Humans as geological agents and the question of scale

摘要

Humans are important geological agents over recent and historic time scales, but whether human agency is significant in the context of longer-term geologic evolution is unresolved. Are anthropic impacts "noise" in the grand trend of Earth's evolution or a fundamen- tal change in the geologic environment. Four approaches to this prob- lem are outlined, based on principles for determining whether or under what circumstances geologic processes or phenomena should be consid- ered interdependent or independent.