+1)/2]O2-->(N)CO2+(N+1)H2O
Re:Um... duh? (Score:4, Informative)
Yes, this is not some groundbreaking new assertion. In fact it is things like this - feedback mechanisms (both positive and negative) that make climate change modelling so hard. If it was a simple matter of "C02 creates more warmth" we'd have figured it all out a while ago. More warmth can produce more water vapor, but depending on what type of clouds are formed you can end up with trapped heat, or more solar radiation reflected and a cooling effect. There are many other feedback mechanisms that I simply can't recall and many more I've never heard of. How and when they respond, and how they interact makes for a very difficult and complex problem indeed.
Jedidiah,
Re:IT'S BUSH'S FAULT!! (Score:5, Informative)
Thousands. They list glaciation, ocean variability, plate tectonics, solar variation, orbital variations, magnetic field changes, vulcanism as some of the natural causes of climate change.
And there's really not anything we can do to affect it, or stop it.
Since the industrial revolution the burning of fossil fuels has increased the amount of atmospheric carbon dioxide to about 1.5 times the level it was in the early 1800s. By 2100 we are expected to be at double the 1800s level, resulting in a temperature increase of about 2 to 5 degrees celsius. So yes, we can affect the global temperature.
Re:Title and Summary are misleading (Score:1, Informative)
and carbon dioxide causes about 1/4 of earth's total greenhouse effect [wikipedia.org]
Title and Summary are Wrong. Feedback != Forcing (Score:5, Informative)
But this vapor is just a feedback effect, not an atmospheric forcing. This is due to the incredibly short residence time of water in the atmosphere of ~10 days. This means that even if you could somehow instantly cause the earth to have 0% humidity everywhere, things would stabalize back to "normal" within about 20-30. True forcings like CO2 have residence time of decades, which makes them the greenhouse gas to worry about.
Everyone posting here should first read this article [realclimate.org] for the full explination. The site in general is excelent.
Re:IT'S BUSH'S FAULT!! (Score:1, Informative)
A quick google shows this:
Founded in 1919 by Herbert Hoover, the Stanford University-based Hoover Institution is one of the country's oldest research institutes. With eight fellows on the Bush administration's Defense Policy Board (DPB), as well as several current and former associates like Donald Rumsfeld and Condoleezza Rice serving in the country's highest policy-making posts, the influence of Hoover is difficult to overestimate. Hoover DPB members include Richard Allen, Martin Anderson, Gary Becker, Newt Gingrich, Henry S. Rowen, Kiron Skinner, and Pete Wilson. (7)
Hoover's connection to the Bush administration and its hardline defense policies has been a source of continuing controversy at Stanford. According to journalist Emily Biuso, in early 2003, various campus groups organized a series of protests calling for Hoover's ouster from the university, which donates about $1 million to the institution every year. (3)
Hoover's focus is not limited to foreign and defense polices. Reports Mediatransparency, "The Hoover Institution's well known antipathy to federal social welfare policies was . . . expressed by the chair of the Hoover board when he declared that 'there is growing realization that we either must accede to the gathering force of the welfare state or return to the more promising ways of freedom.' Hoover . . . has focused particular attention on tax policy, promoting the flat tax for well over a decade and organizing policy briefings and conferences on the issus. . . . It was, according to one well-placed journalist and author, one of four leading policy institutions that pulled the nation's economic policy debate to the right in the early 1980s." (5)
Re:Title and Summary are misleading (Score:2, Informative)
Re:What if.. (Score:4, Informative)
If 1 gallon of water in the atmosphere over 1 year retains an extra, say, 10 thousand calories of heat, and your device only expends 5 thousand calories to condense and trap a single gallon of water (I have a dehumidifier sitting right next to me so I could probably work up some better numbers, but feh, whatever), then you've broken even in 6 months, and get a bonus 5k every 6 months thereafter.
