10. Europe'S Expansion Overseas

Humanity's earliest environmental impacts are known only indirectly, although the case has long since been put for a large-scale effect as early as the Palaeolithic age. A more rewarding avenue for examination is the sequence of changes in agricultural systems, since farming is the main force transforming land use. Agricultural history is organised in different ways. One approach emphasises variations in the distribution of crops and livestock according to geology, topography or land use, while another concentrates on the ownership and occupation of land. Surprisingly few histories make their centrepiece the technical aspects of husbandry, that is to say the actual conversion of inputs into outputs. Fewest of all are treatments that focus on markets dealing in farm products or (in environmental histories) markets for products gathered from uncultivated areas. Yet the import of products collected from the wild paralleled agriculture in influencing Europe's trade and development and brought about change in global ecosystems. They were important in the centuries before manufactured products and synthetic materials became common. The outer world was treated as a giant open access resource.