http://www.clim-past.net/5/21/2009/cp-5-21-2009.pdf

Guo et al

Strong asymmetry of hemispheric climates during MIS-13 inferred from correlating China loess and Antarctica ice records

Z. T. Guo, A. Berger, Q. Z. Yin, and L. Qin1,

Abstract. We correlate the China loess and Antarctica ice records to address the inter-hemispheric climate link over the past 800 ka. The results show a broad coupling between Asian and Antarctic climates at the glacial-interglacial scale. However, a number of decoupled aspects are revealed, among which marine isotope stage (MIS) 13 exhibits a strong anomaly compared with the other interglacials. It is characterized by unusually positive benthic oxygen (δ18O) and carbon isotope (δ13C) values in the world oceans, cooler Antarctic temperature, lower summer sea surface temperature in the South Atlantic, lower CO2 and CH4 concentrations, but by extremely strong Asian, Indian and African summer monsoons, weakest Asian winter monsoon, and lowest Asian dust and iron fluxes. Pervasive warm conditions were also evidenced by the records from northern high-latitude regions. These consistently indicate a warmer Northern Hemisphere and a cooler Southern Hemisphere, and hence a strong asymmetry of hemispheric climates during MIS-13. Similar anomalies of lesser extents also occurred during MIS-11 and MIS-5e. Thus, MIS-13 provides a case that the Northern Hemisphere experienced a substantial warming under relatively low concentrations of greenhouse gases. It suggests that the global climate system possesses a natural variability that is not predictable from the simple response of northern summer insolation and atmospheric CO2 changes. During MIS-13, both hemispheres responded in different ways leading to anomalous continental, marine and atmospheric conditions at the global scale.

The correlations also suggest that the marine δ18O record is not always a reliable indicator of the northern ice-volume changes, and that the asymmetry of hemispheric climates is one of the prominent factors controlling the strength of Asian, Indian and African monsoon circulations, most likely through modulating the position of the inter-tropical convergence zone (ITCZ) and land-sea thermal contrasts.

Interesting extract.

The correlation reveals a number of decoupled aspects between the loess and ice records. Among them, a strong anomaly is observed for MIS-13 compared with the other interglacials.Comprehensive examination of the relevant geological
records consistently suggests a significantly cooler Southern Hemisphere, but an unusually warmer Northern Hemisphere with reduced northern ice volume, and hence, an enhanced asymmetry of hemispheric climates. During this interglacial, both hemispheres responded in different ways to the northern summer insolation and atmospheric CO2 changes.

MIS-13 is therefore a real case of a substantial northern hemispheric warming under relatively low concentrations of greenhouse gases. Smaller northern ice-sheets would have also occurred during MIS-11 and MIS-5e, with apparently
a lesser hemispheric asymmetry than for MIS-13. These also suggest that the coupling of hemispheric climates at the glacial-interglacial scales was significantly unstable in the Mid-Pleistocene and that marine 18O records may not
be always reliable indicators of northern ice-volume. These findings may also have implications for the evolution of the climate system during other periods of the Quaternary.

http://www.clim-past-discuss.net/5/635/2009/cpd-5-635-2009.html

Joel seems to be in the “kill the messenger” camp.

I suspect there are many examples of discoveries made by people who don’t have Harvard Ph.D.s in whatever field is being illuminated. Arguing against the principle, not the man, seems to be a useful construct.

How about your Curriculum Vitae Joel?

Specifically, Loutre and Berger posit that insolation changes are too weak by themselves alone to account for past glacial changes. This is entirely consistent with virtually all the modern literature on the matter (referenced in the study). Yet Dr Archibald seems to contend, with no references, meaningful calculations or descriptions, that insolation changes are alone strong enough to cause the glacial changes. His thesis is consistent with the scientific literature regarding correlation with orbital variaton/insolation changes. I cannot fathom why he ignores/dismisses the rest of the science on the subject of glacial change.
******

As you say, Loutre and Berger are running a model (BTW, it does seems interesting). For their model, they use a CO2 sensitivity of 2C for a doubling. Their results obviously depend on this sensitivity. This sensitivity is disputed by many. Empirical data suggests it is lower — as low as .5C or lower for a doubling.

They should have run their model w/a range of CO2 sensitivities to compare the results.

Thank you so much for your generous response to my post. I really appreciated your comments and the inclusion of the abstract. That said, I hope that you will not take it as ungracious of me if I pose a few questions.

