David Archibald had a guest post at Watts Up With That this morning that is of interest to those concerned with the Next Grand Minimum. He makes the case that Solar Cycle 24 will be longer than unusual and result in a decline in growing season in the gain belt. Less grain will have an economic impact on this nation and those dependent on Norther Hemisphere grain for subsistence .
Please read the full post HERE, but there are the major point relevant to this post.
If Solar Cycle 24 is progressing at 60% of the rate of the previous two cycles, which averaged ten years long, then it is likely to be 16.6 years long. Using that figure of 16.6 years would make Solar Cycle 24 seven years longer than Solar Cycle 22. Using a solar cycle length – temperature relationship for the US – Canadian border of 0.7°C per year of solar cycle length, a total temperature decline of 4.9°C is predicted over a period of about twenty years.
Has a fall of that magnitude happened in that time frame happened in the past? A good place to look is the Dye 3 temperature record from the Greenland Plateau, available here: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/gisp/dye3/dye3-1yr.txt
Figure 4: Dye 3 Temperature Record from Oxygen Isotope Ratios
There is plenty of noise in this record and rapid swings in temperature, for example the 5.2°C fall from 526 to 531 at the beginning of the Dark Ages. [ Note there was major volcano eruptions during this period between 536 to 531, not mentioned in the text.]
Figure 5: Dye 3 Temperature Record 22 Year Smoothed
Averaging the Dye 3 temperature record using the 22 year length of the Hale Cycle produces a lot of detail. What is evident is that there has been a very disciplined temperature decline over the last four thousand years. The whole temperature record is bounded by two parallel lines with a downslope of 0.3°C per thousand years. The fact that no cooling event took the Dye 3 temperature below the lower bounding green line over nearly four thousand years is quite remarkable. It implies that solar events do not exceed a particular combination of frequency and amplitude. From that it can be derived that this particular combination of frequency and amplitude with be ongoing – that is that cooling events will happen just as frequently as they did during the Dye 3 record.
Figure 6: North – South Transect through the Grain Belt
The relationship between temperature and growing conditions at about the latitude of the US – Canadian border is that one degree C will shift growing conditions by about 140 km. With a total 4.9°C temperature decline in train, that means a shift of about 700 km. Figure 6 shows the result of that temperature decline. Witchita will end up with the climate of Sioux Falls, which in turn will be like Saskatoon now. The growing season loses a month at each end.
I am tracking the changes in the length of the growing season in the grain belt on this blog. Stay tuned!