Small and Cohen Continental Physiography, Climate and the Global Distribution of Human Population

Human populations are not uniformly distributed on Earth's landmasses. The spatial distribution of the global human population at any time shows large variations over a wide range of spatial scales. Understanding this distribution is fundamental to understanding the relationships between humans and the environment. The recent availability of moderate resolution population data and higher resolution geophysical data now makes it possible to quantify the spatial relationships between population and basic geophysical parameters related to continental physiography and climate. Multivariate distributions of population and land area in geophysical parameter space reveal patterns that may not be obvious in geographic space. When population distributions are normalized by available land area as a function of a geophysical parameter, the most densely populated ranges of the parameter can be determined. When applied to multivariate distributions, the most densely populated combinations of the parameters are indicated. These integrated population densities are generally distinct from local population densities. We investigate the localization of human population with respect to elevation and coastal proximity and with respect to regional temperature and precipitation. Average population densities are far higher at low coastal elevations and diminish rapidly with increasing elevation and distance from coastlines. Inland population densities tend to be highest in topographic basins adjacent to mountain ranges. We also find that population is significantly more localized with respect to continental physiography than with respect to the climatic parameters we have analysed.