The missing sunspots: Is this the big chill?

[OKIsItJustMe]

http://www.independent.co.uk/news/science/the-missing-sunspots-is-this-the-big-chill-1674630.html

The missing sunspots: Is this the big chill?

Scientists are baffled by what they’re seeing on the Sun’s surface – nothing at all. And this lack of activity could have a major impact on global warming. David Whitehouse investigates

Monday, 27 April 2009

Could the Sun play a greater role in recent climate change than has been believed? Climatologists had dismissed the idea and some solar scientists have been reticent about it because of its connections with those who those who deny climate change. But now the speculation has grown louder because of what is happening to our Sun. No living scientist has seen it behave this way. There are no sunspots.

The disappearance of sunspots happens every few years, but this time it’s gone on far longer than anyone expected – and there is no sign of the Sun waking up. “This is the lowest we’ve ever seen. We thought we’d be out of it by now, but we’re not,” says Marc Hairston of the University of Texas. And it’s not just the sunspots that are causing concern. There is also the so-called solar wind – streams of particles the Sun pours out – that is at its weakest since records began. In addition, the Sun’s magnetic axis is tilted to an unusual degree. “This is the quietest Sun we’ve seen in almost a century,” says NASA solar scientist David Hathaway. But this is not just a scientific curiosity. It could affect everyone on Earth and force what for many is the unthinkable: a reappraisal of the science behind recent global warming.

Our Sun is the primary force of the Earth’s climate system, driving atmospheric and oceanic circulation patterns. It lies behind every aspect of the Earth’s climate and is, of course, a key component of the greenhouse effect. But there is another factor to be considered. When the Sun has gone quiet like this before, it coincided with the earth cooling slightly and there is speculation that a similar thing could happen now. If so, it could alter all our predictions of climate change, and show that our understanding of climate change might not be anywhere near as good as we thought.

…

But around the turn of the century things started to change. Within a few years of the Sun’s activity starting to decline, the rise in the Earth’s temperature began to slow and has now been constant since the turn of the century. This was at the same time that the levels of atmospheric carbon dioxide carried on rising. So, is the Sun’s quietness responsible for the tail-off in global warming and if not, what is?

…

[moez]

1. Y2K redux?

[phantom power]

2. What is this "tail off in warming" of which they speak?

[OKIsItJustMe]

3. Re: the "tail off in warming" of which they speak

There's been a bit of a dip.
http://data.giss.nasa.gov/gistemp/graphs/



It's worth checking out the PDF of this one to see the detail of the graph in the lower right-hand corner. (I don't know why they don't have a large GIF available, but they don't.)
http://data.giss.nasa.gov/gistemp/graphs/2009+2005+2007.gif
http://data.giss.nasa.gov/gistemp/graphs/2009+2005+2007.pdf

In the end, it appears that we're not quite as much warmer than usual as we have been.

[phantom power]

4. Thanks, as I suspected, their "tail off" is noise in the signal.

[OKIsItJustMe]

5. Seems like a fair guess

There have been a number of similar dips.

I think it reinforces the idea that while the "solar cycle" plays a role, its influence is dwarfed by the increase in "greenhouse gases."

[pscot]

9. Googling suggests

that the last time the sun was this quiet was during the 1950s. I seem to remember that I spent a good portion or the early '50s wading through snow up to my butt. Purely anecdotal, of course. The denialists see this as a sharp stick in the eye for AlGore and the IPCC, but the sunspot cycle hasn't been suspended. As cycle 24 developes we will get a better picture of what's actually going on. Lots of information at spaceweather.com

[OKIsItJustMe]

13. Well, only a fool would suggest that the level of solar activity has /no/ effect on temperatures

We're dealing with a complex system here, which is roughly in balance.


Increasing or decreasing the input is bound to have some effect (just as increasing or decreasing the output is.)

http://www.nasa.gov/topics/solarsystem/features/solar_minimum09.html

How Low Can It Go? Sun Plunges into the Quietest Solar Minimum in a Century

04.01.09

The sunspot cycle is behaving a little like the stock market. Just when you think it has hit bottom, it goes even lower.

