This is a review from CO2Science.com of an interesting paper looking at Oxygen 18 records in water driven cave formations (stalactite, stalagmite or flowstone) than span a 4000 year period. Here is a basic description from the NZ Climate Centre:
“These deposits occur within karst terranes in subterranean caverns mainly as calcite (CaCO3) precipitated from groundwater that percolated through overlying limestone or marble rock. Interior cave climates and environments are generally stable; temperatures have little annual variation and are usually close to the external local mean annual air temperature. Oxygen and carbon stable isotope values (18O/16O and 13C/12C) obtained from speleothem calcite have been employed at many locations in the world to determine past climate conditions and can be used to interpret environmental changes.”
– Anthony
Reference
Lorrey, A., Williams, P., Salinger, J., Martin, T., Palmer, J., Fowler, A., Zhao, J.-X. and Neil, H. 2008. Speleothem stable isotope records interpreted within a multi-proxy framework and implications for New Zealand palaeoclimate reconstruction. Quaternary International 187: 52-75.
What was done
Two master speleothem (stalactite, stalagmite or flowstone cave deposit) δ18O records were developed for New Zealand’s eastern North Island (ENI) and western South Island (WSI) for the period 2000 BC to about AD 1660 and 1825, respectively. The WSI record is a composite chronology composed of data derived from four speleothems from Aurora, Calcite, Doubtful Xanadu and Waiau caves, while the ENI record is a composite history derived from three speleothems from Disbelief and Te Reinga caves.
What was learned
For both the ENI and WSI δ18O records master speleothem histories, their warmest periods fall within the AD 900-1100 time interval, which is also where the peak warmth of a large portion of the temperature records found in our Medieval Warm Period Project fall (see our Interactive Map and Time Domain Plot).
What it means
Not wanting to acknowledge that the earth was likely as warm as, or even warmer than, it is currently a thousand or so years ago (when the atmosphere’s CO2 concentration was much lower than it is today), the world’s climate alarmists have been loath to admit there was an MWP or Medieval Warm Period anywhere other than in countries surrounding the North Atlantic Ocean. Consequently, the seven independent speleothem records that produced the results reported by Lorrey et al. are of great importance to the ongoing global warming debate, as they greatly advance the thesis that the MWP was indeed a global phenomenon, and that there is thus nothing unusual, unnatural or unprecedented about earth’s current warmth, and that it therefore need not be attributed to the historical increase in the air’s CO2 content.
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“A carbon tax is honest, clear and effective. It will increase energy prices, but low and middle income people, especially, will find ways to reduce carbon emissions so as to come out ahead.”
Everytime my small business is hit with another tax I raise my prices. How is this scheme supposed to do anything at all?
GeoEngineering? Another way to collect taxes and work on Government programs. Once again, some (wo)men think they know everything about the planet and climate and they can’t even predict the weather 10 days out.
The significance of the MWP is that if the MWP were significantly warmer than currently, then no climate ‘tipping point’ exists until we get very substantially warmer than currently, and consequently far in the future (hundreds of years at least).
In fact, because the MWP and the Roman Warm Period both peaked at about the same level, any tipping point is probably a cooling one. That is, as warming occurs, medium and longer term (negative) feedbacks are triggered and we are tipped back into a cooling phase.
FYI, info on the MWP in China.
http://www.springerlink.com/content/gh98230822m7g01l/
The most recent global warming of the late 20th century was almost entirely in the high northern latitutudes. The obvious question is, how is the recent warming different than the MWP? Could our proxy methods alone detect any recent warming in the lower northern and southern latitudes? Extremely doubtful. Proxy methods are just to crude for measuring such subtle temperature fluctuations.
The main difference between the MWP and the current warm period is that the MWP appears to be greater than the current warming. The spatial distribution of the warming appears to be nearly identical. When AGW catastrophists proclaim that the MWP was a regional event, I simply say “So is the current warming! What’s your point?”
