A few weeks ago I was at a meeting in Cambridge that discussed how (or whether) paleo-climate information can reduce the known uncertainties in future climate simulations.
The uncertainties in the impacts of rising greenhouse gases on multiple systems are significant: the potential impact on ENSO or the overturning circulation in the North Atlantic, probable feedbacks on atmospheric composition (CO2, CH4, N2O, aerosols), the predictability of decadal climate change, global climate sensitivity itself, and perhaps most importantly, what will happen to ice sheets and regional rainfall in a warming climate.
The reason why paleo-climate information may be key in these cases is because all of these climate components have changed in the past. If we can understand why and how those changes occurred then, that might inform our projections of changes in the future. Unfortunately, the simplest use of the record – just going back to a point that had similar conditions to what we expect for the future – doesn’t work very well because there are no good analogs for the perturbations we are making. The world has never before seen such a rapid rise in greenhouse gases with the present-day configuration of the continents and with large amounts of polar ice. So more sophisticated approaches must be developed and this meeting was devoted to examining them.
The first point that can be made is a simple one. If something happened in the past, that means it’s possible! Thus evidence for past climate changes in ENSO, ice sheets and the carbon cycle (for instance) demonstrate quite clearly that these systems are indeed sensitive to external changes. Therefore, assuming that they can’t change in the future would be foolish. This is basic, but not really useful in a practical sense.
All future projections rely on models of some sort. Dominant in the climate issue are the large scale ocean-atmosphere GCMs that were discussed extensively in the latest IPCC report, but other kinds of simpler or more specialised or more conceptual models can also be used. The reason those other models are still useful is that the GCMs are not complete. That is, they do not contain all the possible interactions that we know from the paleo record and modern observations can occur. This is a second point – interactions seen in the record, say between carbon dioxide levels or dust amounts and Milankovitch forcing imply that there are mechanisms that connect them. Those mechanisms may be only imperfectly known, but the paleo-record does highlight the need to quantify these mechanisms for models to be more complete.
The third point, and possibly the most important, is that the paleo-record is useful for model evaluation. All episodes in climate history (in principle) should allow us to quantify how good the models are and how appropriate are our hypotheses for climate change in the past. It’s vital to note the connection though – models embody much data and assumptions about how climate works, but for their climate to change you need a hypothesis – like a change in the Earth’s orbit, or volcanic activity, or solar changes etc. Comparing model simulations to observational data is then a test of the two factors together. Even if the hypothesis is that a change is due to intrinsic variability, a simulation of a model to look for the magnitude of intrinsic changes (possibly due to multiple steady states or similar) is still a test both of the model and the hypothesis. If the test fails, it shows that one or other elements (or both) must be lacking or that the data may be incomplete or mis-interpreted. If it passes, then we a have a self-consistent explanation of the observed change that may, however, not be unique (but it’s a good start!).
But what is the relevance of these tests? What can a successful model of the impacts of a change in the North Atlantic overturning circulation or a shift in the Earth’s orbit really do for future projections? This is where most of the attention is being directed. The key unknown is whether the skill of a model on a paleo-climate question is correlated to the magnitude of change in a scenario. If there is no correlation – i.e. the projections of the models that do well on the paleo-climate test span the same range as the models that did badly, then nothing much has been gained. If however, one could show that the models that did best, for instance at mid-Holocene rainfall changes, systematically gave a different projection, for instance, of greater changes in the Indian Monsoon under increasing GHGs, then we would have reason to weight the different model projections to come up with a revised assessment. Similarly, if an ice sheet model can’t match the rapid melt seen during the deglaciation, then its credibility in projecting future melt rates would/should be lessened.
Unfortunately apart from a few coordinated experiments for the last glacial period and the mid-Holocene (i.e. PMIP) with models that don’t necessarily overlap with those in the AR4 archive, this database of model results and tests just doesn’t exist. Of course, individual models have looked at many various paleo-climate events ranging from the Little Ice Age to the Cretaceous, but this serves mainly as an advance scouting party to determine the lay of the land rather than a full road map. Thus we are faced with two problems – we do not yet know which paleo-climate events are likely to be most useful (though everyone has their ideas), and we do not have the databases that allow you to match the paleo simulations with the future projections.
In looking at the paleo record for useful model tests, there are two classes of problems: what happened at a specific time, or what the response is to a specific forcing or event. The first requires a full description of the different forcings at one time, the second a collection of data over many time periods associated with one forcing. An example of the first approach would be the last glacial maximum where the changes in orbit, greenhouse gases, dust, ice sheets and vegetation (at least) all need to be included. The second class is typified by looking for the response to volcanoes by lumping together all the years after big eruptions. Similar approaches could be developed in the first class for the mid-Pliocene, the 8.2 kyr event, the Eemian (last inter-glacial), early Holocene, the deglaciation, the early Eocene, the PETM, the Little Ice Age etc. and for the second class, orbital forcing, solar forcing, Dansgaard-Oeschger events, Heinrich events etc.
