Promoted from the comments, the download of the BBC Radio 4 ‘Now Show’ (Mar 16) is available here (at least for now). Key bit starts at about 18min in, (the rest of the show is pretty funny too).
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307 Responses to "A much more eloquent rebuttal of TGGWS"
Richard Ordwaysays
re. 45 Phil writes:
…re. why CO2 disappears natually.
“Once this process (co2 being incresed naturally -RO) starts – what stopped it from running completely out of control in the past?”
Again anyone step in. Here is a simplified explanation. There are several processes (can be called negative feedbacks) which stop the Co2 (on Earth…not poor Venus)from going “runaway” (“runaway greenhouse effect”).
The first is, is that rocks (silicate rocks), in the long term, remove the CO2 out of the air with a reaction with rain.
The warmer it gets, the more these chemical reactions increase (because it rains more when it gets warmer-ooops, what does that mean is happening now?).
Now this solution flows to the sea and dumps CO2 into the sea. in other words to paraphase from your high school chemistry that you were required to take: CaSiO3 + 3H2O + 2CO2 turns into Ca2+ + 2(HCO3- ) + H4SiO4).
Notice how the CO2 disappears. This is called the chemical weathering process and is part of the “carbon cycle.” In the ocean, types of animals absorb the carbon out of the water to make shells…they die and sink to the bottom of the ocean.
A second process to stop co2 from growing , is that the warmer it gets (the ice-covered lands disappear and the more trees and plants appear. They absorb more CO2 from the air and transfer it by roots deep in the soil where it combines with water to make an acid “carbonic acid” which disolves calcium silicate in rock to to make calcium carbonate (notice the word carbon in carbonate).
The calcium carbonate (carbon) is then transported in solution to the oceans where it can be dumped out as limestone.
Okay, those are the two basic processes. Otherwise, co2 gets reduced during ice ages when the Earth’s orbit changes the amount of sun energy hitting at least the northern hemisphere during the summer in regular (pretty regular) three cycles of about 26,000 years, 41,000 years and 100,000 years (Milankovitch cycles).
You know the routine: Cool the air. Cool the oceans which can hold more co2 in solution (think of your cold versus hot pop bottle). Now increase the ice on Earth. This makes higher winds by air coming over ice, rapidly sinking and making winds. With an ice age, more dusty land is exposed as sea levels drop as water becomes ice. This carries more dust. Dust has iron. More iron feeds more plankton in the oceans. More plankton (plant variety) eats more co2 and sinks.
In ice ages, the ocean currents often also get more active because of a bigger difference in temperatures between the poles and the equator and this allows even more co2 to be absorbed (subducted).
That is a simplified expanation that leaves a lot out.
Ike Solemsays
RE#45, This was discussed from many perspectives at the “Swindled” thread; my attempts can be viewed at #150, #202, #291, but to quote one of the moderators:
“Response:AFAIK, people don’t know exactly why CO2 stopped at 280 in interglacials and 180 in glacials. It doesn’t have to be feedbacks: there could simply be some reservoir that is exhausted. Also, thats for the previous 4 interglacials: before then, EPICA shows 250. This again is unexplained – William”
If you look at http://news.mongabay.com/2005/1124-climate.html , you can see a graph of the ice core CO2 record (halfway down the page). We know that CO2 stops increasing – why is uncertain.
Once again (as with the solar issue, see Nigel Weiss’s comments above) you have contrarians using one-sided distortions of scientific uncertainties to support their views.
‘Some confusion surrounded the views of the RMS scientists yesterday after Prof Hardaker told the IoS that he could not think of a case where a scientist had overstated the position. He did however mention a statement by the American Association for the Advancement of Science that described an “intensification of droughts, heatwaves, floods, wildfires and severe storms” as “early warning signs of yet more devastating damage to come”.
