This is interesting. While there’s much noise from alarmists that we are on an “Arctic death spiral” the team for this paper’s press release today found evidence that ice levels were about 50% lower 5,000 years ago. The paper references changes to wind systems which can slow down the rate of melting (something we’ve seen on the short term, even NASA points this out for recent historic ice retreats). They also suggest that a tipping point under current scenarios is unlikely saying that even with a reduction to less than 50% of the current amount of sea ice the ice will not reach a point of no return (i.e. a tipping point). From the University of Copenhagen:
Large variations in Arctic sea ice
For the last 10,000 years, summer sea ice in the Arctic Ocean has been far from constant. For several thousand years, there was much less sea ice in The Arctic Ocean – probably less than half of current amounts. This is indicated by new findings by the Danish National Research Foundation for Geogenetics at the University of Copenhagen. The results of the study will be published in the journal Science.
Sea ice comes and goes without leaving a record. For this reason, our knowledge about its variations and extent was limited before we had satellite surveillance or observations from airplanes and ships. But now researchers at the Danish National Research Foundation for Geogenetics at the Natural History Museum of Denmark (University of Copenhagen) have developed a method by which it is possible to measure the variations in the ice several millennia back in time.
The results are based on material gathered along the coast of northern Greenland, which scientists expect will be the final place summer ice will survive, if global temperatures continue to rise.
This means that the results from northern Greenland also indicate what the conditions are like in the ocean.
Less ice than today
Team leader Svend Funder, and two other team members and co-authors of the Science article, Eske Willerslev and Kurt Kjær, are all associated with the Danish Research Foundation at the University of Copenhagen.
Regarding the research results, Funder says, “Our studies show that there have been large fluctuations in the amount of summer sea ice during the last 10,000 years. During the so-called Holocene Climate Optimum, from approximately 8000 to 5000 years ago, when the temperatures were somewhat warmer than today, there was significantly less sea ice in the Arctic Ocean, probably less than 50% of the summer 2007 coverage, which was absolutely lowest on record. Our studies also show that when the ice disappears in one area, it may accumulate in another. We have discovered this by comparing our results with observations from northern Canada. While the amount of sea ice decreased in northern Greenland, it increased in Canada. This is probably due to changes in the prevailing wind systems. This factor has not been sufficiently taken into account when forecasting the imminent disappearance of sea ice in the Arctic Ocean.”
Driftwood unlocks mystery
In order to reach their surprising conclusions, Funder and the rest of the team organised several expeditions to Peary Land in northern Greenland. Named after American Polar explorer Robert E. Peary, the region is an inhospitable and rarely visited area, where summer blizzards are not uncommon.
” Our key to the mystery of the extent of sea ice during earlier epochs lies in the driftwood we found along the coast. One might think that it had floated across sea, but such a journey takes several years, and driftwood would not be able to stay afloat for that long. The driftwood is from the outset embedded in sea ice, and reaches the north Greenland coast along with it. The amount of driftwood therefore indicates how much multiyear sea ice there was in the ocean back then. And this is precisely the type of ice that is in danger of disappearing today,” Funder says.
After the expeditions had been completed, the team needed to study the wood they had collected: wood types had to be determined and it had to be carbon-14 dated. The driftwood originated near the great rivers of present-day North America and Siberia. The wood types were almost entirely spruce, which is widespread in the Boreal forest of North America, and larch, which is dominates the Siberian taiga. The different wood types therefore are evidence of changing travel routes and altered current and wind conditions in the ocean.
Beach ridges and wave breaking
The team also examined the beach ridges along the coast. Today, perennial ice prevents any sort of beach from forming along the coasts of northern Greenland. But this had not always been the case. Behind the present shore long rows of beach ridges show that at one time waves could break onto the beach unhindered by sea ice. The beach ridges were mapped for 500 kilometres along the coast, and carbon-14 dating has shown that during the warm period from about 8000 until 4000 years ago, there was more open water and less coastal ice than today.
