Water vapor is a non-issue when discussing climate change mitigation
Not because water vapor is not a greenhouse gas. It certainly is. But it is purely reactive in effect. If you warm the atmosphere through CO2 emissions, water vapor will amplify that warming. There is absolutely nothing you can do about it, since warmer air can hold more water. Mitigation conversations need to address those greenhouse gases we can do something about, while of course incorporating the water vapor feedback effect.