How was the Sierra Nevada Mountains 3.0 degrees warmer during medieval warming period?

Question

"Working with dead tree trunks located above the current treeline on tephra-covered slopes of Whitewing Mountain and San Joaquin Ridge.....the five researchers say "the Medieval forest on Whitewing was growing under mild, favorable conditions (warm with adequate moisture)," as indicated by "extremely low mean sensitivities [to stress] and large average ring widths." More specifically, they conclude, as reported in their abstract, that annual minimum temperatures during the Medieval Climatic Anomaly in the region they studied were "significantly warmer" (+3.2°C) "than present,".....Once again, we have another example of a paleoclimate study in which the Medieval Warm Period is determined to have been significantly warmer than it is currently....."

http://co2science.org/articles/V10/N4/C3.php

Peer reviewed but will be ignored by the alarmists.

As Jones and his ilk proclaimed-"we need to get rid of the medieval warming period."

Answer 1

Proxy climate information using tree rings, and other "accepted means" of retrospective information gathering, does have some difficulties, however, there is supporting empirical anecdotal information of a warmer period of time complementing this report.



What does it mean? It means the climate changes, with or without an increase in greenhouse gasses. Or, there was a significant increase in greenhouse gasses, from a non-anthropogenic source.

Answer 2

Your link is to an antiwarming selective quotations site. Climate reconstructions have shown the MWP clearly for very many years, and as you know not all locations are affected equally.



The actual paper is from Quaternary Research, vol 66, p. 273.



Here is the abstract, which is publicly available; google "quaternary research". Read, mark, and inwardly digest the last ten words:



Deadwood tree stems scattered above treeline on tephra-covered slopes of Whitewing Mtn (3051 m) and San Joaquin Ridge (3122 m) show evidence of being killed in an eruption from adjacent Glass Creek Vent, Inyo Craters. Using tree-ring methods, we dated deadwood to AD 815–1350 and infer from death dates that the eruption occurred in late summer AD 1350. Based on wood anatomy, we identified deadwood species as Pinus albicaulis, P. monticola, P. lambertiana, P. contorta, P. jeffreyi, and Tsuga mertensiana. Only P. albicaulis grows at these elevations currently; P. lambertiana is not locally native. Using contemporary distributions of the species, we modeled paleoclimate during the time of sympatry to be significantly warmer (+3.2°C annual minimum temperature) and slightly drier (−24 mm annual precipitation) than present, resembling values projected for California in the next 70–100 yr.



Edit: are you being deliberately deceptive, or just pig-ignorant, in failing to distinguish the peer reviewed paper from your link's agenda-driven commentary? I really want to know.

Answer 3

OK Mr. Science let’s look at this.



The authors compare their “reconstruction” favorably with those of Scuderi and Graumlich:



Graumlich, L.J. 1993. A 1000-yr record of temperature and precipitation in the Sierra Nevada. Quaternary Research 39: 249-255.



Scuderi, L. 1993. A 2,000-year record of annual temperatures in the Sierra Nevada Mountains. Science 259: 1433-1436.



Let’s start with “Lonesome” Louis Scuderi.



Tree-ring records are available here (ITRDB):



http://hurricane.ncdc.noaa.gov/pls/paleo/fm_createpages.treering



Try to find Scuderi’s data (you can search by name, so it is not hard). Hell, you can’t even find Louis’s name there – not a single time. The reason for that is that Louis’s tree-ring data were inaccurately dated and, therefore, his reconstruction was built on a foundation of random noise.



I’ll give Louis credit though, when he was shown the evidence proving his data were bad (within a week of his 1993 Science article), he never tried to publish another article using that data (try to find one).



Graumlich’s worthless reconstruction is a little tougher to show you because she does have some data on the ITRDB, and although I know some are no longer available, her main site (Crabtree) from the Sierra Nevada is there.



