By Stefan Rahmstorf, Michael Mann, Ray Bradley, William Connolley, David Archer, and Caspar Ammann
Global cooling appears to be the “flavour of the month”. First, a rather misguided media discussion erupted on whether global warming had stopped, based on the observed temperatures of the past 8 years or so (see our post). Now, an entirely new discussion is capturing the imagination, based on a group of scientists from Germany predicting a pause in global warming last week in the journal Nature (Keenlyside et al. 2008).
Specifically, they make two forecasts for global temperature, as discussed in the last paragraphs of their paper and shown in their Figure 4 (see below). The first forecast concerns the time interval 2000-2010, while the second concerns the interval 2005-2015 (*). For these two 10-year averages, the authors make the following prediction:
“… the initialised prediction indicates a slight cooling relative to 1994-2004 conditions”
Their graph shows this: temperatures in the two forecast intervals (green points shown at 2005 and 2010) are almost the same and are both lower than observed in 1994-2004 (the end of the red line in their graph).
That this cooling would just be a temporary blip and would change nothing about global warming goes without saying and has been amply discussed elsewhere (e.g. here). But another question has been rarely discussed: will this forecast turn out to be correct?
We think not – and we are prepared to bet serious money on this. We have double-checked with the authors: they say they really mean this as a serious forecast, not just as a methodological experiment. If the authors of the paper really believe that their forecast has a greater than 50% chance of being correct, then they should accept our offer of a bet; it should be easy money for them. If they do not accept our bet, then we must question how much faith they really have in their own forecast.
The bet we propose is very simple and concerns the specific global prediction in their Nature article. If the average temperature 2000-2010 (their first forecast) really turns out to be lower or equal to the average temperature 1994-2004 (*), we will pay them € 2500. If it turns out to be warmer, they pay us € 2500. This bet will be decided by the end of 2010. We offer the same for their second forecast: If 2005-2015 (*) turns out to be colder or equal compared to 1994-2004 (*), we will pay them € 2500 – if it turns out to be warmer, they pay us the same. The basis for the temperature comparison will be the HadCRUT3 global mean surface temperature data set used by the authors in their paper.
To be fair, the bet needs an escape clause in case a big volcano erupts or a big meteorite hits the Earth and causes cooling below the 1994-2004 level. In this eventuality, the forecast of Keenlyside et al. could not be verified any more, and the bet is off.
The bet would also need a neutral arbiter – we propose, for example, the director of the Hadley Centre, home of the data used by Keenlyside et al., or a committee of neutral colleagues. This neutral arbiter would also decide whether a volcano or meteorite impact event is large enough as to make the bet obsolete.
We will discuss the scientific reasons for our assessment here another time – first we want to hear from Keenlyside et al. whether they accept our bet. Our friendly challenge is out – we hope they will accept it in good sportsmanship.
(*) We adopt here the definition of the 10-year intervals as in their paper, which is from 1 November of the first year to 31 October of the last year. I.e.: 2000-2010 means 1 November 2000 until 31 October 2010.
Update: We have now published part 2 of this bet with our scientific arguments.
_______________________
Update: Andy Revkin has weighed in at “dot earth”.
Update 5/11/08: so has Anna Barnett at Nature’s ‘climate feedback’ blog
[edit]
On the off chance, then, an observation: why would an escape clause be needed in the event of a volcanic eruption? Aren’t all natural and anthropogenic projections, in the aggregate, included in models that purport to be good predictors?
[Response: Because volcanoes are not predictable and do not form part of the Keenlyside et al experiment. Thus if one occurs then their scenario will no longer be valid, and the test moot. – gavin]
Authors,
There is a flaw in your betting proposal (unless I missed it above or in the subsequent comments). There is no expiration date! As is, the other team can wait 5 years to accept the bet! Legal scholars you’re not.
Re 80:
Has anyone modeled and published the effects of anthropogenic Chinese/ Indian aerosol emissions on monsoonal/ SE Asian climate?
Re 102: ” Legal scholars you’re not.”
Which is to their credit. I once went hunting with a neighbor who happened to be an attorney. We encountered a panther and he started running. I told him it was useless, that he couldn’t outrun a panther. He said that he didn’t have to outrun the panther,he just had to outrun me!
Referring to Lynn’s comment: “So now I have this idea that there probably won’t be a cooling period. And we really could have used one.”
