From UCSB News: (h/t to David Schnare) UCSB Geologist Discovers Pattern in Earth’s Long-Term Climate Record
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(Santa Barbara, Calif.) –– In an analysis of the past 1.2 million years, UC Santa Barbara geologist Lorraine Lisiecki discovered a pattern that connects the regular changes of the Earth’s orbital cycle to changes in the Earth’s climate. The finding is reported in this week’s issue of the scientific journal Nature Geoscience.
Lisiecki performed her analysis of climate by examining ocean sediment cores. These cores come from 57 locations around the world. By analyzing sediments, scientists are able to chart the Earth’s climate for millions of years in the past. Lisiecki’s contribution is the linking of the climate record to the history of the Earth’s orbit.
It is known that the Earth’s orbit around the sun changes shape every 100,000 years. The orbit becomes either more round or more elliptical at these intervals. The shape of the orbit is known as its “eccentricity.” A related aspect is the 41,000-year cycle in the tilt of the Earth’s axis.
Glaciation of the Earth also occurs every 100,000 years. Lisiecki found that the timing of changes in climate and eccentricity coincided. “The clear correlation between the timing of the change in orbit and the change in the Earth’s climate is strong evidence of a link between the two,” said Lisiecki. “It is unlikely that these events would not be related to one another.”
Besides finding a link between change in the shape of the orbit and the onset of glaciation, Lisiecki found a surprising correlation. She discovered that the largest glacial cycles occurred during the weakest changes in the eccentricity of Earth’s orbit –– and vice versa. She found that the stronger changes in the Earth’s orbit correlated to weaker changes in climate. “This may mean that the Earth’s climate has internal instability in addition to sensitivity to changes in the orbit,” said Lisiecki.
She concludes that the pattern of climate change over the past million years likely involves complicated interactions between different parts of the climate system, as well as three different orbital systems. The first two orbital systems are the orbit’s eccentricity, and tilt. The third is “precession,” or a change in the orientation of the rotation axis.
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If feedbacks were dominantly positive, the earth would either move towards a permanent and progressively colder ice age, or a Venus like state of incredible heat.
@red432 (12:46:18) :
“So if I stop going north to ski and south to surf every year will this prevent the Earth tilt increase and avert catastrophic climate change?
Not enough data. How much do you weigh? How much does your surfboard and skis weigh?
Just a comment on the comments….
Look, I dont want to have to go do a search on what Milankovitch specifically relates to, but I DO know it’s news to me as a layman.
Not the concepts of it.. I’ve read that before… I mean the scientific correlations backed up by relatively hard – provable- facts.
So, if this is old ammo, why hasnt it been loaded and fired many times? Even if it’s a TOTAL REHASH, it STILL needs to be gotten out there.
Why are people complaining that she is following the Milankovich cycle theory? This is one of the big problems in science. Everyones so keen to scream how important replication is to the scientific method and independant verification yet as soon as someone actually undergoes that practice and finds new evidence to support it then people shout them down. This is why replication is so poorly done in modern science because although people say they think its important in scientific method thier not actually bothered about it at all.
OT this is a good conspiracy theory wonder if there is any truth to it, two trillion barrels of oil under the rockies
http://www.abovetopsecret.com/forum/thread558871/pg1
mike core (13:00:47) :
Still very little that is new.
Carbon dioxide was like any other molecule, going about, minding its own business… until Al Gore arrived.
Al Gore pointed an accusing finger at an innocent little molecule. But CO2 was proven innocent by scientists that clearly showed that the sun as well as the eccentricity, tilt and precession of the Earth was the real culprit to climate changes on Earth.
However, Al Gore won’t stop at such serious and robust scientific details, he will come back and blame the speed at which we expel CO2… which in his (cooked) science book is responsible for the changes in the Earth’s eccentricity, tilt and precession.
I’ve never heard of it, so it passes as “news” to me.
Thanks for posting it.
“Lisiecki found a surprising correlation. She discovered that the largest glacial cycles occurred during the weakest changes in the eccentricity of Earth’s orbit –– and vice versa. She found that the stronger changes in the Earth’s orbit correlated to weaker changes in climate. “This may mean that the Earth’s climate has internal instability in addition to sensitivity to changes in the orbit,” said Lisiecki.”
I’d recommend caution interpreting “internal”. The solar system (which includes things like Earth’s moon) is full of confounding. Noting a relationship between X & Y is great; noticing that they both relate to Z is sometimes even better.
None of this is new news, but it is real climate science.
Having ploughed through Montford’s book on the Hockey Stick Illusion and being an avid reader of WUWT and Climate Audit, I have no choice but to take every comment and report by any member of the Establishment climate clique with a huge sack of salt.
I still cannot believe so much of the original AGW BS was based on rare, split bark, bristlecone pines, where the ‘true’ temperature is supposedly recorded, rather than using normal trees, where the growth rings are inconveniently small and heretically do not prove global warming.
But even worse – tree ring growth to measure temperature changes? What about variations in rainfall, droughts, CO2 fertilisation, nitrogen fertilisation from lightning or forest fires, the effect of wind? The list goes on and on.
