I’ve always been interest in Dryas events (periods of glaciation). The last period lasted from ~110-12 kyears before preseent (kbp), the 2nd 300-200 kbp and the 3rd ~450-300 kbp. What causes these ice ages to occur? Anthony Watts suggests there may be a relation between sunspots and ice ages. This may lessen your concern about global warming. Watts blog, has 154 comments.
“Sunspots may vanish by 2015″Posted on June 2, 2008 by Anthony Watts
From the “I hope to God they are flat wrong department”, here is the abstract of a short paper on recent solar trends by William Livingston and Matthew Penn of the National Solar Observatory in Tucson. It was sent to me by reader Mike Ward.
I previously highlighted a news story on this paper on May 21st, but didn’t have the actual paper until now. If anyone has an update to this paper, which uses data up to 2005, please use the comment form to advise.
Here is the complete paper, and below are some excerpts:
Abstract: We have observed spectroscopic changes in temperature sensitive molecular lines, in the magnetic splitting of an Fe I line, and in the continuum brightness of over 1000 sunspot umbrae from 1990-2005. All three measurements show consistent trends in which the darkest parts of the sunspot umbra have become warmer (45K per year) and their magnetic field strengths have decreased (77 Gauss per year), independently of the normal 11-year sunspot cycle. A linear extrapolation of these trends suggests that few sunspots will be visible after 2015.