Loading berkshelf sets locale to C

On OS X 10.8.2 I have installed Ruby 1.9.3p327 and Berkshelf 1.1.0. When I load Berkshelf in a ruby script, the locale in the script's environment changes from my default of en_US.UTF-8 to C.

$ cat berkshelf_locale.rb 
#!/usr/bin/env ruby

puts 'Before loading berkshelf'
puts `locale`
require 'berkshelf'
puts 'After loading berkshelf'
puts `locale`

$ ./berkshelf_locale.rb 
Before loading berkshelf
LANG="en_US.UTF-8"
LC_COLLATE="en_US.UTF-8"
LC_CTYPE="en_US.UTF-8"
LC_MESSAGES="en_US.UTF-8"
LC_MONETARY="en_US.UTF-8"
LC_NUMERIC="en_US.UTF-8"
LC_TIME="en_US.UTF-8"
LC_ALL=
After loading berkshelf
LANG="C"
LC_COLLATE="C"
LC_CTYPE="C"
LC_MESSAGES="C"
LC_MONETARY="C"
LC_NUMERIC="C"
LC_TIME="C"
LC_ALL=