Population dynamics refers to the way population size and composition changes over time by birth and death rates, and by immigration and emigration. Topics examined include aging populations, urbanization, population decline, and population projections. Global net migration grids have been generated at 30 arc-second resolution (~1 sq. km at the equator) for the decades of the 1970s, 1980s, and 1990s, where net migration is the balance between in-migration and out-migration. Also, at the same resolution and over the same period of time, global population time series estimates were generated. In addition, global urban, rural, and total population projection grids have been produced based on Shared Socioeconomic Pathways (SSPs) at resolutions of one km (about 30 arc-seconds) and one-eighth degree (7.5 arc-minutes) at ten-year intervals for 2010-2100. At the regional level, county-equivalent population estimates for Latin America and the Caribbean were developed for 1990 and 2000, using spatially consistent and comparable units. County-level population projection scenarios of total population, and by age, sex, and race were generated in five-year intervals for all U.S. counties for 2020-2100.