You can do so with this:
You have to do it month-by-month, but I choose a comma-separated value text file and save it as a rich text file.
Someone else has posted these third-party tools for backing up your journal. I can't vouch for them personally, but here they are:
I don't want to cause a panic, because I don't think anything drastic is going to happen. But I know people will be wanting to find this. I back mine up every month, so it's nothing out of the ordinary for me.