But in reality, it was just another unjustified scare story, a ploy to help promote the politicians’ need for more taxes. In return, as their side of the bargain, the politicians would provide ever larger grants to fund the dubious science of global warming.
pgosselin (12:59:24) :
Keep posting, Anthony!
http://news.cnet.com/8301-13578_3-20001825-38.html?part=rss&subj=news&tag=2547-1_3-0-20
h/t Drudge
You have to read this too! This is not over!
http://www.wired.com/epicenter/2010/04/fcc-next/?intcid=inform_relatedContent
Check out Lisiecki’s CV at:
http://www.lorraine-lisiecki.com/lisieckiCV.pdf
The Treering analyses here did show a Medieval Warm Period and LIA:
http://pages.science-skeptical.de/MWP/MedievalWarmPeriod.html
Note, especially: Luckmann (Central Canada), (among others) Linderholm (Scandinavia), Seppa (using tree pollen profiles from Fennoscandian lake sediments), Treydte (Karakoram Mtns), Zhang (Tibetan Plateau), etc.
Their science may be in question, but so are the other analytical methods in my opinion.
(Two cents from a non-scientist)
“This won’t fly. She does nor sound like a crack pot. Defund her and make sure she never gets anything in print. ” P. Jones
Has anyone read Lisiecki’s paper? I have only read the abstract that Klausb (13:10:45) provided. As others have observed, it seems clear to me that Lisiecki understands the Milankovich theory. IMO, Lisiecki’s contibution to science will depend on the extent to which her analysis of climate by examining ocean sediment cores from 57 locations around the world links the climate record to the history of the Earth’s orbit.
“So let’s face it, the ice is coming and there ain’t nothing we can do about it.”
According to 30,000 scientists we can counter it with CO2. I’ll be counting on their good work to save us all.
Ocean cores provide an excellent potential history of that environmental domain, but seabed temperature cyclicity may be influenced by a whole raft of variables, some independent, some in common with subaerial environments. Comparisons between ocean sediment core and icesheet core, etc seem advisable.
AlexB(14:22:48): I agree with you. Why the attacks here be people who probably have not even read her paper?Please people let us not become RealClimateers.
I rather like this. It appears to be based on proper data and has made me thinkmore deeply about the climate meta-cycles. Excellent.
DavidS
Heck, I did my Geology degree in the 60’s and Milankovitch was well known then. Climate is naturally variable and it irritates the heck out of me for these climate activists to blame CO2 – how arrogant can you get ?. Still, they have a cause to get excited about rather than do the years of interdisciplinary studies to find out how little we know.
The Milankovitch Cycle modulates all paleoclimates on a scale of thousands of years (40,000–100,000), hot and cold. The Milankovitch cycle does not correlate well with tens of millions and hundreds of millions of years duration of the ice ages, because the Milankovitch Cycle is a comparatively minor superimposition on the much grreater amplitude and far far longer duration ice age cycle. The Milankovitch Cycle is detectable in the varves of the Devonian, indicating changes of climate substantial enough to make large changes in sea levels, yet the amplitude of temperature changes remain minor in comparison to the major changes in temperature upon the occurrence of a rare ice age.
In other words, the Milankovitch Cycle is a relatively very very short cycle of minor amplitude in comparison to the two major bi-state conditions represented by the hot house and cold house climates the Earth cycles between.
6 04 2010 Andrew W (13:34:36) : “So while Lorraine Lisiecki’s work may strengthen the evidence linking the Milankovich cycles to the glacial-interglacial cycles, it does nothing to change the evidence supporting AGW.”
Nothing added to zero, does not change zero. Very true.
Will a return of the glaciers (which will return no matter what humans do) be considered proof of AGW?
Here is a reference to the recent Arctic Ice data and a correct call for all of mankind to take a course on humility regarding climate analysis. Good approach. Thanks Anthony for all you do.
http://symonsez.wordpress.com/2010/04/06/arctic-sea-ice-shows-extensive-growth-in-march-2010/
Andrew W (13:34:36) :
“The Milankovich cycles have been long accepted as the driver of the glacial-interglacial cycles, changes in atmospheric CO2 follow this cycle and, in the view of most climate scientists, accentuate the temperature changes that occur through these cycles”
Can you provide references? When I look at the ice core data, CO2 slavishly follows the temperature rise or drop. There should be a different slope on the backside of the temperature drop if CO2 had the ability to “accentuate”.
For those needing a bit of background or a refresher on
Milutin Milankovitch and Milankovtch Theory, NASA has a good starting point at:
http://earthobservatory.nasa.gov/Features/Milankovitch/milankovitch_2.php
To go from obital forcing to a much broader (and much more
controversial) application of orbital dynamics and possible influences on Earth’s climate, you can check out Timo Niroma’s work at:
http://personal.inet.fi/tiede/tilmari/sunspot3.html
None of these take into account gradual continental drift or
magnetic pole reversals as influences on climate… basically
because no one has done much research into possible
connections.
How soon before her funding is slashed since she doesn’t blame CO2?