For more than two years a dramatic conclusion from two researchers at the National Solar Observatory on Kitt Peak, with offices in Tucson, has bounced around smaller news outlets and, notably, among bloggers. After analyzing 20 years of data on the magnetic field strength in sunspots – revealed by a warping of OH spectra known as Zeeman splitting – astronomers Matthew Penn and William Livingston see a trend that could have dramatic impact on Earth. This includes a possible replay of the great cooling in the 1600s and early 1700s known as the Little Ice Age – blamed on a prolonged sunspot drought and slight overall dimming of the sun, the Maunder Minimum.
A new version of the paper gets a big boost from a small but influential science journalism publisher today – the AAAS‘s ScienceNow. Reporter Phil Berardelli doesn’t write it long, but long enough to get outside astronomers saying that the paper is legit. At issue, as he writes, is whether the extrapolation showing magnetic fields dropping in about 2015 below the minimum needed for sunspots reflects a very likely scenario. His hook is an update of the thesis, for an international virtual symposium, on line at the preprint site arXiv astro-ph.
This is a legitimate news topic. A decent chance that the Sun will moderate its overall output (which overall has positive correlation with sunspot number despite intuition that proliferation of big cool dark spots ought to dim a star), and thus counteract to some small or large extent the current warming driven by fossil carbon burning, merits full public airing. It sure would complicate efforts to get the world’s nations to drastically change their energy policies. A Maunder Minimum II could chill any chance for a carbon tax even if, when the minimum wanes, the climate-forcing rebound would cook us for sure. And anyway, ocean acidification would proceed apace.
However, a look at it must let readers know that Penn and Livingston’s work has been making the rounds for awhile. Examples include:
- NASA Science News – Tony Phillips (Sept. 2, 2009): Are Sunspots Disappearing? ; A blogsite within NASA gave it a measured look, and includes the opinion of one of the researchers involved, Penn, that he himself is betting that Sunspots return to their pattern of recent history. But this was a year ago. Maybe he’s shifted his bet?
- AGU EOS Journal – W. Livingston, M. Penn (July 28, 2009): Are Sunspots Different During This Solar Minimum?; The two scientists laid out their data, conclusions, and caveats in the AGU’s official newsletter and journal sent to all its members.
- Watts Up With That? – Anthony Watts (June 2, 2008): Livingston and Penn paper: “Sunspots may vanish by 2015” ; One of the foremost bloggers in the global warming skeptics camp picked up on this thesis early. If scientists plausibly argue that a natural solar fluctuation could soon cool the Earth, one observes, it fosters (if not logically supports) belief among some skeptics that recently rising temps are also the doing of the sun, not the likes of the coal industry and its customers.
- Arizona Daily Star – Dan Sorenson (May 19, 2008): Sunspot cycle more dud than radiation flood ; Cited by Watts (previous bullet), and notable for reporting that AAAS’s Science rejected an early paper by Penn and Livingston. Also interesting here is that from the start the two scientists were stressing that their analysis is not a prediction, but a remark on where the trend would take us if it holds.
The new paper, from a quick read, sees the anemic rise in sunspot number during the first phases of the 11-year solar cycle’s current iteration as evidence that whatever the trend’s fate, it’s not showing signs of stopping now. As it says, “It is important to note that it is always risky to extrapolate linear trends; but the importance of the implications from making such an assumption justify its mention.” That’s a heavily nuanced, if perhaps true, sentence. A reporter who sits down with, or just spends some time on the phone with these two to ask how they regard their paper’s role in political and ideological debates over global warming might get a terrific story.
One prediction seems safe: this series of ever-updated papers will get more press.
Pic Source NASA (image taken today)
– Charlie Petit
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