Point of no return
“Our studies show that there are great natural variations in the amount of Arctic sea ice. The bad news is that there is a clear connection between temperature and the amount of sea ice. And there is no doubt that continued global warming will lead to a reduction in the amount of summer sea ice in the Arctic Ocean. The good news is that even with a reduction to less than 50% of the current amount of sea ice the ice will not reach a point of no return: a level where the ice no longer can regenerate itself even if the climate was to return to cooler temperatures. Finally, our studies show that the changes to a large degree are caused by the effect that temperature has on the prevailing wind systems. This has not been sufficiently taken into account when forecasting the imminent disappearance of the ice, as often portrayed in the media,” Funder says.
Research could also benefit polar bears
In addition to giving us a better understanding of what the climate in northern Greenland was like thousands of years ago, it could also reveal how polar bears fared in warmer climate. The team plans to use DNA in fossil polar bear bones to study polar bear population levels during the Holocene Climate Optimum.
The team’s findings are to be published in the journal Science.
Inda House says:
“… today’s melting of the arctic is not due to solar forcing, but a small anthropogenic CO2 forcing.”
Evidence, please.
And there is no “tipping point”:
http://www.bbc.co.uk/news/science-environment-14408930
Finally, Inda House says: “Unfortunately we are not expecting such a large change in forcing to happen any time soon.”
Question: Why “Unfortunately”? Is it because you want a climate catastrophe so you can say you were right? Sorry, but it just isn’t happening.
SteveSadlov says:
August 5, 2011 at 2:00 pm
R. Gates – Simple question: do you believe that AGW will overcome the pending end of the interglacial, thereby stalling or eliminating it?
________
Based on my latest readings on Milankovitch cycles, our current interglacial is not in any danger of coming to an end for quite some time. The latest estimates show that we could be in for the longest interglacial based on the sum total of Milankovtich cycles in 500,000 years. So I would disagree that there is some “pending end” of the interglacial looming, so your question is probably not meaningful.
But not to totally dodge your question however, if Milankovtich cycles were indicating a glacial period immediately ahead, I would doubt that CO2 levels alone could forestall this as solar insolation on the NH oceans is a powerful forcing effect from Milankovtich, and this would be a hard thing to overcome from CO2 greenhouse effects alone.
Smokey. I used the word ‘unfortunately’ because a forcing to cool the arctic would slow the melting, which would be welcome. Such a forcing could be a reduction in solar irradiance or a reduction in greenhouse effect.
Just as a matter of interest, what is your scientific understanding of the greenhouse effect, and are you against the theory?
Inda House,
First, the use of proper terminology is essential. The greenhouse effect is a hypothesis, not a theory. A theory makes predictions that are at least somewhat accurate, consistent, testable and verifiable. Models of the greenhouse effect have failed to make accurate predictions. The putative greenhouse effect is entirely model-based, which is in turn based on radiative physics. But it has not made accurate, testable predictions, so it is actually more of a conjecture than a hypothesis.
That said, however, there may well be a greenhouse effect, even though there is no testable evidence. But if it exists it is minuscule, accounting for only a part of the small, 0.7°C temperature rise over the past century and a half. The whole “carbon” scare is wildly overestimated and irresponsibly hyped, since there is no verifiable evidence showing any global harm from the rise in CO2. On balance, more CO2 is probably a net benefit to the biosphere. And even if it were to double, it would still be a very tiny trace gas.
India House,
As you may have noticed already, Smokey uses strawman arguments and opinionated rethoric to fool himself into sustaining his biased view of reality.
Of course, ignoring the fact that the greenhouse effect causes this planet’s surface to be some 30 C higher than it would be without it, and then calling this effect ‘minuscule’ simply underlines that he has a predetermined agenda of what the outcome of the experiment on planet Earth that we are currently conducting.
Rob,
It is you who relies on a strawman argument, not I. I was answering a specific question asked of me by Inda [not India] House. My answer explained the putative greenhouse effect, specifically regarding CO2. You are presuming facts not in evidence. There is no empirical, testable evidence, per the scientific method, proving a greenhouse effect. As I stated, it may exist. But there is no empirical, testable evidence; the greenhouse effect is a hypothesis, not a theory.