He said he did not disagree with any of this, but thought the AAAS should have made it clear what could be justified by the scientific evidence and what was based on judgement. He pointed out that he and his colleague were not experts on climate change. ‘
So after all this fuss, he did not disagree with any of the statement, and ‘he and his colleague were not experts on climate change’. Strange, since the BBC Today website still has the interview http://www.bbc.co.uk/radio4/today/listenagain/ram/today2_climate_20070317.ram with the headline ‘Two of Britain’s most senior climate researchers have told the BBC that scientists have been overplaying the message on climate change.’. Still, if you wanted to get lots of pulicity for outfit like Sense about Science (who have some slightly dodgy links to the RCP/Spiked crowd), then this nonsense would have done you no harm…
Robsays
I’ve been following the “pro” and “cons” for a while now and still can’t get to some conclusion of it all. On questions I have for instance is: The CO2 we are releasing now is that not previously free CO2 that have been captured at some time in history? And if so, are these volumes not already in the climate system and we are actually not adding anything that did not exist before?
/Br. Rob
pete bestsays
Re #35, climate change is relative is the answer. Today millions of people live along the coasts of the world, when the seas rise due to climate change they will be in trouble, it does not matter that 50 million years ago the earth was 5 degrees hotter and the seas 70 meters higher does it as it did not impact anyone ?
It is all about forcings or which the earths albedo and vegetation is the strongest followed by greenhouse gases. Both do not need to be high for warming to occur either can cause warming or cooling for that matter. 10,000 years ago the earths natural cycles (known to us as miltankovitch cycles) starting to bring us out of an ice age and hence the albedo effect was the cause of this warming. As you have been told it takes some 800 years of warming before albedo and vegetation had been effected enough although RC tell us that it may not have been this long. Anyway the source of the CO2 is most likely the oceans which absorb CO2 when it is cold and release it when it is warmed and it is this released CO2 that then causes further warming of the atmosphere.
In the modern world 280 ppm seems to be the earths natural limit and we are not at 390 ppm due to industrial burning. Further burning will cause steadily increasing CO2 levels and hence further warming.
Dick Veldkampsays
Re #47 Earth’s atmosphere (Rob)
Yes, most CO2 we are producing at present was at some point in history captured and converted to fossil fuels, which then remained safely underground (and outside the climate system) until we recently started re-releasing it into the atmosphere.
But regardless of where that CO2 was in history, the trouble now is that all that CO2 in the atmosphere will have rather unpleasant consequences.
PhilCsays
re#49
if, at some point, it was all in the atmosphere why have the “unpleasant consequences” (runnaway greenhouse I presume) not been seen in the historical record.
[Response: Who says “runaway greenhouse”? -William]
Robsays
Re #49 Earth’s atmosphere (Dick V)
I should maybe start by stating that I recognize the fact that earth is warming… And with that out of the way… After considering your answer I still don’t understand why many claim that the CO2 levels have never been this high when evidently “all” the CO2 we’re releasing must have been around some point in time. I understand the consequences at present and future time for mankind but in the history of earth (and I’m thinking rather recently) there must have been worse situations than the one that is proposed to be?
/Br. Rob
Philip Martinsays
Rob…the problem is I think pre-Industrial Revoluton levels of CO2 were 270ppm with a very small population and now C02-equivalent levels are way over 400ppm with a population heading towards 9.5 billion by 2050. These people need to be fed, housed, clothed, and have access to clean water and good sanitation. If extreme weather events increase and the temperature gets hotter, then this has severe implications for that larger population. If there were still less than a billion people in the world and the temperature rose naturally rather than being forced there wouldn’t be such a problem. Isn’t this what we are all really worried about?
Robsays
Re #50 Worries (Philip M)
Exactly, we should worrie about the consequences of a warmer world rather than try to rectify something that we might or might not be able to influence. Is it not so that a very high percentage agrees and recognize that the world is getting warmer (independent of source)? And are we also not on agreement that this warming will continue for a long time regardless of any action taken to prevent that? If so, shouldn’t the prudent way of the humankind (as history have told us) be to adapt?
/Br. Rob
Dick Veldkampsays
Re #47, #50 Earth’s atmosphere (Rob)
The claim about “CO2 levels never been this high” is made (as far as I know) for the last 650,000 years (this is found from analysing air bubbles in ice cores).
