That would be a fun project. Iffen I was to attempt it …… I would place Cling Wrap or Saran Wrap on the inside of the globe directly across from the break and overlapping the top edge of the globe.
Then with the globe lying on its side with the break up and the Cling Wrap toward the table …….. spoon or pour enough Plaster-of-Paris on top of the Cling Wrap to make a “mold” of the curvature of the globe, ….. making sure that the Plaster-of-Paris overhangs the top of the globe and is at least 2 inches wider than the “break”.
When the Plaster-of-Paris hardens up, ….. then just slide the “mold” around to the “break” and tape it in place where it overhangs the globe on both sides of the break ….. and start putting the puzzle together. Using a very, very thin coat of glue, otherwise, big trouble getting all the pieces in place. Then put a clear epoxy on the inside to firmly hold the broken pieces in place.
Oh yeah, first do a “dry run” on working the puzzle before you start gluing anything together.