Evaluating alternatives to the Milankovitch theory

The physical process that causes cycles in Earth's precession, obliquity, and eccentricity is well established, and researchers have detected and modeled the orbital cycles for millions of years into the past. The Milankovitch theory postulates that Earth's orbital cycles contribute to similar periodicity in climatic variation with the periods of the climatic cycles primarily ranging from 19,000 years to 1,200,000 years. Even while support for the Milankovitch Theory remains strong, opposition to the process of tuning sedimentary records to Milankovitch models has become increasingly vocal. Here, we discuss another negative aspect of orbital tuning that has been ignored to this point. Specifically, orbital tuning contributes to a type of negative analytical bias against research aimed at modifying the Milankovitch theory as well as bias against testing alternatives to the Milankovitch theory, such as the Universal cycle model, presented in this work. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).