I'm running Ubuntu 12.04

I added

export LD_LIBRARY_PATH=/home/dspies/workspace/hdf5-1.8.11-linux-shared/lib

to .profile

but when I log in and open terminal and put echo $LD_LIBRARY_PATH there's nothing.

When I switch to ctrl-alt-F1 and log in, echo $LD_LIBRARY_PATH
gives

/home/dspies/workspace/hdf5-1.8.11-linux-shared/lib

but then when I run screen, echo $LD_LIBRARY_PATH from within screen is empty again

In what circumstances can I expect environment variables from .profile to be set? (interestingly, it seems any modifications to PATH made in .profile always show up)

EDIT: Sorry, I guess I didn't clarify what I really wanted to know which is:
How can I set an environment variable that I mean to be set anywhere (ie in screen, in terminal, when I log-in, and when I ssh in)?