Further, at ≈1 Bar of pressure on Venus, which corresponds to earth at sea level, there is NO “greenhouse effect.” None. And the dense atmosphere on Venus is over 96% CO2, whereas on earth CO2 is only 0.00039 of the atmosphere. The temperature of Venus is completely explained by its closer proximity to the sun. If CO2 caused heating, Venus would be much hotter.
Instead of going off about agendas and rhetoric, try to get up to speed on the science. A good place to start is by searching the WUWT archives, keyword: CO2.
R. Gates, you better be sitting down. I agree with you on the M. cycle and that any AGW from increased CO2 would not negate this known cycle. Common ground. Whoda thunk it possible.
Smokey. Thanks for your informative answer, you’ve obviously been studying. Climate scientists quite often talk about longwave radiation heating the atmosphere. Which do you believe, that the 700c/cm radiation passes through the atmosphere without interacting with CO2 because its only a trace gas, or that the 700c/cm lines have been saturated, and therefor adding more CO2 makes no difference now?
Pamela…yea, Whoda thunk! From the longest term perspective, Milankovitch cycles will always trump. The only exception would be if the cycle is interrupted by some major shock, such as volcanic eruptions, comet strike, or the sudden release of a large amount of fresh water in to the ocean, as in the case of the Younger Dryas and perhaps even the 8.2. ky event. Where we differ is that I feel there is better than even chance that human activity can influence the climate during these interglacials (thankfully, we haven’t yet experienced a glacial period as an industrialized species to know if we can impact the climate during one of these.) Of course, you and I could be wrong and AGW could turn out to be strong enough to dramatically alter the character and timing of the next glacial period, and by the time it arrives. we may even intentionally decide to use geoengineering to attempt to prevent the worst of the next interglacial. There’s even been a couple of science fiction books about this very thing I believe.
Anyway, I shall cherish this moment, brief and small as it is, of our common ground…
Inda House,
Glad you found my answer so informative. I assume by that that you don’t disagree. However, I answered your question, and now it’s my turn to ask a question before you get to ask another one. This is, after all, a discussion on the internet’s “Best Science” site, not a martinet’s quiz on climateprogress. So, here is my question:
Given that there is no testable, verifiable evidence of any global harm from the ≈40% increase in CO2, and given that agricultural productivity has risen in lock step with the rise in CO2, and given that one-third of the world’s population subsists on less than $2 a day and depends on rising food production to avoid starvation, and given that the climate null hypothesis has never been falsified… would you agree that, on balance, the evidence [or lack thereof] indicates that the added CO2 is both harmless and beneficial?
If not, please provide testable, empirical evidence to the contrary, per the scientific method [and keep in mind that models are not evidence]. Thanx in advance.☺
Inda House (sorry for previous mis-spelling)
Since Smokey seems to be more interested in testing your opinion rather than answering your science question, let me give it a try.
Your question was Which do you believe, that the 700c/cm radiation passes through the atmosphere without interacting with CO2 because its only a trace gas, or that the 700c/cm lines have been saturated, and therefor adding more CO2 makes no difference now?
In the 700/cm band, CO2 absorbs/emits radiation strongly. IOW, it has a short optical depth.
Because of CO2 in our atmosphere, if you were to look at our planet from space in the 700/cm band, you would be able to see only down to some 15 km altitude. At 15 km altitude, temperature of our atmosphere is around -50 C, and the CO2 at that altitude radiates thus much less than the surface would radiate. Radiation to space of planet Earth in IR (including the 700/cm band) is visualized very clearly in this graph :
http://en.wikipedia.org/wiki/File:ModtranRadiativeForcingDoubleCO2.png
Notice the large dip in space-bound radiation in the 700/cm band ? That is CO2 in the (cold) upper troposphere that you are looking at.
Consequently, Earth does not cool very well in this band, which means that the surface needs to warm up before the planet as a whole reaches radiative equilibrium again. This is known as the greenhouse effect of CO2, and this large dip in the radiation spectrum is the key reason that the planet surface is so much warmer than our distance from the Sun and plain Stefan Bolzmann black-body radiation would suggest.