There could still be regional cooling in places like in the north Atlantic, which could slowdown melting on Greenland, and give the world an opportunity to take advantage by putting the reduction of GHGs on the front burner asap to mitigate the effects of albedo reduction and sea level rise from that source, when the heat returns.
Re #64: Ray Ladbury, The type of prediction being tried in the new paper is certainly an initial values problem, much the same as weather prediction. Collins (2002) investigated this type of climate prediction, and found limited skill using a few metrics, in a few regions (one of these included the north Atlantic). In most areas there was essentially no skill. Now keep in mind that these runs assumed perfect initialization, and a perfect model, neither of which are possible in reality. Therefore, I have concluded that these types of forecasts likely have a poor chance of showing any skill, ever. Even if the initial atmosphere/ocean state could be estimated in an accurate quantitative manner, these will likely still hit the predictive wall owing to chaos. Remember that the ocean has a very long memory of initial conditions, and I doubt you wash these out even in multi-decadal predictions, but certainly not in decadal forecasts. Now it is a very big leap of faith to hold that initial conditions definately will not matter for multi-decadal evolution of the climate system as external forcing is perturbed. A big assumption is made that the natural variability of the ocean/atmosphere gets averaged out, and that this leads to no multi-decadal trend (statistical stability of the climate system). The only solid evidence of this is not observation, but rather another hypothesis, which is the model climate itself. Ray, what do you think happens to the system if there are a succession of big El Ninos followed by weak La Ninas or long neutral conditions. Then another big El Nino and a weak La Nina. Now flip the sequence over another period. These must have an important effect on latent and sensible heat fluxes from the ocean to the atmosphere, and ultimately influence the TOA radiative imbalance and the ocean heat storage. Now if the AOGCMs are not skillfully simulating tropical variability, you explain to me how they can possibly correctly model cloud and water vapor feedback correctly, and ultimately skillfully simulate the heat storage changes in the system? Think about this. The long memory in the ocean may mean it is still responding to intial conditions from sometime ago, and much of the intrinsic variability of the system is dictating these big radiative fluxes from ocean to atmosphere. Yes the GHG external forcing is giving the system a shove in the direction of warming, but there is a bunch more taking place. So with this reasoning, I have convinced myself that the initial conditions and short term variability of the ocean/atmosphere may well be very important in influencing the ultimate longer term trajectory of the climate system. The main longer term influence of relatively modest GHG forcing is to increase the probability that longer-term evolution of the system will be toward warming. Skillfully predicting the magnitude of such warming over even a multi-decadal time span is overselling the science in my opinion. Then trying to downscale to make regional predictions in this time frame borders on foolish. You are free to disagree.
Here’s another reference to this post at ClimateArk.org
http://www.climateark.org/blog/2008/05/climate_change_and_cooling_cli.asp
Tamino (94) or H. Roberts (85)
I will defend the science/logic and sociological arguments for the following bets.
1)The planet will abruptly cool because of the current solar magnetic cycle change. The solar cycle has been interrupted, cycle 24 will not appear. There be a recognized direct connection to planetary cloud cover and solar magnetic cycle changes and to galactic cosmic ray (GCR) changes. GCR has and will continue to increase until mid 2009.
2)Next winter will be the coldest winter in 50 years. There will be crop failures next spring and summer due to early and late frosts.
3)Global cooling will become a recognized environmental problem, in 2009. There will be proposals presented to stop global cooling.
4)The deep issues discussed in Anne Leonard’s story of stuff video will be discussed in 2009.
I do not have an answer to the problems raised by Anne Leonard.
http://www.storyofstuff.com/
Solar magnetic cycle update. Cycle 24 is a year over due, there are currently no sunspots.
http://www.dxlc.com/solar/
Ocean temperature anomalies.
http://www.osdpd.noaa.gov/PSB/EPS/SST/climo.html
Is it so unreasonable for someone to be curious as to what exactly is offsetting the greenhouse gas warming in the paper?
Yes, indeed it is.
From fundamental thermodynamics, if heat is being retained at the surface, and in fact is not radiating into space because of some feedback effects (clouds or whatever …) then it must be going into a colder reservoir, and we know exactly where those reservoirs are. Admittedly with the loss of Cryosat were are a bit behind the curve, and the response of the thermocline and deep sea currents is problematic at best, there is no question where the heat is going.
It’s melting ice and warming the ocean.
It’s a trivial thermodynamic result.
