Douglas L. Johnson

Estimation of Tigris-Euphrates streamflow from regional paleoenvironmental proxy data

A six thousand year history of streamflow in Mesopotamia is derived from a synthesis of regional paleoenvironmental proxy data. The proxy data are interpreted with consideration to the climatic signals represented in the records and to the temporal resolution of the records. A consideration of modern synoptic climatology suggests the spatial patterns of streamflow-generating precipitation in relation to atmospheric circulation. These patterns provide a framework for the interpretation of streamflow from the regional proxies. Given the nature of the data at hand, only a low frequency signal is reconstructed. Assessment of the role of small scale climatic fluctuations as a forcing function of population dynamics must await the availability of finer resolution environmental data.

THE HUMAN DIMENSIONS OF DESERTIFICATION

This special issue on desertification grew out of a survey of the human causes and consequences of desertification sponsored by the United Nations Environment Program and the United Nations Fund for Population Activities. The basic group of contributors to this volume of 19 essays are geographers, but the viewpoints of other disciplines and data generated by their research activities are well represented. The initial cluster of essays measures the extent and identifies the process of desertification. A second group of profiles demonstrates the impact of desertification on a human scale. The final cluster examines the prospect for coping with desertification in the future, the experience gained thus far, and some of the creative alternatives that might be employed in the struggle against desertification.

Pauperizing the pastoral periphery: the marginalization of herding communities in the world's dry lands

Environmental degradation and other socio-economic problems are too often discerned in contemporary pastoral systems in the wake of global economic change. This paper identifies cases where pastoral people respond to external pressures and opportunities in positive ways and adapt to changes. We hope that by doing this a framework of pastoral adaptations can be developed. The first part of this paper focuses on impacts of global economic change, which are mostly negative in nature. Through an extensive literature search in geography, anthropology, range management, and development field, the second part introduces cases that we categorize as positive adaptations.