May have a chilling effect

June 14, 2011 1:29 PM

Sunspots, first observed by Galileo, normally follow an 11-year cycle. We are into a few years into (recorded) cycle number 24 but according to NASA it's looking rather underpowered. Nobody is certain exactly what the consequences will be, but one distinct possibility is a cold period; a previous low in solar activity, the Maunder minimum, is correlated with a brief Little Ice Age. Nobody really knows how this unusual solar weather pattern might interact with human-caused climate change. Previously, albeit somewhat controversially.
posted by anigbrowl (28 comments total)

It's deja vu all over again.
posted by dhdrum at 1:33 PM on June 14, 2011

Are there no limits to how far Big Oil will go to cast doubt on global warming?
posted by codswallop at 1:33 PM on June 14, 2011 [2 favorites]

Winter is coming.
posted by chainlinkspiral at 1:34 PM on June 14, 2011 [9 favorites]

In astronomical terms, isn't 24 cycles over a few hundred years like, you know, fuck all.
posted by fullerine at 1:38 PM on June 14, 2011 [2 favorites]

Paging dseaton?
posted by edd at 1:40 PM on June 14, 2011

fullerine: Well, no. The Sun has various timescales associated with it ranging from its billions-of-years lifespan to its ~20 minute dynamical timescale. Not everything in astronomy takes a long time.
posted by edd at 1:42 PM on June 14, 2011

Let me see if I have this right: the previously from 2007 was about how global warming is caused by a 1000 year solar maximum, and now we should believe that because we might be headed for a putative 200 year low based on a 4 year trend, we don't have to worry about the now admittedly anthropogenic warming?
posted by [expletive deleted] at 1:42 PM on June 14, 2011

So it'll get colder, and humanity collectively will see no good reason for continuing to spew greenhouse gasses into the atmosphere. We will have some cool summers and very cold winters and we'll burn through a lot more of the remaining oil reserves and the Republicans will regain power, largely from appearing to be right about global warming and ridiculing environmentalists even more than they do now, and people will just want to be warm, not caring how, and then this sunspot cycle will come to an end in about 30 to 40 years, and the average CO2 level will be around 525 PPM and when the sun starts getting warmer we'll really be cooking.

I am strangely glad that I am likely to be dead by then.
posted by Danf at 1:46 PM on June 14, 2011 [5 favorites]

I just want it to snow like it did when I was a kid. It hasn't snowed like that in 30 years! Well, unless you count the big winter 5 years or so back or the times it snowed big when I was in college. You never see snow like that anymore.
posted by cjorgensen at 1:47 PM on June 14, 2011 [4 favorites]

Let me see if I have this right: the previously from 2007 was about how global warming is caused by a 1000 year solar maximum, and now we should believe that because we might be headed for a putative 200 year low based on a 4 year trend, we don't have to worry about the now admittedly anthropogenic warming?

No, you do not have it right. The previously from 2007 is included because it included some forward-looking predictions and worthwhile discussion of a closely related subject. It was also mentioned as controversial because a lot of people pointed out major flaws in the central thesis of the FPP. However, the background information and supplementary links are still useful, as are the refutations of naively-wrong theories.

If I did not believe in the existence or significance of anthropogenic climate change I would have said so. In fact, I have no idea whether this change in solar weather could lead to a temporary big freeze or not. I can even conceive of scenarios where it results in slightly accelerated warming.
posted by anigbrowl at 1:52 PM on June 14, 2011

Interesting post. Looking at this graph of sunspot maxima numbers from 1750 through today there seems to be a roughly (very) 110 year cycle where the sunspot maxima numbers decrease for several cycles. There was one around 1800, one around 1910 and apparently we are approaching another in the 2015-2020 timeframe. All the previous decreased cycles appear to be consistent with the same numbers we are seeing this cycle so... probably no need to worry :)

It just seems to be a 110 year cyclic variation in maxima numbers.
posted by Poet_Lariat at 1:58 PM on June 14, 2011 [1 favorite]

My understanding is that the relative "forcing" of solar variance is quite small compared to the forcing of increased CO2. So, while we may see less warming in a maunder minimum, when we come out of it the warming will be augmented even more.

Nice summary here--
posted by Michael_H at 2:06 PM on June 14, 2011 [1 favorite]

I will just quote what Nigel Weiss (professor at Cambridge, FRS, past president of the Royal Astronomical Society, etc) says about this on his webpage, since it's a pretty good summary of this stuff.

"The Sun's magnetic activity varies cyclically with a period of about 11 years and activity has been abnormally high for the for the past 80 years. As might have been expected, this prolonged grand maximum is coming to an end. The new Sunspot Cycle 24 looks likely to be the weakest for at least 100, probably for 200, years; it is conceivable that the Sun might even be entering a grand minimum, which would be expected to have a cooling effect on the Earth's climate. I have always maintained, however, that any temperature changes caused by variations in solar activity are small compared to the global warming that we are already experiencing, and very small compared to what will happen if we continue to burn fossil fuel at the present rate."

For a bit of backstory here, Nigel's work was badly misrepresented in a 2007 article in the (Toronto) National Post, which suggested that he thought solar irradiance variations would lead to a global "cooling period." (Notice the "apology to Dr. Nigel Weiss" at the top of the linked page.)