But there is still one element lacking. For most of these cases, our knowledge of changes at these times is fragmentary, spread over dozens to hundreds of papers and subject to multiple interpretations. In short, it’s a mess. The missing element is the work required to pull all of that together and produce a synthesis that can be easily compared to the models. That this synthesis is only rarely done underlines the difficulties involved. To be sure there are good examples – CLIMAP (and its recent update, MARGO) for the LGM ocean temperatures, the vegetation and precipitation databases for the mid-Holocene at PMIP, the spatially resolved temperature patterns over the last few hundred years from multiple proxies, etc. Each of these have been used very successfully in model-data comparisons and have been hugely influential inside and outside the paleo-community.
It may seem odd that this kind of study is not undertaken more often, but there are reasons. Most fundamentally it is because the tools and techniques required for doing good synthesis work are not the same as those for making measurements or for developing models. It could in fact be described as a new kind of science (though in essence it is not new at all) requiring, perhaps, a new kind of scientist. One who is at ease in dealing with the disparate sources of paleo-data and aware of the problems, and yet conscious of what is needed (and why) by modellers. Or additionally modellers who understand what the proxy data depends on and who can build that into the models themselves making for more direct model-data comparisons.
Should the paleo-community therefore increase the emphasis on synthesis and allocate more funds and positions accordingly? This is often a contentious issue since whenever people discuss the need for work to be done to integrate existing information, some will question whether the primacy of new data gathering is being threatened. This meeting was no exception. However, I am convinced that this debate isn’t the zero sum game implied by the argument. On the contrary, synthesising the information from a highly technical field and making it useful for others outside is a fundamental part of increasing respect for the field as a whole and actually increases the size of the pot available in the long term. Yet the lack of appropriately skilled people who can gain the respect of the data gatherers and deliver the ‘value added’ products to the modellers remains a serious obstacle.
Despite the problems and the undoubted challenges in bringing paleo-data/model comparisons up to a new level, it was heartening to see these issues tackled head on. The desire to turn throwaway lines in grant applications into real science was actually quite inspiring – so much so that I should probably stop writing blog posts and get on with it.
The above condensed version of the meeting is heavily influenced by conversations and talks there, particularly with Peter Huybers, Paul Valdes, Eric Wolff and Sandy Harrison among others.
Mike, 50 years, because up til the middle of the 20th Century, the forcings attributable to solar and CO2 were indeed comparable. Since then, not so.
http://upload.wikimedia.org/wikipedia/en/a/a2/Climate_Change_Attribution.png
Mike, another useful chart
http://www.scs.carleton.ca/~schriste/data/Carbon-Atmosphere-Mass_files/State%20of%20the%20World_28025_image001.gif
> without the Arctic sea ice there will
> be no northern polar vortex.
Alastair, you’re approaching a bettable statement. What about during the months when there’s the least sea ice — will there be less of a North polar vortex? Or are you saying after X years with zero sea ice summer and winter, the vortex will change by Z amount?
Just trying to work up some betting activity, it’s fun to watch.
Jim Eager #347 said “News Flash: Albedo does operate independently of CO2. Albedo change is a feedback to warming or cooling, regardless of the initial cause of that warming or cooling. What ever made you think otherwise?”.
Thanks for that. I trust and believe that you are correct in saying that albedo operates independently of CO2. However, the IPCC report shows that they believe that clouds (ie, albedo) are driven by CO2. See my post #211 :
“You could start with the IPCC report, section 8.6.3.2. There, they say that the basic Equilibrium Climate Sensitivity (ECS) of 1.2 (this compares OK with the 1.1 in Stephen E Schwartz’s paper http://www.ecd.bnl.gov/steve/pubs/HeatCapacity.pdf). They then bump it up to 1.9 for “water vapor feedback”, and from there to 3.2 for “cloud feedback”. They also make it abundantly clear that they have no idea how clouds work (that permeates the whole IPCC report), and that the cloud “feedback” they use for ECS is a major uncertainty.”.
tamino #348 said “It’s not because 50 years is more convenient. It’s because it’s more relevant. You’re the one who’s choosing time periods because they’re convenient.”.
I have been referring to the 20th century consistently. As I said before, this climate thing is complex, and among other things there are some big time lags. The longer the periods we deal with, the more likely we are not to be confused by short term fluctuations. However, I’m prepared to look at both periods.
The full 20th century supports my case.
1950-2000 : The graph posted by BPL won’t now come up (BPL is it still on your website?), but from memory it showed an extended period of increasing sun strength from I _think_ well before 1900 but certainly from 1900, up to 1950. From 1950 to 2000 it showed significant fluctuations but no obvious overall trend. In searching for an alternative source, I came across this article in New Scientist vol 178 April 2003 page 14 http://www.restena.lu/meteo_lcd/globalwarming/sun/hyperactive_sun/sun_fuels_debate_on_climate_change.html
It shows that there is or was a raging argument about whether there was in fact an increase over that period.
Given the substantial time lags that can occur, it is possible that the sun’s increase before 1950 would take time to come through. Alternatively, given that during the whole of 1950-2000 there was unusually high sun strength, it would not be at all surprising if it had an overall warming effect that didn’t all show up straight away.
