But realistically Y2038 is only an issue if time_t is still a 4 byte int in 2038.
I'm not trying to be a panic monger (lord knows the Y2K 'bug' brought enough of them out of the woodwork!) but the problem is real now. There are plenty of reasons you might want to do a date calculation that went beyond 2038, for example printing a table of predicted values by year for a retirement investment policy, or calculating a mortgage amortisation table, or working out what day of the week to schedule your retirement party :-).
Don't get me wrong, I'm not suggesting these things are impossible or even hard to do. I'm merely saying that the standard tools like time(), localtime() and Time::Local() will let you down. Dave Rolsky's recent article on Perl.com provides some answers.