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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E.J. Rohling? Hmmmm
is he on the official list of Wikipedia approved climate scientists?
http://en.wikipedia.org/wiki/List_of_climate_scientists
h/t Chuckles at
http://klimazwiebel.blogspot.com/2010/02/science-magazine-confused-about-who-is.html
Fine, if solar radiance is indeed the only influence. But there is another theory, that changes in muon flux alter the Earth’s albedo by altering cloud extent. Muon flux is determined in turn by the cosmic ray flux, of which the local galactic component will vary as the Solar System moves through the spiral arms and up & down through the galaxy disc. There are also streams of cosmic rays within the galaxy whose positions, I understand, are less predictable.
Once here, the cosmic ray flux reaching the Earth is controlled mainly by the solar wind (a function of sunspots) and the Earth’s magnetic field.
All this is due to be tested this year by the ‘Cloud’ experiments at the Geneva LHC.
Any feedback, Sven?
Afraid he isn’t!
Ignore his work!
Or see if one of the approved scientists will okay it.
Have been unable to get your link ‘Tips & Notes to WUWT’ to work for reasons I cannot fathom I am using this to point you to another excellent item in the Guardian http://www.guardian.co.uk/technology/2010/feb/05/science-climate-emails-code-release – hope you can use it.
Nice work.
The way science should be.
Not to nitpick, but “for” is repeated in the title: “…looking for for warming signs”.
My take from the article is that we have a broad understanding of the astronomical causes of ice ages, but the details are still unclear.
Things are really changing now we see scientific institutions backtracking from the AGW mantra.
Not mentioned in the article is that the earth has an elliptical orbit, with an eccentricity of 0.016710219, an Aphelion of 1.0167103335 AU, and a Perihelion of 0.9832898912 AU. This produces a small imbalance between the two hemispheres in terms of solar irradiance reaching the ground, currently in favor of the northern hemisphere (slightly greater average watt /sq. meter). Due to the precession of the equinoxes, with a period of 25,800 years, the imbalance is always in flux, is roughly a sinusoidal function, eventually reaching zero and then changing polarity.
I told you guys once already.
The author is not on the official Wikipedia list of approved climate scientists I mentioned above.
So disregard Rohling’s crap – right now!
Anthony,
“Philhippos C (10:09:33) :
http://www.guardian.co.uk/technology/2010/feb/05/science-climate-emails-code-release – hope you can use it.”
The Guardian article noted here by Philhippos C cuts right to the core of exactly what is wrong with computer modelling in ‘climate science’.
It makes several very important scientific points and seems well worthy of an individual post.
Many thanks PC for the link.
With best regards,
Larry Kirk
“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.”
Why is this bad?
Why do the eco-wackos want the earth covered in ice?
The orbital theory of climate variation has the advantage that we can calculate orbits to almost arbitrary precision in the past, make predictions, and then test them with lots of observational data — assuming that the time precision of the observations is good enough. The other climatic influences are much more difficult to test. Even the impact of CO2 at the present time, where we have a solid grasp of timing of warming versus CO2 change, is difficult to test because the impact is small, despite current hysteria, and mixed with other influences most of which have similar magnitude of effect. Now we have the additional problem of not knowing exactly what the magnitude of temperature is or the true time history.
Larry,
Some climate models are available on line. They are huge and extremely complex, and do not lend themselves to any type of simple analysis of their strengths and weaknesses.
“that the current interglacial has indeed lasted some 2.0–2.5 millennia longer than predicted ”
Interesting because I believe the interglacial actually began the process of ending at around 0 AD. Since about 0 AD the climate seems to me to be generally cooling at a fairly decent pace. We have had major cool periods, each cooler than the one before with the LIA being probably the coldest period since the Younger Dryas. Each warm period has been a little cooler than the previous.
“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.
”
OTOH killing megafauna should have warped us directly into a deep ice age – consider the carbon footprint of a mammoth! (I’m doing this just to add confusion!)
Over on von Storch’s blog we find Carl C saying something interesting:
That is truly scary- if as the article says the Earth is 2.5K years late for the next ice age and the theory they mention allow for another two thousand years “or so”. We could very well be at the end of the “or so”. The quiet sun and more muons causing those low level reflective clouds as per Svensmark theory will tip the climate system over into ice age. Thank goodness my house is further south in the UK than the furthest extent of the ice sheets in all the ice ages 🙂
And CO2 cannot save us…..
The researchers found that the current interglacial has indeed lasted some 2.0–2.5 millennia longer than predicted by the currently dominant theory
…But the anomaly vanished when the researchers considered a rival theory, … Under this theory, sea levels could remain high for another two thousand years or so, even without greenhouse warming.
So, according to the best research available, either CO2 driven global warming is the only thing holding us back from a plunge into an ice age, or it will be the only thing very shortly (on a geologic time scale) and we are on the cusp (+/- 2k yrs, so we’re in the middle).
Fine with me.
So we have about 400 years worth of coal to burn up and we need to “get ‘er done” no later than about 1000 years (to avoid momentum into an ice age). Looks to me like we are more or less right on schedule.
So, save the Planet, burn coal.
or maybe:
Oh! Canada! Burn tar sand oil and oil shales.