Either way, my contention is only that the IPCC was not entitled to simply ignore it.
CobblyWorlds #350 : I saw that bit about rocks weathering some time ago. I thought it rather unlikely that they would manage to weather regularly every 150,000(?) years. Albedo is such a powerful force, it seems a much more likely candidate for delivering such a strong change. And it has the potential to explain both ends of the cycle.
Hank Roberts #351, 352. Those two charts that you posted should both have CO2 on a logarithmic scale not a linear scale, in order to make a meaningful comparison. It would make what looks like a spectacularly brilliant fit into something much more ho-hum.
I am not trying to explain the whole world, here. I am simply saying that the IPCC has ignored something potentially significant, and they were not justified in doing so. The way the climate is behaving at the moment – several years of cooling – it is starting to look like the missing factor really does make a difference. The next few years could be interesting. The next few years could be interesting.
Hank,
I am saying that when the multiyear ice is gone and the Arctic is clear of ice during the summer, the seasonal ice will not reform in the winter. An inversion will form over the Arctic and the clouds will keep the Arctic warm during its six month night.
Alastair, for what value of “gone” — when will the observation be timely to look and see? It’s a solid prediction, if you define the terms clearly enough.
Martin, I think if NaCl is ionized as in solution that each atom counts; if not as in crystals or molten the molecule counts as one. Though I may be wrong… The solid’s molecular vibrations are just like a gasses center-of-mass molecular translation, just has a much shorter path (and never really collides) and more of them.
The single step scenario (photon energy in a molecular vibration energy state) is not at LTE, to the best of my knowledge.
Trying to follow the CO2/solar/albedo thread, I have a simple question I’d like to verify. Is the changes in polar ice really that significant viz-a-viz albedo? Less than 10% of incoming insolation reflects off the surface and I would think the effective watts/m^2 reflected from polar ice would be a very small portion of that — solar rays coming in at large obtuse angles and everything. (In some cases solar rays not hitting the ice at all for long periods.)
[Response: Locally yes, though mostly in spring. – gavin]
Re # 346 Mike, and responses by Tamino (348)and Hank Roberts (351, 352)
Mike,
This paper might help you understand why the past 50 years is considered more relevant than the past 100 years:
David J. Karoly et al (2003) Detection of a Human Influence on North American Climate. Science 14 November 2003: Vol. 302. no. 5648, pp. 1200 – 1203
Several indices of large-scale patterns of surface temperature variation were used to investigate climate change in North America over the 20th century. The observed variability of these indices was simulated well by a number of climate models. Comparison of index trends in observations and model simulations shows that North American temperature changes from 1950 to 1999 were unlikely to be due to natural climate variation alone. Observed trends over this period are consistent with simulations that include anthropogenic forcing from increasing atmospheric greenhouse gases and sulfate aerosols. However, most of the observed warming from 1900 to 1949 was likely due to natural climate variation.
http://www.sciencemag.org/cgi/content/abstract/302/5648/1200
I disagree.
The transition to seasonally ice-free state is likely within 10 years or so (in fact I’ll be stunned if there isn’t at least 1 such occurrence by 2018). After the first occurence of ice-free state in the late summer we may well see the next year with a bit more September ice(not ice-free). Because of winter (e.g. this last winter) there will be a degree of decoupling between each summer minima.
The switch to a seasonal ice cap will be a rapid process, due to aggression of processes causing the rapid loss of perennial ice. But the next transition to a year-round ice free state will be more gradual. As the Arctic region warms, the period of ice free arctic ocean during the summer will start earlier and earlier. But we’ll still have a winter ice cap for decades to come, subject to the amount of IR blocking by the increasing levels of GHGs (mainly CO2/CH4).
I don’t see reason to anticipate the sort of massive and abrupt (~1 year) climatic impact(transition) outside of the Arctic that your suggestion seems to imply.
I would just like to thank you guys for the explanations – there is a saying one madman can ask more questions than ten wise men can answer. Thanks for your time.
The ordovician glaciation period is rather ill-understood by many (including me, until very recently) and sometimes being (mis)used in discussions, so that’s why I asked.
Re: #345
John Finn, Gee, if the warming is coming from a source of heat within Earth, how do you get zero warming for 30 years, followed by 30 years of accelerating warming. That seems to me to be a rather tall order.
Cool PDO in the first 30 years.
Ask yourself this question: based on the Lean TSI reconstruction (as is often quoted here)do you think temperatures should be higher at the end of the 20th century than in the mid-1940s? the same? or lower?
If the AO were to be conducive for retention for several years, how could there not be a recovery of some sort for perennial ice?
[Response: That already happened. But the ice did not recover. – gavin]
Rod B,
Be very careful when transitioning from behavior of gasses to solids. Solids are a collective entity, vibrational energies are quantized as phonons. Likewise, the electronic levels interact and distort, giving rise to energy bands–e.g. valence and conduction bands. This gives rise to some very odd collective behavior. (Google “High-electron mobility transistor” or “quantum hall effect”). Likewise in solution, the solute interacts with the solvent, especially if both are ionic.
