The Fourth Dimension of Interdisciplinary Modeling

Space and time are the domains used by every model in the applied environmental sciences, with the latter normally considered to add a fourth dimension to our simulated versions of reality. Dealing with modern challenges in water-related disciplines requires that we extend our historical perspective as far back as possible to capture underlying long-term dynamics that would otherwise be impossible to detect. At the same time, performing and interpreting retrospective studies demands an understanding of their strengths and weaknesses. Here I attempt to clarify both the importance of the past and the inevitable "paleo conundrum" associated with it by drawing on personal experience and on research projects conducted using tree-ring records in the western U.S. How to best incorporate proxy data, together with instrumental observations, into models used to manage water resources for coping with an uncertain future remains a non-trivial task.