The deep solar minimum continues. The sun remains unusually quiet. Spaceweather.com has recently added an interesting little addition to its website. Under its regular daily sunspot report, it has this:
NEW: Spotless Days
Current Stretch: 25 days
2009 total: 97 days (88%)
Since 2004: 608 days
Typical Solar Min: 485 days
Updated 20 Apr 2009
The average solar cycle lasts 131 months. We're now at 150+ months. Well, is this serious or not? If the standard deviation of solar cycles is 14 months, then we're outside the range of the first standard deviation, but still well within the second. [Figures until this point come from NASA.]

What does this mean? Well, the first standard deviation represents a distance of 34.1% variance from the mean. If you're exactly one standard deviation above the mean, then you're bigger than 84.1% of all samples. Roughly speaking, we're now in a solar cycle that has lasted longer than 90% of all recorded examples. Let's wait a little while, but I would say it might be time to start pushing the panic button if we get two standard deviations away from the mean, meaning about 9 months from now. To put it more simply, if we make it into 2010 and we have not yet emerged from the current solar minimum, 97.7% of all solar cycles will have been shorter (assuming that the 23 recorded minimums are truly representative). Then it appears that we might be moving into a period of extremely low solar activity, and our goose will be the opposite of cooked ... it'll be time to stock up on firewood and canned goods.
[Update] Don't worry. We can always trust the experts.
The Space Weather Workshop held in Boulder, CO in May, 2008, the Solar Cycle 24 Prediction Panel released an update to the prediction for the next solar cycle. In short, the update is that the panel has not yet made any changes to the prediction issued in April, 2007. The panel expects solar minimum to occur in March, 2008.Well, that's alright then.

If Vikings and medieval peasants could cope with warmer temperatures than what is being forecast for the end of the century (ignoring the current cooling trend), then I think we should be able to figure something out as well.
Anyway, warmer weather doesn't always mean drier. Colder, on the other hand, often does. And how many freezing nights in Florida or California does it take to ruin a year's citrus crop? One, right? How much cooling will it take for that to happen? Oh, a tiny bit? Oh...
Comment by Prof X — April 20, 2009 @ 10:28 pm