Necessary to keep the populace calm, too. Keep it at a slow boil, that way the masses don't freak out when they finally come to the realization that it's going to hurt everyone, including them, and it's not going to be long. And even the ones who 'survive' will have to accept their children growing up in a radically different ecosystem, if any remains.
If gen pop knew how fucked we are there'd be riots in the streets.