On a related note, realclimate.org has an issue with geologists:
http://www.realclimate.org/index.php/archives/2008/08/are-geologists-different/#more-590
It’s obvious to me why geologists are different… There findings disagree with what the AGW crowd says happened.
Brooklyn Red Leg (06:54:45), MattN (09:05:25), Dennis Sharp (09:12:17):
MattN (09:05:25) :
“At least as accurate as bristlecone tree rings…”
You guys must have access to the full paper to make these comments. Is there anyone else here who has read the paper? I didn’t want to pay the $31 to download the full article.
Off-topic, but does anyone remember the Mongol Empire? Link. That got pretty big for a while until the late 13th Century.
It is ironic that these horseman preferred to go to war in winter as competition for scare resources may have contributed to the Empire’s disintegration!
I have heard tales of plans to light off volcaones with nukes to cool the Earth.
Diversions of weather patterns by cloud seeding.
All Frankenstein Monster stuff.
What could possibly go wrong?
Everything, that’s what could go wrong.
Hoskald, a few years a go I wrote a piece about Kyoto in which I concluded,
Kyoto isn’t a real solution, but then it doesn’t matter, because global warming isn’t a real problem.’
All the climate ‘mitigation’ activities being pushed on us, are incredibly costly, but otherwise harmless, because they have no material effect on the Earth’s climate.
Undertaking the kinds of geo-engineering activities described takes into areas where the consequences are not harmless, and could well be harmful or even catastrophic for the Earth.
BTW, the piece from the Independant you reference is the kind of psuedoscience that is designed to impress the Kyoto/IPCC crowd, who, while forever going on about the ‘science’, wouldn’t recognize real science if it was wrapped around a brick and dropped on their collective heads.
I can not get through on the co2science.org link and when I try the address myself. Same in the past.
REPLY; Well thats not an issue I can solve. Links wrok just fine, problem on your end somehow with routing or paranoiaware installed on your PC – Anthony
Interestingly, one of the authors of this study is Salinger, J. That would be Jim Salinger from NIWA (which includes our Met office), whom we have become accustomed to seeing on NZ television breathlessly announcing yet another ‘warmest year/ month/day on record’. But not lately…
The link to co2science.org never works for me
Great article. The Multi proxy framework used to back up the cave results provides for a robust comparison between diverse data sets. In regard to the MWP comments in Table 5 note the warmest period (“very warm”) occurred between 950-1050AD, with the period 1050 -1200AD also warmer than present. The little ice age is also well represented in the O18 data.
Readers may also be interested in this earlier (2002) paper from Geophysical Research Letters that confirms a MWP in NZ and the southern hemisphere. This is cited in the current study.
Evidence for a ‘Medieval Warm Period’ in a 1,100 year tree-ring reconstruction of past austral summer temperatures in New Zealand. Edward R. Cook, Jonathan G. Palmer, Rosanne D. D’Arrigo. Geophys. Res. Lett., 29(14), 1667, doi:10.1029/2001GL014580.
Abstract
The occurrence of the Medieval Warm Period (MWP) in the Southern Hemisphere is uncertain because of the paucity of well-dated, high-resolution paleo-temperature records covering the past 1,000 years. We describe a new tree-ring reconstruction of Austral summer temperatures from the South Island of New Zealand, covering the past 1,100 years. This record is the longest yet produced for New Zealand and shows clear evidence for persistent above-average temperatures within the interval commonly assigned to the MWP. Comparisons with selected temperature proxies from the Northern and Southern Hemispheres confirm that the MWP was highly variable in time and space. Regardless, the New Zealand temperature reconstruction supports the global occurrence of the MWP.
Beautiful! Absolutely Beautiful! Makes me want to vist New Zealand.
The authors of the paper do not attribute warmer temperatures around 1000 AD to global conditions but to local changes in circulation patterns. They also report the C and O isotope ratio’s not temperatures but indicate that less negative numbers result from warmer temperatures and more negative temperatures from cooler temperatures.