Still, there is something interesting going on here. The Quality Control program used to check data is COFECHA. A portion of the ITRDB’s COFECHA output for Lisa’s site can be seen here.



ftp://ftp.ncdc.noaa.gov/pub/data/paleo/treering/measurements/correlation-stats/ca638.txt



There are two things to notice:



The date on the output is: 15 Dec 2006. That suggests that the data have been changed and no longer reflect the data she used in building here 1993 reconstruction,



And, there is more. The output also contains the following statement: <<”Notes: This chronology has been revised and updated.”>>



Whoops, looks like we’ll never be able to replicate her original research.



Good thing, too, because her data also were not correct.



Further, you can find a draft of the Millar, et. al. paper here:



http://www.fs.fed.us/psw/programs/snrc/staff/millar/Whitewing_txt.pdf



Check out their “References”. In it they list the tree-ring data that they downloaded from the ITRDB. You’ll notice (if you bother to look) that neither Louis’s or Lisa’s data is in that group.



On the other hand, they downloaded data collected by Graybill and LaMarche, but did not show how these data compared to their own. The reason is that Millar’s et. al. data suck. And this too, you can see for yourself – because their data is listed on the ITRDB.



Check out the COFECHA output that was run on their data. Especially look at the bullsh!t inter-series correlations.



It's here:



ftp://ftp.ncdc.noaa.gov/pub/data/paleo/treering/measurements/correlation-stats/ca644.txt



There are numerous other “fatal” errors in their paper, but if you knew what you were talking about, you would have already spotted them and never asked such a pathetically lame and scientifically illiterate question.



=====

edit –



I do not mean to slam everyone involved here. One of the authors J. C. King and one of Graumlich’s referenced co-authors A. H. Lloyd are great, smart people. It just worked out that Graumlich was their major professor when they were getting their PhDs. It happens like that sometimes.

Answer 4

I think you are using data to mislead. First, I have been scuba diving for 42 years and have seen the change in the oceans. Also there is a report that came out today that I just read, from the NOAA this is the National Oceanic and Atmospheric Administration. This report says June (last month) was the hottest June on record for the world. Also from Jan to June of this year was the hottest Jan to June on record. The coral on the Great Barrier Reef is dieing because the water is getting warmer, this is facts all the ocean people agree with. They are now doing studies on this reef system to get information before it is dead. The reefs around the Keys of Fla. are in the same shape. If the ocean gets warmer the planet gets warmer, any person who thinks can see this. The Northwest Passage was open for the first time in mans history. To look at the glaciers in retreat and all the other things, not the papers people use to say the planet is warmer, that are happening around us and to still say "Hey it is Gore trying to scare us" is when people let their hate of others blind them to what is in front of their face. People let the hate inside them blind them from the real world. You do not need a collage education to see what is happening. Deal with what ever it is that fills your head with hate and then look at where the world is today and where it was when you were a kid.

Answer 5

Who is going to ignore this? I bet you have ignored it You didn't even read it, did you? You just took a biased website's word on the researchers' point-of-view didn't you?



First a warm MWP says nothing conditions in the near future nor the effects of an almost 40% increase in C02 in the atmosphere. Second, the authors note that warming is continuing and reduced snowpack and growing-season drought is uppon us.



Because you were not so helpful as to link the study you refer to, I took the time myself to provide the link (below).



"This situation resembles 20th–21st century trends in the Sierra Nevada, where increasing minimum temperatures, especially in winter, are reducing snowpack accumulation, accelerating early run-off, and leading to effective drought during the spring−fall growing season despite lack of annual average decrease in precipitation (Dettinger et al., 2004)."



It is good that you are actually looking at some research. But if you want to cite the authors as experts then at least read what they say. Miller, King et al -- like all climate researchers -- are telling us that global warming is real and it's effects are already being noticed.



Don't ignore these researchers. Read what they are telling you. (Read the actually study, some some political site's distortion.) Stop denying that global warming is real, and stop pretending that there are any climate researchers who still question it.