Because volcanoes are not predictable and do not form part of the Keenlyside et al experiment. Thus if one occurs then their scenario will no longer be valid, and the test moot. – gavin
Yes, but to win the bet you need warming, or at least less cooling, and you get that based on models that oppose the Keenlyside. Presumably you think the warmer models are more accurate, so is volcanic activity and the resultant cooling haze built into those or not? That’s my point — are the predictive models complete? And if not, what’s the utility of any model that needs to be excused when natural events occur?
[Response: Neither set of models have future volcanoes. Instead their trends are determined by the intrinsic variability in the climate and the far more predictable increases in greenhouse gases. Think of it like a train schedule – that is a prediction for when the train will leave but it doesn’t account for random things that might happen and so when they do, the schedule is thrown off. Yet there is still utility in having a schedule. – gavin]
Re Phillip Shaw #89:
To create links in your posts use the following HTML code
… <a href=”http://www.webpageaddress.net>This text appears in the post.</a>
Test it with the preview button before you post, it’s easy to get it wrong.
Gavin, I found this intriguing remark by you in the comments to the
Should we continue watching the space, or did you give up on the idea?
[Response: Continue to watch, but have patience. – gavin]
Re # 75 John Franklin: “…RealClimate has reduced its level of discussion to that of slightly intoxicated researchers shooting the breeze after hours.I know such discussions take place. I just don’t come to RealClimate to read them.”
Hmmm…that is precisely why I do come to RC. This is a blog, afterall. If I want peer-reviewed science, I’ll read the peer-reviewed journals, or IPCC reports. Instead, like Harold Pierce, Jr. (#93), I want to know what the climatologists really think, unconstrained by the formalities of a journal article. Since I can’t afford to attend AGU meetings, and wouldn’t be invited to drink beer with the scientists if I did attend, this blog is the next best thing to being there, or to sitting in on one of their laboratory meetings (or, joining their Friday afternoon sessions at the pub).
As for allegations that this post will hurt climatalogists’ credibility, I say, Give me a break! With all do respect to the RC staff, I think some of the critics of this post greatly overestimate the influence RC has on the general public’s understanding of global warming. At least in the U.S., if the general public knows anything about global warming (and, clearly, many people don’t), they probably learned it learned it from television, newspapers, news magazines, and, dare I say it, An Inconvenient Truth. I seriously doubt that millions of people are rushing home from work each day to read the latest RC post.
I’m not qualified to judge if the proposed wager is sound scientifically, or statistically, but as long as neither side has the power to alter the climate in order to win the bet, I’m confident the bet will have absolutely no impact whatsoever on the earth’s climate. Therefore, I see no reason to get upset about it. Your time and energy might be better spent debating the potential impact of the proposed summer-time moratorium on federal gasoline tax on CO2 emissions. Or, debating the scientific issues that prompted this wager in the first place.
Dhogaza@92
“It is when that person is Jim Cripwell, whose postings here make it clear that he’s a denialist …”
My hunch is his question in part stems from discussions between gusbobb and Gavin concerning gusbobb’s notions of ocean heat loss.
Recently there was a press release about a paper written by J. Willis:
Perhaps this exchange between gusboob and Gavin is what is driving his question:
gusbobb:
Jim Cripwell:
According to the press release, the Willis paper found the ocean was cooling slightly, but also found no corresponding reduction in SLR. Doesn’t that sort of point to the heat going deeper in the ocean?
Unless I read the WRONG paper, and I followed the link provided here, what I read
doesn’t seem to jive with any of the comments, other than one, that is being posted here.
What I got out of the paper was that their prediction hinges on
…”the current Atlantic meridional overturning circulation will weaken to its long-term mean; moreover, North Atlantic SST and European and North American surface temperatures will cool slightly, whereas tropical Pacific SST will remain almost unchanged. “….
And if such were to happen, isn’t their thinking along historical lines, another words they are more or less echoing a set of circumstances that predicated and brought in cold times in Europe
in the past due to a weak gulf stream that carries the warm weather up into Europe’s latitudes.
And this was released this week by UCAR
Climate Models Overheat Antarctica, New Study Finds
NCAR & UCAR Press Releases, (07 May 2008)
http://www.ucar.edu/news/releases/2008/antarctica.jsp
“”Computer analyses of global climate have consistently overstated warming in Antarctica, concludes new research by scientists at the National Center for Atmospheric Research (NCAR) and Ohio State University.”…”The error appeared to be caused by models overestimating the amount of water vapor in the Antarctic atmosphere, the new study concludes. The reason may have to do with the cold Antarctic atmosphere handling moisture differently than the atmosphere over warmer regions.Part of the reason that Antarctica has barely warmed has to do with the ozone hole over the continent. The lack of ozone is chilling the middle and upper atmosphere, altering wind patterns in a way that keeps comparatively warm air from reaching the surface. “…
Regarding 91: “Have to agree with the crowd here, I think this is a poor way to judge confidence in the findings of the paper and a little below the level of discourse expected here.”
