ABSTRACT
The importance of what speakers said is underlined by the fact that arid and semiarid environments cover 37% of the terrestrial glove. Despite aridity however, there are still problems with moisture, in restricted areas; indeed these have the added dimension that moisture may bring very marked changes to thoroughly desiccated materials. Even if the absolute degree of variability may be any greater in arid climates, variability occurs across very critical moisture thresholds, which bring about in turn distinct changes of phase for many materials. The arid environments, despite the visibility of their landforms and soils, and the apparent simplicity of the controls on their formation, show a high degree of complexity, and this has yet to be unravelled in the great majority of cases. New technology, as in the use of remote sensing, new instruments and modelling techniques, is often particularly appropriate to research in these environments, so that research, though still restricted, is now much effective.