~Lake
Re:What if.. (Score:4, Informative)
Water evaporates when it gets hotter. The fact that more water is evaporating indicates that the Earth's system has gained heat (from the sun), even if that's stored when the water vaporizes. And water is a greenhouse gas. Much moreso, in fact, than CO2. That's presumably (without reading the article) the feedback loop.
Re:IT'S BUSH'S FAULT!! (Score:3, Informative)
Whoa whoa, those are big numbers we're throwing around. First, carbon dioxide was at what level in 1800? I hunted down some sources images for long term CO2 concentrations:
http://en.wikipedia.org/wiki/Image:Carbon_Dioxide
So, CO2 levels were at, lets say 260ppm. Now they're at 375ppm. That, is indeed, a rise of 44%. First, I'm surprised. If we've been pumping out so much CO2, why have we only raised the concentration by 44%? Wouldn't you figure it'd be a lot more?
Next, we're still talking 375ppm - that's 0.0375%. How can we be certain that such a small portion of our atmosphere is causing such a huge change? The answer is we can't. We only have guesses about what the climate is going to be like in 5, 10, 20 years. Computer models are so far off - if they're within 400% they're doing well - that it can be considered no more than a guess. In fact, this article is much more on target - it is likely water vapor that would cause a large increase in global temperature. But water vapor in our atmosphere varies a lot based on weather patterns.
Put simply: there is simply no way that you can say that a 100% increase in carbon dioxideconcentration is going to do or not do anything. We simply do not know. I am certain some scientist somewhere "predicted" that this could happen. And sure, it could. But we could also trigger the next ice age. It's nothing more than a guess.
I am not saying we shouldn't cut back. We should. Anything we do on the planet will affect it in some way, and certainly the less we affect the better. But, I am much more worried about the pollution problems in China, and that 60% of petroleum is consumed for transportation, than the CO2 output of the industrialized world.
Well Established Science (Score:5, Informative)
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
Sorry, but you're wrong. (Score:5, Informative)
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).
Well, here I go pulling stuff out of my ass (and by "my ass" I mean "the positions of the most influential bodies in the field") [my bold].
From the Position Statement [agu.org] of the American Geophysical Union:
Human activities are increasingly altering the Earth's climate. These effects add to natural influences that have been present over Earth's history. Scientific evidence strongly indicates that natural influences cannot explain the rapid increase in global near-surface temperatures observed during the second half of the 20th century.
From the Position Statement [ametsoc.org] of the American Meteorological Society:
* The theory of how greenhouse gases directly interact with atmospheric radiation is not controversial. If no other factors counter their influence, increases in their concentration will lead to global warming.
* A steady rise in the concentration of greenhouse gases began over 200 years ago and is continuing. Atmospheric concentration of carbon dioxide, the principal greenhouse gas, has increased from pre-industrial concentrations of 280 ppmv (parts per million by volume) to over 367 ppmv in 2000, an increase of more than 30%; methane has increased from 0.7 to about 1.8 ppmv, an increase of more than 150%; nitrous oxide has increased from 0.27 to over 0.31 ppmv, an increase of 16%. Tropospheric ozone is estimated to have increased by 35% since the industrial revolution...
The first line of the National Academy of Sciences 2001 report titled "Climate Change Science: An Analysis of Some Key Questions" [nap.edu], performed at the request of President Bush:
Greenhouse gases are accumulating in Earth's atmosphere as a result of human activities, causing surface air temperatures and subsurface ocean temperatures to rise.
In short... there is no controversy. Yes, there are a handful of very loud people who are attempting to create one, who are assisted by the media's dedication to "balance," which consists of giving equal weight to totally unequal positions. Really, though, in the scientific community, anthropogenic warming is considered to be a fact.
Now, to be clear, this doesn't mean that we should necessarily do anything about it. The existence of a phenomenon is not de facto support for any particular policy position. But let's not screw around-- the "controversy" over whether global warming is at least partially anthropogenic is manufactured and does not reflect the views of the scientific community.