ToraToraTora,
As temperature rises so is the water vapour in the atmosphere. This creates a positive feedback for the greenhouse effect originally due to increase in CO2 levels.
According to the links you supplied, this positive feed can accelerate global temperatures rises to 3 degrees centigrade!
The links you supplied
https://www.skepticalscience.com/print.php?r=44 stated, "As water vapour is directly related to temperature, it's also a positive feedback - in fact, the largest positive feedback in the climate system (Soden 2005). As temperature rises, evaporation increases and more water vapour accumulates in the atmosphere. As a greenhouse gas, the water absorbs more heat, further warming the air and causing more evaporation. When CO2 is added to the atmosphere, as a greenhouse gas it has a warming effect. This causes more water to evaporate and warm the air to a higher, stabilized level. So the warming from CO2 has an amplified effect"
The links continued, "How much does water vapour amplify CO2 warming? Without any feedbacks, a doubling of CO2 would warm the globe around 1°C. Taken on its own, water vapour feedback roughly doubles the amount of CO2 warming. When other feedbacks are included (eg - loss of albedo due to melting ice), the total warming from a doubling of CO2 is around 3°C".