You would have to smoke 2000 pounds of industrial hemp to get the same amount of THC (the chemical that produces the "high") that is in one marijuana cigarette. While it has the wrong advocates, industrial hemp is not a bad agricultural product. At some point, legitimate agricultural organizations such as Farm Bureau are going to back the crop and you will see it legalized once again.
I'll get started on that right away. I'll hafta make a few more of them Marley-sized reefers...
There are some hemp growers in Ontario (IIRC the USA is the only country that bans it) and their biggest problem is security. Too many dumb@$$es think it's pot and try to steal it from the fields.