The only real ‘climate crisis’ is the next glacial. Something we can do nothing to stop and can only hope to delay a tiny bit. All we can really do is hope that it is going to happen closer to the 2k years away than ‘now’. And hope is not a strategy…
But with any luck, some of the “climate science” being done will help us figure out how to warm things up a little bit. Buy ourselves a few decades or maybe even a century or two more.
Maybe a bit off topic, I want to express my surprise at the sudden change in the BBC radio program “One Planet”. We get it in Canada in the wee-smalls of Sunday morning, 0500 or 0530. By chance I woke up within a couple of minutes of its beginning today and listened to the rest of the program via mini radio and earphone. The programs that I have heard in the past have been the usual promotion of AGW, as we expect from the BBC. The program today, nearly all of it, could have been scripted by any of us sceptics and was an excellent presentation with a sharp interviewer. If your computer has speakers, you can hear the broadcast at:
http://www.bbc.co.uk/podcasts/series/oneplanet/
It runs close to 30 minutes.
I couldn’t believe my ears!
IanM
TFN Johnson (10:08:05) :
Fine, if solar radiance is indeed the only influence. But there is another theory, that changes in muon flux alter the Earth’s albedo by altering cloud extent. Muon flux is determined in turn by the cosmic ray flux
There does not seem to be any effect of large changes of cosmic ray flux:
http://www.leif.org/EOS/2009GL041327.pdf
From the paper: “We find no response of global cloud cover to Forbush decreases at any altitude and latitude.”
What’s really scary is contemplating what the scientists who are coming up with CO2 mitigation strategies were, instead, trying to figure out ways to warm the Earth.
toyotawhizguy (10:33:59) :
Not mentioned in the article is that the earth has an elliptical orbit, with an eccentricity of 0.016710219, an Aphelion of 1.0167103335 AU, and a Perihelion of 0.9832898912 AU. This produces a small imbalance between the two hemispheres in terms of solar irradiance reaching the ground, currently in favor of the northern hemisphere (slightly greater average watt /meter). Due to the precession of the equinoxes, with a period of 25,800 years, the imbalance is always in flux, is roughly a sinusoidal function, eventually reaching zero and then changing polarity.
From the actual paper:
“”Comparison of the ends of MIS-11 and the Holocene based on timings relative to their respective maxima in mean 21 June insolation at 65°N suggests that the end of “Holocene conditions might have been expected 2.0-2.5 ky ago.”
Mike Ramsey
I’m pleased to see more geological imput into climate science these days. Paleoclimatology as a discipline was, before the global warming hysteria, pretty much a secret outside of geological science. Its recent discovery by the new climate science has been the silver bullet that has decimated much of AGW theory of late. There are few geologists that bought into the story that this is the hottest age in earth history, chiefly because of paleoclimatology’s teachings, and there are no geologists who do not know that climate change is the norm rather than the exception. But I see this orbital geometry/sea-level stuff as part of only a piecemeal wearing away of the AGW edifice.
With all the very recent new stuff coming out that ravages AGW theory, it is time to examine, not just the folly and fraud, but the anatomy of how this whole thing got started and where we should be going (a good long post on this is warranted). It started with an astronomer musing on how hot Venus is with its atmosphere choked with CO2. Surmising or researching the growth in CO2 on earth, led to this AGW leap of faith without delving more broadly to discover that paleoclimatology had important things to say. Rather, everybody (mostly the wrong people) became climatologists (as late as 2007, MS word underlined the term climatologist in red). An AGW sceptic physicist (source forgotten) some few months ago said something to the effect that: You can’t do climatology without physics but you can do physics without climatology. Although somewhat true, this pretty well sums up the wrong thinking that led to the half baked theory of AGW. Physics is helpful in trying to understand the phenomena but history and geology are more powerful tools in the investigation of natural and anthropogenic climate change (if it indeed is real).
Once paleoclimatology (and history) was discovered to exist, all sorts of problems began to arise with AGW. Having entrenched themselves into the AGW faith so deeply, the main occupation became to get rid of the embarassment of the Little Ice Age and the MWP and a number of other WPs. Dendrochronology, and the other tools of paleoclimatology were abused and misused and what started out to be well-meaning but naive scientists finished by being dishonest, destructive anti-scientists. Anyway, lets embrace new studies like the one of this thread, but lets also remake political climatology into scientific climatology.
Aggiornamento!!
Open the windows!!
Hark! T’would that be fresh air I smell?
Amazing that when the Berlin Wall came down how fast everything changed in Europe.
We seem to be experiencing another such event. God has not foresaken us and left us to the mercy of the heathen Warmists.
Ack (10:45:51) :
Why is this bad?
It’s bad because civilization was not supposed to last long enough to figure out how this thing works. Well, almost. Maybe we will, provided certain Dr. Frankensteins don’t hit the Panic Button and launch Operation GCM Bring on the Ice Age.
The article above leaves me with a Darned if we do, Darned if we don’t taste in my mouth.
Maybe the EPA has it backwards: C02 is not a pollutant, it’s an endangered trace gas. Geologic forces have been overly-sucessful at sequestration.
380ppm, are you kidding me? “I didn’t inhale”.