"Can't you people ever get inconstant in what you claim? Of course not, you need a new argument every time the current one is shot down."

I think you meant to say something like "Can't you people ever stay CONSISTENT in your claims?"

What you actually said contradicted yourself. Oh the irony!

Read my last few posts on Water Vapour and my link. You haven't said anything that actually challenges the IPCC hypothesis I am discussing, but I don't think you know enough about the subject to actually understand what GrahamY and I are talking about. I'm no scientist, but even I can see you're struggling. Read this link twice or three times and you might catch on.
http://skepticalscience.com/water-vapor-greenhouse-gas.htm

Your post is contradictory Max, you say there isn't more water vapour and then you say there is. The problem with the forcing idea is that water vapour will enter the atmosphere as the temperature increases, not because CO2 has increased. So if there were a runway Greenhouse effect we would have seen it in the past when the planet was a lot warmer.

Because of the logarithmic effect you need a lot more CO2 just to raise the temperature another 1 degree or so. So CO2 is not going to mimic those earlier conditions anytime soon.

We can't model the water cycle particularly well, so no one is sure what the exact effect of water vapour is, but we do know that while it reradiates IR, it also cools through transfers of latent heat. So as water evaporates it has a cooling effect, and when it condenses it has a warming effect. It also reflects light back into space, which has a cooling effect.

While we know the sign of the heating effect of CO2, we're not even sure what the sign is for water vapour. Some think it might even be a negative feedback.

Hi Max.

Exactly how many gigatons of atmospheric CO2 will cause a 0.1% rise in global temperatures?

First Atlantic Warm Period about 7750 BC
Second Atlantic Warm Period about 7000 BC
First Saharan Warm period about 5800 BC
Second Saharan Warm Period about 5000 BC
Egyptian Warm period about 3200 BC
Sumerian Warm Period about 2200 BC
Minoan Warm Period about 1200 BC
Roman Warm Period about 400 BC to 300 AD
Medieval Warm Period about 1000 AD
Modern Warm Period about 2000 AD

If the earth has warmed and cooled 10 times in the last 8000 years, what caused the previous cycle of 9 warming periods? An unknown race of prehistoric intelligent life forms that existed up until the Medieval Warming Period, who had coal fired power stations and SUV's?

GrahamY:

MORE OR LESS?
I admitted that the science says water vapour traps heat. But I was responding to the assertion by another that CO2 doesn't matter because... water vapour traps heat. I was asking what's causing the demonstrable rise in global temperatures IF there's no space rain? No extra mystery water from aliens or space or whatever, just the same water going around and around? It's not more water vapour that's making the global temperature rise to then store more water vapour and create a feedback, it's CO2. The only fraction of the atmosphere we can demonstrate is increasing — CO2 and methane and a few trace super-greenhouse gases.

"The problem with the forcing idea is that water vapour will enter the atmosphere as the temperature increases, not because CO2 has increased."

Try this from YALE:
__________________________

The primary reasons why water vapor cannot be a cause of climate change are its short atmospheric residence time and a basic physical limitation on the quantity of water vapor in the atmosphere for any given temperature (its saturation vapor pressure). The addition of a large amount of water vapor to the troposphere would have little effect on global temperatures in the short term due to the thermal inertia of the climate system. The Earth’s thermal inertia, largely due to the enormous amount of water covering two thirds the planet’s surface, is the primary reason why half the Earth does not freeze over every night and bake every day. As a result, different areas warm over the course of years (for land surface temperatures), decades (for ocean surface temperatures), and even centuries (for deep ocean temperatures and ice sheets).
http://www.yaleclimateconnections.org/2008/02/common-climate-misconceptions-the-water-vapor-feedback-2/

The CO2 logarithmic explanation is complex, and I'll just link here.
"Scientists agree that the greenhouse effect is approximately logarithmic — which means that as we add more CO2 to the atmosphere, the effect of extra CO2 decreases.
However, the IPCC projects that if we don't take steps to reduce our emissions, global warming won't just get worse, it will speed up:
The explanation takes more than 350 words."
http://skepticalscience.com/why-global-warming-can-accelerate.html

Dear Don,

Of course you are selling something, you are selling your brand of cure to a disease you have diagnosed the causes of.

You are specifically ignoring the high temperature of the patient which is the result of a higher concentration of a specific gas.

Now there might well be a demographic for the elixir you are spruiking but the rest of us are firmly set on paying attention to the more qualified

Dear LEGO,

Your problem can be answered in one word: Milankovitch!