(Part of the How to Talk to a Global Warming Skeptic guide)
Objection: The sun is the source of warmth on earth. Any increase in temperature is likely due to changes in solar radiation.
Answer: It's true that the earth is warmed, for all practical purposes, entirely by solar radiation, so if the temperature is going up or down, the sun is a reasonable place to seek the cause.
Turns out it's more complicated than one might think to detect and measure changes in the amount or type of sunshine reaching the earth. Detectors on the ground are susceptible to all kinds of interference from the atmosphere -- after all, one cloud passing overhead can cause a shiver on an otherwise warm day, but not because the sun itself changed. The best way to detect changes in the output of the sun -- versus changes in the radiation reaching the earth's surface through clouds, smoke, dust, or pollution -- is by taking readings from space.
This is a job for satellites. According to PMOD at the World Radiation Center there has been no increase in solar irradiance since at least 1978, when satellite observations began. This means that for the last thirty years, while the temperature has been rising fastest, the sun has not changed.
There has been work done reconstructing the solar irradiance record over the last century, before satellites were available. According to the Max Planck Institute, where this work is being done, there has been no increase in solar irradiance since around 1940. This reconstruction does show an increase in the first part of the 20th century, which coincides with the warming from around 1900 until the 1940s. It's not enough to explain all the warming from those years, but it is responsible for a large portion. See this chart of observed temperature, modeled temperature, and variations in the major forcings that contributed to 20th century climate.
RealClimate has a couple of detailed discussions on what we can conclude about solar forcing and how science reached those conclusions. Read them here and here.
What to make of the new climate poll
‘Copenhagen Diagnosis’ offers a grim update to the IPCC’s climate science
Comments
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Delay And Deny Posted 2:24 am
05 Mar 2007
Low level clouds are responsible from shielding us from sunlight. It's documented that cosmic ray activity from the sun has decreased in proportion with the increase in global mean temperature.
Here are a list of early papers:
Cosmic rays and Earth's Cloud Cover
There is also the pop-sci version:
The Chilling Stars: The New Theory of Climate Change (Paperback)
The Texeme Construct offers international text memetics construction and textcasting services.
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Coby Beck Posted 2:05 pm
07 Mar 2007
"The problem with people who have no vices is that they tend to have some pretty annoying virtues."
-- [paraphrased] Elizabeth Taylor
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GreyFlcn Posted 3:57 am
07 Apr 2007
http://stephenschneider.stanford.edu/Publications/PDF_Pap ...
However I have a much simpler debunk for cosmic rays.
When there's less sunlight, there's more cosmic rays, and it gets cold.
Is this because of the increase in cosmic rays?
No.
Is it because of the decrease in sunlight?
Duh!
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cmarkged Posted 6:13 pm
09 Apr 2007
However, you might say there is no solar cycle of 1470 years. True, but there is a cycle of 87 and 210 years, which are factors of 1470. Human global warming activists with beards say that water vapour is the major greenhouse gas. Climate models can not yet model clouds. See the fatal flaw? The water vapour in the climate models can not turn into clouds, and so it just lingers in the atmosphere. Each extra increment of CO2 has less effect.
I ask this. The Kyoto Protocol is dead and was never going to work, because all that is happening is that countries above their limits are buying off however much countries below their limits are below it. Whether or not "greenhouse gases" are responsible for global warming, surely, instead of trying to reduce CO2, we should be using the technology we already have to prevent or lessen the "disastrous" side-effects of global warming.
To try and reduce CO2 emissions, crops are going organic. Organic crops have half the yield per acre than nitrogen fertilised crops. To convert all our fossil fuels to wind power would take up one quarter of our landspace. Can you see? The loss of life from trying to prevent global warming will be far, far greater than the (supposed) loss of life from global warming.
So, in a nutshell, I have presented evidence which disproves the greenhouse theory, and then, assuming that the greenhouse theory is correct, says why reducing CO2 emmisions is not the correct plan of action. So mr gullible scientist who wrote the above article, shave off your beard and get real. Global warming is moderate, most probably beneficial, and, most importantly, unstoppable.
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Coby Beck Posted 12:17 pm
12 Apr 2007
"human global warming activists with beards say..."
"What if this weren't a hypothetical question?"
-- unknown
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GreyFlcn Posted 1:15 pm
12 Apr 2007
http://www.mps.mpg.de/images/projekte/sun-climate/climate ...
What does it tell you?
It tells you that it's not possible that the current warming in the last three decades is linked to solar activity.
However it does tell you that the warming (and cooling) before that in the 19th century was primarily caused by changes in solar radiation.
_
As for the "time lag between CO2 and warming temps"
Yes. That shows that changes in solar activity is the primary factor in altering the climate.