With a little googling I found this temperature graph: http://www.scotese.com/climate.htm which has several maxima at ca 22 deg C global T, for example in the Cretaceous some 100 million years ago (currently we’re at 15-16 deg C). Presumably CO2 concentrations were also higher then (but I am no paleoclimate expert).
However, as people have often pointed out in the hockeystick discussion, whether CO2 levels were higher at some time in the past is really not the issue*). Even if we had no clue whatsoever about the climate before 1800 there is plenty of evidence that the theory of global warming is sound and we’re involved in a dangerous global experiment.
*) Of course I don’t mean to deny the importance of paleoclimatology. It it is a good thing to have the complete picture, and to check our theories wherever we can.
“…I still don’t understand why many claim that the CO2 levels have never been this high when evidently “all” the CO2 we’re releasing must have been around some point in time.”
Bear in mind that the coal / oil deposits we’re burning through weren’t laid down overnight. The CO2 we’re re-releasing WAS all in the atmosphere in the past, but not necessarily all at the same point in time (unless you go billions of years back, before life on the planet).
[[You don’t explain why there’s global warming on Mars, Jupiter, Triton and Pluto. ]]
All we know about Mars is that one of its polar caps has shrunk a bit in the past three years. That proves exactly nothing relevant to the overall thermal balance of Mars.
Jupiter is not undergoing global warming. Where did Lindzen get that idea?
Triton? Where is Neptune in its orbit just now? Ditto Pluto. Neither Triton nor Pluto has an atmosphere worth speaking of, but they do have summer and winter. Is Lindzen aware that Pluto takes 248 years to go around the Sun, and therefore that its seasonal change in any direction will last a lot longer than on Earth?
Alvia Gaskillsays
Different Kind of Debate
Coming up at 10am on C-SPAN, another episode of “Stop Interfering with My Research.” Today, the big boys go at it. The CEQ head’s name is actually James Connaughton, a fairly important policymaker on climate change, but who is seldom seen or heard. C-SPAN usually repeats these hearings, so check the schedule.
Global Warming Research
Rep. Henry Waxman (D-CA) chairs an Oversight and Gov’t Reform Cmte. hearing on claims of poli-
tical interference with government scientists & their research on climate change. Witnesses include James Hansen, Dir., NASA Goddard Inst. for Space Studies; John Connaughton, Council on Environmental Quality & others.
PhilCsays
thanks for the replies so far – I do appreciate the time people take to put forward information but…
All of this started off in the 1970’s with the simple idea that Co2 warms the atmosphere. This has developed so that now ice coverage, methane, CO2 etc all contribute. Throw in solar and cosmic activity and I’d say you have a very, very complex system youâ��re trying to model. Anyone who is willing to take a firm stand on any prediction being right is a brave sole.
A computer model of this would have to take account of every contributing factor in exactly the right amount for its predictions to have any chance of being right. Not only the initial conditions but also the exact nature of how everything interacts with everything else. Should any of these be out (or some other as yet unrecognized factor be missed altogether) then after a few interations the model would bare no relation to how the world’s real climate will change.
Perhaps this is why the GW predictions I read range from �not too bad� to �the end of life as we know it�.
Other theories like relativity or quantum mechanics stand or fall on very definite predictions. The predictions from GWT have such a wide variation that the theory itself seems very under-developed.
Terry Mieslesays
Re:63
Perhaps Lindzen is suggesting Earth’s orbit is as eccentric as Pluto and Neptune. This seems an unusually amateurish attempt at baiting and misdirection.
[[I watched the program and read the rebutals but still cannot for the life of me understand if CO2 levels lag behind the temperature by 800 years how CO2 causes the temperature to change. ]]
Try reading the past posts in the blog. RealClimate and posters have covered this many, many times.
We know more CO2 in the air raises the temperature of the ground. That’s basic radiation physics which goes back at least to Arrhenius in 1896. If any temperature increase for another reason raises CO2, the CO2 will raise the temperature further. It can’t be avoided unless there’s some counteracting factor, and no one has ever found one despite diligent search for many decades.
[[If I understand this correctly, an initial rise in temperature causes an increase in CO2 which then causes an increase in termperature which would cause another rise in CO2.