The energy levels of an atom/molecule, etc. depend on what matter is around and how much and how strong the interactions between atom/molecule and surrounding matter are.
John Finn, TSI is not changing much, and insolation is actually decreasing. Given the increase in ghgs, which is the dominant change, I would expect increasing temperatures. You are of course free to try construct a climate model that explains current climate without an enhanced greenhouse effect. Good luck with that. Of course, you’d still have to explain why the influence of CO2 magically stops at 280 ppmv, but I think the model task ought to keep you busy for now.
Ray (364), I meant to offer just a simple comparison, and went a bit to far. Thanks for the correction.
Hank,
In #356 you wrote:
Earth science is fractal, so for every rule there is an exception. I am saying that the Arctic will be ice free but there may be some ice forming each year off the coast of Greenland. And what about calving glaciers and ice shelves? Do they count?
Anyway I am not a betting man, and I see Gavin et al.’s betting challenge as trivialising the dangers of climate change, especially with the catastrophe that will unfold when the Arctic sea ice goes.
More to follow,
Cheers, Alastair.
Rod B #357:
Yes, I would agree, sort of. And certainly see your point. But you could meaningfully say so only about a large number of molecules, not one. LTE, or non-LTE, are meaningful concepts only statistically. But in the real Earth atmosphere (except very high up) you will have LTE and a mix of vibrational and translational states.
What you’re trying to do is a bit like trying to study the moment between a cartoon character stepping off a cliff, and beginning to fall. Not necessarily very wrong, but not very helpful for understanding either :-)
BTW there are no molecules in a salt crystal — it’s a 3-D checkerboard grid of Na+ and Cl- ions. You see my problem now?
Rod,
Re #386 where Gavin responded: “Locally yes, though mostly in spring.” I think he was referring to your comment:
Your question was:
The Arctic ocean covers an area of 14 M km^2. The area of the globe is about 510 M km^2. Taking the average albedo of the surface as 0.1 and the average albedo of the Arctic ice as 0.9 then the Arctic contibutes 0.9 * 14 = 12.6 compared with an overall surface albedo of 510 * 0.1 = 51. In other words about a quarter or 2.5% of incoming insolation. That is 2.5% * 348 = about 8 W/m-2, twice the forcing from doubling CO2! And it is going to happen much faster as well :-(
As Gavin pointed out, the obtuse angle to the ice applies mainly in the spring, but that increases the albedo because the sun’s rays glance off. Without the ice in the autumn when much of the ice has melted the rough sea surface absorbs the solar rays reducing the albedo. Without the formation during winter of the seasonal ice, then in the spring any wind will roughen the sea surface and its albedo will be much lower.
One point not often realised is that in the Arctic the sun shines for the same amount of the year as every where else – 50% of the time. In the Arctic it shines continuously for six months with no chance for the surface to cool down over night. This constant radiation will raise the sea surface to a high temperature, without the ice ot reflect the radiation or the melting ice to absorb the heat.
HTH,
Cheers, Alastair.
Re #360 where Cobblyworlds says:
I won’t be surprised if the Arctic is ice free all year round by 2018, although the collapse of the Arctic sea ice has taken longer than I expected :-)
There is no guarantee that in the winter following an ice free Arctic that the ice will grow to a greater extent than the previous year. There may well be a tipping point below which when the summer ice is less than a minimum the winter ice is always less than that of the previous year.
For instance, the increase in winter ice this year over last may be due to the fresh water produced by the melting of the multi-year ice last sumer. When there is no multi-year ice left to melt, then the winter ice will not extend over that of the previous year.
At present there is enough solar radiation, despite the high albedo of ice, to melt the multi-year ice by about 0.1 m ( 6 inches) per year. Without the ice, the albedo will decrease and the solar flux will be warming the ocean surface rather than melting ice. That means instead of melting the top 6″ of ice, it will be able to raise the temperature of the top 6″ of the ocean by over 80 degrees Celcius or 144 F! Of course much of the heat will be lost to the latent heat of evaporation, but this will create water vapour which is a greenhouse gas. It is the runaway effect of water vapour we should be fearing, not that of CO2 or CH4.
It has happened in the past, when the Younger Dryas ended in just three years. I suspect last year was year one of the end of the Holocene. Let’s hope I am wrong :-(
Cheers, Alastair.
Chuck Booth #359 your paper said “Comparison of index trends in observations and model simulations shows that North American temperature changes from 1950 to 1999 were unlikely to be due to natural climate variation alone.”.
That’s fine. But that statement clearly suggests that at least some of the temperature change came from natural forces, otherwise it would have said something like “… it was likely that none of the temperature change was natural …”.
All I am arguing is that there is likely a significant factor that the IPCC was unjustified in ignoring, and that if this factor was allowed for properly then the effect of CO2 on climate in the models would likely be reduced (because of the way the models were built). I don’t think I have stated it explicitly, but this would undoubtedly weaken the IPCC’s case.
