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

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.