ABSTRACT
The preservation of the geosphere — that part of the solid Earth on which humans live and from which they extract most of their food, minerals, and fuels — is one of the greater challenges affecting humankind today. Humans greatly alter the geosphere. Billions of tons of Earth material are mined or otherwise disturbed each year in the extraction of minerals and coal. Excess atmospheric carbon dioxide and acid rain (see Chapter 9) may cause major changes in the geosphere. Too much carbon dioxide in the atmosphere may cause global heating (greenhouse effect), which could signifi cantly alter rainfall patterns and turn currently productive areas of the Earth into desert regions. Acidic rainfall can change the solubilities and oxidationreduction rates of minerals. Erosion caused by intensive cultivation of land is washing away vast quantities of topsoil from fertile farmlands each year. The geosphere has been a dumping ground for large quantities of toxic, persistent chemicals.
