What is the uncertainty of the measurement of water vapor in the atmosphere in comparison with CO2 level?

Question

Water vapor is a much much more effective green house gas in comparison to CO2. Water vapor contribute much more to global warming then CO2. It is critical that we can measure the average water vapor in the atmosphere acurately to the extend that we can compair the uncertain with the average CO2 level in the atmoshere. If we can't measure water vapor in the atmosphere with certainty greater than CO2 level in the atmosphere then we can't attribute global warming to human activity.

Answer 1

Water vapor makes up 1-4% of our atmosphere as compaired to CO2 whcih makes up .03%.
Water vapor accounts for most of the greenhouse effect no matter what source you look at.

http://en.wikipedia.org/wiki/Water_vapor

Answer 2

The amount of water vapour in the atmosphere varies greatly from location to location, day to day and is determined by the natural environment, physical constraints and meteorological conditions.

For all intents and purposes water vapour is evapouration from the seas and oceans, in a hot and humid climate there will be substantially more water vapour than in a cold and dry environment.

The maximum level of water vapour that can exist in the atmosphere is primarily determined by temperature and to a lesser extend by air pressure. Once the maximum level is reached the excess water vapour falls to earth as precipitation or is deposited on surfaces as dew.

Because it's so variable it's not possible to provide an accurate measurement, what we can do is to look at averages taken from multiple readings across the planet. This tells us that typically the atmosphere consists of 1% water vapour, the range being between 0% and 4%.

Water vapour isn't more effective than carbon dioxide per se, if they existed in equal quantities then carbon dioxide would have a much greater effect on global warming. The different gases that contribute to global warming have different levels of effectiveness, this is measured using a scale called Global Warming Potential (GWP), all measurements are relative to the GWP of CO2 which is always 1. There are for example, some gases that are many times more effective than carbon dioxide; methane being 23 times as effective, nitrous oxide being 296 times as effective and the CFCs HFCs and HCFCs being many thousands of times more effective.

There is many times the volume of water vapour than all other greenhouse gases combined but it forms part of a natural cycle, no matter what we do we can't increase levels of water vapour in the atmosphere. If we tried all that would happen is it would rain. The other greenhouse gases build up in the atmosphere and therefore do have an effect on global warming.

Water vapour has a very short atmospheric lifetime, just 4 days. Carbon dioxide has a 115 year atmospheric lifetime, the synthetic greenhouse gases stay in the atmosphere forever.

Water vapour forms part of a natural cycle (the water cycle) whereas the greenhouse gases that we've emitted have overloaded the natural carbon cycle by a factor of nearly 10. So whilst it's very true that water vapour is natural and the largest contributor to global warming it has to be taken into context that this forms part of a natural cycle and a natural greenhouse effect which keeps our planet at a habitable temperature.

In short, it's all about a delicate balancing act. Left alone then nature is fine but were upsetting the natural balance.

Answer 3

Whether Water Vapor is a more effective greenhouse gas than CO2 seems irrelevant. CO2 would still be a contributing factor, and any way we can reduce that should help, assuming the reduction doesn't cause other, larger problems.

Think of it this way. You and I both accidentally drive our cars off of a cliff. Now, you happened to buckle your seat belt before the accident, I didn't.

Who's better off?

Sure, we both probably will die, but I might have a 95% of dying, while you only have a 80% chance. And If we don't die, I still have a 75% of traumatic spinal injury compared to your 55% chance.

Now sure, I made those numbers up. Don't go quoting them on "Rush Limbaugh," (whose a drug addict anyways.)

But wouldn't it be better to be you in that circumstance?

So if CO2 is a small part of the problem, but the only part we can control, then yes, we should look for ways that we can control it.

Answer 4

actually, high levels of water vapor in the atmosphere, as well as dust and smog particles, reduce global warming, as clouds are the most effective way to reflect sun rays back into space, before they warm the earth, and water vapor + dust increase the amount of clouds.