Industrial cooler manufacturers and DC PR teams have their ways to greenwash the truth.

"40% of data centers are using evaporative cooling" doesn't mean that other 60% are fully closed loop water to air coolers or what would be called "dry cooling systems" by the manufacturers. The other 60% could be "adiabatic coolers" or "hybrid coolers" or if data center is close to large body of water/water heat exchangers, where 2/3 of those still depend on evaporating water, but the manufacturers would put them in separate category from evaporative coolers.

Just took a looked at offering of one of the industrial cooler manufacturers. They had only 1 dry cooler design, compared to a dozen more or less evaporative ones. And even that one was advertised as having "post install bolt-on adiabatic kit option". Which feels like a cheat to allow during initial project and build claim that you are green by using only dry coolers, but after the press releases are done, grant money collected and things are starting to operate at full capacity, attach sprinklers to keep the energy costs lower.

Am I missing something? How data centers in US/EU evaporating water thousand of miles from Iran affect it? Does it disturb the rain cycle in Iran or something?

The grandparent comment asserts that as data center roll-out continues, water scarcity becomes an even bigger issue globally.

The parent comment said DCs don't use water. This claim is easily proven to be incorrect.

But, correct, DCs outside Iran have little/no impact on the situation in Iran today.

Being overly pedantic doesn't help make your point.

And, yes, our food supply also has an impact on water availability in areas where food production occurs.

I am not being overly pedantic, I am merely pointing out the obvious fact that datacentres have +- 0 bearing on water problems in Iran, and even bringing them up in this conversation while ignoring corn or beef is ignorant at best and malicious at worst.

Iran will probably roll out data centres, as will other countries.

I wasn't speaking specifically US/EU.

A theocracy having that level of access to people's private info will be interesting.

And coal, gas CCGT and nuclear electricity plants to power them also use water to cool the steam.

Yes, they do, but Iran's nuclear development has been somewhat interrupted.

Does cooling destroy H20 molecules somehow?

Not sure if serious... but just in case, very simply put...

DC pulls water out of local water supply. DC uses evaporative cooling (not all use closed systems, and even those that do see some loss over time) Water lost to cooling is now in the atmosphere.

If the DC (and other local users) withdraw water faster than local conditions allow it to be replenished, you end up without any local water.

of course not, but as far as i understand there are a few factors that are relevant for local water supplies:

- evaporation from cooling. the water will come down as rain again, but not necessarily in the same region

- when disposing the water into the sewers, the water might get "lost" into the oceans, where it's not available as drinking water

- when disposing water used for cooling into the rivers it was taken from, there might be environmental issues with water temperature. i know that this is an issue with rivers in europe where the industry is allowed to measure and report their adherence to the laws regarding the maximum allowed water temperatures themselves and, to no ones surprise, the rivers are too warm.

so water is not destroyed, but it can be made unusable or unavailable for the locally intended purpose.

So? If anything, evaporated water could lead to more rainfall in Iran, not less.

It would have to be a lot more than that. As a rule, rain is produced by large lakes and seas, and some evaporation from tree cover. At a guess, I suppose Iran would get precipitation from the Gulf and Caspian, maybe the Mediterranean to a lesser extent, and some of their water renewal must be off snow melt.

I flew over Iran many years ago. Much of it reminded me of central Australia. Very arid and desolate, but beautiful from thousands of feet up.

My argument is not that said evaporation would make any sort of measurable improvement for Iran water situation, it is that it would not make it worse. I agree that there are local problems with water access, but that is a local concern, not a blank "AI/Datacentres bad" as it is being pushed right now.