Why are climate models from computer scenarios being used as scientific predictions for Global Warming?

Question

Let's put it this way. Why aren't actual climate observations being used instead? Observations like C02 is not the green house gas most prominent in our atmosphere, water vapor is. Not only that but at any given depending on the temperature and where you are on the planet, water vapor makes up 30-70% of the greenhouse gas where C02 is only present in quantities of 9-26%.

I personally can't wait for an attack on water vapor in the next global warming debate.

Comments?

Answer 1

Climate observations are used extensively.  As far as predictions are concerned, you can't observe the future so you have to use some sort of model (math or computer).

You are correct in stating that water vapor is the most abundant green house gas in the atmosphere, but did you also know that without any green house gases in the atmosphere the planets global average temperature would drop 33 C from the current 15 C to about -18 C?  And I hope you also realize that not all green house gases have the same radiative forcing?  Methane, for example, is about 23 times as powerful as CO2.

Just for simplicity sake, let's assume that all greenhouse gases provide the same radiative forcing (clearly not the case, but sufficient to show how percentage data can be misleading).  If 30 - 70% of the greenhouse effect are from water vapor, that would mean  it's responsible for between 9.9 C & 23.1 C of the warming (earths global average temperature above what it would be with no green house gases).  If 9 - 26% of the greenhouse effect are CO2, that would mean it's responsible for between 2.97 C - 8.58 C of the warming.

Now if you double the CO2 level in the atmosphere (again with a simplified linear relationship), that would give you a ballpark warming of an additional 2.97 C - 8.58C.  Doesn't that concern you?

We aren't changing the level of water vapor, but we are increasing the level of CO2 (and other green house gases).  So while their effect may be small relative to water vapor it's an additive effect.

Answer 2

I really wish I knew why they are using them, since they are inaccurate and they can't put the effects cloud cover into their programs.

Answer 3

Climate observations are used.  Observations only tell us what happened in the past.  

Wouldn't it be prudent to figure out what might happen in the future, and know if there are consequences that we might be able to influence?  That's what the computer models are an attempt to do.  Long term climate trends are more subtle than short term weather influences such as the El Nino Southern Oscillation, so the models are not useful to predict weather or even yearly temperratures or fluctuations.

DENIER MYTH#18: The influence of CO2 cannot match the influence of water vapor, and since the impacts of water vapor are largely unknown and outside direct human control, human beings cannot be the source of global heating -

http://www.scholarsandrogues.com/2007/07...

It is correct that water vapor is involved.  As the globe warms (including due to CO2 emissions) there is more water vapour in the atmosphere and this further strengthens the greenhouse effect.

Answer 4

J S is wrong once again. Did you get a laugh out of his link?

Sometimes I wonder if these guys are Hollywood writers trying to pass the time during the strike

Answer 5

Is this a rhetorical question?

Climate models omit water vapor and clouds because they are too complex to model, not because they are unimportant.

Since water vapor increases the greenhouse effect, that increases temperature, that evaporates more water, it should lead to a runaway positive feedback.  Since it doesn't, something must moderate this process, like clouds.

No on is going to blame water vapor, for the same reason global cooling/impending ice age never caught on.  You can't blame mankind.

Climate prognosticators and VooDoo witch doctors have a lot in common.  Cross them and they will find a way to do some evil to you.