Most of it comes from South American oranges and is concentrated there in evaporators using heat and vacuum (and fossil fuels), packed and shipped as frozen concentrate (requiring electricity to keep cool). It is then reconstituted with water and packed in PET bottles. Some is sold as "not from concentrate" like Tropicana (owned by Pepsi) which flash-pasteurizes it to extend its shelf life. They have an entire refrigerated "juice train" to move it from Florida to the Northeast. If you squeeze your own, (using a manual juicer, we hope) you are "you throw away skins and husks that have used up energy travelling thousands of miles."
What can you do? Go local. We start the day with apple cider harvested and pressed 128 kilometers (80 mi.) from home. ::Guardian