Our Earth is a Magic Sink-Hole. What follows?

Question

This Earth does not have magic that can be directed by people to their own desires. It follows low-level laws of physics with exceptions detailed below.

Rather, some other parallel reality has magic with wizards and useful control over said magic. Our reality is on the receiving end of it only.

In that reality, if someone uses magic to produce a waffle for breakfast, where does it come from? From our reality! Now that's not the most typical example, since locating an object with matching properties—if the same thing even exists here at all—somewhere on the planet requires a great deal of mana to animate a low-level intelligence on this end to find one.

Places line up between the two realities, with the broadest geographical features of the planet being the same as well. If you (in the magic Earth) want to get rid of some trash, you can vanish it magically and it shows up in the same spot in this un-magical Earth, un-invited and unannounced.

Sometimes people are vanished, so we've had a few immigrants to learn the situation from and piece together the full story.

Certain magical locations there correspond to natural resources or unique conditons here, so getting energy to power more advanced magic or getting hot or cold across happens at locations where conditions are different. Yellowstone caldara here is a mundane plane there, and once discovered used as a source of energy for magical forges and a huge industrial center sprung up there.

The American Great Lakes don't exist there (I guess glaciation was different) and suddenly become a source of irrigation there.

In this reality, we can't control any of it. Science and engineering work, except that matter, energy, and entropy somehow appear and disappear at the command of someone on the other, magical, Earth.

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What would happen if this started happening now?

What would the technological and industrial development have been if this started happening some time in pre-history, and increased in scope over time just as our exploitation over natural resources have in reality?

How might we interfere with or benefit from it, anyway?

Answer 1

Arbitrage:

Any commodity of sufficient value in their world to justify the expenditure of magic in their world rapidly disappears.

What items have value there depends on a lot of factors.

What's the cost of summoning an item? presumably low if it can be used for summoning water for irrigation.

If the manna needed to summon one gold bar costs less than a gold bar then Fort Knox will empty until the price of manna rises or the price of gold falls in their world.

Data exchange:

The other world can far more easily gather data about us by summoning books of all kinds. This would also give them detailed info on commodities and goods available in our world and approximately where.

If geography matches then the locations of ore reserves are also likely to match. Any canny mage in their world is likely to summon mining surveys which will let them know where the unexploited reserves are in their world.

If this society is using our world as a rubbish dump then we're likely to be able to gather a great deal of info from their garbage and discarded paperwork. Of course if anyone writes this down in some book or paper that gets summoned away the other world might know to start shredding/burning their garbage before sending.

War and blackmail:

If the cost of manna is low enough then they could hold us hostage by threatening to summon away all the oxygen from an area or threatening to dump magical weapons into an area. They might start demanding tithes and specific goods be prepared in such a manner as to make summoning them cheaper.

Trade and smuggling:

There's also the possibility of less violent trade. If the cost of Manna is high and if there's anything we can do on our end to make the summoning of items cheaper then mages could trade with drug lords, they lay out guns and wrist watches in a perfectly aligned summoning grid, the mages in exchange summon heroin from pakistan and banish it into a basement in new-york.

You get very different answers depending on the cost of manna and depending on whether people in our world can do anything to assist with the process to reduce the manna-cost or if custom goods are of great value on the magical side.