RICHARD B.NORGAARD

Associate Professor of Agricultural and Resource Economics, University of California, Berkeley, California

The global loss of biological diversity has been described as a product of two phenomena. First, population levels have forced the transformation of heretofore relatively undisturbed areas into lands used for agriculture. Second, both industrial and agricultural pollutants have applied a new and narrowly uniform selective pressure on species. Population growth and technological changes have a multiple, rather than simply additive, impact on biological diversity. There has, however, been a third and probably equally important change that factors into the explanation. During this past century, world agriculture has been transformed from a patchwork quilt of nearly independent regions to a global exchange economy. This change in social organization also contributes to the loss of diversity.

While historians and anthropologists maintain a wealth of knowledge about our past, most people—including developmental economists, planners, and agricultural scientists—have little conceptual understanding of the development process prior to modernization. The past was traditional instead of modern, preindustrial instead of industrial, earlier on the road of progress, a void relative to the present. Neither neoclassical nor Marxist economic theory explains how the human population doubled eight times between the agricultural revolution and the industrial revolution without a proportionate accumulation of capital and use of materials and energy (Norgaard, 1984). A richer vision of the past might help us understand the present.

The world before the industrial revolution can be envisioned as a mosaic of coevolving social and ecological systems. Within each area of the mosaic, species