We have an interesting situation right now, with
cooling surface http://www.cru.uea.ac.uk/cru/data/temperature/hadcrut3gl.txt,
cooling oceans http://www.agu.org/pubs/crossref/2006/2006GL027033.shtml http://www.npr.org/templates/story/story.php?storyId=88520025,
(I don’t know what the troposphere is doing – anyone?),
record high S.H. sea ice area http://nsidc.org/data/seaice_index/,
winter N.H. ice this year beating 2004,5,6,7, and even matching 1996 http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.area.jpg,
and the Sun resolutely refusing to give us another sunspot http://www.swpc.noaa.gov/ftpdir/forecasts/SRS/0516SRS.txt.
The natural factors are clearly outweighing the dramatically increasing CO2 at least in the short term. If nothing else it tells us that maybe solar variation is more powerful than was thought and that we should look very very carefully to see if the IPCC really was justified in ignoring it for the computer models. There is support for this from many places, eg. http://www.sciencedaily.com/releases/2002/11/021113070418.htm http://www.abc.net.au/news/stories/2008/04/24/2225980.htm
Hank Roberts #337. I read the attached paper on winds. Thx. The paper only dealt with intraseasonal fluctuations, so I don’t know that it throws much light on anything to do with long timescales???
PS. http://www.spaceweather.com/ says that three new sunspots are emerging.
Alastair McDonald (370) wrote “I suspect last year was year one of the end of the Holocene. Let’s hope I am wrong”. Beyond hope. The only quibble is what year to pick as the last one of the Holocene and then the next is the first of the Anthropocene.
Rod B. #357, Think about this. How do you get anything like thermal equilibrium with a single molecule–equilibrium is a purely statistical concept. So is temperature. It only makes sense when viewed in terms of a statistical mechanical state.
Mike, What part of La Nina do you not understand? That is all the “natural factors” you need to explain what is going on. It is virtually certain that there are missing factors, and just as certain that they aren’t all that important. If you are going to propose another factor, you first have to explain why the constraints on CO2 forcing are wrong.
I think it’s fair to say that the Holocene is long gone. The Anthropocene started in, what, 1850? 1900 at the latest.
Re: the transition to an ice-free winter Arctic. I tend to agree with Cobblers. The Arctic heat budget includes a large (though decreasing as GHGs increase) negative term during winter. For every summer that’s ice-free, heat will accumulate in the upper ocean and it will take longer for the winter freeze-up to begin. That’s what will have the immediate impact on NH climate. Lots of heat and water vapour hanging around into early winter. The last NH winter perhaps gives an idea of what to expect…
With virtually all the multi-year ice gone, the freeze-thaw cycle will probably look a lot more like Antarctica’s, and I wouldn’t be surprised if increased freshening of the Arctic from river run-off meant that for a few years we had unusually high winter extents as well as record summer lows.
However, as long as the positive terms in the heat budget exceed the winter negative, the Arctic will warm. Over the last decade(s), much of that has gone into melting multi-year ice. When that’s all gone, the medium/long term outlook is for an ice-free Arctic all year round. The only question is how long will it take…
Mike, you quote Lyman.
That suggests a useful exercise.
Put the name in the Search box at the top of the page here.
And, put the reference into Google Scholar, like this:
http://scholar.google.com/scholar?q=doi%3A10.1029%2F2006GL027033
(Note the top three hits, read them, consider what difference it makes to what you posted above.)
General advice — whenever you talk about a study, always look up the original, you can get at least the basic info, and usually the abstract. Then click the link usually available for ‘cited by’ or ‘related’ to see newer papers that reference the one you found.
This is why you have to look at the original work, to track it forward in time.
Ray Ladbury #374 said “you first have to explain why the constraints on CO2 forcing are wrong”.
I have done that, at some length, in some detail, and over many posts. I really doubt that anyone here wants me to go through it all again.
Hank Roberts #376. Thx. I’ve not done it yet, but I will.
Arctic (my current obsession),
Water vapour is a greenhouse gas, but it’s concentration in the atmosphere is limited by temperature. So when insolation disappears as the Arctic “night” begins, cooling will occur and atmospheric water vapour concentrations will be reduced. The reason I focus on CO2/CH4 levels as key to the winter ice’s fate is that their atmospheric levels will not be reduced by a reduction in temperature. Although of course water vapour will still be able to act as an amplifier.
For me water vapour is the source of the primary climatic impact in summer because of baroclinicity and latent heat impacts being able to extend up into the arctic troposphere (and subsequently stratosphere). It seems to me that any wider climatic impact will come from this rather than (direct) sensible surface heat changes due to insolation. The risk of a wider climate impact outside the Arctic seems to me to be linked to impacts on the Polar Vortex, affecting the AO/NAO. Also the possibility of Rossby waves teleconnecting to pressure patterns in the Northern Pacific seems to me to suggest potential for influence on ENSO (and needless to say, US weather). The most dangerous impacts could be from changes in timing/amounts of precipitation. Manageable in themselves, but worrying in view of the current food-price situation and risks to political stability. In my post #174 I allude to what I see as the most worrying single implication, to which I would add that the Arctic Basin has become more stormy due to increased baroclinicity.
