by Judith Curry
The Annual Meeting of the Solar Physics Division of the American Astronomical Society has announced some very interesting results in this press release entitled “Sun’s fading spots signal big drop in solar activity.”
Some brief excerpts:
The results of three separate studies seem to show that even as the current sunspot cycle swells toward the solar maximum, the sun could be heading into a more-dormant period, with activity during the next 11-year sunspot cycle greatly reduced or even eliminated.
“Cycle 24 started out late and slow and may not be strong enough to create a rush to the poles, indicating we’ll see a very weak solar maximum in 2013, if at all,” Altrock said. “If the rush to the poles fails to complete, this creates a tremendous dilemma for the theorists, as it would mean that Cycle 23’s magnetic field will not completely disappear from the polar regions. … No one knows what the sun will do in that case.”
If the models prove accurate and the trends continue, the implications could be far-reaching.
“If we are right, this could be the last solar maximum we’ll see for a few decades,” Hill said. “That would affect everything from space exploration to Earth’s climate.”
This is all over the news and the blogosphere, but not too much discussion yet in the climate blogosphere. WUWT has several posts, and Andy Revkin raises some issues of relevance to climate change (note: I borrowed ‘snooze’ from Revkin’s article). See also this later post at dotearth.
I haven’t done a solar thread yet, it’s a topic about which I am not that knowledgeable. I look forward to your contributions to the discussion.
Feulner G., Rahmstorf S. (2010),
Geophysical Research Letters, 37, L05707.
(h/t Douglas Keenan at Bishop Hill)
Abstract. The current exceptionally long minimum of solar activity has led to the suggestion that the Sun might experience a new grand minimum in the next decades, a prolonged period of low activity similar to the Maunder minimum in the late 17th century. The Maunder minimum is connected to the Little Ice Age, a time of markedly lower temperatures, in particular in the Northern hemisphere. Here we use a coupled climate model to explore the effect of a 21st‐century grand minimum on future global temperatures, finding a moderate temperature offset of no more than −0.3°C in the year 2100 relative to a scenario with solar activity similar to recent decades. This temperature decrease is much smaller than the warming expected from anthropogenic greenhouse gas emissions by the end of the century.
Some excerpts from an article posted at msnbc:
Gavin Schmidt, a climatologist at NASA’s Goddard Institute for Space Studies and one of the founders of the RealClimate blog, said the effects of solar activity on climate over the past 30 years have been “at the margin of what we can detect.”
“They are detectable in the high atmosphere, but when you get down to the surface, there is so much other stuff going on that it’s been really hard to get a clean signal,” he told me.
One of the reasons why so little is known about solar effects on climate is that the sun’s highs and lows have been within such a narrow range in recent history.
“If we were to see a return to what’s called Maunder Minimum conditions in the next 50 years or so, that would be interesting,” Schmidt said. “I think we’d learn a lot about solar physics and solar variability. … It’s going to be scientifically very exciting if all this pans out.”
Even then, however, he estimated that the effect of greenhouse-gas emissions would be on the order of 10 times as great. “What you might see over a 20- to 30-year period is a slight slowdown in the pace of warming,” Schmidt said. “In terms of how we should think about climate change prediction in the future, reducing emissions and so on, it really wouldn’t make much of a difference.”
“Parsing out how much of that was solar, how much of that was volcanic and how much of that was just noise … that’s tricky,” Schmidt said.