That's an aspirational goal but there has been no practical methods proposed to actually achieve it. Good intentions are a start I suppose. I don't think anyone really thinks we can do it at this stage. It's openly stated that it would require as-yet unknown technology to achieve.

e.g. We could engineer something to kill possums, but the Aussies are gonna be straight up pissed at us for wiping out their marsupials, if (when) it crosses the ditch.