Original sentence: Climate models theorize that an increase in atmospheric temperature caused by the greenhouse effect will in turn lead to an increase in the water vapor content of the troposphere, with approximately constant relative humidity.This in turn leads to an increase in the greenhouse effect, a further increase in temperature and, consequently,  an increase in water vapor until equilibrium is reached.Thus, water vapor acts as a positive feedback (but not a runaway feedback) to the forcing provided by greenhouse gases such as CO2 (, see B7).Water vapor, of all greenhouse gases, accounts for the largest percentage of the greenhouse effect although water vapor levels fluctuate regionally
Edited sentence: However, climate models theorize that an increase in atmospheric temperature caused by the greenhouse effect due to anthropogenic gases will in turn lead to an increase in the water vapor content of the troposphere, with approximately constant relative humidity.This in turn leads to an increase in the greenhouse effect and thus a further increase in temperature, and thus an increase in water vapor, until equilibrium is reached.Thus water vapor acts as a positive feedback (but not a runaway feedback) to the forcing provided by human-released greenhouse gases such as CO2 (, see B7).Water vapor is a natural greenhouse gas which, of all greenhouse gases, accounts for the largest percentage of the greenhouse effect.Water vapor levels fluctuate regionally, but in general humans do not  produce a direct forcing of water vapor levels