Well, theres the obvious effects that using hemp for fuel would have on the environment. For one, we wouldnt be producing as much greenhouse gases, which are caused by burning fossil fuels (coal, oil, gas), deforestation and the use of fertilizers. Although cutting down trees to use for paper produces carbon dioxide, hemp seems to thrive at high levels and also absorb it quickly and efficiently.
The secondary effects would come later, when we eventually phase out the use of fossil fuels and replace them with hemp. Growing hemp for clothes and building housing would further decrease the carbon dioxide emissions.

It is actually possible to produce all of our energy via hemp. Any CO2 released from burning hemp would be the same CO2 the plant had already taken from the environment - creating a 'closed carbon cycle'. This system of energy production would slow down, if not halt, global warming entirely. You can even run cars on hemp oil - admittedly, it would still release CO2, but only the amount that the plant had used up from the atmosphere, and with no other emissions such as sulphur.

As I said earlier, cannabis hemp can be used to build houses. Not just houses though, we can also use it for insulation, furniture, and drywall. There is no more need to waste our land when hemp could easily replace our timber. This destruction reaches into the homes and pockets of every taxpayer, and meanwhile our children cannot play in the streams and the logging industry gets another needless government refund. Now it is time to turn to the future.

Hemp is our solution.