ABSTRACT
Long-standing debates on human migration, the spread of languages and the domestication of plants and animals enjoy unprecedented support and strong evidence from accurate environmental reconstructions, paleobotany and genetic evidence. Molecular genetics has opened up an entirely new approach to human history. DNA evidence is being used not only in studies of early human evolution, but is increasingly helping to solve the puzzles of history. Changes in land use and land cover due to human activities produce physical changes in land surface albedo, latent and sensible heat, and atmospheric aerosol and greenhouse gas concentrations. The emergence of wheat agriculture is one of the most important changes in the history of humanity due to its social implications in the formation of modern human societies, including higher population densities and more urban-based, stratified social systems. Humans respond in a variety of ways to climate and environmental change.
