Posted on 09/13/2006 2:01:24 PM PDT by Ernest_at_the_Beach
OSLO (Reuters) - The sun's energy output has barely varied over the past 1,000 years, raising chances that global warming has human rather than celestial causes, a study showed on Wednesday.
Researchers from Germany, Switzerland and the United States found that the sun's brightness varied by only 0.07 percent over 11-year sunspot cycles, far too little to account for the rise in temperatures since the Industrial Revolution.
"Our results imply that over the past century climate change due to human influences must far outweigh the effects of changes in the sun's brightness," said Tom Wigley of the U.S. National Center for Atmospheric Research.
Most experts say emissions of greenhouse gases, mainly from burning fossil fuels in power plants, factories and cars, are the main cause of a 0.6 Celsius (1.1 F) rise in temperatures over the past century.
A dwindling group of scientists says that the dominant cause of warming is a natural variation in the climate system, or a gradual rise in the sun's energy output.
"The solar contribution to warming over the past 30 years is negligible," the researchers wrote in the journal Nature of evidence about the sun from satellite observations since 1978.
They also found little sign of solar warming or cooling when they checked telescope observations of sunspots against temperature records going back to the 17th century.
They then checked more ancient evidence of rare isotopes and temperatures trapped in sea sediments and Greenland and Antarctic ice and also found no dramatic shifts in solar energy output for at least the past millennium.
SUN NOT GUILTY
"This basically rules out the sun as the cause of global warming," Henk Spruit, a co-author of the report from the Max Planck Institute in Germany, told Reuters.
Many scientists say greenhouse gases might push up world temperatures by perhaps another 3 Celsius by 2100, causing more droughts, floods, disease and rising global sea levels.
Spruit said a "Little Ice Age" around the 17th century, when London's Thames River froze, seemed limited mainly to western Europe and so was not a planet-wide cooling that might have implied a dimmer sun.
And global Ice Ages, like the last one which ended about 10,000 years ago, seem linked to cyclical shifts in the earth's orbit around the sun rather than to changes in solar output.
"Overall, we can find no evidence for solar luminosity variations of sufficient amplitude to drive significant climate variations on centennial, millennial or even million-year timescales," the report said.
Solar activity is now around a low on the 11-year cycle after a 2000 peak, when bright spots called faculae emit more heat and outweigh the heat-plugging effect of dark sunspots. Both faculae and dark sunspots are most common at the peaks.
Still, the report also said there could be other, more subtle solar effects on the climate, such as from cosmic rays or ultraviolet radiation. It said they would be hard to detect.
I'm still waiting for the explanation of warming 1000 years ago and the little ice age that occured after that.
Horse exhaust?
That surely explains why the Anisasi Indians left the Southwestern United States 900 years ago.
Mars is these researchers *Achilles' Heel* ; it's their fatal weakness.
They report a variance of 0.077%, which translates to a change of 154 kW per square kilometer.
The surface area of the earth is around half a billion square kilometers. Of course, only have of that is illuminated at a given time, so we have around a quarter billion square kilometers illuminated at any time. And of course it's illuminated for 24 hours (well, half of it is).
That means around 924,000 GWh of variation of power delivered to our planet. Which is around the 12% of the total energy consumption of the US.
I'd say that if the US is a contributor to climate change, then the sun very well is too! It's like adding a whole new California to the world; I'm sure the "global warming activists" would love to be able to eliminate a California-worth of energy use from the ecosystem. Well, the sun simply added that and there's nothing we can do...
I guess "doesn't contribute" is somewhat relative!
Neither.
There's always another side to the story, EATB.
Not really; see link in post 46.
The Sun is deeply relieved and will now dedicate itself to finding the real global warmers on golf courses in Florida.
The Little Ice Age is pretty much attributable to a decrease in solar activity (the Maunder Minimum), and natural variability, particularly ocean circulation. The earlier warmth was more of a "normal" climate setting. Now we're in a period at least as warm as back in the Medieval period, and we're adding a factor (CO2 to the atmosphere) that should, if you believe basic physics, augment Earth's temperature. There are obviously variables in the climate system, but what the study shows (on top of other studies showing essentially the same thing, in different ways) is that the currently observed warming trend can't be attributed to solar variability. Thus there isn't much else to blame it on except increasing concentrations of atmospheric CO2.
Whew! That's a relief. For a while there I thought we were going to have to go to an alternative energy source.
Oh really?
Yes, really.
They were making solar observations back then?
Yes they were.
There is a disconnect in this statement.
The only disconnect is the one between your lack of knowledge on this topic and the amount of scorn you direct at those who actually do know something about the topic.
Galileo was making detailed records of sunspots starting in 1610. That's still in the 17th century the last time I checked. Here's one of his many documents on his observations:
That's the pattern of sunspots on July 6, 1613. Here's a movie made from Galileo's detailed drawings of the sunspots from each day over the course of one month (June 2 through July 8, 1613): http://galileo.rice.edu/sci/observations/ssm_fast.mov
And Galileo wasn't the only one recording sunspots. Thomas Harriot also made records of sunspot activity. For example, here are his notes for the sunspots of December 1610:
Christoph Scheiner was also recording sunspots in the 1600's. Here are some of his notes from October 1611:
Here's a page from Scheiner's massive volume of solar observations, "Rosa Ursina", published in 1630:
Johannes Hevelius made his own records of sunspot activity, such as this one from 1644:
Also recording sunspots in the 1600's were Pierre Gassendi, Giovanni Battista Riccioli, Benedetto Castelli, and Johannes and David Fabricius, among others.
Many of these men used a device such as the helioscope, which allowed for extremely accurate observations and the direct recording of sunspot locations onto paper:
For a Java apple that lets you view the monthly sunspot data for any date between 1750 and 2000, see this webpage.
So yes, Virginia, there really is detailed sunspot data available for as far back as the 17th century, despite your uninformed incredulity and sarcasm.
Ask NASA why it's getting warmer on Mars.
Yes, if you consider getting pwned by pure data being "flamed." Fragile, huh?
"Yet, the only solid measure of the warming, the NASA satellite data, shows that over the 27 years that data has been available, warming has been at a negligible rate of 0.13 degrees Celsius per decade. This level is engulfed by the statistical variation for reliability."
Interesting.
Well, they only had accurate daily sunspot measurements dating back to 1854.
A much better article on the report:
http://news.nationalgeographic.com/news/2006/09/060913-sunspots.html
This ain't even "junk" science.
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