Political leaders in Cape Town, South Africa, realized that climate change was a threat years ago.
The reservoirs are down to just 26 percent capacity.
The crisis in South Africa could foreshadow future events that may cripple urban centers by depriving residents of water access.
"There is no contingency plan for what happens when we run out of water."
Some of them are political; others are related to engineering.
In that way, Cape Town underscores how climate change can expose political passivity, observers say.
At the same time, its water capacity has grown by just 15 percent.
However, when natural drought cycles are intensified by rising temperatures and increased dryness of the soil, it could lead to water shortages, he said.
"We have seen increases in climate variation, with an increased frequency of droughts and floods, in many countries.
"Water out West is going to be an issue," Zinke said.