You actually do have something of a buffer, but it's invisible to most terminal emulators (which is why e. g. scroll bars don't appear to work). One way to get at it is to enter copy mode (Ctrl-A,[ followed by arrow keys, PgUp, et cetera). The size of this buffer can be configured in .screenrc, but I don't believe it can be changed inside a running screen session.

You actually do have something of a buffer, but it's invisible to most terminal emulators (which is why e. g. scroll bars don't appear to work). One way to get at it is to enter copy mode (Ctrl-A,[ followed by arrow keys, PgUp, et cetera). The size of this buffer can be configured in .screenrc. You you an change its allocation inside your screen session:

Ctrl-a + : and typing

scrollback 1000

gives you a 1000 line buffer.