What is the connection between sunspot cycle and global warming/cooling ?

[BigAl]

Last night I was listening to someone describe the recent sunspot cycle as being at historic lows and about to about to approach zero. I'll accept this statement. He then went on to say that "the sun is cooler when there are fewer sunspots" without providing any support for that claim. He went on to argue that there has been recent global cooling that correlates with the cycle and that it is attributable to the sunspots.

Is there any decent science that connects sunspots with global temperature?

[BenBurch]

http://www.realclimate.org/index.php/archives/2007/05/start-here/

[Jorghnassen]

IIRC, sun spots are associated with increased solar activity thus, in the absence or constance of other factors, more sun spots imply warmer temperatures, fewer sun spots lower temperature. The issue here is that there are other factors that change over time, thus their effect needs to be taken into account...

[lomiller]

I guess that depends on what you mean by “connects”. Sunspot numbers are a proxy for the amount of energy the sun is emitting at any given time which in theory will have some effect on climate.

The problem is that over this change in energy output is very small. I.E. Sunspots “dropping to zero” generally only means a 0.1% drop in solar output. This is too small to show up in global temperatures in the 11 year sunspot cycle because of the massive amount of energy it takes to warm/cool the oceans.

Not surprisingly attempts to find direct correlation between global temperatures and sunspot numbers fail. There was a paper last year that purported to find some indirect correlation by comparing regional trends. I.E. they looked for oscillations, where one region warms and another cools, this change in solar energy may be inducing. This study involved some heavy duty data mining, so while it’s interesting I personally don’t think it will hold up.


During the “little ice age” there was apparently a prolonged period of reduced sunspot activity, which would suggest a longer period of reduced solar activity. Over 100+ years such a reduction would indeed show up in the Earth’s climate. For reference, most temperature reconstructions show a drop of less then 0.5 deg C between the heights of the Medieval Warm Period to the bottom of the Little Ice Age. This occurred over several hundred years. We have had >0.5 deg warming in the last 30 years, so any climate change from solar activity can’t come close to explaining current climate change.

[casebro]

It's not so much the height of the cycles, it's how frequent they come.

Farther apart = cooling, closer together = warming.

"Approaching zero" is probably normal, between peaks. Peaks come at 8-12 year intervals. Several eights in a row= warm, several 12s = cool.

[macdoc]

A crock...

show us "several 8 year peaks in a row".....I'll make it easy show us two....:popcorn1

[Megalodon]

http://forums.randi.org/imagehosting/thum_28147cd552a6b14e.jpg (http://forums.randi.org/vbimghost.php?do=displayimg&imgid=11122)

You can see for yourself. Please note that the "trendlines" are polynomials, and are strongly affected by the end values. Meaning that that final dip in the blue line wouldn't be there with a decent trending method (that I couldn't be bothered to apply). I could do the figure again without them, but I can't be bothered to do that either...

[DogB]

Is there any decent science that connects sunspots with global temperature?

There’s an OK Wiki page (http://en.wikipedia.org/wiki/Solar_variation).

[CapelDodger]

There’s an OK Wiki page (http://en.wikipedia.org/wiki/Solar_variation).

It pretty much says it all.

Statistical studies that correlate weather (http://forums.randi.org/wiki/Weather) and climate (http://forums.randi.org/wiki/Climate) with solar activity have been popular for centuries, dating back at least to 1801, when William Herschel (http://forums.randi.org/wiki/William_Herschel) noted an apparent connection between wheat prices and sunspot records.

I'd just add that the process of demolishing these studies contributed greatly to the development of time-series statistics, from what I've read.

[CapelDodger]

It's not so much the height of the cycles, it's how frequent they come.

It's not that either.

Farther apart = cooling, closer together = warming.

Where does the extra energy come from?

"Approaching zero" is probably normal, between peaks.

It's no doubt normal, but also very unusual.

Peaks come at 8-12 year intervals. Several eights in a row= warm, several 12s = cool.

If the cycle remains the same how does the frequency create energy? Answer : it doesn't.

What's happened is that a direct correlation with climate being demonstrably false as an explanation for global warming, an indirect correlation has been sought out, and naturally claims have been made to discovery.

Sadly such discoveries have all failed the test of time. Tailored to what had happened they were wrecked by what did happen.

I imagine the next refuge will be in the second derivative of the solar cycle. And so ad infinitum.

[macdoc]

That would be galactic I do believe.....still waiting on back to back 8 year..:popcorn1