Did you know Sunspots have been more common in the past seven decades than at any time in the last 8,000 yrs?

Question

http://www.space.com/scienceastronomy/sunspot_record_041027.html

http://images.google.com/imgres?imgurl=http://www.coyoteblog.com/photos/uncategorized/irradiance.gif&imgrefurl=http://www.coyoteblog.com/coyote_blog/2007/02/index.html&h=393&w=640&sz=50&hl=en&start=75&um=1&tbnid=2dFLlwAYIQqyVM:&tbnh=84&tbnw=137&prev=/images%3Fq%3Dsunspot%2Bcycle%2Btemperature%2B2007%26start%3D72%26ndsp%3D18%26svnum%3D10%26um%3D1%26hl%3Den%26rls%3Dcom.microsoft:en-us%26sa%3DN

http://physicsworld.com/cws/article/news/18692

Sergio, read the first link.

Tomcat, thanks for the info, I will read it when I get a chance.

Griz & Bob, I would just refer you to the previous question.

Sergio=Dario=?

Ben, they explain how they learned about past climates in the first link.

Bob, I wasn't really looking for an answer. I was just referring you to scientists who beleve the sun is the major climate driver.

Bob, I was just reading your first link, here are some quotes from your sorce:

"The authors and other experts are quick to point out that more complicated solar mechanisms could possibly be driving climate change in ways we don't yet understand."

"There are numerous studies that find a correlation [between solar variation and Earth climate]," said Sami Solanki of the Max Planck Institute for Solar System Research in Lindau, Germany.

"These authors have looked at the simplest mechanism, and they find that this mechanism does not produce the same level of change that has been observed," he continued.

"This could be suggesting that there are other mechanisms acting for the way that the sun influences climate."

Thor, this paper from the US Geological Service does a good job of explaining it.

http://pubs.usgs.gov/fs/fs-0095-00/fs-0095-00.pdf

Answer 1

I was not aware of that statistic, have you seen the paper that was just published about the Gulf of Mexico temperature proxy reconstruction that indicates that the Gulf was as warm or warmer during the medieval warm period? Notice the graphic in Figure 1. of the correlations with the sunspot minimums; Maunder, Spoerer, Wolf and Oort documented in the Little Ice Age. Hopefully the Sunspot minimum we appear to have entered does not last.

http://www.marine.usf.edu/PPBlaboratory/paleolab_pdfs/Richey_etal_2007.pdf

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Answer 2

This is something that has been speculated about for a long time now. We've always known that sunspot numbers have been at their highest levels since accurate records first began to be kept approx 400 years ago and have been pretty confident they've been at their highest level for 1150 years. The new research further confirms what had been thought to be the case.

The new research also provides more evidence that global warming is not driven by sunspot activity except over very long periods of time. In short, it's nothing new, it just provides further validation of what has long been understood.

Historically, there is a partial long term correlation between sunspot numbers and average global temperatures but these are events of low magnitude spanning hundreds of years. By comparison, what we've seen in recent decades is a high magnitude short-term event where changes in temps have been upwards of 15 times as fast as previous part-solar driven events.

This is to be expected. The difference between insolation maxima and minima is a variation from the mean of less than one two-thousandth and as such any changes occasioned by solar variation can only affect our climate over many hundreds or even thousands of years.

An interesting side issue, many of the graphs linking solar activity and global temps are distorted. This was perhaps most evident in the documentary 'The Great Global Warming Swindle' in which a large section of 'missing data' had been substituted simply by drawing a line that tracked temperature changes. When the real data is put into the graph there is a dramatic divergence with temps rising rapidly whilst solar activity declines. Similarly, many of these graphs end in 1980; a convenient end point as from then onwards there has again been a divergence with no correlation between solar activity and temps. It's annoying and irresponsible that some people do this as it gives the impression that global warming and solar activity are inexorably linked.

Answer 3

I don't take anyting seriously if a scientist is "reconstructing" events 10,000 years ago.

We have no way to verify such "measurements", especially when we are talking about inferring sunspot activity from something like fossilized tree rings...

And even if true, they don't have any idea if it means anything in terms of climate change or not.

It IS interesting that 10,000 years ago was the end of the last ice age, and it coincides with a supposed increase in sunspots....

Answer 4

Larry - read the second paragraph of your first link:

"Many researchers have tried to link sunspot activity to climate change, but the new results cannot be used to explain global warming, according to the scientists who did the study."

More reasons why that's true here:

http://news.nationalgeographic.com/news/2006/09/060913-sunspots.html
http://environment.newscientist.com/channel/earth/climate-change/dn11650

chocolahoma - The end of the Ice Age 11,000 years ago corresponds to a peak in a 100,000 year solar cycle called the Milankovic cycle. Unlike sunspots, the Milankovic cycle DOES increase solar radiation received by Earth.

EDIT - Larry. OK, I answered your other question (which didn't really seem to need answering). My answer here stands as written.

Answer 5

Milankovich cycles are actually quasi-periodic changes in the Earth's orbit and tilt, resulting in greater or lesser amounts of solar radiation reaching the Earth. Milankovich cycles do not involve any change in the Sun as such.

Answer 6

Man, I knew I should've reduced my carbon footprint on my last visit to the Sun! On Saturday there were zero sunspots to report on SpaceWeather.com.

Answer 7

Yeah, but it's a bit hard to check. We can't get in a time machine and go back a few thousand years and do some tests.

Answer 8

Who counted them 8K years ago and where are the records??

Answer 9

What's your point? It has already been proven that sunspot activity has no influence on GW.

Answer 10

How can anyone know it?