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
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
Brian G Valentine (20:53:23) :
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
No need to drag this out. The link I gave you is a good intro to how the convection in the Sun works. This is complicated business and is not easily absorbed. Miesch is also good: http://solarphysics.livingreviews.org/Articles/lrsp-2005-1/
Jeff (20:36:03) :
“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. >
Really? I’m being told that CO2 retaining 3.7 watts/m2 world wide is a freakin disaster. So I’ll replace my natural gas furnace and my gasoline engine in my truck with solar thermal electric. To stay well under that disaster 3.7 watts/m2 I will limit my aborption of solar energy over normal earth absorption to say 1/2 watt/m2. How many square meters of space will I need to capture an amount of solar energy that is safe for the planet and will replace my 100,000 BTU furnace and my 250 horsepower truck?
Leif/Brian
No need to drag this out. The link I gave you is a good intro to how the convection in the Sun works>
My understanding is that the earth’s magnetic field is also generated by convection currents but in the earth’s molten outer core. From time to time the earth’s magnetic field reverses polarity. Most likely the various convection cells pretty much cancel each other out, leaving behind a very weak magnetic field that can easily be reversed by a slight change in strength of one of the cells (by easily I mean over a geologic time period, we know the reversal takes about 5000 years for a full transition). But this does raise a new question (for me anyway) that I don’t think I have seen discussed. Has there been any work done comparing earth’s magnetic field orientation to ice ages and milankovich cycles?
davidmhoffer (22:39:40) :
Has there been any work done comparing earth’s magnetic field orientation to ice ages and milankovich cycles?
The last reversal, the Brunhes-Matuyama reversal, is thought to have occurred some 780,000 years ago. Many Milankovich cycles have rolled by during this long interval, so there does not seem to be any connection.
Jeff (20:03:18)
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.:
Another paper which is constrained (or better rejected) by a simple fact.Evolution this is well understood eg Darwin 1856
Jeff (20:03:18) :
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]
Reference 52:
I see why you left that one out. So, to refute a debunking of Solomon (2009) about atmospheric retention time, you refer back to Solomon (the person) and IPCC AR4 (which is being questioned and debunked) without explicitly saying so, which basically just says “No one knows for sure.”
Then you throw up a red herring about “recovery from a large input of atmospheric CO2.” The first reference (53) concerns modeling about the hypothetical injection of vast amounts of CO2 into the oceans. Thus tries to pass off the results of a model as evidence of something in the real world. The other reference (54) does the same, in a paper largely considering “ocean acidification.” In both cases there are considerable variables and processes that are necessarily left out for modeling purposes.
So against real-world measurements, your “rebuttal” is someone who stated a figure also saying no one can know the figure for certain, and computer models showing hypothetical amounts of CO2 being pumped directly into the ocean.
Such a convincing rebuttal. Not.
Way back there was a discussioa about solar wind9 I’ve always written solar wind off as a major climate driver because the amount of energy is so small compared to the sun’s output that it seems like a rounding error. Even concentrated at the poles by earth’s magnetic field sucking it in doesn’t change a whole lot. But there were also some comments about solar wind affecting cloud formation. Is there any truth to that#
davidmhoffer (11:20:53) :
But there were also some comments about solar wind affecting cloud formation. Is there any truth to that
The effect is supposed to work through the mediation of Cosmic Rays. The solar wind at times screens us from the cosmic rays when a big solar storm is in progress leading to a significant decrease in cosmic rays, called a Forbush Decrease (FD) [after Scott Forbush who discovered this phenomenon]. If you through a softball against a big brass bell, you might get a weak ‘ping’ as response. An FD is like hitting the bell with a sledgehammer: you would expect as loud and overwhelming response.
A recent paper in GRL http://www.leif.org/EOS/2009GL041327.pdf examines the effect of the five largest sledgehammer blows [FDs] during 1989–2001 on global cloud cover and finds to response at all.
