From a press release by: National Oceanography Centre, Southampton (NOCS)
Understanding past and future climate
The notion that scientists understand how changes in Earth’s orbit affect climate well enough for estimating long-term natural climate trends that underlie any anthropogenic climate change is challenged by findings published this week. The new research was conducted by a team led by Professor Eelco Rohling of the University of Southampton’s School of Ocean and Earth Science hosted at the National Oceanography Centre, Southampton.
“Understanding how climate has responded to past change should help reveal how human activities may have affected, or will affect, Earth’s climate. One approach for this is to study past interglacials, the warm periods between glacial periods within an ice age,” said Rohling.
He continued: “Note that we have here focused on the long-term natural climate trends that are related to changes in Earth’s orbit around the Sun. Our study is therefore relevant to the long-term climate future, and not so much for the next decades or century.”
The team, which included scientists from the Universities of Tuebingen (Germany) and Bristol, compared the current warm interglacial period with one 400,000 years ago (marine isotope stage 11, or MIS-11).
Many aspects of the Earth-Sun orbital configuration during MIS-11 were similar to those of the current interglacial. For this reason, MIS-11 is often considered as a potential analogue for future climate development in the absence of human influence.
Previous studies had used the analogy to suggest that the current interglacial should have ended 2-2.5 thousand years ago. So why has it remained so warm?
According to the‘anthropogenic hypothesis’, long-term climate impacts of man’s deforestation activities and early methane and carbon dioxide emissions have artificially held us in warm interglacial conditions, which have persisted since the end of the Pleistocene, about 11 400 years ago.
To address this issue, the researchers used a new high-resolution record of sea levels, which reflect ice volume. This record, which is continuous through both interglacials, is based on the ‘Red Sea method’ developed by Rohling.
Water passes between the Red Sea and the open ocean only through the shallow Strait of Bab-el-Mandab, which narrows as sea levels drop, reducing water exchange. Evaporation within the Red Sea increases its salinity, or saltiness, and changes the relative abundance of stable oxygen isotopes.
By analysing oxygen isotope ratios in tiny marine creatures called foraminiferans preserved in sediments that were deposited at the bottom of the Red Sea, the scientists reconstructed past sea levels, which were corroborated by comparison with the fossilised remains of coral reefs.
The researchers found that the current interglacial has indeed lasted some 2.0–2.5 millennia longer than predicted by the currently dominant theory for the way in which orbital changes control the ice-age cycles. This theory is based on the intensity of solar radiation reaching the Earth at latitude 65 degrees North on 21 June, the northern hemisphere Summer solstice.
But the anomaly vanished when the researchers considered a rival theory, which looks at the amount of solar energy reaching the Earth the same latitude during the summer months. Under this theory, sea levels could remain high for another two thousand years or so, even without greenhouse warming.
“Future research should more precisely narrow down the influence of orbital changes on climate,” said Rohling: “This is crucial for a better understanding of underlying natural climate trends over long, millennial timescales. And that is essential for a better understanding of any potential long-term impacts on climate due to man’s activities.”
The study was funded by the United Kingdom’s Natural Environment Council and the German Science Foundation.
Publication:
Rohling, E.J., et al., Comparison between Holocene and Marine Isotope Stage-11 sea-level histories. Earth and Planetary Science Letters (2010). doi:10.1016/j.epsl.2009.12.054
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Leif Svalgaard (12:45:53) “If not above the noise [so sophisticated statistics is needed to flush them out], then the effects are not important.”
Although I disagree with your assessment (in part because I like a puzzle more complicated than a 1+1=2 wiggle-matching exercise), I’m content with disagreement.
Leif Svalgaard (12:45:53) “I have not looked at his other work. The day only has 36 hours.”
He is making some fairly lofty claims about solar effects on the Earth. If he is not coming under aggressive attack for his views, this may be informative.