Once this process starts – what stopped it from running completely out of control in the past? ]]
The math governing it is essentially a converging series — each increment is smaller than the last, so the total comes to some finite sum. Compare the series 1 + 1 + 1 … which diverges to infinity, with 1 + 1/2 + 1/4 … which converges to 2.
[[I’ve been following the “pro” and “cons” for a while now and still can’t get to some conclusion of it all. On questions I have for instance is: The CO2 we are releasing now is that not previously free CO2 that have been captured at some time in history? And if so, are these volumes not already in the climate system and we are actually not adding anything that did not exist before?]]
Most of the carbon on Earth is not in the climate system, but in sedimentary rocks on the ocean floor. It does eventually get recycled to the air, but the process takes millions of years.
You’re right that the total amount of carbon is fixed — mass is conserved in any non-nuclear reaction. But what’s happening now is that carbon is being released from the rocks — fossil fuels — and dumped into the atmosphere faster than natural recycling can handle it.
[[I should maybe start by stating that I recognize the fact that earth is warming… And with that out of the way… After considering your answer I still don’t understand why many claim that the CO2 levels have never been this high when evidently “all” the CO2 we’re releasing must have been around some point in time. I understand the consequences at present and future time for mankind but in the history of earth (and I’m thinking rather recently) there must have been worse situations than the one that is proposed to be?]]
There have been times in geological history when CO2 was much higher and the world was much warmer, and life survived. It will survive now. But the transition to that warmer state will be faster than our agriculture and our economy can handle. In the Jurassic when the sea level was higher, there were no cities built on the coastline. There are now.
Dick Veldkampsays
Re #65, PhilC
The model problems are not so severe as you make them out to be.
1. Some factors are less important than others, so it doesn’t matter whether we know them accurately, as long as we’re in a reasonable range. There are also some statistical ‘tricks’ to deal with uncertainty, as they do in the ClimatePrediction project.
2. Some important factors (what CO2, CH4 etc do with radiation) are well known from independent experiments.
3. It gives A LOT of confidence that the models reproduce measurements fairly well, not only over time, but also in space: temperature and rain distributions over the globe for example.
There is the matter of lacking knowledge of ice dynamics (melting) of course, but from what I gather this will probably make matters worse than better.
And what’s the alternative? Just ignore the best predictions science has to offer?
Richard Ordwaysays
re. 54. Rob wrote:
“On questions I have for instance is: The CO2 we are releasing now is that not previously free CO2 that have been captured at some time in history?
And if so, are these volumes not already in the climate system
and we are actually not adding anything that did not exist before?”
My over-simplified explanation was too simplified on how Earth’s systems keep CO2 in check. I named only two general processes.
There is at least a third important process at work that keeps the CO2 naturally in check…sometimes known as biological sequestering or a biological pump. This is also part of the carbon cycle.
This third process is approximately as follows (again very simplified)… the CO2 levels rise, Earth’s average surface temperatures rise.
Now trees, plants, algae (in comparatively now stagnant oceans and lakes-[algae are plants]…think scum on a summer pond surface) and swamps and bogs spread massively.
Oceans often become more stagnant during long warm periods because of fewer temperature differences between the poles and the equator.
The warmth spreads to almost the poles. Palms and ferns grow at the equivalent of the artic circle area…ie most of the Earth’s land surface now becomes covered by swamps and the oceans by algae.
Trees, plants, algae and other single-celled animals absorb CO2. They die and are covered by newer trees, plants and algae in this stagnant wet swamp/bog/ocean envriroment.
They sink (in swamps, bogs and oceans) and are covered my more plants and trees. After a while (millions of years) this is turned by pressure and heat…into coal, oil and gas full of…carbon.
It basically stays this way…unless we humans suddenly dig it up and release it to the atmosphere by burning oil, coal and gas. This carbon now combines with oxygen to form…co2 when you burn it.
Guess what one of the biggest geological ages was called when this “biological sequestering or biological pump” was occurring about 300 million years ago…the “Carboniferous age” (note the word carbon).
That is a third major process that keeps co2 in check…and has severe implications for today and the future. In short…”this ain’t natural.”
