Solar proton event seen in paleo records (Carbon 14 in Tree Rings)

Watts Up With That? ^ | March 12, 2013 | Anthony Watts

[Ernest_at_the_Beach]

From the AGU weekly highlights:

Large solar proton event explains 774-775 CE carbon-14 increase

Tree ring records indicate that in 774-775 CE, atmospheric carbon-14 levels increased substantially. Researchers suggest that a solar proton event may have been the cause. In solar proton events, large numbers of high-energy protons are emitted from the Sun, along with other particles. If these particles reach Earth’s atmosphere, they ionize the atmosphere and induce nuclear reactions that produce higher levels of carbon-14; the particles also cause chemical reactions that result in depletion of ozone in the ozone layer, allowing harmful ultraviolet radiation to reach the ground.

A previous group of researchers suggested that to cause the observed eighth century carbon-14 increase, a solar proton event would have had to be thousands of times larger than any that has been observed from the Sun. However, Thomas et al. believe that group’s calculations were incorrect. They modeled the atmospheric and biologic effects of three solar proton events with different energy spectra and fluences (number of protons per area). They find that an event with about 7 or more times greater fluence (depending on the spectrum) than an observed October 1989 solar flare event could explain the 774-775 CE carbon-14 enhancement. With a hard (high-energy) spectrum, an event with this fluence would result in moderately damaging effects on life but would not cause a mass extinction. They rule out an event with a softer spectrum because such an event would cause severe ozone depletion and mass extinction, which were not observed in the eighth century. The authors estimate that solar proton events of this magnitude occur on average once in a thousand years, and more often if the estimate is based on astronomical observations of flares on Sun-like stars. They note that although that may seem low, such an event would have severely damaging effects on the technology on which society relies.

Source:
Geophysical Research Letters, doi:10.1002/grl.50222, 2013 http://onlinelibrary.wiley.com/doi/10.1002/grl.50222/abstract

Title:
Terrestrial effects of possible astrophysical sources of an AD 774-775 increase in carbon-14 production

Abstract:

We examine possible sources of a substantial increase in tree ring¹⁴C measurements for the years AD 774-775. Contrary to claims regarding a coronal mass ejection (CME), the required CME energy is not several orders of magnitude greater than known solar events. We consider solar proton events (SPEs) with three different fluences and two different spectra. The data may be explained byan event with fluenceabout one order of magnitude beyond the October 1989 SPE.Two hard spectrum cases considered here result in moderate ozone depletion, so no mass extinction is implied, though we do predict increases in erythema and damage to plants from enhanced solar UV.We are able to rule out an event with a very soft spectrum that causes severe ozone depletion and subsequent biological impacts.Nitrate enhancements are consistent with their apparent absence in ice core data. The modern technological implications of such an eventmay beextreme, and considering recent confirmation of superflares on solar-type stars, this issue merits attention.

Authors:
Brian C. Thomas, Keith R. Arkenberg and Brock R. Snyder II: Department of Physics and Astronomy, Washburn University, Topeka, Kansas, United States;

Adrian L. Melott: Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas, United States.

###

[Darksheare]

I don’t recall hearing if anything similar was noted about the Carrington flare.

[Deathtomarxists]

That explains all the crazyness that erupted at that time.

[EEGator]

What is CE?

[DannyTN]

Doesn’t most Carbon-14 dating depend on the assumption of a constant level of production of Carbon-14 in the atmosphere. It also depends on no groundwater leaching of carbon-14 into or out of the sample.

[Ernest_at_the_Beach]

Coronal Ejection or maybe Coronal Explosion.

Terminology used by Solar Scientists.

See:

Coronal mass ejection

[Psalm 73]

"What is CE?"

That's "A.D." for athiests.
(CE = "Childish Enlightenment")
They can't bring themselves to admit that Jesus Christ is the center of human history.

[Psalm 73]

Sure - I know EC stands for “Common Era”, as BCE stands for “Before the Common Era”

[Ernest_at_the_Beach]

Maybe Coronal Event....

Another ref:

Large solar proton event explains 774-775 CE carbon-14 increase

[Ernest_at_the_Beach]

Could be Carbon Enhancement.....

[norwaypinesavage]

"such an event would have severely damaging effects on the technology on which society relies."

Oh Noes! This means we'll have to give up SUVs and increase taxes and the size of government, and give up on gasoline.

[Ernest_at_the_Beach]

From the link at #9:

could explain the 774-775 CE carbon-14 enhancement.

[Ernest_at_the_Beach]

Leftie politicians will be right on that very soon.

[EEGator]

Thank you everyone.

[winodog]

CE = Christ Era
BCE = Before Christ Era

[Ernest_at_the_Beach]

ScienceShot: What Struck Earth in 775?

**********************************************************

by Ken Croswell on 3 June 2012, 1:00 PM |

Credit: Adrian Pingstone/Wikimedia Commons

In 775 C.E., while Charlemagne was ruling his Frankish kingdom, something mysterious struck Earth. An analysis of the rings of two Japanese cedar trees (typical tree rings shown above), reported online today in Nature, reveals that from 774 to 775 C.E., the atmospheric level of radioactive carbon-14 jumped by 1.2%. This indicates that cosmic rays—high-speed, charged particles from space—bombarded our planet and converted some atmospheric nitrogen-14 into carbon-14. Earlier work had found a rise in radioactive carbon during the same decade; the new discovery means that scientists have been able to narrow down the date of impact to within just 1 year. The scientists argue against two logical suspects: solar flares are too weak to do the job, and no supernova explosion was seen at the time, nor do any nearby supernova remnants date back to Charlemagne's time. There's also nothing unusual in the history books. So the cause remains a mystery, but whatever it was, something similar could presumably strike again.

[winodog]

I should have read the rest of the thread before posting.
There are many answers : )

[ModelBreaker]

I call it “Christian Era.”

[NonValueAdded]

ping to 16. historical xref

[EEGator]

You were being helpful, that’s good by me. :)