2008 was a bear. There were no sunspots observed on 266 of the year's 366 days (73 percent). To find a year with more blank suns, you have to go all the way back to 1913, which had 311 spotless days. Prompted by these numbers, some observers suggested that the solar cycle had hit bottom in 2008.

Maybe not. Sunspot counts for 2009 have dropped even lower. As of March 31st, there were no sunspots on 78 of the year's 90 days (87 percent).

It adds up to one inescapable conclusion: "We're experiencing a very deep solar minimum," says solar physicist Dean Pesnell of NASA’s Goddard Space Flight Center in Greenbelt, Md.

…

Deep calm was fairly common a hundred years ago. The solar minima of 1901 and 1913, for instance, were even longer than what we're experiencing now. To match those minima in depth and longevity, the current minimum will have to last at least another year.

In a way, the calm is exciting, says Pesnell. "For the first time in history, we're getting to observe a deep solar minimum." A fleet of spacecraft — including the Solar and Heliospheric Observatory (SOHO), the twin probes of the Solar Terrestrial Relations Observatory (STEREO), and several other satellites — are all studying the sun and its effects on Earth. Using technology that didn't exist 100 years ago, scientists are measuring solar winds, cosmic rays, irradiance and magnetic fields and finding that solar minimum is much more interesting than anyone expected.

…

http://www.nasa.gov/topics/earth/features/glory_irradiance.html

New Sun-Watching Instrument to Monitor Sunlight Fluctuations

03.23.09

During the Maunder Minimum, a period of diminished solar activity between 1645 and 1715, sunspots were rare on the face of the sun, sometimes disappearing entirely for months to years. At the same time, Earth experienced a bitter cold period known as the "Little Ice Age."

Were the events connected? Scientists cannot say for sure, but it's quite likely. Slowdowns in solar activity -- evidenced by reductions in sunspot numbers -- are known to coincide with decreases in the amount of energy discharged by the sun. During the Little Ice Age, though, few would have thought to track total solar irradiance (TSI), the amount of solar energy striking Earth's upper atmosphere. In fact, the scientific instrument needed to make such measurements -- a spaceborne radiometer -- was still three centuries into the future.

Modern scientists have several tools for studying TSI. Since the 1970s, scientists have relied upon a collection of radiometers on American and European spacecraft to keep a close eye on solar fluctuations from above the atmosphere, which intercepts much of the sun's radiation. When NASA launches the Glory satellite this fall (no earlier than October 2009), researchers will have a more accurate instrument for measuring TSI than they've ever had before.

…

After examining the historical TSI database, some scientists have suggested that solar irradiance could account for as much as a quarter of recent global warming. But without a continuous and reliable TSI record, Kopp and Lean point out, there will always be room for skeptics to blame global warming entirely on the sun, even when most evidence suggests human activities are the key influence on modern climate changes.

Beyond that, there's a big "what if" percolating through the scientific community. The 0.1 percent variation in solar irradiance is certainly too subtle to explain all of the recent warming. "But, what if -- as many assume -- much longer solar cycles are also at work?" said Lean. In that case, it's not impossible that long-term patterns -- proceeding over hundreds or thousands of years -- could cause more severe swings in TSI.

Could a modern day Maunder Minimum offset the warming influence of greenhouse gases or even throw us back into another little ice age? "It's extremely unlikely," said Lean, "but we won't know for sure unless we keep up and perfect our measurements."

[AlecBGreen]

17. hmm

I really cant picture how sun spots would affect global climate. The diagram shown is for insloation ("incoming solar radiation") and AFAIK this light is the only thing that counts. Even during extreme sunspot activity (or lack thereof) the total amount of light reaching the earth should be relatively stable.