Answer 6

Personally, I think too much is made of tree rings but it is interesting nonetheless. I think the MWP might have been much warmer than some suggest. The Sargasso Sea proxy showed a similar result as well but it wasn't that warm

Answer 7

Looking OBJECTIVELY at the facts…



The article you have quoted is from CO2 Science and not surprisingly it’s biased. The quote is a selectively edited extract from the 2005 revision of “Late Holocene Forest Dynamics, Volcanism and Climate Change at Whitewing Mountain and San Joaquin Ridge, Mono County, Sierra Nevada, CA, USA” by Millar, King, Westfall, Alden and Delaney.



The temperature anomaly of 3.2°C relates to the January paleoclimatic figure for Whitewing Mountain (800 to 1350CE) as compared to the 1971-2000 base period mean.



If CO2 Science were being more open and honest they would have used the annual mean and not selected a specific month. The temperature difference is therefore not 3.2°C but 2.3°C (I’m being generous here as this figure is a somewhat optimistic estimated adjustment extrapolated from model values).



Then we need to account for the fact that a historical base period mean has been used, this is going to give a larger anomalous value because the temperature is being compared to a period which was colder than it is now. It is therefore necessary to adjust the figure downward by a further 0.5°C.



So the true difference in temperature isn’t 3.2°C but 1.8°C. Still significant but almost half of that claimed by the oil company (sorry, did I say oil company, I meant to say CO2 Science. I guess they don’t want people to know that they’re a front organisation operated and funded jointly by the Western Fuels Alliance and Exxon Mobil).



So the real question is – why was Whitewing Mountain 1.8°C warmer during the Holocene than it is now and the skeptics themselves can provide the answer to this.



We can turn now to Al Gore and his Inconvenient Truth movie. In this he implies that the snows of Kilimanjaro have melted significantly because of global warming. The skeptics point out that mountain temperatures are affected by micro and mesoclimates more than by macroclimates and as such Gore’s claims should be ignored. And the skeptics are quite right.



Being an afforested and volcanic mountain, Whitewing will be subjected to significant climatic fluctuations caused by factors unique to that mountain. A change in the hydrology or flora can significantly affect microclimates, in afforested mountain environments changes of a significant magnitude can happen quite quickly and could be the result of a volcanic eruption or degassing, ground movement, forest fires, reforestation, deforestation, invasive and / or destructive species, human activities etc.



Without studying this further I can’t say for certain what caused changes to the microclimates on Whitewing Mountain but it’s most likely one of the aforementioned – these account for pretty much all such changes in these environments.



One thing is for certain, the Medieval Warm Period did not cause temperatures to increase by 3.2°C. Not least because the figure is an exaggeration but because the MWP barely affected the western US, it’s effects were felt more in the Eastern US but most of all in Europe.



There were some places that were warmer in Medieval times than they are now but I very much doubt the Sierra Nevada was one of them. In fact, when we look at all the sites that were studied by Millar et al (Carson Range, Grizzly Peak, San Joaquin Ridge and Whitewing Mountain) the temperature across all the sites was virtually identical to the present temperature.



Isn’t it strange what happens when you look objectively at the broader picture and don’t just select a single value and exaggerate it?

Answer 8

when climate change occurs, as the difference between the MWP and LIA, jet streams shift and climactic conditions shift. I see skeptics constantly bringing up the 1930s in the US and how it was as warm, or even warmer, than today in the US. This is because the jetstream switched positions. However, there is no more heat being provided to the planet. Therefor the warmth just gets redistributed.

Answer 9

Please note Figure 2 in the article which I use in my source. You will note an orange spot in the area of the Sierra Nevada Mountains. It is interesting how denialists believe scientists when they hear what they want to hear.yet slander these same scientists when they hear what they do not want to hear. Please also note that the lead author of that study is the infamous Michael Mann.



Natural climate change does occur. No one, or at least no scientist, says that natural climate change does not occur. One characteristic of natural climate change is that it has regional variability as well as temporal variability.