Did Quiet Sun Cause Little Ice Age After All?

The latest on the argument from Science Magazine.

However, scientists have debated whether the effect could have been large enough. For instance, in a recent paper in Geophysical Research Letters, solar physicist Karel Schrijver of the Lockheed Martin Advanced Technology Center in Palo Alto, California, and his colleagues argue that during the Maunder Minimum, the sun couldn’t have dimmed enough to explain the Little Ice Age. Even during a prolonged minimum, they claim, an extensive network of very small faculae on the sun’s hot surface remains to keep the energy output above a certain threshold level.

Not so, says Peter Foukal, an independent solar physicist with Heliophysics Inc. in Nahant, Massachusetts, who contends that Schrijver and his colleagues are “assuming an answer” in a circular argument.

According to Foukal, who presented his work yesterday here at the summer meeting of the American Astronomical Society, there is no reason to believe that the network of small faculae would persist during long periods of solar quiescence. In fact, he says, observations between 2007 and 2009, when the sun was spotless for an unusually long time, reveal that all forms of magnetic activity diminished, including the small-faculae network.

What’s more, detailed observations from orbiting solar telescopes have shown that the small faculae pump out more energy per unit surface area than the larger ones already known to disappear along with the sunspots. So if the small faculae start to fade, too, that would have an even stronger effect on the total energy production of the sun. “There’s tantalizing evidence that [during the Maunder Minimum] the sun may have actually dimmed more than we have thought until now,” Foukal says.

Even so, Foukal concedes that other factors, such as enhanced volcanic activity around the globe, may also have played a role in causing Europe’s Little Ice Age. Meanwhile, the biggest worry to solar physicists—and to society—is that no one knows what caused the sun’s prolonged quiescence in the first place. As far as anybody knows, a repeat of the Maunder Minimum could start within a few years with the next dip in the number of sunspots.

Comments

[chillguy33]

I hope they considered the reflection of solar energy by low clouds (albedo)!

Variable albedo is the dominant climate indicator in the next few 1000s years.

What a shame that we don't track this critical indicator!