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Author Topic: How much do cosmic rays vary over time?  (Read 5469 times)

Offline litespeed

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How much do cosmic rays vary over time?
« on: 07/01/2010 16:32:39 »

I have seen estimates that cosmic rays been as much as 200 percent higher centuries ago and that they are at the highest now then they have been in 50 years. However, I have not been able find a graph of cosmic rays over time. From NASA:

http://news.softpedia.com/news/Cosmic-Ray-Concentrations-Highest-in-Half-a-Century-122993.shtml

This is important because I have seen some claims that as much as 2/3 of GW 20th century warming can be correlated with cosmic rays.

"In practical terms, says Dr. Shaviv, "The operative significance of our research is that a significant reduction of the release of greenhouse gases will not significantly lower the global temperature, since only about a third of the warming over the past century should be attributed to man."

http://www.scienceagogo.com/news/20030713212408data_trunc_sys.shtml

This is not the only citation I have concerning this, but it is pointless if I can not find chart showing WHEN cosmic rays were double in the past 1,000 years. Any ideas where else to look? I will pick up on this research myself, but would not mind some help!

THANKS

The importance of cosmic rays to climate is illustrated by the price of grain in the middle ages:

"For all ten solar cycles between 1600 and 1700, high wheat prices coincided with low activity, and vice versa. The probability of this happening by chance is less than 1 in 500, the researchers say."

http://www.bioedonline.org/news/news.cfm?art=686
« Last Edit: 07/01/2010 16:59:35 by litespeed »


 

Offline Madidus_Scientia

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How much do cosmic rays vary over time?
« Reply #1 on: 08/01/2010 13:12:07 »
There's a difference between cosmic rays and solar radiance, did you mean solar radiance? I would tend to think so since you refer to the growth of grain.

If so then here's one:



Note how solar radiance levels out while temperature continues to rise. This is why climatologist believe the current warming is due to greenhouse gasses, and not solar radiance.

And here's a dozen or so papers that reach the same conclusion:

    * Erlykin 2009: "We deduce that the maximum recent increase in the mean surface temperature of the Earth which can be ascribed to solar activity is 14% of the observed global warming"
    * Benestad 2009: "Our analysis shows that the most likely contribution from solar forcing a global warming is 7 ± 1% for the 20th century and is negligible for warming since 1980."
    * Lockwood 2008: "It is shown that the contribution of solar variability to the temperature trend since 1987 is small and downward; the best estimate is −1.3% and the 2σ confidence level sets the uncertainty range of −0.7 to −1.9%."
    * Lockwood 2008: "The conclusions of our previous paper, that solar forcing has declined over the past 20 years while surface air temperatures have continued to rise, are shown to apply for the full range of potential time constants for the climate response to the variations in the solar forcings."
    * Ammann 2007: "Although solar and volcanic effects appear to dominate most of the slow climate variations within the past thousand years, the impacts of greenhouse gases have dominated since the second half of the last century."
    * Lockwood 2007: "The observed rapid rise in global mean temperatures seen after 1985 cannot be ascribed to solar variability, whichever of the mechanism is invoked and no matter how much the solar variation is amplified."
    * Foukal 2006 concludes "The variations measured from spacecraft since 1978 are too small to have contributed appreciably to accelerated global warming over the past 30 years."
    * Scafetta 2006 says "since 1975 global warming has occurred much faster than could be reasonably expected from the sun alone."
    * Usoskin 2005 conclude "during these last 30 years the solar total irradiance, solar UV irradiance and cosmic ray flux has not shown any significant secular trend, so that at least this most recent warming episode must have another source."
    * Solanki 2004 reconstructs 11,400 years of sunspot numbers using radiocarbon concentrations, finding "solar variability is unlikely to have been the dominant cause of the strong warming during the past three decades".
    * Haigh 2003 says "Observational data suggest that the Sun has influenced temperatures on decadal, centennial and millennial time-scales, but radiative forcing considerations and the results of energy-balance models and general circulation models suggest that the warming during the latter part of the 20th century cannot be ascribed entirely to solar effects."
    * Stott 2003 increased climate model sensitivity to solar forcing and still found "most warming over the last 50 yr is likely to have been caused by increases in greenhouse gases."
    * Solanki 2003 concludes "the Sun has contributed less than 30% of the global warming since 1970".
    * Lean 1999 concludes "it is unlikely that Sun–climate relationships can account for much of the warming since 1970".
    * Waple 1999 finds "little evidence to suggest that changes in irradiance are having a large impact on the current warming trend."
    * Frolich 1998 concludes "solar radiative output trends contributed little of the 0.2°C increase in the global mean surface temperature in the past decade"
« Last Edit: 08/01/2010 13:17:19 by Madidus_Scientia »
 

Offline BenV

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How much do cosmic rays vary over time?
« Reply #2 on: 08/01/2010 13:44:05 »
Looking at the NASA post, it is cosmic rays rather than radiance that Litespeed is referring to - the strength of which seems to be inversely proportional to solar activity.

