Slides from a talk given at the Faculty Club of the University of California, Berkeley on 29 May 2010 for A Celebration of Hugh DeWitt’s Contributions on His Eightieth Birthday .
Climate Change: The Sun’s Role-DeWitt Symposium 29 May 2010-Viewgraphs
Climate Change, Energy, and National Security
A talk given on 18 May 2010 at the 4th International Conference on Climate Change.
Are U.S. Nuclear Weapons Reliable?
An exchange in Nature on the reliability of of U.S. nuclear weapons and the need for the Reliable Replacement Warhead (RRW).
Interglacials, Milankovitch Cycles, and Carbon Dioxide
The existing understanding of interglacial periods is that they are initiated by Milankovitch cycles enhanced by rising atmospheric carbon dioxide concentrations. During interglacials, global temperature is also believed to be primarily controlled by carbon dioxide concentrations, modulated by internal processes such as the Pacific Decadal Oscillation and the North Atlantic Oscillation. Recent Work challenges the fundamental bases of these conceptions.
Journal of Climatology, Volume 2014, Article ID 345482
http://dx.doi.org/10.1155/2014/345482
Quantum Mechanics and Motion: A Modern Perspective
Physics Essays Vol. 23, pp. 242-247 (2010)
This essay is an attempted to address, from a modern perspective, the motion of a particle. Quantum mechanically, motion consists of a series of localizations due to repeated interactions that, taken close to the limit of the continuum, yields a world-line. If a force acts on the particle, its probability distribution is accordingly modified. This must also be true for macroscopic objects, although now the description is far more complicated by the structure of matter and associated surface physics.
Blessing in Disguise
The real tipping point for civilization is the beginning of another Ice Age—not a world a few degrees warmer.
Global Warming: A Blessing in Disguise
USA Today Magazine (November 2009)
“The real tipping point for civilization is the beginning of another Ice Age–not a world a few degrees warmer.”
The Demystification of Emergent Behavior
Emergent behavior that appears at a given level of organization may be characterized as arising from an organizationally lower level in such a way that it transcends a mere increase in the behavioral degree of complexity. It is therefore to be distinguished from systems exhibiting chaotic behavior, for example, which are deterministic but unpredictable because of an exponential dependence on initial conditions. In emergent phenomena, higher levels of organization are not determined by lowerlevels of organization; or, more colloquially, emergent behavior is often said to be “greater than the sum of the parts”. The concept plays an especially important but contentious role in the biological sciences. This essay is intended to demystify at least some aspects of the mystery of emergence.
(This is an updated and expanded version of the original post with some portions rewritten to enhance clarity.)
Initiatives to Enhance Nuclear Stability and Non-Proliferation in the 21st Century
Physics & Society Vol. 38, No.3 (July 2009). Coauthored with George S. Stanford.
Three initiatives that the Obama Administration can undertake that would greatly increase nuclear stability and enhance the non-proliferation regime for many years to come.
Climate Change: Sources of Warming in the Late 20th Century
The role of the North Atlantic Oscillation, the Pacific Decadal Oscillation, volcanic and other aerosols, as well as the extraordinary solar activity of the late 20th century are discussed in the context of the warming since the mid-1970s. Much of that warming is found to be due to natural causes.
A somewhat abbreviated version appears in Energy & Environment Vol. 23, No. 1, p. 95 (2012)
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