A revised framework for coupled human and natural systems, propagating thresholds, and managing environmental problems

Frameworks for solving environmental problems have been presented over the past 40 years from many organizations and disciplines, often with a strong focus on their own discipline. This paper describes a modification of an existing framework that can be better applied to manage environmental problems. Human well being, environmental policy, human activities, stressors (contaminants and habitat alterations), and ecosystem services are highlighted as five elements of the coupled human and natural system in the proposed framework. Thresholds in relationships among elements in coupled human and natural systems are key attributes of couplings because of their use in development of environmental criteria by facilitating stakeholder consensus and preventing catastrophic changes. Propagation of thresholds through coupled human and natural systems is hypothesized to be a significant driver of policy development. The application of the framework is related to managing eutrophication and algal bloom problems.