Leif Svalgaard (11:45:59) :
A recent paper in GRL http://www.leif.org/EOS/2009GL041327.pdf examines the effect of the five largest sledgehammer blows [FDs] during 1989–2001 on global cloud cover and finds NO response at all.
Leif would probably have his own take on solar winds, mine is this:
Solar winds are [mostly] protons of a modest k.e..; and when the k.e. of these winds exceeds exceeds a certain magnitude related to soundspeed in the ionosphere the winds can cause a (visible) bow shock at the boundary of the Earth’s magnetosphere (which does interact with the Sun’s), and that shock (the rarefication and expansion of mesosphere plasma) could influence cloud formation (which has been documented).
Otherwise, I would say the influence of solar winds on cloud formation is probably marginal
Leif Svalgaard (12:56:27) :
Some of the 90 W is stored too. The OHC isn’t constant over the year, as you know of course (and you showed a graph long ago I think).
There are several delays. One very short, weeks/months(?) to distribute the heat through the well mixed layer, but the delay for all of the ocean is much longer, around 800 years I would think judging from the temp-co2 lag in the ice cores. And an even longer delay, thousands of years probably, to adjust the snow and ice cover.
lgl (12:01:30) :
Some of the 90 W is stored too.
Not my point, which is that people want all of the 1.3 W/m2 stored, so unless ALL of the 90 W/m2 is also stored, how does the Sun know to store ALL photons from the 1.3 and only some from the 90?
lgl (12:01:30): …but the delay for all of the ocean is much longer, around 800 years
This makes sense. I am no expert here, but my gut feeling is that the oceans with an average depth of ~4000 meters and a resulting huge thermal mass may have many characteristic time constants covering a wide range of time scales.
Leif Svalgaard has a brilliant argument that the large planets in our solar system have negligible impact on the behaviour of the sun – the force from Jupiter on a sun molecule is vanishingly small compared to the force from the sun itself.
Similarly, however, one could argue that a water molecule at, let’s say, 700 metres depth, may be only marginally influenced by the “rapid” surface temperature fluctuations. In a fluid with good mixing the energy redistribution would be nearly immediate; however, the oceans are so huge that I suspect that the thermal transients may cover a wide range of amplitudes and time scales. The dominant time constant may very well be 3 months; still other transients may exist with dominant time constants in the order of decades, centuries and millennia.
http://en.wikipedia.org/wiki/Ocean#Regions_and_depths
Sure, below 1000 metres the temperature approach 4 ºC, but the ocean heat content may still be subject to substantial oscillations, see this curve by Loehle.
http://jennifermarohasy.com/blog/2009/03/the-ocean-really-is-cooling/
http://jennifermarohasy.com/blog/wp-content/uploads/2009/03/loehle_ocean-heat-content-blog.jpg
“Jeff (20:29:49) :
[…]
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”
Hello. I’m german. We’re doing mitigation. Your 1% number could be about right. What can i say? Unemployment rises, wages drop, standard of living goes down, electricity prices rise with 6% a year. But we’re all very glad that we have so many wind turbines. We’ll last for a few more years.
Jeff (20:14:43) :
That Kopp paper on interglacial sea-levels is a piece of junk science. They use coastlines that have been glaciated for their estimate (e. g. Bröggerhalvöya and Jameson land). Those coasts have been depressed several hundred meters by the ice and rebounded since the last glaciation. There is no way you can use the present level of those coastlines to estimate Eemian sealevels. They try to hide the bad data by a lot of fancy bayesian statistics, but no amount of statistical juggling can create data out of random numbers.
The other cited papers are junk too. As a matter of fact it was one of them that originally got me interested the AGW controversy. I just couldn’t understan how such garbage could be published in Nature, so I started digging into things.
It is actually extremely difficult to determine the sealevel during the last interglacial, but the most likely figure, based on the most tectonically stable areas in the World (like the Gawler Craton and the Cooroong coastal plain) is about 6-10 feet higher than today.