You describe the transition from a 41,000 cycle to the 100,000 cycle as beling something like missing a “pulse” while the abstract describes it as more of a gradual transition. Is this a situation where there isn’t enough good data available, so that a certain amount of speculation is necessarily involved in arriving at such conclusions? My limited reading on the subject has not included research findings that describe intermediate length cycles. I think that this is a key issue and that your “pulse” notion is more nearly correct. But on the other hand, I wonder if the growth of more extensive ice sheets isn’t more likely to be an effect of an X factor(s) rather than the cause of the sudden shift from a 41,000 cycle to a 100,000 cycle.

Am I correct in recalling from my reading that interglacial periods have extended for of a failry similar time periods? If so, this would support the notion that the earth has been in a prolonged cool phase for the past 20 to 40 million years, with recurrent heat cycles being introduced (for largely unknown reasons) periodically. The coolness includes but is not necessarily dependent upon glacial conditions. For example, the Andrill project of a few years ago found that the earliest indication of a collapse of the Ross Ice Shelf in Antartica dates back about 17 million years. This seems like evidence of a ing phase occurring during a non-glacial period of the prolonged (still going) period of cold.

From this “heat clcyes” notion I suggest that unknown factors might have pushed the 15.000 to 20,000 year recurring warm phase (which accounts for the interglacial periods) into a 100,000 cycle, and that in turn wouild have caused much increased growth of the ice sheets. These heat cycles that I propose also seem to regularly warm things up a bit beyond our current Antarctic regional (or possibly global) temperature, in that the Andrill pras reported in Science the Scott Ice Shelf has apparently been warmed to the point of collapsing some sixty times or so in the past 17 million years..

“The Earth’s current ice age is primarily caused by Antarctica drifting over the South Pole 30 million years ago. This meant that a large area of the Earth’s surface changed from being very low-albedo ocean to highly reflective ice and snow. “

Incorrect. Antarctica was already moving into the Antarctic circle some 125 million years ago, and it was at the South Pole during the Early Cretaceous about 120 million years ago. Although Antarctice experienced cool temperate conditions with winter snowfalls and icing and very limited periods of small permanent polar ice caps, much warmer conditions free of polar ice caps dominated from the Late Cretaceous 117mya to the onset of the latest ice ages about 30-32mya. In other words, Antarctica was located at the South Pole for tens of millions of years without causing an ice age and polar galciations to occur.

There were species of of dinosaurs and flora adapted to nocturnal habits well suited to the six months of darkness prevalent in an Antarctic in the antarctic circle.

Oxygen can only be produced by sunlight. At the bottom of the ocean there is no light source, other than the very faint bioluminescence powered by chemical reactions, and so no oxygen gas can be formed. In the ocean, oxygen is created in the surface waters, where sunlight allows marine algae to photosynthesise in the euphotic zone and storms, that produce breaking waves, permit atmospheric oxygen to mix in. The presence of oxygenated water at oceanic depths in the aphotic zone requires a process of gas transport and replenishment throughout the water column. Thermohaline circulation is the mechanism by which the world’s ocean waters overturn and the process by which oxygenated water reaches the ocean depths.

Throughout millions of years of geological history, the overturn of the world’s oceans has operated in one of two modes, either the “Haline” mode of mid-latitude warm water oceans or the “Thermo” mode of polar cold water oceans. In the Jurassic and Cretaceous eras the haline mode of ocean water overturn dominated. The world was warm and so the bottom waters the oceans were warm also. During the Cenozoic era, since the Paleocene-Eocene Thermal maximum 55 million years ago, as the world has cooled and Antarctica has become an ice continent, the cold thermal mode of ocean water overturn has prevailed.

Haline circulation is a warm world process, it relies on the creation of dense saline water in mid-latitude oceans where evaporation exceeds rainfall, it dominates today only in the waters of the Mediterranean. The Mediterranean Sea occupies an enclosed series of basins. Its waters experience high temperatures in summer and insufficient input of river water from Southern Europe and the Nile, to maintain the total seawater mass balance.

Because of the loss of water to the atmosphere through evaporation, the Mediterranean Sea is more salty than the adjacent Atlantic Ocean. If it wasn’t for the continuous surface influx of new ocean water through the Gibraltar Strait, then the Mediterranean Sea would eventually dry out. In the past the Mediterranean, with an area of 2.5 million sq kms, did indeed greatly reduce in size, as the presence of deeply buried canyons of the ancient River Nile and River Rhone testify. In addition, seabed boreholes in the abyssal plains of this small ocean prove the presence of ancient thick salt layers. Think Dead Sea, but two and a half thousand times bigger.

