Update: PDF of this paper is available, see link below
The fear that global temperature can change very quickly and cause dramatic climate changes that may have a disastrous impact on many countries and populations is great around the world. But what causes climate change and is it possible to predict future climate change? New research from the Niels Bohr Institute at the University of Copenhagen shows that it may be due to an accumulation of different chaotic influences and as a result would be difficult to predict. The results have just been published in Geophysical Research Letters.
For millions of years the Earth’s climate has alternated between about 100,000 years of ice age and approximately 10-15,000 years of a warm climate like we have today. The climate change is controlled by the Earth’s orbit in space, that is to say the Earth’s tilt and distance from the sun. But there are also other climatic shifts in the Earth’s history and what caused those?
Dramatic climate change of the past
By analysing the ice cores that are drilled through the more than three kilometer thick ice sheet in Greenland, scientists can obtain information about the temperature and climate going back around 140,000 years.
The most pronounced climate shifts besides the end of the ice age is a series of climate changes during the ice age where the temperature suddenly rose 10-15 degrees in less than 10 years. The climate change lasted perhaps 1000 years, then – bang – the temperature fell drastically and the climate changed again. This happened several times during the ice age and these climate shifts are called the Dansgaard-Oeschger events after the researchers who discovered and described them. Such a sudden, dramatic shift in climate from one state to another is called a tipping point. However, the cause of the rapid climate change is not known and researchers have been unable to reproduce them in modern climate models.
The climate in the balance
“We have made a theoretical modelling of two different scenarios that might trigger climate change. We wanted to investigate if it could be determined whether there was an external factor which caused the climate change or whether the shift was due to an accumulation of small, chaotic fluctuations”, explains Peter Ditlevsen, a climate researcher at the Niels Bohr Institute.
He explains that in one scenario the climate is like a seesaw that has tipped to one side. If sufficient weight is placed on the other side the seesaw will tip – the climate will change from one state to another. This could be, for example, an increase in the atmospheric content of CO2 triggering a shift in the climate.
In the second scenario the climate is like a ball in a trench, which represents one climate state. The ball will be continuously pushed by chaos-dynamical fluctuations such as storms, heat waves, heavy rainfall and the melting of ice sheets, which affect ocean currents and so on. The turmoil in the climate system may finally push the ball over into the other trench, which represents a different climate state.
Peter Ditlevsen’s research shows that you can actually distinguish between the two scenarios and it was the chaos-dynamical fluctuations that were the triggering cause of the dramatic climate changes during the ice age. This means that they are very difficult to predict.
Warm future climate
But what about today – what can happen to the climate of the future? “Today we have a different situation than during the ice age. The Earth has not had such a high CO2 content in the atmosphere since more than 15 million years ago, when the climate was very warm and alligators lived in England. So we have already started tilting the seesaw and at the same time the ball is perhaps getting kicked more and could jump over into the other trench. This could mean that the climate might not just slowly gets warmer over the next 1000 years, but that major climate changes theoretically could happen within a few decades”, estimates Peter Ditlevsen, but stresses that his research only deals with investigating the climate of the past and not predictions of the future climate.
Contact:
Peter Ditlevsen, climate researcher, PhD. Dr. Scient., Associate professor, Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, +45 3532-0603, +45 2875-0603, pditlev@gfy.ku.dk
Link to article in Geophysical Research Letters: http://www.agu.org/journals/gl/papersinpress.shtml#id2010GL044486
Update: PDF of full paper now available here
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Vince Causey says:
August 30, 2010 at 9:39 am
“Neither of these two models are correct, imo, as they both misunderstand (or ignore) chaos theory. A system that exhibits chaos behaviour does not remain in a single state but constantly bifurcates, or cycles, through a sequence of states. Bifurcation was used in the article to describe the ‘seesaw’ model, but this is misleading because it implies that once the seesaw tips, it will remain in that state. This is not how a chaotic system behaviours.
I believe that rather than requiring explanations of mysterious ‘forcings’, the earth’s natural climate variations are a near textbook example of chaos in action – the system moves from state to state. […]”
The earth’s climate over geological time never repeats exactly. Even the current climate cycling between glacials and interglacials doesn’t end each cycle with the climate winding up in the same place. I don’t understand how that can be modeled.
England was pretty much where it is now 15 million years ago.
http://www.ucmp.berkeley.edu/geology/anim1.html
Sun Spot says:
August 30, 2010 at 9:24 am
Regarding the “10-15,000 years of a warm climate like we have today” , where are we in this time period today ?
Watch video clip and use comman sence.
I don’t think we should sell this work short, at least until we can read the paper. I just hate pay walls. It seems to me that if one can not easily predict, due to chaos-dynamical fluctuations, when you know the result it would be impossible to precinct anything at all, if you don’t. Notice Ditlevsen did stress his research only deals with the past, not predictions of the future.