I think cosmic ray intensity would be pretty hard to model, as it depends on solar wind, solar activity, Earth's magnetic field, other magnetic field fluxes, latitude & longitude etc.  That's probably why graphs of cosmic rays vs time are hard to come by.

Having said that, there's almost certainly some people far more intelligent than I who are modelling it!
 

Offline Madidus_Scientia

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How much do cosmic rays vary over time?
« Reply #3 on: 08/01/2010 13:56:03 »
Ah, I see. I didn't read the articles, my bad. But the papers I showed do discuss both solar radiance and cosmic rays.
 

Offline litespeed

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How much do cosmic rays vary over time?
« Reply #4 on: 08/01/2010 19:45:51 »
Ben

You sell yourself short.  Cosmic Ray strength can be measured over time in much the same way as the age of organic matter can be measured by relative ratios of C14.  However, Cosmic Rays have something to do with beryllium. What I have yet to determine is WHAT is used as the proxy material, and where do I find a graph.

Clearly such a graph exists, since NASA itself lists Cosmic Rays as varying over the last 1,000 years by as much as 200%. This is important in two ways. First, cosmic rays themselves are strongly implicated the larger ice age cycle driven by the earth's position in our own galactic spiral; with corresponding increases and decreases in cosmic rays over geologic time.

Second, cosmic ray variance within historic times is a proxy for solar activity. The more cosmic rays, the lower the solar output and the lower the protective effect against cosmic rays.  Lower output and more cosmic rays BOTH would tend to force a cooling effect.

Lower solar output is obviously associated with cooling. However, cosmic rays seem increasingly associated with low level cloud formation that reflects more light energy back into space then it does reflecting heat back to the surface. I have seen reports that solar activity has generally increased in the last century or so so, and has force warming in both ways.

However, NASA points out cosmic rays are now at a 50 year high. Why? If solar output has been high recently, that should mean fewer rays, not more! Further, we have the lazy sunspot cycle 24. This means lower solar activity then if sunspots increased. That certainly is consistent with the higher rays NASA reports.

I have not provided citations since my investigation is WAY less then complete and I do not have my bookmark library organized yet. I would say my Cosmic Ray bookmark list is probably less then 1/3 filled. Until I find a cosmic ray chart that compares rays with temperature over very long historical time periods I don't want to claim anything.

So far the closest I have is an interesting chart showing grain prices in Europe with sunspots observed. This is something that I have known about for decades. I believe even the original Adam Smith stated he could predict grain prices by sun spots.

http://www.bioedonline.org/news/news.cfm?art=686

PS: CERN has done cosmic ray experiments with large cloud chambers that throws some question on whether the rays produce low level clouds. However, the experiments have drawn criticism for a variety of reasons. I believe the strongest criticism is they are much removed from the actual atmospheric 'column' in nature, and can not include a number of variables that exist in nature.

In the mean time, the current actual climate is getting a bit scary. My North Georgia Mountain thermometer reads 21%F at this very moment. The daytime temperature has not gone above 32% for the better part of a week.  This has been hard on the cold hardy pansies I routinely plant in late December. And it SNOWED! This is the very first time I have ever almost not been able to drive up my little mountain.

If this keeps up I will need to press my rear engine 1965 Corvair convertible into Winter Service. Its something I used to do up North when it become similarly inclement. The car can just about climb trees in the snow....

Midwest bracing for heavy snow -- wind chills of 50 below!
Cold weather packing hospitals...
Texas power usage sets another winter record...
« Last Edit: 08/01/2010 20:11:30 by litespeed »
 

Offline jason_85

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How much do cosmic rays vary over time?
« Reply #5 on: 12/03/2010 14:37:23 »
I just wrote an article on cosmic ray influence on temperature if anyone's interested:

newbielink:http://www.warmdebate.com/jason/cosmic-ray-levels-and-cloud-forming-effects-temperature [nonactive]
 

Offline LeeE

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How much do cosmic rays vary over time?
« Reply #6 on: 12/03/2010 16:11:42 »
Is it safe to assume that only solar cosmic rays are significant here?
 

Offline frethack

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How much do cosmic rays vary over time?
« Reply #7 on: 12/03/2010 20:17:19 »
I actually think he is referring to the work of Svensmark.  In that case, galactic cosmic rays are the focal point
 

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How much do cosmic rays vary over time?
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