Jeff (20:41:03) :
MIS 11 (the 4th interglaciaial back, that we are talking about) was about 400,000 years ago. 400,000 x 0.1 mm = 40 meters. The Bab el Mandeb sill is 137 meters below sea level so + or -40 meters means that it would have been either 97 or 177 meters deep 400,000 years ago, which equals to about a factor 3 difference in flow. So actually 0.05 mm/yr would be enough to invalidate the results.
Jeff (20:36:03) :
“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.”
We have 11 power reactors in Sweden, the oldest 38 years old. They have been well maintained, and have no major problems. The two oldest have recently been upgraded and now produce 20% more power than when they were new.
Leif Svalgaard (11:45:59) :
A recent paper in GRL http://www.leif.org/EOS/2009GL041327.pdf examines the effect of the five largest sledgehammer blows [FDs] during 1989–2001 on global cloud cover and finds NO response at all>
Read through it, seems reasonably conclusive. As I read it, your other response about lack of any obvious climate spikes during periods of earth magnetic pole reversal also sprang to mind. Seems to me that since the time period with no magnetic field at all is about 5000 years during which “shields down” would be a good descriptor, that time period would be more like an artillary batallion with rapid fire howitzers aimed at the bell than a sledgehammer. One would think any effect on cloud formation would correlate to some clear and obvious spikes in the geological record.
Leif Svalgaard (12:15:36) :
Because it’s +1.3. From min 1300 and max 1390 (yes, just an incorrect example) to 1301.3 and 1391.3
lgl (12:39:57) :
Because it’s +1.3. From min 1300 and max 1390 (yes, just an incorrect example) to 1301.3 and 1391.3
No, from
(1300+1.3)+0 to (1300+1.3)+90
How does the Sun know to react to the 1.3, but no much to the 90?
If 10% of the 90 is stored, then 10% of the 1.3 would also be, yet people claim that 100% is.
“but no much to the 90?”
Doesn’t it? (the earth you mean). The ocean surface temp doesn’t change much in the tropics. It does at high latitudes which of course is more caused by the tilt, so isn’t most of the 90 W stored? or actually the 45 above average, which is released again during the second half of the cycle. Same with a possible 400 year cycle. If we are at max now, most of the 1.3 (or 0.7) is stored and if the 1.3 disappears again for 200 years the accumulated 1.3 will be released.
lgl (05:55:14) :
“or actually the 45 above average, which is released again during the second half of the cycle.
So it knows to hold on to the 45 for 6 months but to the 0.7 for 200 years [or 6 years – as the solar cycle varies the 1.3 W/m2]. Clever bastard 🙂
What you lack is explaining how the Sun knows this. That said, a 0.1% change in TSI still only means 0.07K change in temperature, and even if doubled cannot even be measured.
Leif Svalgaard (13:57:20) :
Yes it does. The 1.3 gives the well mixed layer a higher average temp year after year after year, the 45 does not. With your logic the TSI could increase hundreds of watts without affecting the deeper ocean.
I am missing why I have to explain how the Sun knows this. Who said the Sun needs to know anything?
lgl (03:03:22) :
Yes it does. The 1.3 gives the well mixed layer a higher average temp year after year after year
Assume for illustration that the solar cycle was a perfect sine-curve with a 1.3 W/m2 variation. You maintain then that in every cycle heat is added [year after year after year] and that the OHC would increase indefinitely. I say that there will be no change whatsoever in the long run.
lgl (03:03:22) :
The 1.3 gives the well mixed layer a higher average temp year after year after year.
the temperature records do not show much increase the past several hundred years:
http://wattsupwiththat.com/2010/02/13/congenital-climate-abnormalities/#more-16395
Leif Svalgaard (07:52:17) :
Not?
Only a doubling of the temperature since last glacial in a couple of millennia, well… (if the temps in your link were global 🙂
lgl (12:02:53) :
Not?
Only a doubling of the temperature since last glacial in a couple of millennia, well… (if the temps in your link were global 🙂
Doubling? is the scale F, C, or K?
The temperature has steadily fallen the past several thousand years as we are moving away from the Milankovic optimum.
I guess you have lost me.