Problem is that it can't be the primary reason time around. Since there has been no significant increase in solar radiation during the recent warming period.
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Sven1olaf Posted 7:18 am
27 Apr 2007
This was posted on my blog:
On global warming - "appeal to the people" (http://en.wikipedia.org/wiki/Argumentum_ad_populum) is a logical fallacy. Just because a majority of people have been duped, doesn't make it true.
There was global cooling between 1940 and 1980 and that cooling doesn't track CO2 levels, it tracks sun spot and sun radiation activity. Scientists have taken the last 1000 years of CO2 levels, earth temperatures, and sun activity and have found that sun activity tracks closely to earth's temperature, not CO2. This could explain why Mars, Pluto, and other planets are also warming along with earth right now. This also matches the fact that the sun is at a 1000-year high in sun spot activity right now.
See http://rcronk.wordpress.com/2007/04/02/i-think-the-global ... for more detail.
See http://video.google.com/videoplay?docid=44995620224784421 ... for a documentary that also covers these topics.
I have to find any other arguments about this topic and would like to be able to help these guys understand that global warming IS happening + that humans are affecting this rate of change.
Thanks =]
"Great spirits have always encountered violent opposition from mediocre minds..." Einstein
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marron Posted 7:10 am
11 Jun 2007
http://press.web.cern.ch/public/content/Chapters/Spotligh ...
The roots of the experiment can be traced as far back as two centuries, when the Astronomer Royal, William Herschel, noticed a correlation between sunspots and the price of wheat in England. This marked the first observation that Earth's climate may be affected by variations of the Sun. Solar-climate variability has remained a great puzzle since that time, despite an intensive scientific effort. During the ‘Little Ice Age’ around the 17th and 18th centuries, when sunspots all but disappeared for 70 years, the cosmic ray intensity increased and the climate cooled.
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GreyFlcn Posted 12:27 pm
11 Jun 2007
i.e. They are looking at Henrik Svensmark's theory.
Henrik Svensmark has put forward this theory three times so far, and each time he was found to guilty of data fraud.
http://physicsweb.org/articles/world/20/6/8/1
What ya bet CERN proves him wrong for the fourth time?
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marron Posted 4:26 pm
11 Jun 2007
They don't know how to waste their time? Or they are working for Exxon? ;-)
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GreyFlcn Posted 3:15 am
12 Jun 2007
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Delay And Deny Posted 4:36 am
12 Jun 2007
http://seedmagazine.com/news/2006/10/the_cosmic_climate_c ...
When cosmic rays react with the air, they form radioactive elements called isotopes. By analyzing layers of these isotopes in tree rings or ocean sediment, scientists can piece together the amount of cosmic radiation that has reached the Earth over thousands of years.
Ten years ago, Svensmark and his colleagues reported that this historical record of cosmic radiation correlated strongly with satellite data on the Earth's cloud cover.
"It made a lot of attention at the time," Svensmark said, "because no one could think of any explanation for why cosmic rays would form clouds."
John Bailo, The "Denier Guy"
You Read It Here First
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Tazilon Posted 10:01 am
01 Aug 2007
The physicists said that their findings indicate that climate models of global warming need to be corrected for the effects of changes in solar activity. However, they emphasized that their findings do not argue against the basic theory that significant global warming is occurring because of carbon dioxide and other "greenhouse" gases.
Nicola Scafetta, an associate research scientist working at Duke's physics department, and Bruce West, a Duke adjunct physics professor, published their findings online Sept. 28, 2005, in the research journal Geophysical Research Letters.
West is also chief scientist in the mathematical and information sciences directorate of the Army Research Office in Research Triangle Park.
Scafetta's and West's study follows a Columbia University researcher's report of previous errors in the interpretation of data on solar brightness collected by sun-observing satellites.
The Duke physicists also introduce new statistical methods that they assert more accurately describe the atmosphere's delayed response to solar heating. In addition, these new methods filter out temperature-changing effects not tied to global warming, they write in their paper.
According to Scafetta, records of sunspot activity suggest that solar output has been rising slightly for about 100 years. However, only measurements of what is known as total solar irradiance gathered by satellites orbiting since 1978 are considered scientifically reliable, he said.
But observations over those years were flawed by the space shuttle Challenger disaster, which prevented the launching of a new solar output detecting satellite called ACRIM 2 to replace a previous one called ACRIM 1.
That resulted in a two-year data gap that scientists had to rely on other satellites to try to bridge. "But those data were not as precise as those from ACRIM 1 and ACRIM 2," Scafetta said in an interview.
Nevertheless, several research groups used the combined satellite data to conclude that that there was no increased heating from the Sun to contribute to the global surface warming observed between 1980 and 2002, the authors wrote in their paper.
