Friday, July 11, 2008

Quiet Sun No Big Deal

Anthony Watts has been toying with this one for awhile: Its all quiet on the solar front. Too quiet.

And other some have been even more direct: no/few sun spots = dangerous global cooling.

The sun undergoes cyclical changes on multiple time scales that appear to correlate very well with temperatures. Long and relatively quiet solar cycles historically have been associated with cold global temperatures, short and very active cycles, warm periods. The current cycle 23 appears to be the longest in at least a century and may project to quieter subsequent cycles and cooling temperatures ahead.

Except: how unusual is a situation like the current one really? Not very, according to NASA's David Hathaway:

"There have been some reports lately that solar minimum is lasting longer than it should. That's not true," said NASA solar physicist David Hathaway. The ongoing lull in sunspot numbers "is well within historic norms for the solar cycle.

"The sun has been relatively quiet for more than two years. Hathaway said there were stretches in the 20th century when the slack periods lasted twice this long.

"It does seem like it's taking a long time," Hathaway said, "but I think we're just forgetting how long a solar minimum can last."

And here's a chart that compares the latest minimum in terms of "spotless days" to the 1933 minimum. Contra D'aleo (2nd quote above) our current quiet period is not even close to being the longest observed minimum this century:



Another way to examine the length and depth of a solar minimum is by counting spotless days. A "spotless day" is a day with no sunspots. Spotless days never happen during Solar Max but they are the "meat and potatoes" of solar minima.

Adding up every daily blank sun for the past three years, we find that the current solar minimum has had 362 spotless days (as of June 30, 2008). Compare that value to the total spotless days of the previous ten solar minima: 309, 273, 272, 227, 446, 269, 568, 534, ~1019 and ~931. The current count of 362 spotless days is not even close to the longest.

Cycle that, Anthony.

12 comments:

Jerome Bastien said...

Interesting post BCL. So the conclusion is that the current cycle is perfectly within the norm?

No ice age coming? Sweet.

But how does that relate to global warming?

bigcitylib said...

Well, some people have been arguing that the cool Spring we've had is somehow related to the lack of sunspot activity, rather than La Nina. And therefore that Gw is not Anthropogenic.

Doubting Thomas said...

I don't know about you jermo, but just to be safe I'm buying some carbon offsets from this dude I know.

Jerome Bastien said...

Okay fair enough. But coudlnt' it be a bit of both?

In any event, even if the current cool weather is related to sunspots or la nina, that doesnt really have any effect on whether GW is anthropogenic or not.

And besides, as your post states, quiet solar cycles have been associated with cold global temperatures - that's not really disputed is it?

Jerome Bastien said...

DT: im selling offsets if you want some.

for 1000$, you can drive your SUV guilt-free, and i'll use your $ to make myself a nice carbon-consuming garden. it's win win really.

bigcitylib said...

Jermo,

Well, low sunspot numbers have been associated with for example the Maunder Minimum, but there is debate as to whether one caused the other. Fewer sunspots do not correlate well with lower solar energy output. There's at least one guy (Svelgard I think ihis name is) who thinks the only solar cycle is the 11 year one and that energy output hasn't changed at all in centuries.

buckets said...

It's interesting that the 568 spotless days in the 1930s include 1934, which denialists sometimes cite as one of the hottest on record, which doesn't fit well with an argument that spotless days lead to cooling.

Anonymous said...

"The Kingdom of the Cults":

(1) Leadership by a New Age prophet — in this case, former Vice President Al Gore.

(2) Assertion of an apocalyptic threat to all mankind.

(3) An absolutist definition of both the threat and the proposed solution(s).

(4) Promise of a salvation from this pending apocalypse.

(5) Devotion to an inspired text which embodies all the answers — in this case Mr. Gore's pseudo-scientific book "Earth in the Balance" and his new "An Inconvenient Truth" documentary.

(6) A specific list of "truths" which must be embraced and proselytized by all cult members.

(7) An absolute intolerance of any deviation from any of these truths by any cult member.

(8) A strident intolerance of any outside criticism of the cult's definition of the problem or of its proposed solutions.

(9) A "heaven-on-earth" vision of the results of the mission's success or a "hell-on-earth" result if the cultic mission should fail.

(10) An inordinate fear (and an outright rejection of the possibility) of being proven wrong in either the apocalyptic vision or the proposed salvation.

Ti-Guy said...

That's "Biff;" I recognise the style.

When did he get out rehab?

Steve Bloom said...