After reading Climategate: The CRUtape Letters I think it is pretty obvious that we cannot be certain that we did not have a MWP and a LIA. Thus, the first place to start would be to ask: what caused the MWP and what caused the LIA?
What is your theory Leif? My own speculation at the moment is that we may have reaction diffusion type ocean cycles that last several hundred years. Sometimes it can be relaxing to watch Rayleigh-Bénard convection and wonder whether similar patterns can cause a MWP and a LIA?
In Rayleigh-Bénard convection the external force is completely constant.
Paul Vaughan (13:14:26) :
because I like a puzzle more complicated
Puzzle away then :-). As long as you it’s just a puzzle, everything is fine.
He is making some fairly lofty claims about solar effects on the Earth. If he is not coming under aggressive attack for his views, this may be informative.
Hundreds of people over hundreds of years have made such claims. One cannot expend energy to aggressively attack yet another one.
Invariant (13:23:35) :
What is your theory Leif?
I don’t think I need to have one to resolve the AGW issue. Solar and stellar activity are confined to stars with a deep convection zone and thus prone to oscillations and that without any external influences needed. The cooler a star is, the greater is it’s activity, so one could hardly blame that on some planetary external influences [this is for die-hard astrologers]. If there are small random wobbles [and convection is just that] it is easy to get situations where the wobbles will interact and sometimes stochastically add up to larger fluctuations. Even on the Sun we see this, where in addition to the fine-scales granulation there are complexes of such cells forming a larger scale super-granulation, extending to somewhat greater depth. Most studies of convection in the laboratory have been about very shallow layers [because they are easier to study], but in stars we have a continuum of cell sizes from very small all the way up to a significant fraction of the radius, and that in a spherical shell to boot, so hard to study experimentally.
Leif Svalgaard (14:31:28) :
Invariant (13:23:35) :
What is your theory Leif?
I used an analogy with the Sun, rather than directly addressing your point, because I’m more comfortable with that, and because the widely different stars show us a wider range of phenomena than just our own planet’s.
OK. Thanks. I am not certain whether we fully understand convection in the oceans either, in particular since we do not (and never will) have sufficient computational power to calculate convection with the required precision for the huge oceans.
We cannot predict any of the ocean cycles, in particular we did not predict the north atlantic oscillation that hit us this winter. This tells me that we really do not know have a clue in our climate models…
China is making solar cells and windmills for you to buy, Jeff, because the Chinese know they have a greenie weenie market for them, and they know they can beat the price of green stuff made in the West because of the cost of manufacturing is too high (if regulations will permit any manufacturing at all). The US isn’t going to sell solar cells or wind mills to China, Jeff.
Who are you going to believe about “climate change,” Jeff – the geologic history of the Earth or Al Gore? What is the basis of your decision of who or what to believe?
Invariant (14:47:55) :
we do not (and never will) have sufficient computational power to calculate convection with the required precision for the huge oceans.
People try to calculate that in the much larger Sun: http://solarphysics.livingreviews.org/Articles/lrsp-2005-1/
Wow! Brave people! Impressive work and an enormous challenge! Could be quite difficult to tune this model without any reliable measurements inside the sun. In theory it is possible to have a “complete” understanding of the physics and the equations involved, but to develope a model with predictive capabilities from this must be nearly impossible. Any model needs to be tuned with experiments, and as far as I know we do not even have any experimental results for convection in systems that are more than a couple of meters in size…
Invariant: You wrote, “I am not certain whether we fully understand convection in the oceans either, in particular since we do not (and never will) have sufficient computational power to calculate convection with the required precision for the huge oceans.”
We have limited knowledge of the subsurface processes taking place within the oceans, too. Surface measurement coverage was poor before the satellite era. Subsurface sampling was… (Add your own descriptor)
The two systems aren’t really comparable, Leif – mainly because of the pressure gradients, which are basically radially symmetric in the Sun and arise from radiation and gravity; the pressure gradients in the oceans are of a number of different origins and it is their interactions that become terribly difficult to model.
