Understand this: That much water, Mead and Powell, in the middle of the desert is not natural.
If those two lakes were formed by nature and were now drying up, then maybe one could assume the climate was changing. But Lake Mead and also Lake Powell are nothing more than man made water holding tanks. They exist to provide water for down stream users. If they are low, it is because water was regulated out of the reservoir at the dam. Water is collected , in the spring from snow runoff from the western slope of the Rockies, mostly. More water is pouring into Lake Powell right now, than is being released at the dam. The lake is rising, right now, today. Some people see the pictures of a desert reservoir that is dangerously low and many exclaim, "Oh dear, what will we do? There is a drought, there is no more water!" And the conclusion is that maybe, even probably, that climate change has caused a water shortage catastrophe. That is just not the case. Those lakes are low because the water has been requested by down stream entities that have a legal right to it. People, corporations and state and federal agencies have been fighting over that water for a long time. And now there are claims on about 125% of it. So yes it is going to be low.
The climate: Rainfall average for the whole United States is 38 inches of precipitation per year. The state of Colorado, where most of the river water comes from is less than half the national average at 17 to 18 inches per year. There are only half a dozen states drier than Colorado. No one knows how much rain or snow the Colorado River Basin will get in a year. Certainly some years are wetter than others. Predictions are for a strong El Nino and more rain this year than last.
Las Vegas has an annual rainfall of just 4.5 inches. So the climate is very dry. It is a desert, there is not going to be any filling of a lake the size of Lake Mead, aside from the Colorado with area average rainfall of 4.5 inches. It's just not going to happen. Has zero to do with climate change. It a engineering marvel that that much water storage was created in the first place.
Also the news media people didn't show pictures of the two Colorado River lakes below Lake Mead, and I'll bet it is because both Lake Havasu and Lake Mohave are standing at a whopping 93% full, right now. That's right, 93% of total capacity, both lakes.
Jump down to Phoenix, we are in the desert and our average total rainfall is only 9 inches. Yet we also have storage reservoirs and the current levels are: Roosevelt Lake 73% full, Apache Lake 93% full, Canyon Lake 95% full, Saguaro Lake 94% full.
My point is this, a picture of a low man made reservoir in the middle of a desert, with everyone downstream wanting the water, is not proof of anything except water greed and mismanagement.