Lacking a standardized, uninterrupted data stream measuring any rising solar influence, those groups thus surmised that all global temperature increases measured during those years had to be caused by solar heat-trapping "greenhouse" gases such as carbon dioxide, introduced into Earth's atmosphere by human activities, their paper added.
But a 2003 study by a group headed by Columbia's Richard Willson, principal investigator of the ACRIM experiments, challenged the previous satellite interpretations of solar output. Willson and his colleagues concluded, rather that their analysis revealed a significant upward trend in average solar luminosity during the period.
Using the Columbia findings as the starting point for their study, Scafetta and West then statistically analyzed how Earth's atmosphere would respond to slightly stronger solar heating. Importantly, they used an analytical method that could detect the subtle, complex relationships between solar output and terrestrial temperature patterns.
The Duke analyses examined solar changes over a period twice as long - 22 versus 11 years - as was previously covered by another group employing a different statistical approach.
"The problem is that Earth's atmosphere is not in thermodynamic equilibrium with the sun," Scafetta said. "The longer the time period the stronger the effect will be on the atmosphere, because it takes time to adapt."
Using a longer 22 year interval also allowed the Duke physicists to filter out shorter range effects that can influence surface temperatures but are not related to global warming, their paper said. Examples include volcanic eruptions, which can temporarily cool the climate, and ocean current changes such as el Nino that affect global weather patterns.
Applying their analytical method to the solar output estimates by the Columbia group, Scafetta's and West's paper concludes that "the sun may have minimally contributed about 10 to 30 percent of the 1980-2002 global surface warming."
This study does not discount that human-linked greenhouse gases contribute to global warming, they stressed. "Those gases would still give a contribution, but not so strong as was thought," Scafetta said.
"We don't know what the Sun will do in the future," Scafetta added. "For now, if our analysis is correct, I think it is important to correct the climate models so that they include reliable sensitivity to solar activity.
"Once that is done, then it will be possible to better understand what has happened during the past hundred years.\
Duke University
----------------------
The Duke actually said a MINIMUM of 10-30% was caused directly by the sun and they leaned towards the upward limit of the range.
~Taz~
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GreyFlcn Posted 11:10 am
01 Aug 2007
But his research is based off of Judith Lean's paper 1995
As for Judith Lean's 2005 paper, I thought this was rather insightful.
http://greyfalcon.net/lean2005.png
Thats a pretty damned good fit.
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GreyFlcn Posted 11:13 am
01 Aug 2007
Where it had a similar range 10-25% range MAXMIMUM, but it also had this chart:
http://greyfalcon.net/redline.png
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GreyFlcn Posted 11:15 am
01 Aug 2007
Here's a slightly altered picture of the chart.
(I trimmed off the vertical line, and the ACRIM, while leaving the PMOD)
http://greyfalcon.net/solanki2003.png
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thechartersofdreams Posted 8:43 pm
19 Nov 2007
. . . for a connection between cosmic rays and climate to be interesting, it does not have to account for the already well-explained climate history of the past 100 years. Even a small effect, to which Earth is only sensitive under some conditions, would be an exciting find. The CLOUD experiment does not have to overturn the consensus of the world's climatologists to be a success; it just has to throw a little light on some physics. "In a nutshell," says Kirkby, "we want to go after the microphysics between a cosmic ray and a cloud droplet or ice particle. How significant are they in the atmosphere, or in certain parts of the atmosphere?"
. . . how significant are they in the atmosphere, or in certain parts of the atmosphere?
These sound like important questions for which there are yet no answers.
You can see more about this here:
Will the Debate on Global Warming Ever be Over?
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barry schwarz Posted 5:25 pm
15 Jun 2008
http://www.intellicast.com/Community/Content.aspx?a=130
If the sun is the main contributor to climate change (besides the Milankovitch cycles), one would expect to see a strong and consistent correlation between solar output and global temperatures (leaving aside more arcane theories of cosmic rays). This doesn't appear to be happening, not in the mid-century and not in the last 20 - 30 years. Something seems to be overwhelming the solar cycle effect on climate shifts.
I can think of only two ways around the periodic discrepancies. One is to posit a lag between solar output and global climate response - about 30 years would provide a better fit to the temperatures of the past century. But I don't think anyone has even attempted to demonstrate how such an interval might occur (ocean heat retention?)
Alternatively one could posit the mid-century global dimming hypothesis to explain at least a part of the discrepancy, but then we're straying closer to mainstream AGW theory, and beginning to accept that particles in the atmosphere can have a profound effect on global temperatures (temperature drops coinciding with extreme volcanic activity certainly corroborate the premise for global dimming hypothesis).
Has anyone made a comparison with the amount of aerosols spewed out by industry and stirred up by bombing and such during WWII, with that ejected by massive volcanic eruptions?
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