Puhleez, this is how humans resolve it. Get off your high horse.
Actually as a framing device, I think the bet is a very good idea. Sometimes it just takes brute force to make people listen whenever science is the topic at hand.
re #41+79
The EOS Aura satellite has some good plots of the Sulfur dioxide from Chaiten, many orders of magnitude lower than Pinatubo (15-20Mt SO2)… so far.
#103 CW Magee,
Have you read this?
“Atmospheric brown clouds: Impacts on South Asian climate and hydrological cycle” Ramanathan 2005.
http://www.pnas.org/cgi/reprint/102/15/5326.pdf
Or this:
“Warming trends in Asia amplified by brown cloud solar absorption.” Ramanathan 2007
http://www-cas.ucsd.edu/personnel/vram/publications/Ram_etal_Nature2007.pdf
Ray Ladbury (no 64) “However, we must weigh the consequences of the event as well as its probability, and over time, probabilities–and therefore risks–increase. If we have a threat with a possible consequence of the destruction of human civilization, we cannot dismiss that threat until we are certain that there is zero probability of that threat being realized.”
The climate threat with the highest chance of destroying human civilization would be the next ice age. Are we dismissing that, or doing something to reduce its probability to zero?
“The science of climate change is sufficiently settled that it is unlikely that what we learn in the future–and we have much to learn–is unlikely to significantly alter the likely consequences of a business as usual approach. We now have to look at how business as usual must change to become business as sustainable.” No argument with this. But we are a long way from having the knowledge or the technologies to genuinely achieve this goal. (BTW, the second “unlikely” in the quoted passage should be “likely” or words to that effect.)
wmanny, perhaps you could come up with a model-crystal ball interface so the models could include this important effect on the WEATHER!!!! Until that point, all one can do is look at various runs with various volcanic aerosol contributions for potential effects and include a mean contribution in the models.
Alex Heyworth, Jim Hansen’s work has suggested that we are very unlikely to have an ice age with CO2 as high as it currently is. Therefore, I would say that the probability is certainly fairly remote. Also, I would contend that some of the warming scenarios Lovelock has painted hold equally grim prospects for human civilization and are more probable.
I agree, that a lot of work is needed to achieve sustainability, but starting now by serious conservation efforts, investment in alternative energy sources, etc. is a start and buys us the time we need to achieve this goal (hopefully, at least).
RE, Re #56, Another article appeared in the UK Daily Telegraph the other day regarding the Antarctic computers models being inaccurate for this region.
http://www.telegraph.co.uk/earth/main.jhtml?view=DETAILS&grid=A1&xml=/earth/2008/05/08/eatemp108.xml
However the DT tone for this article is far more downbeat and you would expect from a boradsheet newspaper.
Those who think that betting on scientific matters trivialises the issues should be aware that there is something of a tradition among scientists of betting on scientific outcomes.
For example, in 1997 Stephen Hawking and Kip Thorne made a bet with John Preskill of the California Institute of Technology who had argued that information carried by an object entering a black hole was not destroyed. Hawking famously lost when he changed his mind some 30 years after declaring that information entering a black hole would be destroyed. The prize in this instance was an encyclopedia “from which information could be freely retrieved”.
Another well known, still-unresolved bet was made by futurist Ray Kurzweil when he wagered $10000 against Lotus Development Corp founder, Mitchell Kapor. Kapor believes that “by 2029 no computer – or “machine intelligence” – will have passed the Turing Test” while Kurzweil takes the opposing view.
Ther are many others, as Hank Roberts link (#85) shows.
Ref 112 from RCH “Doesn’t that sort of point to the heat going deeper in the ocean?”
and # 108 Thomas Lee Elifritz “From fundamental thermodynamics, if heat is being retained at the surface, and in fact is not radiating into space because of some feedback effects (clouds or whatever …) then it must be going into a colder reservoir, and we know exactly where those reservoirs are. Admittedly with the loss of Cryosat were are a bit behind the curve, and the response of the thermocline and deep sea currents is problematic at best, there is no question where the heat is going.
It’s melting ice and warming the ocean.”
