No perfect forward secrecy. If someone gets your PGP key, they get all of your messages (past / present / future) and you might not even know your key was compromised.
Of course you can use forward secrecy (PFS) and ephemeral keys with PGP/GPG/GnuPG. I've been doing that for ages. Any public / private key system is able to do that. Simply generate new key pairs and send the new signed public key when ever that's necessary. I've blogged about that several years ago, when someone claimed that it can't be done. You can freely select if you want to rotate keys on every message, daily or so.