All that said, I am on a very steep learning curve, so may have completely the wrong end of the stick. ;)
Feel free to correct me if that’s the case. (I can provide references for the statements above – but it’s early Saturday morning and I’m too bushed right now to go trawling for them.)
When did the Anthropocene begin?
Good question: For me it’s about 1975, when the first key indicator (global average temperature) clearly started to deviate well outside natural variability).
Hank Roberts #376. Thanks for your advice re finding papers etc. I do always try to access original papers, but sometimes can’t get access. I’ve looked at ‘Lyman’, and it appears that the oceans are not cooling, and they’re not warming either. That’s OK. It still suggests that something more powerful than CO2 is operating out there – surface cooling, oceans not warming, global ice growing, etc.
I asked about the troposphere a while ago, and I don’t think anyone replied. I have gone looking for it, and found this page http://www.remss.com/msu/msu_data_description.html
I read the site’s explanations, and it looks to me, from the 4 line graphs about 3/4 down the page, like all the layers of the troposphere and stratosphere have been cooling since about 2002. Have I misread it?
Alastair writes:
Not really. Water vapor rains out quickly. The average molecule of water vapor stays in the atmosphere nine days.
Mike posts:
We know. And we’ve been telling you that you’re wrong and that the models aren’t built the way you think they are. And you keep on repeating what your point is.
We know what your point is. Your point is wrong.
#377
No, Mike, you have not explained (at least convincingly) why you think estimates of CO2 sensitivity are wrong. You have merely asserted that it is the case and suggested that there might be some climate scientists (unnamed) who say that is possible. How said factor would affect multiple independent constraints (from very different times, etc.) on CO2 forcing and somehow magically lead to the same range of values. You’ve posited no mechanism for the effect. If it is a feedback, you also need to explain why it reinforces solar forcing, but not greenhouse forcing. If it is an external source of energy, you need to identify it.
Ray (373), isn’t molecular equipartition a sort of (or a bit like) local “thermal equilibrium”? Or is that stretching too far?
Mike, look again, the trend line is drawn for each of the four channels. (Last letter of the acronym is T for Troposphere or S for Stratosphere, to explain for later readers.) Here’s the TMT:
http://www.remss.com/data/msu/graphics/plots/sc_Rss_compare_TS_channel_tmt.png
This and the links in the first few lines of it may help:
http://julesandjames.blogspot.com/2008/04/has-global-warming-stopped.html
There’s a basic step in a first course in statistics that is very hard to take — that’s letting go of the strong human ability to find patterns in anything whether they’re there or not, and instead relying on doing the math before claiming any pattern or what pattern is there in the data.
Looking at charts without the numbers makes this pattern-finding ability even harder to let go of.
We’re built to expect patterns. Our ancestors thought tigers were lurking in the jungle far more often than tigers were there. Our non-ancestors, early in life, failed to notice just one tiger.
Rod, yes, but how do you get equipartition without an large assembly of molecules?
I’ll answer all your recent posts in one way rather than individually. I’ve obviously reached the point where I’ve said just about everything I can say. It doesn’t look like I’ve convinced anyone of anything, but it was worth a try.
Hank Roberts #384 said “We’re built to expect patterns.”.
The problem with the IPCC models is that they are built to expect the patterns already seen, and they are all built with the same underlying assumption. This is why they agree with each other so well, and why it is possible for them all to be wrong. If you look at the latest IPCC report (and I’m not, I’m relying on memory), it expects a certain result for the 1st decade of this century, followed by a temperature gradient as delivered by their calculations for AGGs.
But at the time the report was printed, the result for at least half of that decade was already “in the bag”. The way the models are constructed, natural forces are so weakly represented that it doesn’t matter what recent pattern you feed in, the models must ALWAYS turn upwards again fairly soon.
Under my logic, the downturn in recent years is expected, because there has been a decline in solar activity, which would probably only be partly offset by AGGs. (It is complicated by a La Nina too, but I don’t know how strong that is). Because of the time lags, certain doubts about temperature measurements, and lack of knowledge about the mechanism, I can’t possibly predict exactly when, where or how much temperatures will change. But temperatures falling below the model calcs for AGGs, at some time, is exactly what I would expect, and it is happening now. It won’t go in a straight line, so it will take a long time before it convinces you that it is real. No matter what it does, if you feed it into the models they will turn up again for future years.
We all know that a decade is a short time in climate, and a decade’s events do not signify much. But if you check the IPCC report, you will find at least one place where natural forces are dismissed simply on the grounds that they do not match the last decade of the 20th century. I call that double standards, and bad science.
This page began with the paleoclimate. I’m not quite sure how to put this, because Hansen is such a respected scientist, but, frankly, his paper on the paleoclimate cycle is not very impressive. He tries valiantly to explain everything in terms of CO2. He turns himself inside out trying to come up with extraordinarily unconvincing mechanisms that can explain the changes of direction of the cycle. Compare what he has written with papers that propose changes in insolation (that I believe includes both solar activity and albedo?) as the major mechanism, and simply by applying Occham’s razor he is in big trouble.
