Sticks to facts, doesn't preach or condemn, but pretty powerful, by the sheer accumulation of warning signs.
One fact in particular tells us that we, or our children, are going to have to change our lifestyle: if the rest of the world consumed only half of what we do (raw materials, plastics, energy, etc), we would need 2 earths to sustain us; so we know that with development, the prices will go up so dramatically that the sheer cost of things will force us to conserve... Meanwhile, we and our children will have plenty of time to rue all we've wasted, and are wasting still.