A major number of problems concerning the nature and consequences of natural or anthropogenic environmental change can be solved only by the geological sciences. Many of these problems require separation of first-order driving mecha­ nisms from background processes. Long-term as well as short­ term variations during geological time in the numerical magnitudes of different environmental parameters are not weU understood, however. The maximum and minimum rates of en­ vironmental change that occurred during geological time also remain unknown, and their global as well as local scale and consequences are poorly understood.