This paper describes the Philippine demographic situation with a focus on the findings from the 1990 Census and the recent intercensal period (1980-1990). Results include the decline in absolute numbers of farmers, fishers and forest workers over the period of interest. Roughly half of the increase in population in urban areas occurred not because of migration but because of continuing urbanization. Indeed, urbanization is exactly the kind of demographic phenomenon likely to have significant environmental consequences and should therefore be a candidate in Population, Development and Environment (PDE) modeling efforts.
Aniceto Orbeta (Sat,) studied this question.