What do demographers and urban planners do

Demographers study population: migration, birth and aging/death.
urban planners study land for environments for population to see if the land is good enough for a community to build on, that water is safe and the air is clean enough.
they find areas fit for neighborhoods to be built and or cities. make sure everything is safe and the fight size in land.

Water flows along the east coast and across the western tropical pacific towards south america, while they both are directed towards that way,  el niño does not directly affect the southern flow of water along the coast.