If memory serves water vapor in the mesosphere is broken down by UV fairly readily and migrates into the thermosphere. I think the stratosphere would be in dire

If memory serves water vapor in the mesosphere is broken down by UV fairly readily and migrates into the thermosphere. I think the stratosphere would be in dire shape by the time the mesosphere had any real effect and would be the least of our worries. But I am going off of old memories from school days and am far from an expert.