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Originally Posted by NeilBlanchard
Carbon dioxide is not the only thing causing climate change - but it is the most important factor, and it is the only way that the numbers work.
11 years is a half cycle. ~22 years is the cycle. We have just come through a an unusually low minimum of sun spot activity, and the sun's output is lower when there is low sun spot activity. This is actually counterintuitive since sunspots themselves are much cooler than the rest of the surface of the sun.
Here's an excellent NOVA program on the Sun that aired earlier this year:
NOVA | Secrets of the Sun
As I understand it, the sun is increasing its output over the very long term - but the output over the short term can drop off, and it does drop off during sun spot minimums. The most well know minimum was the Maunder Minimum. |
Yes it is a good video. Go to 43minutes into the video, and rewatch, they clearly state the solar cycle is 11 years.
What is the solar cycle?
NASA
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The amount of magnetic flux that rises up to the Sun's surface varies with time in a cycle called the solar cycle. This cycle lasts 11 years on average. This cycle is sometimes referred to as the sunspot cycle. Near the minimum of the solar cycle, it is rare to see sunspots on the Sun, and the spots that do appear are very small and short-lived. During this "solar maximum", there will be sunspots visible on the Sun almost all the time (often there are more than 100 spots visible at a time!), and some of those spots will be very large (up to 50,000 km in diameter) and last several weeks. There was a sunspot maximum in 1989-1990 and we expect another one in 2000-2001.
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www.swpc.noaa.gov/info/SolarMax.pdf
NOAA
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Over the last 300 years, the average
number of sunspots has regularly waxed and
waned in an approximately 11-year sun-spot
cycle (see figure 1). The Sun, like the Earth, has
its seasons—but its “year” equals 11 of ours.
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Its really not that important in the context of overall global warming.
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...it's sorta analogus to the famous "A.A. Prayer":
"...grant us the serenity to accept the things we cannot change,
courage to change the things we can,
and wisdom to know the difference."
We can't change what the SUN does, but we can change what WE do here on earth.
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Exactly, I just prefer that the reasons I change be as true and honest as possible.