The adjective "global" and adverb "globally" imply that the verb or noun to which they are applied applies to the entire Earth as one unit. It is sometimes used as a synonym for international/internationally but this is incorrect:
Nonetheless, "global" has passed into common usage, especially in the media, academia, and the business world, and among left-wing supporters of a "one world" concept. Many use this term in situations where "international" would clearly be the more appropriate term, as there are few things that are truly global (even the much-touted "global economy" for example does not include Antarctica, North Korea, etc.)
The usage of "global" is correct when referring to things which do involve the Planet Earth as one single unit, for example: global maps, global weather patterns, global satellite photos.
The terms "world" or World-Wide are also sometimes used as a synonym for either global or international.
In computer programming, global means accessible throughout the whole program. The most common global objects are probably global variables, considered undesirable by some.
In physics, geometry and topology, global is usually the antonym of local.
In Canada, Global often refers to the Global Television Network.