[admittedly, there are other phenomena in the Sun such as MHD that need to be accounted for]
Invariant (15:37:06) :
Could be quite difficult to tune this model without any reliable measurements inside the sun.
SDO [Solar Dynamics Observatory – launching Wednesday]] will give us a lot better data than what we already have from GONG and SOHO [and those are already quite good].
Brian G Valentine (15:59:40) :
The two systems aren’t really comparable, Leif – mainly because of the pressure gradients, which are basically radially symmetric in the Sun and arise from radiation and gravity; the pressure gradients in the oceans are of a number of different origins and it is their interactions that become terribly difficult to model.
There are some differences, but there are magnetic fields inside the Sun that made the pressure tensor vary with direction and time [no real symmetries here], so although different, much the same equations [even more difficult for the Sun because of the magnetic field] apply. Jupiter is another case that we’ll be able to tackle decades from now, presenting us with yet other complications. But er learn from all those differences.
Leif Svalgaard (13:08:25) :
I might have been one of those people your cite that think you can ‘store’ heat in the ocean. Many people are just trying to get all of the aspects of climate science into focus. Of coarse you cannot store heat, anywhere and never. But the term might be used to speak of the difference in heat between a system at a deemed normal 68 defF and the energy in the oceans after the normal has risen to 69 defF. Some might term that storage. I might have done that also. Wish you could read between the lines. Actually I think I was talking of that ‘storage’ as the temperature had risen slowly over some period. Sorry for not being exact in my words. I see your point, it’s instantaneous. But in that case the change was happening year after year after year per the trend line which brings into mind the word storage for visualization purposes.
“[even more difficult for the Sun because of the magnetic field]”
But even still, that field remains divergence free!
: )
wayne (17:37:28) :
I might have been one of those people your cite that think you can ’store’ heat in the ocean.
I’m perfectly happy with the notion of storing heat [or heat content, OHC]. Some misguided ‘purists’ want to obscure the issue by saying that ‘heat’ is ‘energy in transit’ and therefore cannot be stored. IMHO that is nitpicking. Part of the confusion comes from the English language where the verb ‘to heat’ is conflated with the noun ‘heat’. The process ‘energy in transfer’ is better translated as ‘heating’ or even ‘warming’. That removes the problem. Most other languages don’t have that problem.
the change was happening year after year after year
The change can only happen if you can ‘hide’ the ‘old’ heat somehow in the interior year after years after year, and that does not happen in a fluid medium because warmer water [above 4C] is buoyant and will rise to the surface [cold water sinks, warm water rises]. You want warm water to sink in order to store its heat.
Brian G Valentine (18:00:00) :
But even still, that field remains divergence free!
No, because the field acts a seed for generation of more field by a dynamo process through the induction equation. That’s why this is so hard to compute.
to kadaka (00:56:33) :
http://en.wikipedia.org/wiki/Greenhouse_gas#Atmospheric_lifetime
Carbon dioxide has a variable atmospheric lifetime, and cannot be specified precisely.[52] Recent work indicates that recovery from a large input of atmospheric CO2 from burning fossil fuels will result in an effective lifetime of tens of thousands of years.[53][54]
53
http://geosci.uchicago.edu/~archer/reprints/archer.2005.fate_co2.pdf
The mean lifetime of anthropogenic CO2 is dominated by the long tail, resulting in a range of 30–35 kyr. The long lifetime of fossil fuel carbon release implies that the anthropogenic climate perturbation may have time to interact with ice sheets, methane clathrate deposits, and glacial/interglacial climate dynamics.
54
http://www.ipsl.jussieu.fr/~jomce/acidification/paper/Caldeira_Wickett_2005_JGR.pdf
Simulations of deep ocean CO2 injection as an alternative to atmospheric release show greater chemical impact on the deep ocean as the price for having less impact on the surface ocean and climate. Changes in ocean chemistry of the magnitude shown are likely to be biologically significant.