I just walked three miles to drop off some completed engineering paperwork for auditing. There must have been a 10-15 degree temperature change since I got to work this morning. Must have reached a Global Warming Tipping Point!
No wait…the sun came up and it got hotter. Maybe the sun had some thing to do with temperature changes in the past. Hmmmmmm.
Oh no, another study, based…….on computer modelling! I’ve about reached my tipping point with such studies.
snow depth in australia ski fields 2 meters 31/8/20010
I would also like to go on record to state that I also predict that the climate change that accrues within the forthcoming indeterminate time frame will in fact be of an unpredictable nature. Rather than a model involving a marble and two troughs, I prefer to conceptualize climate as a pea possibly found under any one of three inverted cups in an indeterminate changing sequence which model more closely resembles the state of climate modeling art.
Warning: Tomorrow is tipping point day!
Stay in bed, watch TV…
Dear Peter Ditlevsen,
how come that the tipping point did not happen in the recent warmer past? It says the ice core, you know.
http://i45.tinypic.com/2uzz32v.jpg
How come that most of the last interglacial was warmer without those “unprecedented levels of CO2”?
How long shall we listen to this BULLSHIT from government-paid academics?
So, the climate’s temp could suddenly drop ten degrees with glaciers once again hitting the road south out of Canada …
or
The climate’s temp could suddenly rise ten degrees with summer sea ice and most glaciers vanishing and most of the temperate zone turning semi-tropical.
Either way, the authors of this article can point to their study in triumph and declare that they told us so. And this is what passes for science these days?
Reality check — mankind’s level of apprehension of climate science is at the level of a baby crawling; we’re working at it and trying to totter upright to try to make our first tottering steps, despite some claiming to be able to run a marathon.
Sun Spot, I think we’re in the error bands right now. Enjoy the sun while it lasts.
The noise induced scenario is a good one to do an FMEA on.
I get a very high RPN. So, where are the contingency plans?
H.R. says:
August 30, 2010 at 10:41 am
“The earth’s climate over geological time never repeats exactly. Even the current climate cycling between glacials and interglacials doesn’t end each cycle with the climate winding up in the same place. I don’t understand how that can be modeled.”
It can be modeled. But a chaotic system is driven by its start parameters. A very small difference in the start parameters and the resultant system behavior can rapidly diverge from the previous iteration. The problem is that no-one knows the parameters that will affect the climate which is a chaotic system of chaotic systems and no-one knows the values of these parameters that will be important and no-one knows the critical states at which those parameter values will have their greatest impact. It may well be that at some states a parameter can vary wildly and have no effect whereas with the system in another state a tiny variance in that same parameter may lead to a large behavior change in the system. This is why looking for simple statistical correlations for ’cause and effect’ in a chaotic system is exhibiting ignorance of chaotic systems. A cause has to happen at the right time at the right level to have an effect.
I don’t know why people here bash this study. As they say, they found out that small “chaos-dynamical fluctuations” suffice for a sudden regime shift. In other words, with or without CO2 concentration rises, there can be dramatic unpredictable changes; and current climate models cannot simulate this. For me, this is a very important step towards discarding the predictions made with current climate models.
“The fear that global temperature can change very quickly and cause dramatic climate changes that may have a disastrous impact on many countries and populations is great around the world.”
Frankly, no there is no great fear of sudden dramatic climate change. With the exception a minority of people all from the white middle class in the western world not many people are paying much attention, what with earning their daily bread and all. And in fact, the sudden change, the warmests themselves tell us, it really only weather. You need 30 plus years for weather patterns to morph into climate.
“the ball is perhaps getting kicked more and could jump over into the other trench.”
I think Peter Ditlevsen has perhaps misunderstood what the Dansgaard-Oeschger events are telling us. The “other” trench is a glacial period.
We are so used to jumping down the throats of the authors of fiddled CAGW treatises by members of The Peer Review Back-slapping Society that we need to be more thoughtful about new climate science papers that are emerging from the climate dark ages. Folks, this is an interesting alternative to the throwaway science of the past 3 decades. It may not turn out to be a description of reality but I think it is a reasonable conjecture (among other alternatives) at this stage of the crawling-out. Their hat tip to CO2 is best seen as a timorous genuflexion that is necessary in the transition-to-science. Try not to be too mean!
Sun Spot says:
August 30, 2010 at 9:24 am
Regarding the “10-15,000 years of a warm climate like we have today” , where are we in this time period today ?
