Indeed. Don't give me an amazing goal plus a far-off horizon. If you want me to take you seriously, give me a concrete smaller goal and a very soon time-frame.

Instead say, "we will drop it by 10% in 3 years." Now you're telling me some useful truth to which I can hold you accountable (ooh, politicians HATE that). Incidentally, 10% in 3 years would be a perfect milestone to 100% in 30 years, so if these politicians WERE being honest (they're not), then they should have no reason to refuse the 10% in 3 years idea.