Tehran contemplates "evacuation" as many cities across the globe face water dilemmas

I've put the word "evacuation" in the title of this piece in quotes because it's not clear where Tehran's 9.8 million people or some significant number of them would evacuate to as water supplies run dangerously low. Iranian President Massoud Pezeshkian has been criticized for saying out loud how bad the situation is: "If it does not rain in Tehran by December, we should ration water; if it still does not rain, we must empty Tehran."

Doubtless Iranian water authorities will force severe restrictions on Tehran's residents if the rains—which have been 82 percent below the long term averages for the past year—do not come. And there is almost certainly room to conserve. But the relentless heat (and thus increased evaporation from reservoirs) and lack of rain are not something that can be put down to water system mismanagement unless (as you should) you count not understanding and reacting to climate change as a failure of management.

Back in 2018 Cape Town, South Africa was facing a severe water shortage for lack of rain during which the city began making announcements of a specific date which it called "Zero Day" when water would have to be shut off to most of the city. Dramatic conservation which drove water consumption down 30 percent and the return of seasonal rains saved the city (for now).

Wherever water is in short supply in urban areas, the subject of overuse becomes a hot topic. But, agriculture and thermoelectric (mostly coal and natural gas) power generation are typically the largest users taking 43 percent and 42.5 percent, respectively, of total water withdrawals in the United States, for example, from 2010 through 2020, according the U.S. Geological Survey. What may be surprising to most people is that what's called "public supply," the water that comes out of taps of homes and businesses, amounts to just 14.5 percent of consumption. When water gets short, squeezing "public supply" may be useful but far less important than addressing agricultural and power generation use over the long run.

Situations similar to what happened in Cape Town and what is happening in Tehran are now increasingly repeating themselves across the globe. Here's a recent headline: "13 U.S. Cities Facing Alarming Water Shortages That Are Being Ignored." Those cities include ones you might expect such as Phoenix, Las Vegas and Los Angeles and ones you probably wouldn't such as Salt Lake City, Denver and Atlanta. In some cases dwindling supply looms large as, for example, the shrinking Colorado River which supplies Phoenix with much of its water. In others it's rapid development which is increasingly taxing supply such as in Colorado Springs. In truth, both dwindling supply and rapid development play a role in water difficulties in most cases.

Here's another headline: "25 Countries, Housing One-Quarter of the Population, Face Extremely High Water Stress." The five most water-stressed countries not surprisingly are in or near the Middle East: Bahrain, Cyprus, Kuwait, Lebanon, Oman and Qatar. Some not so likely candidates for the extremely stressed category include Chile, Belgium and Greece. The World Resources Institute which wrote the study linked above defines water stress as follows: "Water stress, the ratio of water demand to renewable supply, measures the competition over local water resources. The smaller the gap between supply and demand, the more vulnerable a place is to water shortages."

Nearly everywhere climate change is challenging water managers who are often dealing with systems built in the last century and before that have been expanded willy-nilly without climate change in mind. If Tehran does start to empty out due to water shortages sometime next year, it will be a stark reminder that the systems we built pre-climate change are dangerously ill-adapted to the new and increasingly hostile climate.

Kurt Cobb is a freelance writer and communications consultant who writes frequently about energy and environment. His work has appeared in The Christian Science Monitor, Resilience, Common Dreams, Naked Capitalism, Le Monde Diplomatique, Oilprice.com, OilVoice, TalkMarkets, Investing.com, Business Insider and many other places. He is the author of an oil-themed novel entitled Prelude and has a widely followed blog called Resource Insights. He can be contacted at kurtcobb2001@yahoo.com.