I do not hide the fact that I am a denialist. However, I am a scientist as well. If the heat we are wondering where it “hides” is, in fact, going into the oceans, then it cannot be going into the surface of the oceans, otherwise these would heat up, and the average global temperatures would rise. The forecast, from Keenleyside, is that this is not going to happen. So the heat must be going into the deep oceans. Simple physics says that warmer water is lighter, and therefore this heat should rise to the surface. I know it is much more complicated that this, and I know my physics isn’t good enough to work it out. But I can understand any arguments, based on fundamental physics, that proves this is the meachanism I am looking for. What I am looking for is a properly argued discussion that proves that a process that “hides” the heat in the deep oceans,(or anywhere else for that matter) exists. Until such a detailed paper has been published, I simply cannot accept the idea that this heat can “hide” anywhere. To me, this is simply, inadequate science.
Alex Hayworth writes:
Dismissing it. The next ice age is due 20,000-50,000 years from now. It’s something that can be calculated with fair accuracy, since it depends on the Earth’s orbit and other astronomical factors.
BryanS, I would qualify the effort as extremely difficult of having limited probability of success rather than foolish. It is hardly a frivolous undertaking. And one can always envision a scenario that invalidates assumptions of the model. The question is how probable these scenarios are. Are such asymmetric ENSO patterns the norm. It is more likely that the events will follow some sort of probability distribution. And even if there were no predictability, I don’t know of any scientist worth his salt who would throw up his or her hands and declare defeat.
In any case, the purpose of modeling is not necessarily predition, but rather to gain insight into the problem and–from a risk mamagement perspective–to explore the probability space. Neither of these goals is foolish.
Simple physics says that warmer water is lighter, and therefore this heat should rise to the surface. I know it is much more complicated that this, and I know my physics isn’t good enough to work it out. But I can understand any arguments, based on fundamental physics, that proves this is the mechanism I am looking for. What I am looking for is a properly argued discussion that proves that a process that ‘hides’ the heat in the deep oceans,(or anywhere else for that matter) exists.
I just gave you one, simple, direct and to the point.
Heat doesn’t hide, it’s energy, it’s always there. It’s what drives the atmospheric circulation and the ocean currents that mix the upper warm layers of the ocean with the deeper colder layers, and vice versa.
The oceans aren’t static, they circulate, as observed.
Did you miss the rotation of the Earth as well?
Jim Cripwell, OK, now I know you can figure this out. Temperature is not the only determinant of density–there’s also salinity and even CO2 content. Even turbulence can change the amount of mixing from below. There are several places on Earth where cold water upwells continually–just ask the fishermen, as they are the most fertile areas of the oceans. The thing is that unless there is a permanent change, such events average out over time. And if we are talking a permanent change, that bodes ill–from the point of view of ocean fertility and for stability of greenhouse gasses sequestered in the briny deeps.
re #124
The science of the next Ice Age must very “proven” since Barton tells us we can calculate it with “fair accuracy” to a 30,000 year range.
Don’t give a lecture about the Milankovitch cycles. There also a number of known problems with the theory, which means we still may have something to learn, even if it may be mostly right.
Ref 127. OK, and fair enough. But what I am looking for is a paper giving the DETAILED physics as to how the heat in the Keenleyside paper “hides” for 10 years or more. I am quite sure there are all sorts of hypotheses as to how this happens. But no-one seems to be able to come up with a reference giving, as I note, the detailed physics. Until I can read such a paper, my funny internal feelings tell me that there is no viable mechanism as to how this can happen. We are, I hope, talking science. Where and what is the reference I am looking for?
Barton wrote
“The next ice age is due 20,000-50,000 years from now. It’s something that can be calculated with fair accuracy, since it depends on the Earth’s orbit and other astronomical factors.”
Obviously I (and I suspect many others) are ill-informed on this question, since I had no idea that the timing was known with such accuracy. I’d be grateful for some pointers on where to read up on it.
Jim, The reason you can’t find it is because the heat isn’t hiding. If it goes into the briny deep, it has a tiny effect on the huge mass of water. All that has to happen is you get more upwelling of cold water–as happens with La Nina, and we know that can have significant effect. That’s that much more cold water at the surface that needs to be heated up. Such a state is, however, not sustainable. Eventually, the situation turns around. Now, you have less upwelling cold water to heat up, and you get more warming–as in El Nino (a la 1998).
Re #129 Jim Cripwell: “Where and what is the reference I am looking for?”
