Not necessarily. If you're coming up to the end of a logistic ("S") curve, then assuming a linear growth (or worse, a fixed rate of increase each year, ie expo

Not necessarily. If you're coming up to the end of a logistic ("S") curve, then assuming a linear growth (or worse, a fixed rate of increase each year, ie exponential growth) is much worse of an assumption than assuming zero change, if you extrapolate too far.