Natural forces are clearly overriding AGGs in the short term, which makes it very likely that they really are more powerful than allowed in the models. Natural forces clearly overrode GGs quite comfortably in the paleoclimate cycle. I believe I am right in saying that GG concentrations were sometimes higher back then than they are now (?). GGs have only increased 40% since 1750, and the scale is logarithmic, so it is approaching the absurd to argue that AGGs will now overpower the natural forces.
Sorry, Mike, stuff like
“… and the scale is logarithmic so …”
“… explain everything in terms of CO2…”
“… simply by applying Occham’s razor …”
“… there has been a decline in solar activity …”
is hodgepodge, not from any science journal. It’s PR stuff.
Read Spencer Weart’s history. Read some primary sources.
And cite sources for what you believe and tell us why you believe what you’re reading, and why you trust the places you’re reading it.
Hank Roberts #387 : “cite sources for what you believe and tell us why you believe what you’re reading, and why you trust the places you’re reading it”.
My main source of information is and always has been the IPCC report, as I believe I have made clear in my posts. I have been through it many times, and it is a source of what appears to me to be reliable scientific information.
Unfortunately, as a person with computer modelling experience, it appeared to me that there was a fundamental error in the way that they had used the scientific information in the computer models. In order to take this further, I had to work through the report to find out how much of it flowed from the science and from valid modelling and was therefore likely to be reliable, and how much flowed from the invalid modelling and was therefore likely to be unreliable.
I found some places in the report, which I have quoted in previous posts, which gave me a handle on the likely scale of the error, and found that it was, to say the least, non-trivial. I then went looking for external information that could confirm or deny what I had found. That brought me to this page, because obviously the paleoclimate cycle was a very sensible place to look for information on the long term relationship between climate and GGs.
I find that in all areas, debate is raging. That means that there are plenty of papers that support my case, and plenty of papers that support the IPCC. The latter reduces if I eliminate anything that starts with the assumption that the IPCC view of AGGs is correct – that is why I have generally avoided looking at any partisan website on either side. It is also why a lot of the external information that I have been relying on most has been the actual climate – temperatures, albedo, etc. This information is much less susceptible to manipulation and distortion than theoretical papers.
There has been a decline in solar activity this century. There was an increase in solar activity over the last century, including a sustained period of high solar activity in the 2nd half. There was a decline in cloud cover from around 1980-2000, and there has been a recovery since. Lots of things add up, that are not driven by CO2.
I’ll stick my neck out and make what I have said falsifiable : Given the recent decline in solar activity, then if the Sun remains relatively inactive I have to expect at the very least a decrease in the rate of warming to show up. If over say two decades this does not happen, then my findings are falsified and I can admit it and go away.
I’ll go further, in the interest of trying to achieve a faster result : if the Sun remains at a low level of activity for one more year, then there will be a significant decline in Northern Hemisphere temperature within the next 2-3 years.
I can’t be more specific than that, because the mechanism is not known.
Mike, if you’re submitting a paper for possible publication, I realize you need to keep it private til it’s considered-Just say so.
But if not, citations, please?
“external information that I have been relying on …”
“Given the recent decline in solar activity …”
Cite?
“a decline in solar activity this century”
(activity: sunspots? TSI? insolation? measured and counted where?)
(century: the last 100 years? Last 7-1/2 years?)
“falsifiable … a decrease in the rate of warming”
Falsifiable would mean an unambiguous prediction that can distinguish — how are you distinguishing your prediction from the ‘Global Cooling studies discussed in threads here? Two different forward-looking climate models suggest a decrease in the rate of warming. What’s different about yours?
“plenty of papers that support my case …”
List, pointer to your website, something?
Mike,
http://scholar.google.com/scholar?num=100&q=%22recent+decline+in+solar+activity%22&as_ylo=2003&btnG=Search
What’s up? Where are you finding your information?
Hank Roberts #389. I’m not preparing a paper for publication, and I don’t have a website. I’m just an individual who has put a lot of time and effort into this topic.
For most of the things I have referred to, I have provided a link at the time. However, I will go through all your questions and try to retrieve all the relevant links. This will take me a day or two.
Hank Roberts #390. You won’t find anything I have said anywhere else on the web, except by coincidence, or if my comments have been posted on by someone. Whenever I use material from anywhere else I try to attribute it. I have posted comments on some other websites, but every post has been written individually – little or no cut-and-paste from post to post.
Mike writes:
No, Mike, you have no idea how the models are built. No idea at all. Why don’t you look up a book on climate modeling at your local university library? Ann Henderson-Sellers and coauthor’s (can’t remember the name) A Climate Modeling Primer is a good place to start. Or try here:
http://en.wikipedia.org/wiki/Global_climate_model
Mike (388) says, “….as a person with computer modelling experience,…”
Barton (392) says, “…Mike, you have no idea how the models are built. No idea at all….”
Gettin’ weird.
Rod B., Parse the two phrases. Just because Mike has experience with computer modeling does not imply that he has any understanding of how the [climate] models are put together. Indeed, he has demonstrated quite the contrary.