You say you are a scientist – if that is true, then you should know now to search the peer-reviewed literature for the information you are seeking. Check the references cited in the Keenleyside paper, and the references those papers cite. Search the oceanography and climatology journals. Do a Google Scholar search. Those are the things that real scientists do when they are searching for specific information. And if you are totally incapable of looking for information outside of RC, then check the links provided on the site and in the posts by the RC moderators – this site has tremendous resources, if you bother to use them. But, don’t expect the readers of RC, most of whom are not climate scientists or oceanographers, to do your work for you.
A lot of people really have a distorted idea of both the purpose of scientific model. First, the purpose is not to get an “answer,” but rather to gain insight into the phenomenon. As such the goal is to identify those elements that are most important in the model, nail those down and then 1)bound and 2)quantify the contributions of of secondary factors. With regard to climate models, we have a good fix on the main factors and have good bounds on most of the secondary factors. One could even argue that since most of the uncertainty resides on the high sides of the estimates, that the models are a conservative treatment–certainly from a risk perspective.
The ARGO buoys found the oceans to be colder than expected. The Nature paper forecasts a cooler ocean region.
The big stuff about the ocean that Thomas LF is referring to, surely those were incorporated into the original expectation by which this coolness has been determined to be whatever – unexpected?
Even a noted climate scientist (Trenberth) is quoted as sort of wondering out loud about the mystery of where this expected heat is ‘hiding”. If this is such a simple issue, then why was he wondering? When interviewed by the press, he obviously did not know the exact answer to this simple question.
I’ve read various presentations as to how deep the ARGO system is gathering data – from the upper 700 meters to more than twice that. The press release on the WIllis paper seemed to indicate findings that sea level and surface temperature were somewhat at odds. Why would that be? If the heat simply went down under, why would the scientist who wrote the paper have an expectation of SL drop? Is the expansion of a better-mixed ocean equal to that of a normally, temperature wise, layered ocean?
On the Keenlyside paper and the denialosphere, the denialists seem to think Keenlyside and the RC group are on opposing sides as to AGW. Unless I totally misunderstand the Keenlyside work, they are not at all on opposing sides. That is the only downside I see to this bet. It belies their extensive agreements. They’re perceiving this like Monkton stalking Al Gore.
As I said earlier, Jim doesn’t believe that GHG-forced warming is happening, that’s where everything he posts leads, without exception.
He’s “disproved” global warming in so many different ways one can’t keep track.
I think that one might be wise to consider what warming and cooling mean when considering the effects of varying MOC.
Warming as measured by increased global heat, (heat in greater than heat out) and warming measured as increased globally averaged temperatures are closely linked but are still different things. As the distribution of land and ocean areas in the two hemispheres is markedly different the redistribution of heat via MOC leaves open the possibility of the world getting hotter in the first sense whilst the averaged temperatures only rise a little or stagnate. Alternatively the averaged temperatures could rise significantly with little increase in net heat. This would be purely an effect of the two hemispheres having different thermal properties.
Such effects can be achieved without needing to “hide” or “find” any heat merely to redistribute it in such fashions that its affect on globally averaged temperatures is minimised or maximised.
This is obvioulsy not the whole story but it is worth keeping in mind regarding the MOC whose primary effect is to redistribute heat.
Best Wishes
Alexander Harvey
> next ice age
Alex, your library will be able to get you the Science article referred to here:
http://www.sciencemag.org/cgi/content/summary/297/5585/1287
Follow the citations and related links on the page and using search terms you find there. Stay with Google Scholar, there’s much chaff in Google searches on this subject.
Oh, from the very bottom of that page, the ‘citing articles’ will be helpful, many of those link to more detailed text. One example:
http://cel.isiknowledge.com/CEL/CIW.cgi?SID=V1K@5L7H7aM7GpO2hcE&Func=Abstract&doc=2/9
Given the ‘global warming is stopping’ stuff in the media, this is exactly the kind of thing an interested, scientifically literate (but non climate scientist) wants to read. Keep it up, bets and all. Where I come from, ‘Want a bet?’is fighting talk.
Jim Cross & others — The next orbital forcing for a stade (massive ice sheets) is about 20,000 years from now. But it is such a weak forcing that perhaps little ice will form. The next one is in 50,000 years and that is respectably large.
I have this from papers by Archer & Ganapolski, with copies available on David Archer’s publications page. But also see
http://www.uni-saarland.de/…/Buch/DPG2007_SYEE1.2_Crucifix_AstronomicalTheory_ofPalaeoclimates.doc
for a more current summary of the state of knowledge regarding major climate ‘cycles’.