Purakanui,
The answer is yes. Also the same Jim Salinger who was mildly disparaging on the TV1 television news when sceptical meteorologist Prof Augie Auer passed away a year or so back. More specifically with resect to Augie’s views on AGW.
So it should be no surprise when the abstract to the speleothem article omits comment on the implications of the work regarding a global MPW and what it means in terms of comparison with modern wartming.
But note also that Salinger is a great scientist who has been researching Holocene climate for decades and has published temperature curves for New Zealand that demonstrate multiple warming and cooling phases, and notably a very strong early Holocene climatic maximum/optimum. I suspect he might be a closet climate realist who hasn’t “come out” via any form of public statement.
Huuhm, have to check RC, how the ‘non-scientists’ there try muddle through and around that.
CO2 Science is a great web site for imformation
http://co2science.org/index.php
‘Medieval Warm Period Record of the Week
Was there a Medieval Warm Period? YES, according to data published by 650 individual scientists from 380 separate research institutions in 40 different countries … and counting! This issue’s Medieval Warm Period Record of the Week comes from Southern California, USA. To access the entire Medieval Warm Period Project’s database,’
As I understand it and I don’t know the full story, their web site got shut down. But they are back better than ever.
The words ‘Medieval warm period’ are not in the body of the paper but do occur in the references.
Ed Scott (10:55:53) :
. . . Giant mirrors in space
Some scientists suggest it would be possible to deflect sunlight with a giant mirror or a fleet of small mirrors between the Earth and the Sun.
This is honestly a good idea for sometime in the (we hope) far future. Thousands of square miles of aluminized mylar, like the old Echo 1 satellite. Once they get them up there, they’ll be able to move them to the L4 and L5 Lagrange points where they can reflect extra sunlight to counter the coming ice age.
Try this link and you can click through from there
http://www.co2science.org/about/rss.html
Mark (11:13:41) : On a related note, realclimate.org has an issue with geologists:
http://www.realclimate.org/index.php/archives/2008/08/are-geologists-different/#more-590
It’s obvious to me why geologists are different… Their findings disagree with what the AGW crowd says happened.
Checking in with RC, I found this: Svensmark [said] that the 90% confidence in the human influence on recent trends is derived only from models (not true).
I had to laugh at the implications of these scantily-clad nubile female models being the human influence on certain trends which RC maintain is not true. Good luck, geologists!
Mike McMillan
Alas, the solar wind would blow those Mylar reflectors out of the solar system, with far more force than the weak gravitational effect of the LaGrange points. Anything light enough to launch and big enough to reflect a decent amount of light will sail quite well.
Al Gore has really stepped in it this time. He could have spent the rest of his global warming career collecting money by spreading fear over events that were a centure or at least half century in the future. Oh, but that wasn’t good enough for Big Al. He’s now told the biggest global warming whopper of his alarmist career:
AL GORE HAS GUARANTEED THAT THE NORTHERN POLAR ICE CAP WILL BE COMPLETELY GONE IN FIVE YEARS!!!
When I heard this I assumed it was a rumor started by skeptics to make Gore look bad. It wasn’t until I viewed the video that I realized what Gore had done. Gore has started a five year credibility countdown timer ticking and it’s up to all of us to make sure that he is held accountable and proven to be a fraud when his dire prediction aimed at drumming up support doesn’t come close to comming true.
The mainstream media isn’t going to let this video see the light of day because they, unlike Al, understand the precarious position in which he has placed himself.
It is therefore up to us to spread the word about Big Al’s prediction. He must be exposed for the fearmongering opportunist that he has become.
To view the video, please visit the following site and click on the picture of Big Al holding up five fingers.
http://www.hootervillegazette.com
While visiting this site, you might want to watch a preview of the film “Not Evil, Just wrong” or watch “The Great Global Warming Swindle” which is found in the video section. Happy Viewing!!!