Solar Cycle Update

I did my last update to the progress of the current solar cycle, Cycle 24, at the end of January.  Six months later is probably a decent time to update things.  Here is the progress to date:

(source)

The black line is the monthly solar sunspot number (an average), the blue is a smoothed average of a few months (three months, IIRC) and the red curve is the prediction for the cycle at this point.  As was the case in January, you can see we are rather far below the predicted Sunspot Number. 

Geek out note - you can skip this and not miss anything: the sunspot number is not what you think it is.  It's not obtained by taking an image of the sun and counting all the dark spots.  It's a two digit number where the first is ten times the number of spot groups and the second the number of spots.  If there was a single dark spot on the entire earth-facing hemisphere of the sun, the SSN would be 11: one group, one spot.  In general the number is k*(10*G+S). (where k is a coefficient for each observatory that helps adjust for differences in their capabilities).  The point of this note is that when you see that SSN of 100 back in late '12, it's not 100 spots,  it's some number of groups and spots.  

To adapt some of what I wrote back in January to today, the prolonged minimum between cycle 23 and 24 was the second longest since the Dalton minimum of the early 1800s.  The thing is, the low activity may not be ending there.  In the '90s, astronomers Dr.s William Livingston and Matthew Penn of the Kitt Peak observatory in Arizona noted that their readings on the intensity of sunspots were trending downward.  They checked data many times and plotted trend lines.  Once they saw the lines, they published a paper showing that by 2015 there may be no sunspots left at all.  The paper was not well received, which is fine, but about a decade later they gathered another ten years' worth of data, reanalyzed everything and concluded they were right the first time.  (summary pdf here)  It's important to say they may well be wrong, but completely independent predictions from NASA and others are saying the next cycle, 25, is going to be even weaker than this one, and may approach quiet sun levels at its peak.  Which is to say the cycle simply may not happen. 

What does this mean to us?  Several things.  First the good news: those dire predictions you read about a killer solar flare taking out everything are much less likely than before - and it wasn't very likely to start with.  The other side is much less positive.  Prolonged solar minima have happened before, and they are associated with mini-ice ages.  I use the tentative language because humans simply haven't been able to measure sunspots for most of history.  In extended minima, the growing seasons become shorter and weather changes to become less friendly to crops.  Widespread food shortages are a real possibility.  And while people talk of the possibility of a real ice age, not a mini-ice age, I think we don't know enough about how those start to talk with any credibility. 

Of course, it's politically incorrect today to assert that the Sun, the ultimate source of every erg of energy on this planet, could effect climate.  That's just talking crazy.