Final Fantasy: of Crystals and (Information) Elements
First off, it's obvious enough that the "crystals" are a proxy for weak Ti. Belief in "magical" things and happenings, or things that have an "effect" on other things simply due to special properties, indicates weak Ti. McNew tried to correlate Aristotle's elements to information elements. He failed.
Rather, it is most useful to think of Aristotle's elements as specific effects of Ti that have a certain character.
Without the effect of the crystals, the harmony in the Aristotelian elements ceases. (Ostensibly) the rain ceases to fall, the plants begin to die, the soil becomes dry and barren. Maybe even radioactive decay sets in, who knows? The wind ceases to blow; the earth becomes hot... the seas are wild. (sounds like global warming!) Certainly the draining of the crystals' energy by these fiends is having some kind of negative effect, a Te phenomenon that manifests itself in all manner of Ti consequences.
The effect is more explicit in Mystic Quest.
Without the earth crystal's blessing, the people of Foresta age prematurely, and the plants die away.
The water crystal's draining results in freezing temperatures in Aquaria.
Of course you can only take the Ti analogy so far. At some point you have to take stock of the profundity of such an effect. But the effect is, again, suggestive and not intended to be thought about in any real depth. The loss of the crystal's power causes the crystals (Te inducing Ti) and that's all you really need to know.
Now let's suppose you did investigate the situation further. You'd first want to evaluate what the effects actually are, something that Ti alone may not be able to tell you. Instead you'd have to use the full gamut of other functions to assess what the actual effects are on the world. Ti tells you that there is a definite causal effect created by the draining, and that's all. To figure the situation further, you must ask questions like, "what are the ramifications of the effect" and "how does this effect trigger other effects?" An LIE-LII might observe that the decay of the earth causes lower crop yields, an observation an LIE-SLE later observes to be the cause of increasing wars by SLE-LIEs. And so it goes around as every creative subtype of every dual-type pitches in to figure out what the ramifications are of this one single effect (particularly on dominant subs), each person using their EM as a base from which to build on the discoveries of the IM identicals to their EM.