I asked Tony Watts over at Watts up with that a question, was wondering what you thought. And please, go gently on me boys, I’m just a layperson & a partial skeptic (I believe CO2 causes warming but haven’t been convinced it’s dangerous. Actually I’m more worried about sootfall on the boreal environment, esp. the tundra permafrost situation).
Verbatim cut & paste of my question to Tony Watts:
“…NPR did a bit about the Argo data not finding the warming anticipated by the climate models.
I was thinking …. the 1998 el Nino burped out a pile of heat & then the next year temperatures dropped almost the same amount in response. Could that be where all that errant heat went?
This makes me think. The warmist models might be half-right. Could it be that the el Nino / la Nina oscillations are gaining in amplitude. They’re modeling a more-stable system. Could that mean the warmists “natural variations” from Los Ninos are actually reflecting the system’s ability to shed the excess heat they can’t find right now?
Another aspect could be the upwelling of warm water going into the Arctic. Most of the year Arctic insolation is weak, meaning that the now-open waters have more emissivity outbound than insolation inbound, a 2:1 ratio.
The gist of this is that the oceans, being real big like they are, are functional heat exchange systems that can shed excess inbound heat from extra warming, making the time constant/heat latency shorter than modeled.
This would explain why we have ice ages but not heat ages. The oceans tend toward a thermal constant and big El Ninos or Arctic thaws will regulate the backlog by shoving the heat back out into space. The Antarctic fringes would thaw in a likewise manner, dumping heat out in the fall and spring before solar heating takes over.
This concept wouldn’t exculpate CO2 terribly well for those who’d like to otherwise, but that might explain the discrepancies that are inciting we skeptics and puzzling the warmists.
I’m also wondering what effect aerosol dimming would have on the surface in the ability of the seas to off-load the heat due to reduced evaporation, and hence, reduced evaporative cooling. I think it’d reduce evaporation in high-aerosol regions but would get offloaded as increased rain clouds elsewhere where surface dimming wasn’t as prevalent (the southern hemisphere?).
Eventually the heat piles up into a big el Nino like ‘98. Makes me wonder if the 2000-2007 double set of PDO oscillations were unusual in any regard (amplitude, frequency).
V. Ramanathan, et al, in 2008 noted that the net heating effect of tropospheric brown clouds over the Pacific alone was about 40 percent. That’d reflect a fair amount of surface dimming as well, I reckon (don’t have my handy dandy quick climatology/oceanography data facts almanac handy… :-).
So the next question is whether that’d moderate direct surface heating since the brown clouds are actually net heat traps, or what that’d do for T-storm strength (although the N. Pacific is seeing unusually big winter T-storms from aerosol cloud seeding).
So, watt would this mean? Could the next big release of heat show up early, with heat-burps piling out as aerosol shading increases. Bigger amplitude, both ways, since all that heat leaving the system in one big belch makes for big coolth afterwards, tending toward a self-regulating state.
Is there any merit in this idea? What would the realclimate boys have to say about this?
Interesting in seeing your reaction.
Best regards,
/leebert
Gavin and Ray,
You appear to contradict each other — one of you states there are no volcanoes in the models, and the other implies that volcanic aerosols are included in the aggregate. It would be good to know which models do attempt to include major eruptions, solar flare-ups, wildfires and the like, which are hardly random on a geological timescale. Ray makes my point, ironically, when he chides me for not having developed an eruption crystal ball. It’s another way of saying we have not yet developed the crystal ball we need to accurately predict future climate. Until we understand how all the various and chaotic climate forcings work, I am afraid we are mere climate alchemists. That greenhouse gas emissions are predictable is not a good excuse for making those emissions the overriding factor in models.
Walter Manny
[Response: You are extremely confused. Historical eruptions are of course included in historical model runs. For future scenarios you can either make a WAG about when they might occur or not. For the simulations being talked about here, no volcanoes were included in the future simulations. But if you look at the Hansen et al (1988) paper, they assumed some future eruptions. There is no right answer for this, since we lack any basis to forecast whether a volcanic eruption will happen and what it’s contribution to stratospheric aerosols will be. However, your leap of logic to concluding that there is no point in doing any forecasts unless we know exactly when the volcanoes will erupt is completely fallacious. Climate modellers didn’t make greenhouse gas changes the dominant effect – human civilisation did. We’re just reporting the consequences. – gavin]
“The climate threat with the highest chance of destroying human civilization would be the next ice age. Are we dismissing that, or doing something to reduce its probability to zero?” – Alex Heywood
The danger of climate change for human civilization and possibly the human species comes not from ice or heat. It comes because merely rapidly changing the average temperature of a location must upset the ecosystem there. Worldwide average temperature change will upset ecosystems everywhere.