[Brian G Valentine (15:15:15) :
China is making solar cells and windmills for you to buy, Jeff, because the Chinese know they have a greenie weenie market for them, and they know they can beat the price of green stuff made in the West because of the cost of manufacturing is too high (if regulations will permit any manufacturing at all). The US isn’t going to sell solar cells or wind mills to China, Jeff.
Who are you going to believe about “climate change,” Jeff – the geologic history of the Earth or Al Gore? What is the basis of your decision of who or what to believe?]
Possibly you found climatology that agrees with your world view. This is an interglacial that can give us information on what will be a high provbability that will happen to us. 23 to 26 feet sea level rise. This may take several hundred years. If co2 has the long residency time that many scientists say that it has this will then happen.
http://www.skepticalscience.com/Working-out-future-sea-level-rise-from-the-past.html
Working out future sea level rise from the past
Carbon free energy is the way of the future. Why not do all we can at home. I have met people here that live off grid. Would you rather buy American if you can?
I’m confused, Leif. Doesn’t the non-divergence of B imply the existence of magnetic monopoles?
(I think you are referring to the curl of H)
The magnetic field is solenoidal and that gives an additional symmetry that makes it tractable
Brian G Valentine (20:14:50) :
I’m confused, Leif. Doesn’t the non-divergence of B imply the existence of magnetic monopoles?
Imagine you have a coil without current. There is no magnetic field through it. Now, switch on a current in the coil: a magnetic field appears threading the coil. No monopoles needed.
Now, where does the current come from in the Sun? You need an emf to drive the current. There are weak magnetic fields inside the Sun [remnants from surface fields dragged into the Sun]. The solar material is a plasma and is thus a conductor [albeit a weak one – like sea water]. The plasma is circulating, probably due to temperature differences [like air in the Earth’s atmosphere]. Moving a conductor across a magnetic field creates an emf [VxB]. As the magnetic field is nearly frozen into the plasma [MHD] the differential rotation will wind the field up, thereby amplifying it. All this is complicated by the back-reaction of the field on the plasma movements. Here is more about how this works: http://solarphysics.livingreviews.org/Articles/lrsp-2009-4/
[To John Galt;
“Carbon” emissions and other greenhouse gases simply are not a problem. There is no climate crisis and the earth is in no more or less peril than it’s been for millions of years.
We should all focus our limited time, energy and money on solving real problems.]
We have a co2 spike unparrelled in geologic time. Our way of life we have now depends on a narrow level of GHG’s. There is uncertainty of what will really happen and yet it is more than clear geologically that we will warm and change in climate. By economic analysis that I have read, adaptation will cost aprox 20% of world wide GDP and mitigation starting today is less than 1% GDP.
[tty (12:04:11) :
“Some renewables are easily competitve with Nuclear now and have 7 hours storage built in now with 16 hours in development later”
Such as….?]
Solar thermal electric.
Nuclear is having a tough time right now. There are tritium leaks at 27 of the 104 nuclear power reactors. The 40 year life cycle just might be holding true.
[tty (11:53:55) :
Jeff (15:33:31) :
Its an interesting question. How much change in the underlying plates would invalidate his work?
0.1 mm/year either up or down would suffice to invalidate the results.]
That is an extremely small value. Could you tell me why such a small value would disqualify the work?
to Mooloo;
http://www.skepticalscience.com/Peer-reviewed-impacts-of-global-warming.html
Here is a list of peer reviewed positives and negatives of the coming warming climate.
Too much of too little general interest for me to reply here, Leif, so write to me bgvalentine@verizon.net if you want to keep the discussion going
Jeff,
“Carbon free energy is the way of the future. Why not do all we can at home. I have met people here that live off grid.”
It is not possible for [innumerable] people to survive without “carbon energy” in this society, Jeff and I unfortunately lack the capability to convince you of that.
Suffice to say, I would have no interest in this “climate change” stuff at all I don’t think, if weren’t for that inescapable corollary