Quote:
Originally Posted by William
There is evidence in the paleoclimatic record that significant climatic climate changes have occurred at the same times as solar magnetic field changes. (The solar magnetic field changes affect the amount of isotopes produced in the earth’s atmosphere. The high amount of these isotopes provides a tracer to identify the solar changes.)
The paper “The role of solar forcing upon climate change” by Van Geel, linked below provides a summary.
The last significant solar/climatic event occurred 1400 years ago. There is some evidence of a 1470 year and 2400 year strong cycle in solar magnetic field. There is also some evidence of a 180 year cycle. Some of the weak cycle solar predictions for cycle 24/25 are based on the isotopic data.
I became interested in solar physics and solar mechanisms which could modulate climate after reading Mayewski’s Ice Chronicles which summaries the evidence for abrupt climate change from an analysis of the Greenland Ice core data.
I am not aware of any single mainstream theory as to why the solar magnetic field would be cyclically varying. There are, however, some interesting speculative papers and recent solar data.
http://www.gg.rhbnc.ac.uk/elias/teaching/VanGeel.pdf |
Hello William,
I just read Van Geel’s paper and found it very interesting. His approach of looking for a method of amplification of solar irradiance seems to me to be right on target.
You mentioned in your post the solar magnetic field changes related to the amount of isotopes produced in the earth’s atmosphere and their connection to a 1470 and 2400 year cycle and I’m not sure I understand since the sun goes through a magnetic pole flip every 11 years or so. The 11 year flip would just be noise in any long term data.
Is someone suggesting another source of magnetic field variations? I saw in Van Geel’s paper where the 2400 year cycle was “believed” to be of heliomagnetic origin and I have not read Mayewski’s Ice Chronicles. If there were paleorecords that show long term changes in the suns magnetic field would be very interesting; especially if they were tied to climate change.
Jim