Glacial cycles: exogenous orbital changes vs. endogenous climate dynamics
R. K. Kaufmann1 and K. Juselius21Department of Geography and Environment, 675 Commonwealth Avenue, Boston University, Boston, MA 02215, USA 2University of Copenhagen, Department of Economics, Øster Farimasgade 5, Building 26, 1353 Copenhagen K, Denmark
Received: 22 Mar 2010 – Accepted for review: 09 Apr 2010 – Discussion started: 20 Apr 2010
Abstract. We use a statistical model, the cointegrated vector autoregressive model, to assess the degree to which variations in Earth's orbit and endogenous climate dynamics can be used to simulate glacial cycles during the late Quaternary (390 kyr–present). To do so, we estimate models of varying complexity and compare the accuracy of their in-sample simulations. Results indicate that strong statistical associations between endogenous climate variables are not enough for statistical models to reproduce glacial cycles. Rather, changes in solar insolation associated with changes in Earth's orbit are needed to simulate glacial cycles accurately. Also, results suggest that non-linear dynamics, threshold effects, and/or free oscillations may not play an overriding role in glacial cycles.
Kaufmann, R. K. and Juselius, K.: Glacial cycles: exogenous orbital changes vs. endogenous climate dynamics, Clim. Past Discuss., 6, 585-626, doi:10.5194/cpd-6-585-2010, 2010.