Cagliostro has scattered magic-to-cold transducers around the poles to
preserve his planet's icecaps.

They'll need to be dumped out at the equator every so often, but that
should keep a regular cycle.  They will get more powerful and need to
be swapped more often over the years.

The planet was cracked in Africa, the Middle East, and Asia.  Several
warring factions are now split. 

A deep pit around what used to be New Amsterdam - the radiation-soaked
land could not be perceived, and was not grabbed.

Cagliostro sets up two concentric magic-based walls - an outer wall,
blocking physical things and acting as a magical ward, and an inner
wall blocking light (and powering the spells with that light.)  There
is a 13' gap between the two walls.

The spell is designed so that as it gets stronger, the climate will
not deteriorate.  The spell will go up approximately 120 miles, and go
down into the desert sands.  It should not be powerful enough to cause
a problem at the 'bottom' of Darkover.

Cagliostro sets up a talisman system that allows people in and out of
the outer barrier.  The talismans can be invalidated, altered,
tracked, and define a boundary area.

Breeding populations of flying things have been imported.  There is an
infestation of harpies included in this, which is in a contained area.

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At some point, Cagliostro gets stuck in the Overworld.