
Since at least 2008, scientists have warned that unchecked groundwater pumping for the city and for agriculture was rapidly draining [Iran’s] aquifers. The overuse did not just deplete underground reserves—it destroyed them, as the land compressed and sank irreversibly. One recent study found that Iran’s central plateau, where most of the country’s aquifers are located, is sinking by more than 35 centimeters each year. As a result, the aquifers lose about 1.7 billion cubic meters of water annually as the ground is permanently crushed, leaving no space for underground water storage to recover, says Darío Solano, a geoscientist at the National Autonomous University of Mexico, who was not involved with the study.
Some of the largest cities in the world, including São Paulo, Mexico City, Cape Town, Bangalore, and Tehran, are today facing critical water shortages. In the case of Tehran, the situation is so dire that Iranian president Masoud Pezeshkian has publicly said that the country now has no choice but to move its capital from Tehran to the southern part of the country:
Amid a deepening ecological crisis and acute water shortage, Tehran can no longer remain the capital of Iran, the country’s president has said.
The situation in Tehran is the result of “a perfect storm of climate change and corruption,” says Michael Rubin, a political analyst at the American Enterprise Institute.
“We no longer have a choice,” said Iranian president Masoud Pezeshkian during a speech on Thursday.
This will be expensive, and it won’t solve all of the country’s problems, but forcing a bunch of people out of the city will help to relieve some of the localized pressures. Tehran has a population of nearly 10 million, and the metro region is estimated at over 14 million, making it the second largest city in the Middle East.
Of course, there’s a city-building lesson in all of this: If you’re at this stage of capitulation, it means you’re too late. Water scarcity is about physical scarcity, but it’s generally also a failure of governance, infrastructure, and demand management. Proactive adaptation is always cheaper, easier, and safer than waiting until the last minute to adopt desperate measures.
Cover photo by Behnam Norouzi on Unsplash

As a follow-up to yesterday's post about infill housing and overall urban densities, let's look at some basic math.
The City of Toronto has an estimated population of 3,025,647 (as of June 2023) and a land area of 630 square meters. That means that its average population density is about 4,803 people per km2. Obviously this number will be higher in some locations, and lower in others. But overall, this is the average.
Now let's consider how many people we could actually fit within the existing boundaries of the city (city proper not the metro area) if we were to simply match the average population densities of some other global cities around the world.

Again, what this chart is saying is that if we took the same physical area (Toronto's 630 square meters) and just increased the population density to that of, say, Paris, we would then have a total population of over 13 million people and we'd be housing an additional 10,011,573 humans on the same footprint.
I am not suggesting that this is exactly what should be done. (Though, you all know how much I love Paris.) What I'm suggesting is that calling a place "full" isn't exactly accurate. How would you even measure that? What someone is really saying is that they are content with the status quo in terms of built form and density.
Note: The above population densities were all taken from Wikipedia, except for Toronto's figures, which were taken from here.
Toronto has a lot more CCTV cameras than I would have thought.
According to this (2022?) data from Comparitech, there is estimated to be about 19,236 cameras installed around the Greater Toronto Area. With a population of around 6.31 million people, this translates into a per capita rate of 3.05 (CCTV cameras per 1,000 people). What this means is that there is almost surely footage of me enjoying a late-night shawarma sandwich after the bar somewhere on the streets of Toronto.
In some ways, this is a high number of cameras. Tokyo, which is usually considered to be the largest metro area in the world with nearly 40 million people, only has 1.06 cameras per 1,000 people. Dhaka is 0.71. Sao Paulo is 1.04. Osaka is 1.57. And Montreal is 1.03. Though to be totally fair here, Rio de Janeiro is up at 3.34 (and it may be the most dangerous city mentioned in this post). Paris is 4.04. New York is 6.87. Los Angeles is 8.77. And London is 13.35.
But where things get really exciting is in authoritarian places. Moscow is estimated to have 16.85 CCTV cameras per 1,000 people. And in China as a whole, there is estimated to be roughly 540 million cameras scattered around its cities, which works out to an average of 372.8 cameras for every 1,000 people. For a city like Shanghai, this crudely equals something like 10.6 million cameras.
It turns out that surveillance is pretty important for things other than shawarma-eating videos:
Vyborov wasn’t arrested that day, but the police informed him that he was under surveillance through Sfera, one of Moscow’s face recognition systems, for participating in unsanctioned rallies. Considered one of the most efficient surveillance systems, Sfera led to the detention of 141 people last year. “Facial recognition, and video cameras in general in a totalitarian state, are an absolute evil,” Vyborov says.
Here's the other thing. Safety is usually touted as the reason to have lots of cameras. But Comparitech's data suggests that there's an almost non-existent correlation between lots of cameras and lower crime. I mean, just look at Tokyo. It is basically the model megacity, and its per capita camera rate is only 1.06. The real utility, it would seem, is using cameras and face recognition software to restrict personal freedoms.