If we were to increase CO2 concentration in the atmosphere as we have been doing for the past 150 years, the altitude where CO2 becomes opaque (as seen from space) will increase. Due to the lapse rate, the temperature of CO2 radiating to space will drop, and thus the amount of energy radiated will drop as well. This means that the surface has to again increase in temperature to compensate for the reduced emissions from high altitude CO2. In a nutshell, that is the theory of Anthropogenic Global Warming.
Notice that, because radiation happens from the upper troposphere, water vapor has little influence and there is no ‘saturation’ point for increased CO2, unless the radiating altitude reaches the tropopause.
Does this help ?
Smokey. CO2 is harmful if it causes global warming, so to answer your question I need to prove that it does. If you build a dam across a river, the potential energy will increase behind the restriction and will continue to do so until the water flows over the dam at the same rate as it did before you built your dam. However, the potential energy will have increased. As you must be aware, it’s no different to restricting the flow of energy leaving planet earth, you don’t need to be a scientist to know that, however, within the previous question I asked you, are 2 very good objections to this ‘proof’, which is why you shouldn’t avoid answering my question. You might just prove that AGW is a myth. So please state which objection you agree with: That CO2 is a trace gas and therefor there is not enough to restrict LWR, or, that CO2 has saturated it’s vibrational frequencies, so adding more won’t make any difference.
Rob says:
“In a nutshell, that is the theory of Anthropogenic Global Warming.”
Did someone strike up Send In The Clowns?? Rob still doesn’t understand that AGW is not a “theory,” it is an evidence-free conjecture. See here. Wake me when CAGW can make a reliable prediction. Rob’s talking points come straight out of Skeptical Pseudo-Science, and they ignore the fact that the comparison with Venus completely debunks his entire globaloney scare. That’s why he doesn’t respond to the Venus comparison: it totally destroys the CO2=CAGW conjecture.
Rob has provided exactly zero evidence for his CAGW fantasy. In place of scientific evidence, he offers only computer model conjectures. But models aren’t evidence, they are only tools – very inaccurate tools, which can not make reliable predictions.
Science is based on the Scientific Method. But climate alarmists run and hide from the Scientific Method like Dracula hides from the dawn. The Null Hypothesis is a function of the Scientific Method, and it has never been falsified; the Null Hypothesis debunks the wild-eyed runaway global warming scare. Where are those 20-meter sea level rises? Answer: they are only in the cognitive dissonance-afflicted fevered imaginations of the CAGW True Believer Cult.
If Rob is a sock puppet running interference so ‘Inda’ can avoid answering my legitimate question, it isn’t working. Or, if Rob is operating on his own, he’s living in his own bubble universe: nothing unusual is occurring. The climate is well within its normal historical parameters, despite the red faced, spittle-flecked squealing of the Cult of Doom, whose influence is rapidly dwindling. Sucks to be them, and they know it. Best that Rob steps aside, and allows Inda to respond to my fair question, as I responded to Inda’s. I’m still waiting for Inda House’s answer to my question.
Inda House says:
“CO2 is harmful if it causes global warming…”
That is a baseless opinion. Warmth is good; cold kills. More CO2 is, on balance, a good thing for the biosphere. That fact is undeniable.
You have provided zero empirical evidence showing that CO2 causes global harm – the central conjecture of the climate alarmist crowd. In fact, CO2 is a harmless trace gas. And it is undeniably beneficial. But those afflicted with cognitive disonance cannot accept those simple facts.
And you still have not answered my question.
Hi Smokey, thanx 4 pointing me 2 the very concise Crossfit journal article. I’m getting a much better understanding of where your arguments are coming from now. Your frame of reference is very interesting. Just as a matter of interest, do you tilt towards Creationism more than Darwinism?
IndaHouse says:
“Just as a matter of interest, do you tilt towards Creationism more than Darwinism?”
No.
And you still haven’t answered my question.
Hello Smokey & Rob. Thanks 4 both answering my comments.