___________________________________
Here are two “peer reviewed” studies on that subject:
Temperature and precipitation history of the Arctic
“..Solar energy reached a summer maximum (9% higher than at present) ca 11 ka ago and has been decreasing since then, primarily in response to the precession of the equinoxes. The extra energy elevated early Holocene summer temperatures throughout the Arctic 1-3° C above 20th century averages, enough to completely melt many small glaciers throughout the Arctic, although the Greenland Ice Sheet was only slightly smaller than at present… As summer solar energy decreased in the second half of the Holocene, glaciers reestablished or advanced, sea ice expanded, and the flow of warm Atlantic water into the Arctic Ocean diminished. Late Holocene cooling reached its nadir during the Little Ice Age (about 1250-1850 AD), when sun-blocking volcanic eruptions and perhaps other causes added to the orbital cooling, allowing most Arctic glaciers to reach their maximum Holocene extent…”
This paper also agrees that we are at the point in the earth’s Milankovitch cycle that should usher in an ice age. The biggest question of course is why we are not covered in ice yet.
Lesson from the past: present insolation minimum holds potential for glacial inception (2007)
“Because the intensities of the 397 ka BP and present insolation minima are very similar, we conclude that under natural boundary conditions the present insolation minimum holds the potential to terminate the Holocene interglacial. Our findings support the Ruddiman hypothesis [Ruddiman, W., 2003. The Anthropogenic Greenhouse Era began thousands of years ago. Climate Change 61, 261–293], which proposes that early anthropogenic greenhouse gas emission prevented the inception of a glacial that would otherwise already have started….”
Here is an article similar to the one above by Woods Hole Oceanographic Institution
Abrupt Climate Change: Should We Be Worried?
“Most of the studies and debates on potential climate change, along with its ecological and economic impacts, have focused on the ongoing buildup of industrial greenhouse gases in the atmosphere and a gradual increase in global temperatures. This line of thinking, however, fails to consider another potentially disruptive climate scenario. It ignores recent and rapidly advancing evidence that Earth’s climate repeatedly has shifted abruptly and dramatically in the past, and is capable of doing so in the future.
Fossil evidence clearly demonstrates that Earth vs climate can shift gears within a decade….
But the concept remains little known and scarcely appreciated in the wider community of scientists, economists, policy makers, and world political and business leaders. Thus, world leaders may be planning for climate scenarios of global warming that are opposite to what might actually occur…“
And then there are “the ball kickers” The Forthcoming Grand Minimum of Solar Activity
”A method for predicting the next Grand Episode, based on previous results on the modes of oscillations in the solar dynamo (summarized in De Jager and Duhau, 2010) was introduced by de Jager and Duhau (2009). One of the results was the recognition of a transition from the Grand Maximum of the 20th century to another Grand Episode. This transition period started in 2000 and is expected to end in 2013.
Based on the above mentioned methodology and by using new data for the geomagnetic aa index we foresee that a Grand Minimum is immanent. Thus, a prolonged period of relative global cooling is forecasted. The relevant mechanisms are described….”
Joe Bastardi is saying both the AMO and PDO will be in the negative phase in 10 to 15 years, so all that will be left is the final trigger – a major volcanic eruption.
Ian W says:
August 30, 2010 at 12:04 pm
(Ref. H.R. says:)
August 30, 2010 at 10:41 am
“It can be modeled. But a chaotic system is driven by its start parameters. [… omitted a very nice discussion of unknowns for brevity]”
But as you point out, we don’t know all of the parameters and we don’t know the initial conditions. Also, even if we actually knew all of the parameters and the initial conditions, we still have to account for the random asteroid strike here and there. How and where does one put such events in a skilled climate model? (And anyway, who needs a climate model for an asteroid strike? You really don’t need a model for, “We’re screwed!”)
P Walker says:
August 30, 2010 at 9:10 am
I’m going to regret asking this , but how does onr drtermine the makeup of the atmosphere from fifteen million years ago ? Accurately , that is .
_________________________________________________
If you are really interested in the other side of the CO2 analysis story look at http://www.co2web.info/
Especially the pdf http://www.co2web.info/ESEF3VO2.pdf
That pdf gives the politics and history behind the CO2 measurements. It is a real eye opener.
Temperature variations are not increasing.
http://motls.blogspot.com/2010/08/temperature-variations-are-not.html
If we simply take the warmest and the coldest periods from the past 2000 years and call everything in between “Climate Variation” we can dump the Climate Change where it belongs, in the dumpster together with all the other propaganda acts of the past century.
It would be a great help because it would make the IPCC OBSOLETE and save us a huge amount of money.
That said, I reject any report that mentions climate change.
Warm future climate
“But what about today – what can happen…? …the ball is perhaps … and could jump over … This could mean … theoretically could happen…”
This idiotically dense thicket of subjunctive terms should be given a name – something like “dancing round the may-pole”.