There was recently a lethal heat wave in Karachi.
If you go about 1000 meters below the surface of the ocean, the water gets very cold.
Why don't people try to cool off hot places by piping cold water up from the ocean? Or just bubbling air through the deep water?
About a quarter of people in Pakistan regularly practice "open defecation" due to lack of access to basic plumbing infrastructure, which probably causes a much higher casualty rate than lack of access to air conditioning (old people are usually the casualties in heat waves, so the number of QALYs lost is much lower.) I know this isn't directly an answer to your question, but I'm trying to illustrate that there is a huge infrastructure gap in there.
Also, I'm not sure how you envision this working; just having open trenches of cold evaporating saltwater throughout the city?
This thread is for asking any questions that might seem obvious, tangential, silly or what-have-you. Don't be shy, everyone has holes in their knowledge, though the fewer and the smaller we can make them, the better.
Please be respectful of other people's admitting ignorance and don't mock them for it, as they're doing a noble thing.
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