Rob: I’ve played with the web-based models, which plot the spectrum of out going radiation, & I’ve seen the satellite plots, which actually measure this. Is a 99% correlation good enough? A rhetorical question.
Smokey, as you are so passionate about this topic, I’m sure you’ve already played with the models and compared it with the actual satellite measurements. Smokey, I think we have a lot in common. We both enjoy warm weather, and both realise that carbon, when placed correctly in the biosphere is a good thing.
I think the question of how harmful CO2 is comes down to how much warming we think is acceptable. Could you both give a figure in degrees centigrade of what rise in temperature you think would be damaging. Is it one degree, two, 10, 20 etc. Please don’t beat around the bush. Answer the question quantitatively, and then if you like, try and support your argument. For example, my answer would be one degree Celsius over the next 400 years. It’s probably a bit extreme, but being a vegan, I wouldn’t want to see any pressure put on our fellow organisms to adapt!
Hmm, sort of a CO2 Feng Shui? Fits right in with the Hockey Stick, just as bogus.
Jeff Alberts,
Fits right in with the vegan thingy, too. Me, I love red meat and roaring down the freeway in my 271 horsepower carbon-spewing monster.☺
As for the temperature, warmer is better. So long as the climate is within the natural parameters of the Holocene, everything is fine. Warm is good; cold kills.
So my question to the vegan in the house: what is the correct temperature for the planet; and who determines it, and on what presumed authority?
Heh, 362hp for me. Nothing like it!
Inda House – How is Carbon Dioxide like a dam? What are you describing here?
Smokey asked.
“So my question to the vegan in the house: what is the correct temperature for the planet; and who determines it, and on what presumed authority?”
Didn’t think you’d answer my question. Mmm, 271 HP, a beautiful Ford Mustang by any chance? I love big Mustangs.
I’m European, and even though I try and push for just a 1.5 C limit, democratically elected governments are aiming at 2 C. (It’ll probably be China and India who have the final say though)
There, that answers your question, but I guess your next question is who will pay for this when governments have no money?! Let me explain.
For example I just had a $18000 Solar PV installation fitted. The government paid half because I’ve recently had my house insulated, also paid for by the government. The government also guaranteed $1600 per year for 25 years as an incentive. There is a further guaranteed 60 cents per kW/h feed in tariff when I sell what I don’t use to my electric company (a 70% subsidy). All tax free, and that’s only half the story. When the smart grid arrives I’m gonna get a Tesla Roadster. The government will pay me to attach it to the grid to smooth out renewable energy fluctuations. Who pays? Well, green taxes of course. A 271HP mustang pays $210 green road tax, which will increase to $3000 as more green energy comes on line. Green petrol tax is expected to raise $30bn next year.
But the best part is being a vegan. I don’t cook because I only eat fresh fruit and veg. That’s a saving of $100 per month which I sell to the Electricity Company, $70 of which is subsidised by people who drive lovely big Mustangs.
I’m sure Steven Chu, your Secretary of Energy will introduce the European model to the US soon, I mean, he gets it, after all he is a physicist.
http://www.guardian.co.uk/money/2010/feb/06/solar-power-bright-investment
http://www.thisismoney.co.uk/money/cars/article-1704964/Petrol-price-fear-under-22bn-green-tax-plan.html
http://www.energysavingtrust.org.uk/Generate-your-own-energy/Sell-your-own-energy/Feed-in-Tariff-scheme#tarifflevels
http://www.direct.gov.uk/en/Motoring/OwningAVehicle/HowToTaxYourVehicle/DG_10012524
First off, it’s not a Mustang. And freeloading off the taxpayers has a long EU history. Sounds like Inda’s got both front feet in the public trough. If that kind of policy was widespread, whole sovereign nations would implode economically.
…oh, wait…
The funny thing is, it’s the countries in Europe that have invested heavily in renewable energy, which haven’t lost their AAA credit ratings.
Inda House says on August 7, 2011 at 1:49 pm
Which countries are those? France? Spain? The UK? Please tell us those countries that have invested heavily in renewable energy and have retained their AAA ratings so we can go and check their progress.