Mike, Until your “logic” becomes a “model,” all you have is handwaving. For someone with “computer modelling experience,” constructing a simple model should not be too taxing. Why don’t you see if you can match the climate record without assuming significant warming from CO2. What is not clear to me is what level of CO2 induced warming you assume from CO2 at pre-industrial levels and how you get it to simply stop increasing while increasing CO2 concentrations by 38%.
Mike, I’m just another reader here.
I don’t recommend you spend days documenting everything you’ve posted here and try to post it here — it’d go way off topic!
These threads aren’t about us readers. The scientists posting here generally do cite their statements (and we can check their Publications pages easily to fill in any conceptual leaps).
I mean to suggest that when you post a factual statement in a topic, including a cite helps us all to not only know where you got it, but to be able to check the cite ourselves and see who else has cited the study. Often, there are new studies worth reading to catch up on.
Ray (or Barton), I just thought at the fundemental level all computer modelling was quite similar, while maybe differing significantly in the implementation. Is climate modelling a whole different animal?
Ray (385): a single molecule can not redistribute its energy among its own different stores (DoFs)?
I don’t want to resurrect our debate on single molecule capabilities and characteristics (probably no one else does either :-) ), but I still can not accept your premise until you verify that a single molecule can not have either mass or velocity.
Hank Roberts #396. I have tried to post a link to anything that I have got from elsewhere, unless I thought it was common knowledge.
I’ll let a number of recent comments by others go through to the keeper, and concentrate on your #389:
By “this century” I mean the 21st century.
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“The recent decline in solar activity” was not very clearly defined. We had been talking about TSI, so let’s start there. The last graph in ESA/NASA SOHO’s
http://www.pmodwrc.ch/pmod.php?topic=tsi/virgo/proj_space_virgo#VIRGO_Radiometry
shows TSI decreasing from about 2002 onwards.
But it could equally well relate to sunspots, as there is a correlation. See the graph in
http://www.global-greenhouse-warming.com/solar-irradiance-measurements.html
There is also a link to a Judith Lean paper
http://lasp.colorado.edu/sorce/news/other/SORCEwebsite_News_Solar_Cycle.pdf
which spells out a bit more detail.
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“plenty of papers that support my case …” :
My case is built on the premises that (a) the IPCC said that solar variation has more effect on climate than is built into the models, (b) they said that they ignored this in the models because they couldn’t model it.
My case is that they were not justified in ignoring it, and there should be some allowance for it.
There really are plenty of papers that provide support for the view that either the Sun has more effect and/or the models don’t reflect it. Apart from the IPCC report itself, see the Judith Lean paper above : “Comparisons of the empirical results with model simulations suggest that models are presently deficient in accounting for these pathways [of solar irradiance impacts from atmosphere to surface and climate].”…”Even relatively small changes in the Sun’s output could impact the Earth because of potential amplifying effects in how the atmosphere responds to those changes.”…”Before we can truly
interpret the role that human’s are having in changing Earth’s climate we must first more accurately assess the role that natural “forcings” have on the climate system, and the Sun is by far the most significant of those natural “forcings”.”.
or
http://www.agu.org/pubs/crossref/2007/2006GL028764.shtml
“If changing brightnesses and temperatures of two different planets are correlated, then some planetary climate changes may be due to variations in the solar system environment.”.
or
http://www.physorg.com/news129483836.html
“absence of solar activity may have been partly responsible for the Little Ice Age” [NASA]
I haven’t kept links to the various papers like these that have flowed past my eyes over the last few months. You can appreciate that finding them again will be time-consuming. Obviously, I have avoided citing anything that comes from a “skeptic” stable.
—–
Coming up with a falsifiable prediction is more difficult. We all acknowledge that the mechanism is not known so a detailed prediction is not possible. The Sun has to put in a period of lower activity in order for any prediction to be effective, but we are still necessarily working off a short period. Given the recent decrease in solar activity, and the delay in build-up of cycle #24, there probably is just such an opportunity right now. I’ll work a bit more on the detail, but basically I expect the N.H. over the next year or three to have significantly lower temperatures than the last decade.
I can’t help it if two climate models make the same prediction, because I can’t dictate the Sun’s behaviour to the point that it can falsify everyone except me. However, if only two models predict this, then presumably all the others don’t? Getting a distinguishing prediction against all but two models would be a nice start.
—–
PS. I seem to remember Kevin Trenberth (IPCC) saying the models didn’t do predictions, they only gave “what-if” projections. Are you able to say on what basis the two models’ “predictions” were made?
Hank Roberts #387. About “the scale is logarithmic” being hodgepodge.
I was referring to the warming effect of CO2 being proportional to Log(CO2 concentration). I understood that to be common knowledge so didn’t cite anything for it. It’s in the IPCC report, 2.3.1.
Ray Ladbury #395 – “see if you can match the climate record without assuming significant warming from CO2”.
That’s not what I’m saying at all. I’m saying that the models don’t make enough allowance for natural factors.