How can I reduce the size of Google closure library for deployment?
I don't think the library (as is) is intended to be used in production. Use the Closure Compiler.
See also Shrinking Code with ClosureBuilder and the Closure Compiler in the Google Closure documentation.
It isn't a standalone library. It is intended to be used in parts. For simple hacking you can however use http://www.programmingclosure.com/closure-lite/