[15155]

Whoa: is this the only possible form of cooling?

What if there were a cooler that somehow didn't evaporate water, you might even call it a "dry cooler" - that would be a sweet invention. This might even be required in areas where adiabatic cooling isn't effective (humid climates)!

[MathMonkeyMan]

Even if the ambient relative humidity is near 100%, water's latent heat of vaporization is nothing to shake a stick at.

I like the idea of a giant heat pump into the ground, but heat exchangers are expensive and so is digging.

[15155]

Nobody is talking about a giant ground-exchange heat pump: liquid-to-air dry coolers exist and are used everywhere. Adiabatic cooling is just cheaper.