Today the Mediterranean Sea exports its salty water back into the Atlantic Ocean through the Gibraltar Strait as a dense bottom water counter-current. This warm saline-rich water falls under gravity to depth in the Atlantic, but does not now reach the abyssal ocean plain. Instead it floats at depth above the denser 3C, polar ocean derived, bottom waters of the modern cold water world.

I’m not allowed to use your data, possibly for another issue than that for which you gathered same, and come to a conclusion differing from yours?

You are certainly allowed to, but it seems like the least you should do is explain clearly what the other person’s interpretation was and why you interpret it differently.

barry says:

I now wonder if Dr Archibald is a serious scientist qualified in the field he has undertaken to weigh in on.

Here is one piece of information that I found on him ( http://www.sourcewatch.org/index.php?title=David_Archibald ):

Archibald is a scientist operating in the fields of cancer research, climate science, and oil exploration. In oil exploration, he is operator of a number of exploration permits in the Canning Basin, Western Australia.

Perhaps Dr. Archibald can fill us in with more detail on his qualifications and publications in the field.

It didn’t. It changed from 1*41kyr to 2, 3 or 3*41kyr, probably caused by the connection of the Americas, bringing more moist (snow) to the high north.
And the interglacials last 1 mill. years have never survived an obliquity minimum so why would it this time?

I’m not allowed to use your data, possibly for another issue than that for which you gathered same, and come to a conclusion differing from yours?

Whatever.

Sorry but it’s not that simple, as the Indian plate keeps moving north and ppushing up the Himalaya, the latter is being eroded and filling out the Indian ocean. The Ganges fan is the largest accumulation of submarine sediments on Earth.

On the Indian Ocean (IO) uplifts attendant on the tsunami-generating seism, let’s agree that it was 100 meters uplift by 5 KM wide by 1200 KM long. That gives us (0.1×5×1200) km^3 in volume = 600 KM^3. The IO has a volume of 292M KM^3 (wikipedia). So the delta volume is 600/292M = .0002%. Does this calculate to a measurable increase in sea level? And remember, in dealing with with faults, something is moving up – and something is moving down or being attenuated somewhere. Google “rift and graben”. There is no new volume created – just things adjusting up, down or laterally.

My understanding is this specific type of rebound of a stressed plate would result in the subsidence of the above sea level portion adjacent to the fault (the island of and the sudden upward thrust of the subsurface plate, as shown in the following video.

http://www.iris.edu/hq/programs/education_and_outreach/aotm/5

No single event like that probably would have a very large effect, although it would be interesting if there was a detectable step change in world wide sea surface height measurements. I was speculating on the over all stability of the shape of the basin, with this as an example of some of the distortions that might be taking place along the ring of fire due to thousands of small earth movements.

In the case of the Good Friday 1964 earth quake in Alaska, they estimate total displacements underwater were on the order of 120 cubic kilometers.

http://www.drgeorgepc.com/Earthquake1964Alaska.html

It is not clear what the net change in undersea volume was, as some of the changes were uplift and some were subsidence, some areas effected were submerged and others were above sea level prior to the quake.

As mentioned in my other post, I am just brainstorming about alternate mechanisms I have not seen discussed much in the context of world sea level changes.

Larry

Jim F (20:11:23) :
hotrod – re “check the numbers”.

…

So we get 8.5×10^14 cc x (1km^3/1×10^15cc) = .85 km^3 of new material deposited in the Yangtse delta annually.

Thanks for the check Jim! It has been a long time since I worked with scientific notation, and I think you are correct. It looks like I dropped a decimal place doing my quick calculation, and was off by a factor of ten using my assumptions.

On reworking it with 2.2g/cc density as I did the original, I came up with 6.3636 x 10^8 cubic meters rounding to 6.4x 10^8 cubic meters, rather than my original value of 6.4 x 10^9 cubic meters, or about 0.00176278 of 1 mm sea level rise which would be about .1% , not 1% of an annual sea level rise of 1.8 mm which was the number I was working with.

I must have dropped a decimal point some place. Thanks for the check!
That change would drop the effect of sedimentation to a minor contributor to annual sea level rise.

It just bothers me when no one even mentions a mechanism like this. I would much rather have them work the numbers and then state it was of negligible effect.

Years ago I worked as an emergency planner and my job basically involved looking for the unstated assumptions or pointing to the 600 lb gorilla in the room no one wanted to talk about. As a result, my first instinct when looking at a problem, is to brain storm every possible other explanation and then start eliminating them one by one to see if one of them refuses to go away.

Larry