A New Theory of Glacial cycles
Also see the article Glacial Cycles and Astronomical Forcing, published in Science vol 277, pp 215-218 (11 July 1997). Also look at our book:
Ice Ages and Astronomical Causes (with coauthor Gordon MacDonald) published by Springer-Praxis in 2000. Click to read the Table of Contents, the Preface or Chapter 1, which contains brief introductions to the History of Climate, Ice Age Theories, and Spectra. It is meant for students or researchers who want to learn how to do spectral analysis of paleoclimate data.It can be ordered from Amazon.com, from Springer New York, Springer Germany, and from Amazon in the UK. . For see the wonderful movie illustrating the changing orbits. I've posted a table of the Earth's orbital inclination for the last 3 MyrOrbital Inclination
A New Theory of Glacial Cycles
Much of this work has been done in collaboration with Gordon MacDonald.
Read a quick Summary
If you have a fast connection, you can view a movie of the orbits of the inner planets for the past 3 Myr.
- In January 1994, I wrote Lawrence Berkeley Laboratory Report LBL-35655 suggesting that the standard theory of the ice ages was wrong. I attributed the glaciations not to variations in sunlight, but instead to accretion of cosmic dust and/or meteors.
- In 1995, a short paper Glacial cycles and orbital inclination by me and Gordon MacDonald was published in Nature.
- At the heart of much of this work is the orbit of the earth. I have transformed the orbital inclination and omega for the last 3 million years to the invariable plane.
- A report, Origin of the 100 kyr glacial cycles: eccentricity or orbital inclination? discusses many of our thoughts on the subject (as of 1996).
- Read the abstract for my invited talk at the Fall 1996 AGU meeting.
- Our long-titled paper "Simultaneous presence of orbital inclination and eccentricity in proxy climate records from Ocean drilling Program Site 806," was published in GEOLOGY vol 25, pages 3-6 (1997).
- Our paper on bispectra serves as a tutorial and description of our initial application of this method to the mystery of the ice age cycles.
- Spectrum of 100-kyr glacial cycle: Orbital inclination, not eccentricity, was published in the Proc. Natl. Acad. Sci. USA, Vol 94, pp 8329-8334 (August 1997). This articles includes details of the coordinate transformation from the zodiacal plane to the invariable plane.
- Glacial Cycles and Astronomical Forcing, published in Science vol 277, pp 215-218 (11 July 1997). Argues that the ice ages are astronomical in cause (without invoking the Milankovitch model), and that insolation is not responsible for the 100 kyr cycle which dominated for the last million years.
- Ice Ages and Astronomical Causes, a text meant for graduate students and Ph.D.s interested in the driving force for glacial cycles, with emphasis on the spectral analysis of global ice proxies. Click to read the Table of Contents, the Preface or Chapter 1, which contains brief introductions to the History of Climate, Ice Age Theories, and Spectra. It can be ordered from Amazon.com, from Springer New York, Springer Germany, and from Amazon in the UK.
- San Francisco Chronicle news article, by science journalist Charles Petit, appeared on Jan. 16, 1996.
- A long article about our ice age work (and other things), written by Robert Hurwitt (the Drama Critic for the SF Examiner) appeared in the July 19 East Bay Express.
- An update of the status of the theory, and the reactions of others, in the October 4, 1997 issue of Science News. You can read selected excerpts from this article.