BCL, Svalgaard's view is very close to being a consensus among solar physicists. The prior general view that there had been a lot of past solar variation was based on 1) a lack of other explanations for past climate variations, 2) several astrophysics papers in the early '90s (Baliunas and Soon go their start with this stuff) purporting to demonstrate that the Sun is a variable star and 3) analysis of the Be-10 proxy. Subsequent work found 1) evidence for volcanic activity that pretty much explains things, 2) fundamental errors in the variable Sun papers and 3) bias in the Be-10 proxy. Also, while sunspots do vary through the solar cycle in a manner that tracks the irradiance change, modern observations have made it clear that there's no particular correlation between irradiance and the quantity of sunspots. Finally, many of the older sunspot counts may have been undercounts due to volcanic dust, meaning that the Maunder Minimum in particular is probably largely an artifact.

Denialists like Watts are still operating on the old discarded views. They cling to some sort of solar explanation because it's their only real alternative to GHGs. I find myself referring to the Dunning-Kruger Effect rather a lot these days.

hahajohnnyb said...

Funny, Science is supposed to be DISPASSIONATE. I assume that everyone who is following this climate change stuff is an adult who is reasonably intelligent, but for some reason most discussions on this issue always evolve into a school yard argument of "huh ah, bull, bull honkey, yes so, no way" before everyone runs away with their fingers in their ears singing "na na na, I can't hear you."

The solar cycle hypothesis has been around since I started following this debate back in the late 90s. This is the first live test that we have had of this hypothesis, and so far it does fit the observed truth that global temperatures have cooled. Could this just be a happy accident, yes of course it could!

Now, that La Nina thing. First, everyone I have read accepts that the ENSO cycle effects global temperatures, just like volcanos effect the climate in the short run. This latest La Nina was nothing exceptional, but it was a La Nina, and now its gone. I know that the La Nina had an effect, but we saw a pretty radical drop in Global Temperatures, from January 2007 which I do not think can be completely explained by a minor La Nina. Question is, "What happens from here now that the Pacific has returned to normal?"

May and June were both cool, and the La Nina was pretty much faded by then. At the same time the North Atlantic has been much warmer than usual for what seems like years now, but this month something seems to be happening in the North Atlantic, and some scientists are speculating that the Atlantic Multi-Decadal Oscillation is turning into a cool phase. This is roughly co-inciding with the PDO turning to a cool phase. What is causing these phase changes? Could it have something to do with the sun?

We all know the influence that the moon has on our oceans by observing the tides, but could it be possible that something else effects our oceans like magnitism? After all, we know that the Earth has a magnetic field and the sun does too, and both have been weakening as of late, could this hve an effect on our oceans? After all the simple observational experiment of holding a bar magnet up to a steam of water flowing from a kitchen sink does bend the flow of water, so it is rational that magnets might have an effect on our oceans. We know that sun spots are magnetic storms on the surface of the sun, so could it be possible that altering these magnetic fields could cause an upwelling of cold ocean water to the surface, such as what occurs during a La Nina?

Simply enough, I do not know, but I do understand that ocean surface temperatures do seem to have the greatest effect on the climate, so what ever controls these upwelling would have a great deal of effect. I know that there are also an hypothesis about the solar wind and cosmic rays, and all sorts of other things, but the only thing that we really know for certain that that the climate has changed in the past, and it will change again in the future.

CO2 driven climate change is just another hypothesis, and really has no greater validity than any of the other ones out there, but unfortunately some people have decided to make it a political issue, and these same people are succeeding in greatly upsetting the normal function of nations in dealing with economic issues and have caused a spike in food and fuel prices as a result of their meddling. Naturally this is going to piss people off, when they know that there is little evidence to support this hypothesis that is already causing so many problems. If allowed to go unchallenged, it will doubtlessly lead to the collapse of all of the economies of the Western World, no to mention mass starvations and domestic unrest in poor nations.

Maybe, Global Warming caused by CO2 is a concern, but it is hardly a crisis and it should be properly relegated back to the 4th tier of concerns that nations and people face in their daily life. It's likely if we drop all of the hype and propaganda and genuine insanity surrounding this issue we can find common ground on solutions which will benefit our civilization, rather than acting on a crazy hunch based on shakey science which will destroy our civilization. Until then, I deeply resent being lied to by the Global Warmists and I will oppose everything they want. I say we water board Dr. Hansen and Algore to see what they really know about Global Warming, really it's the least we can do to save the Earth.

Auntie Liberal said...

No! MAN is causing this as well! We MUST DO SOMETHING! Even if we know it will have no effect, we need to send the message that we support the Sun! We must tax things that use sunlight, and somehow blame it on GWB!