The best average temperature for the ecosystem earth is the present one, but in the long run it only matters to humans if it is also a stable, sustainable, temperature.
I’m not confused, Gavin, though I’m guessing that is simply your way of saying we disagree. I merely referred to what you and Ray wrote. (“Neither set of models have future volcanoes” and “mean [volcanic] contribution in the models”). The Hansen piece, which predictions didn’t pan out in any of the famous scenarios, demonstrates the difficulty of getting all the contributions right, though he would argue, and rightly so, that the science was in its infancy in ’88. I would argue that it still is.
[Response: Hansen’s predictions did as well as you could possibly expect as we have discussed previously. With the scenario closest to the what happened, the temperature trends match the obs with the uncertainty. – gavin]
It would indeed be a leap of logic for me to say there is no point in doing forecasts, as you infer. Of course we need to do forecasts and to continually measure their accuracy as the models improve. It would be absurd to do otherwise. What we don’t need to do is to base sweeping policy on demonstrably incomplete science. This is what I meant when I said I question the models’ utility. Ray puts it well when he explains the distorted view people have of models, which should be used to get insights rather than answers. Policymakers are only too happy to substitute answers for insights, though, and are given to report that “we know” the human contribution to global warming when, of course, we know no such thing.
If the recent temperature plateau and/or brief cooling period were to cause the wheels to come flying off the AGW vehicle, so to speak, then it would be the theory’s proponents’ own fault for overstating the case, however noble their motives. When the idiots then went out and purchased ever more SUVs in backlash, I would be more annoyed with the advocates than the skeptics, because there were always more compelling reasons to be good, non-polluting citizens than to save an iceberg or polar bear that was never at risk.
RE # 129
Jim Cripwell, your posts are a mile wide and an inc;h deep, in general.
You said:
We are, I hope, talking science. Where and what is the reference I am looking for?]
Find that which you are asking RC to find for you!!! Then, share it.
Your comment sounds as if you are asking out loud to anyone nearby: “where the heck did I leave my car keys?”
John McCormick
The whole “global cooling” bandwagon is a big premature in claiming current temperatures reflect a real change.
But solar cycle #25 is reasonably forecast to be a half-amplitude dud, with its solar max in 2025. Odds are better than even it’ll be the full onset of a multi-cycle trend.
And a multi-cycle solar grand minimum of half-amplitude solar cycles can have moderate globe-cooling effects that’ll be felt within continental interiors as longer and colder winters.
Leebert, The oceans are indeed large heat reservoirs (though in fact most of the ocean is quite cold) and can have a big effect for a relatively short time. And indeed there has been some speculation that climate change could affect ENSO. The thing is that while ENSO and other such oscillations are not periodic as such, their net contribution averages out. As Raypierre says, “the sun goes up and down and up and down, and temperature (trend) goes up.” Same goes for ENSO.
Walter Manny, Just what should we base policy on if not the insights we gain from sound modeling? And climate models are indeed sound. That is not to say that we don’t still have much to learn, but rather that what we learn is very unlikely to change the important takeaway message: Human activity is adding greenhouse gasses to the atmosphere and thereby changing the climate. There is very little wiggle room for CO2 sensitivity to change significantly–and most of the uncertainty is on the upside rather than the downside.
Policy should be optimized to mitigate risk, and the science is unequivocal–climate change poses a serious risk.
leebert Says:
10 mai 2008 at 7:13 PM
> … solar cycle #25 is reasonably forecast
> …. Odds are better than even that ….
How much are you willing to bet?
I thought the originally sited article was pro-AGW, reading their discussions does as well. Their models just seem to be predicting a temporary slow down in the heat level due to previously unforeseen alterations in Atlantic Conveyor. If their models turns out to be more accurate, what is the harm.
I guess I don’t understand why the ‘bet they are wrong, but they won’t bet so that proves they are wrong’ has any place in serious discussions of Climate modeling.
[Response: This has nothing to do the AGW – instead it is related to how near term predictions are made and received in the media. Everyone involved is already in agreement on the long term effects of CO2. – gavin]