Humans have altered the Earth′s land surface over many millennia, with the most dramatic changes coming in recent decades as population has grown, urban areas have spread, and technology and environmental changes have transformed ecosystems worldwide. A unique data set, Historical Urban Population, v1 (3700 BC‒AD 2000), is now available that documents the location and size of urban populations over the past 6,000 years. Developed by Meredith Reba of Yale University, Femke Reitsma of the University of Canterbury in New Zealand, and Karen Seto of Yale, the data set was assembled by digitizing, transcribing, and geocoding historical, archaeological, and census-based urban population records from diverse sources. The data set illuminates long-term urbanization trends and patterns, supporting better understanding of both current and future urbanization trends and associated implications for population, land use and land cover change, and environment.
In 2002, the first Human Footprint/Last of the Wild (HF/LOW) data sets, developed by the Wildlife Conservation Society in collaboration with CIESIN, were released through the NASA Socioeconomic Data and Applications Center (SEDAC). Version 1 mapped human influence on the planet′s land surface drawing on spatial data for population, settlements, roads, railroads, agriculture, power infrastructure, and other factors, mostly dating from the early 1990s. The least influenced or “wild” areas in each biome were identfied in the LOW data set. In 2005, version 2 of the data set was released, with more complete and consistent data from about the year 2000.
Version 3 of the Human Footprint data sets, providing snapshots of human influence circa 1993 and 2009, is now available through SEDAC. The Human Footprint, 2018 Release (1993) and Human Footprint, 2018 Release (2009) were developed by an international team of scientists led by Oscar Venter of the University of Northern British Columbia. The team included Eric Sanderson of the Wildlife Conservation Society, who led development of the first HF/LOW data sets, and CIESIN deputy director Marc Levy. The new HF data sets are based on a modified methodology and more recent data inputs on built-up environments, population density, electric power infrastructure, crop lands, pasture lands, roads, railways, and navigable waterways. The data are available at a spatial resolution of about 1 kilometer and may be downloaded as a GeoTIFF file or accessed through open online web map services.