Image
Back on December 12th 2009 I posted an article titled:

Solar geomagnetic activity is at an all time low - what does this mean for climate?

We then had a string of sunspots in December that marked what many saw as a rejuvenation of solar cycle 24 after a long period of inactivity. See December sunspots on the rise

It even prompted people like Joe Romm to claim:

The hottest decade ends and since there's no Maunder mininum - sorry deniers! - the hottest decade begins

But what Joe doesn't understand is that sunspots are just one proxy, the simplest and most easily observed, for magnetic activity of the sun. It is the magnetic activity of the sun which is central to Svensmark's theory of galactic cosmic ray modulation, which may affect cloud cover formation on earth, thus affecting global temperatures. As the theory goes, lower magnetic activity of the sun lets more GCR's into our solar system, which produce microscopic cloud seed trails (like in a Wilson cloud chamber) in our atmosphere, resulting in more cloud cover, resulting in a cooler planet. Ric Werme has a nice pictorial here.

When I saw the SWPC Ap geomagnetic index for Dec 2009 posted yesterday, my heart sank. With the sunspot activity in December, I thought surely the Ap index would go up. Instead, it crashed.
Image
© swpc.noaa.gov

Annotated version above - Source

Source data

When you look at the Ap index on a larger scale, all the way back to 1844 when measurements first started, the significance of this value of "1″ becomes evident. This graph from Dr. Leif Svalgaard shows where we are today in relation to the past 165 years.
Image
© leif.org

Source

With apologies to Dr. Svalgaard, I've added the "1″ line and the most current SWPC value of "1″ for Dec 2009.

As you can see, we've never had such a low value before, and the only place lower to go is "zero".

But this is only part of the story. With the Ap index dwindling to a wisp of magnetism, it bolsters the argument made by Livingston and Penn that sunspots may disappear altogether by 2015. See Livingston and Penn - 'Sunspots may vanish by 2015.'
Image
© WUWT.com

Above: Sunspot magnetic fields measured by Livingston and Penn from 1992 - Feb. 2009 using an infrared Zeeman splitting technique. [more] from the WUWT article: NASA: Are Sunspots Disappearing?

The theory goes that once the magnetic strength falls below 1500 gauss, sunspots will become invisible to us.

Note where we are on this curve that Dr. Svalgaard also keeps of LP's measurements:
Image
© Leig.org

Source

It appears that we are on track, and that's a chilling thought.