February 11, 2012 at 12:12 pm
Further in reply to William Connolley.
You appear to be out of the loop. Are you aware of Livingston and Penn’s finding that the magnetic field strength of newly formed sunspots is linearly declining with time?
Solar cycle 24 appears to be an interruption rather than a slowdown in the solar magnetic cycle. It appears solar cycle 24 will be a lead into a Dansgaard-Oesgher event .
There are multiple cycles in the paleoclimatic record that correlate with cosmogenic isotopes changes. All researchers agree the cosmogenic istopes are modulated by solar magnetic cycle changes. The question is how does the solar magnetic cycle changes modulate planetary climate.
The change 3C average drop in arctic temperatures and 6C drop in the winter would be due to a reduction in high altitude clouds. An increase in ions results in an increase in low altitude clouds and a reduction in high altitude clouds. The net affect (albedo less GWG warming of the water vapour/ice particles in the clouds) is for low altitude clouds to cool and high latitude clouds to warm. (See my comment above concerning the mechanism electroscavenging whereby solar wind bursts remove cloud forming ions. The late 20th century warming was caused by solar wind bursts which removed cloud forming ions.)
There very regular cycles of warming and cooling (1500 year cycle with 95% confidence the cycle is maintained to better than 12% over at least the last 23 cycles) which are too regular to be caused by an internal planet based mechanism. As there are cosmogenic isotope changes that are concurrent with the planetary temperature changes it is obvious the driver is solar cycle changes.
Timing of abrupt climate change: A precise clock by Stefan Rahmstorf
Many paleoclimatic data reveal a approx. 1,500 year cyclicity of unknown origin. A crucial question is how stable and regular this cycle is. An analysis of the GISP2 ice core record from Greenland reveals that abrupt climate events appear to be paced by a 1,470-year cycle with a period that is probably stable to within a few percent; with 95% confidence the period is maintained to better than 12% over at least 23 cycles. This highly precise clock points to an origin outside the Earth system; oscillatory modes within the Earth system can be expected to be far more irregular in period.
Svensmark has an interesting paper that analyzes the record of the cyclic climate changes using ice sheet bore hole temperatures comparing the Antarctic to the Greenland Ice sheet temperature. The affect on temperature due to an increase in planetary cloud is opposite for the Greenland Ice sheet as compared to the Antarctic ice sheet. The albedo of the Antarctic ice sheet is greater than clouds so an increase in clouds over the ice sheet causes an increase in temperature due greenhouse effect of greater moisture above the ice sheet.
The Antarctic climate anomaly and galactic cosmic rays
Borehole temperatures in the ice sheets spanning the past 6000 years show Antarctica repeatedly warming when Greenland cooled, and vice versa (Fig. 1) [13, 14]. North-south oscillations of greater amplitude associated with Dansgaard-Oeschger events are evident in oxygenisotope data from the Wurm-Wisconsin glaciation. The phenomenon has been called the polar see-saw[15, 16], but that implies a north-south symmetry that is absent. Greenland is better coupled to global temperatures than Antarctica is, and the fulcrum of the temperature swings is near the Antarctic Circle. A more apt term for the effect is the Antarctic climate anomaly.
On the 1470-year pacing of Dansgaard-Oeschger warm events
The oxygen isotope record from the Greenland Ice Sheet Project 2 (GISP2) ice core was reanalyzed in the frequency and time domains. The prominent 1470-year spectral peak, which has been associated with the occurrence of Dansgaard-Oeschger interstadial events, is solely caused by Dansgaard-Oeschger events 5, 6, and 7. This result emphasizes the nonstationary character of the oxygen isotope time series. Nevertheless, a fundamental pacing period of ∼1470 years seems to control the timing of the onset of the Dansgaard-Oeschger events. A trapezoidal time series model is introduced which provides a template for the pacing of the Dansgaard-Oeschger events. Statistical analysis indicates only a ≤3% probability that the number of matches between observed and template-derived onsets of Dansgaard-Oeschger events between 13 and 46 kyr B.P. resulted by chance. During this interval the spacing of the Dansgaard-Oeschger onsets varied by ±20% around the fundamental 1470-year period and multiples thereof. The pacing seems unaffected by variations in the strength of North Atlantic Deep Water formation, suggesting that the thermohaline circulation was not the primary controlling factor of the pacing period.
It is our attitude toward free thought and free expression that will determine our fate. There must be no limit on the range of temperate discussion, no limits on thought. No subject must be taboo. No censor must preside at our assemblies.
–William O. Douglas, U.S. Supreme Court Justice, 1952