And always - ALWAYS! - the so-called experts on climatology seem to totally discount the effect that water vapor has on the atmospheric temperature. As a greenhouse gas, water vapor is some 30 to 100 times the effect of carbon dioxide, but more importantly, it is also a transfer medium for regulating the daily average temperature of the atmosphere. The water molecule has tremendous capability to either absorb heat energy, or conversely, to release this same energy, and in fact, water has a very high index of energy absorption, much higher than most other compounds.
Water absorbes an enormous amount of energy from surrounding matter in the process of becoming water vapor, and releases a respectable amount of energy when it changes into ice. So to even remotely imagine that mankind could melt all the glaciers and polar ice on this planet is to imagine an omnipotence that not even God would tinker with. The heat has to come from somewhere, and it is being radiated off the dark side of the planet at night at just about the same rate as it being absorbed from ALL sources (solar radiation, internal heat from the planet core, or whatever feeble little bit that mankind manages to emit over the course of a day’s activities). Simple physics - the hotter a body gets, the faster it radiates energy. All matter is seeking equilibrium of energy distribution, and the earth is no different. And carbon dioxide is such a infinitesimally small player in this balance, it makes no difference either way. That compound neither absorbs nor re-emits energy in anything like the magnitude of water vapor, or the movement of water from solid (as ice) to liquid, to water vapor.
Not really. The first 1/5 of the CO2 concentration makes it possible to have water vapor stay in the air. Without CO2 earth would be an ice cube with a little melting on the day side. Each subsequent fifth of CO2 provides a lot less warming than the prior (logarithmic curve). So as a whole CO2 is important. The increase in CO2, not so much.