The world is in a weird place..

[Squall of SeeD]

The world's name is "Gaia." The Advent Children pamphlet handed out at the Square-Enix booth at the last Electronics Entertainment Expo (E3) referred to it by this name: Linkage to a picture of the pamphlet.


In regard to another of your questions, there's only one polar ice cap because the Planet focuses its Spirit Energy in that area on healing the Planet's wound (the Northern Crater), rather than growing life. Recall Gast's conversation with Ifalna as seen in the Original Crisis Report tapes in Gast's house at Icicle Inn:

"The first ones to discover the Planet's wound were the Cetra at
the Knowlespole."

"Tell us Ifalna... Where is the land called 'Knowlespole'?"

"Knowlespole refers to this area. The Cetra then began a
Planet-reading."

"Ifalna, what exactly does Planet-reading entail?"

"...I can't explain it very well, but it's like having a
conversation with the Planet..."
"It said something fell from the sky making a large wound."
"Thousands of Cetra pulled together, trying to heal the Planet..."
"But, due to the severity of the wound, it was only able to heal
itself, over many years."

"Do the Ancients, rather, the Cetra, have special powers to heal
the Planet?"

(She shakes her head.)

"No, it's not that kind of power. The life force of all living
things on this Planet becomes the energy."
"The Cetra tried desperately to cultivate the land so as not to
diminish the needed energy..."

"Hmm, even here so close to the North Cave, the snow never melts."
"Is that because the planet's energy is gathered here to heal its
injury?"

(She bows her head.)

"Yes, the energy that was needed to heal the Planet withered away
the land... then the Planet..."

That area wasn't always a desolate, icy region.


By the way, the Planet is round. Recall either of the FMVs involving Meteor in space:
From the FMV in which the Shin-Ra No. 26 Rocket hits Meteor.
From the FMV in which it's shown that Meteor survived the collision with the Rocket.