What is the cause of global warming?

[Almighty Colin]

Abstract of a recent article found at AIP Bulletin

Solar Flares and Global Warming

A recent study by researchers at Duke University and the Army Research Office has found new evidence of a link between solar flare activity and the earth's temperature. The work is another contribution to the ongoing debate over global warming and its causes. A strong link between solar flares and our climate, if it exists, could override the influence humans have on the temperature of our environment. One of the challenges of determining the connection between solar flare activity and the atmosphere stems from the fact that the motion of the air that blankets our planet is turbulent and complex. A sudden burst of solar activity would, in effect, be smeared out by moving air and its interaction with the earth's surface. Any temperature increase caused by a given period of solar flare activity would be difficult to determine, at best. Rather than focus on such challenging one-to-one correlations, the new study compares the form of the statistical fluctuations in solar flare activity with the form of the statistical fluctuations of the earth's temperature. The researchers (contact: Bruce J. West, 919-549-4257) explain that solar flare activity can be characterized by a type of statistics described by a Levy distribution, which is generated by a "Levy-walk." (Many natural phenomena, from foraging patterns of spider monkeys to complex hydrodynamic flows, are well described by Levy walks, although the coefficients in the relevant equations typically vary from one phenomenon to another. See Update 510-3 for one example.) Analyses of global and local temperature fluctuations are also well described by a Levy-walk. In fact, a comparison of the mathematical coefficients that describe the fluctuations suggest to the researchers that the atmosphere directly inherits its temperature fluctuations from the variation in solar flare activity. Unless some other underlying cause is responsible for the unlikely correspondence between solar flares and the earth's temperature, the research suggests that for the large part variations in global temperatures are beyond our control and are instead at the mercy of the sun's activity. (Nicola Scafetta and Bruce J. West, Physical Review Letters, 20 June 2003)