[OKIsItJustMe]

18. Solar Radiation

http://climate.gsfc.nasa.gov/research/solar_radiation.php

The solar radiation input is the major energy source for the Earth's biosphere, and the direct driving force for atmospheric, and oceanic circulations. The Sun is a typical main sequence star with spectral class of G2, one of 100 billion stars in the galaxy system. The energy generated in the fusion processes in the inner core is transported though radiative processes in the radiation zone, and by convections in the convection zone to the photosphere, which is what we can see. The photosphere has a thickness equal to 500 km, a small fraction of the total solar radius that equals 6.6 x 10⁵ km, and is often called the 'surface' of the Sun, and is the region from which solar energy is emitted to interplanetary space. The photosphere has an effective temperature of 5780°K.

The Sun is not a uniform fireball. Some areas on the Sun are darker, and some areas are brighter. These relatively darker areas are called sunspots with temperature 1500°K cooler than the sun’s effective photospheric temperature. It was found that solar activity has an 11-year cycle with typically 50~150 number of sunspots during solar maximum and nearly zero in the solar minimum. Because of the lower temperature of sunspots in the photosphere, the presence of sunspots decreases the emitting energy to space. Surprisingly, at the solar maximum when sunspots are numerous, the average luminosity is larger. This is because the increase of brightness in the faculae (Latin meaning torches) areas surrounding the sunspots over power the darkness due to the sunspots, consequently leading to a brighter sun in solar maximum than in solar minimum. Another well known phenomenon is solar the 27-day rotation cycle observed from tracing the sunspots passage.

The Sun-Earth climate relation has been a very hot topic since the discovery of sunspots with related subjects ranging from rainfall changes, lake level variations, river flow changes, drought cycles, storms, pressure systems, to biological phenomena such as insect populations, circumpolar mammal populations, seaweed density, agricultural yields etc. The two most well founded SunÐEarth's climate connection topics are the early faint young Sun paradox, and the Little Ice Age during the Maunder minimum time period.

The total solar irradiance (TSI) arriving at the mean Sun-Earth distance is about 1368 W/m², and was often referred to as solar constant. Whether or not TSI is actually constant, or how it might vary, was much debated before satellite observations showed that it does indeed vary, though only by about 0.1% over the 11-year cycle. The spectral solar irradiance (SSI) in UV spectrum has been observed to vary during an 11-year solar cycle with much larger amplitude compared with the variability of TSI.

…

[AlecBGreen]

20. thanks!

:hi:

[phantom power]

12. What it tells me is that when the sun comes out of this sunspot trough...

we're all going to see some eye-opening shit.

[glitch]

15. It would be nice if we could have another minimum period.

That might give us a bit more breathing room while we get our act together.

[Nihil]

19. That's my take on it too ...

... and so I really can't see why the deniers are so happy about the
current situation being a minimum (as far as solar effects are concerned) ...
:shrug:

[14thColony]

6. I'm confused

"Sunspots (were)...first noticed in 1843. They were absent in the 17th century – a period called the “Maunder Minimum” after the scientist who spotted it."

So...sunspots were first noticed in 1843, but Maunder knew enough about them 200 years prior to spot the lack of sunspots...?

Is The Independent's editor gone on holiday or something?

[TheWraith]

7. Maunder made the discovery in the late 1800s....

...Based on historical observations of the sun during the 17th century.

[14thColony]

8. Bam! OK, that makes sense now

Thanks. Although the author could a made that a tad clearer.

[pscot]

10. Sunspots were discovered by Galileo

in 1610. The Swiss began systematic observations in 1749. Google is your friend.

[starroute]

14. Sunspots might have been known much earlier

I've seen it suggested that some of the Egyptian temples were set up to cast an image of the sun on the rear wall of a passage -- essentially acting as a camera obscura -- and in that sort of magnified image any sunspots would have been plainly apparent.

If that did happen, though, it was part of the priests' secret knowledge. Galileo staring at the sun through an early telescope was the one who brought sunspots into the scope of modern scientific investigation.

[OKIsItJustMe]

11. FWIW

http://solarscience.msfc.nasa.gov/SunspotCycle.shtml


http://solarscience.msfc.nasa.gov/predict.shtml

[glitch]

16. Thanks for these, most informative.

Looks like our little trough is about to end. :(