You might also check out work by Sami Solanki's group, which has done a bunch of characterization of irradiance variations, their link to magnetic activity, and the possible impact of those variations on climate.

The bottom line is that while the Sun's irradiance does vary along with the sunspots (in a somewhat non-intuitive way: it's actually a little brighter when there are spots), most people working on this stuff agree that the effect is quite small.
posted by chalkbored at 2:33 PM on June 14, 2011 [2 favorites]

It dawned on me recently that we will still be arguing about global warming for decades after my death. Its a big long story that I'm never going to know the end of.
posted by memebake at 2:38 PM on June 14, 2011 [2 favorites]

The Register article by Lewis Page is a little suspect, take a look at his past history of contrarian science sensationalism. Much of it anti-green in slant. I'd like to see a more neutral and expert source about this. chalkbored has some good links.
posted by stbalbach at 3:07 PM on June 14, 2011

It'll all be fine once the Cheela remove the black holes that are orbiting around inside the Sun.
posted by localroger at 5:10 PM on June 14, 2011 [2 favorites]

Its a big long story that I'm never going to know the end of.

See, there you go being an optimist.

I fully expect the warming side of the debate to finally win the argument sometime a few decades after it's too late to do anything about it. I intend to live that long.
posted by cjorgensen at 5:22 PM on June 14, 2011

Danf: "I am strangely glad that I am likely to be dead by then."

And in the cold, cold ground?
posted by bwg at 5:55 PM on June 14, 2011

There ain't gonna be much ground left when all that ice melts.
posted by MattMangels at 7:22 PM on June 14, 2011

Michael_H has provided the relevant scientific link (here again), there's no need for more pointless pontificating.

[T]he authors conclude the most likely impact of a Maunder Minimum by 2100 would be a decrease in global temperature of 0.1°C . With all uncertainties taken into account, the estimated maximum decrease in global temperature is 0.3°C.,

This is in context of a possiblelikely temperature increase of four to six degrees by 2100.
posted by wilful at 7:58 PM on June 14, 2011

God always has a plan, doesn't he?
posted by klanawa at 8:40 PM on June 14, 2011 [1 favorite]

Hide the decline!
posted by uncanny hengeman at 9:19 PM on June 14, 2011

[T]he authors conclude the most likely impact of a Maunder Minimum by 2100 would be a decrease in global temperature of 0.1°C . With all uncertainties taken into account, the estimated maximum decrease in global temperature is 0.3°C.,

So basically, this won't even buy us a decade of extra time to get under 350ppm. How comforting.
posted by [expletive deleted] at 9:28 PM on June 14, 2011

Sunspots are a left wing plot designed to
posted by the noob at 10:05 PM on June 14, 2011

The sunspot number is consistently one of the most controversial questions in solar physics, partly because of the historic relationship between sunspots and climate, but also because the number is very difficult to compute. It's highly subjective, adding up the area of all these tiny blobs and dots on the sun, and observers have to be very careful to keep their measurements consistent over time.

The SIDC in Belgium, which is where I work (though I study flares and am not involved in sunspot measurements) is the keeper of the official sunspot count. So I'm constantly reminded of the difficulties in making some of these measurements. (If you want to see a discussion in depth of some of these issues, we saw an interesting talk on the subject last year.)

You can see the data on our current situation here. After a long and deep minimum, we do seem to be returning to more normal activity. Although the cycle does appear weaker than other recent cycles, there is little evidence from the sunspot number that we're headed for anything like a Maunder-type minimum. On the other hand, many people in my field have been discussing the overall decline in solar magnetic field strength that is reported in one of the news articles linked above, and that is definitely very intriguing. Unfortunately, predictions about this are all over the place, so we'll have to wait and see who's right over the next several years.

On the sunspot-climate connection: Of course this is highly controversial, and plenty of people have used this question to fight proxy battles about the nature of human-driven climate change. But there is a lot of good work, and a lot of interesting work, coming about about the effects of the sunspot cycle and possible mechanisms by which sunspots (which actually reduce overall solar brightness a bit) can cause warming or cooling on earth.

A few examples include studies of correlation between water level in the Nile and sunspots, discussions of the role of solar variability on human development, and some interesting suggestions on how sunspots—or lack thereof—might influence global atmospheric circulation.
posted by dseaton at 10:11 PM on June 14, 2011 [4 favorites]

cjorgensen: See, there you go being an optimist.

I fully expect the warming side of the debate to finally win the argument sometime a few decades after it's too late to do anything about it.

I respectfully would say that you are the optimist. I think that even if we're all sweltering in a venusian climate and its too late to do anything about it, there still won't be a conclusive end to the argument. Its a cause-and-effect argument about the most complex cause-and-effect system imaginable, and the stakes are high. Its a debate in an area where the key points take years of study and research and huge simulations to establish. There will always be strong political reasons for taking a contrarian view, and plenty of powerful people will do so.
posted by memebake at 12:27 AM on June 15, 2011 [1 favorite]

Here's some additional information: the original sunspot press release & a NASA article on the relationship between the solar activity cycle and geomagnetic activity.
posted by dseaton at 4:52 AM on June 15, 2011 [1 favorite]

Winter is coming.
posted by daHIFI at 1:55 PM on June 16, 2011 [1 favorite]