SomeBeanssays
PhilC @ #65 – all of this started a long time ago, long before the 1970’s. I was curious and found this timeline:
on the American Institute of Physics website. Arrenhius’ (1896) prediction was that for a doubling of CO2 there would be roughly 5degree increase in temperature, I believe the current estimate for this sensitivity is a little lower.
I wonder if he intended for us to test his prediction experimentally?
Adamsays
For those who’d rather not install RealPlayer to listen to BBC programmes (those that aren’t podcast), Google “Real Alternative” for an, er alternative.
Adamsays
RE SomeBeans #73 see the top “Science Links” link on the RHS side bar for the full history.
tomsays
AHHH, if only you guys were 1/10 as diligent and skeptical of the info in Inconvemient Truth…
The Waxman hearings are on now on C-Span. The Souder from Indiana is particularly vile and hostile to Hansen.
PhilCsays
re #71
1.. “The model problems are not so severe as you make them out to be.”
you can only know how severe they are by waiting until the predictions have come true – or not. If it turns out to have even a slightly different effect that you origianlly thought your model can be way off.
2. “Some important factors (what CO2, CH4 etc do with radiation) are well known from independent experiments.”
experiments that actually show their overall effects on the real climate, or do they just extrapolate an effect in the laboratory.
Am I wrong in thinking that the different models report widely varying predictive effects (between 1-6 degree temperature changes for example)
How can they be accurate yet produce widely differing at the same time
[Response: There are two parts to making a projection. The first is the scenario that is used that determines how much CO2 etc. might change, and secondly, the physical model is to project the change in the climate. The range you quote is for both sorts of uncertainty, and most of it is related to the different scenarios, not the different models. The model sensitivity is significantly less for any one scenario. See the SPM for details. – gavin]
Hank Robertssays
Mark, did you notice, on the website, the age of the flag next to that WSJ opinion piece? 48 stars on it.
Chuckle.
john mannsays
Re #72
Richard – an amplification.
Carbon trapped in limestone deposits is returned to the atmosphere when the limestone is subducted during a plate collision. It can then react with silicate rocks
and the CO2 is expelled, through volcanoes funnily enough (so much for the assertion that volcanoes emit CO2 – it’s often fossil atmosphere anyway).
And of course, the organic stuff can be returned when their strata are eroded and the material is then oxidised.
But of course, all this happens very slowly.
Richard Ordwaysays
#76 [[AHHH, if only you guys were 1/10 as diligent and skeptical of the info in Inconvemient Truth…]]
The above shows little understanding of how science works.
Scientists were harsh of the climate disaster movie the 2004 Day After Tommorow’s science.
Scientists also critiqued and thought the science was generally sound for “An Inconvienient ruth.”…although they were quick to nitpick a few scientific points.
“So, because you don’t fully understand the computer models of global climate, you assume everyone else is a ignorant as you?”
while someone (admittedly not me) may fully understand a model I just question the idea that you can accurately model the entire atmosphere of a planet.
But it didn’t take long for the name calling to start :)
Lynn Vincentnathansays
I’ve been busy & need to catch up, so this might be off topic, but several posts ago Chris Mooney raised the issue of Al Gore being incorrect on something in AIT, and how that might damage credibility or something.
If Gore underestimated GW, then that is a bad mistake & morally reprehensible (if done purposely). If he overestimated the harm, then that is perfectly okay.
The only debate in my view is between the scientists, avoiding false positives (not making a claim re GW unless they are extremely sure), and the environmentalists (and everyone else), avoiding false negatives (being cautionary in assuming and trying to prevent the worst). So, the skeptics and contrarians and denialists are all in the “avoid the false positive” camp, with only the scientists having a morally valid reason to be there.
So any mistake on the “assuming the worst & trying to prevent it side” is a non-problem. It’s perfectly okay. That’s were everyone, except the scientists, should be.
You needn’t take offense, Phil, the word “ignorant” was used in its literal rather than pejorative sense.
You do have a point. Climate models have a lot of utility in investigating climate, but the boundaries between their uses and abuses are complex and controversial. It’s not especially easy or obvious what we should trust about them and what not to.
The public and much of the scientific community focuses on the conceptually simple use of prognostication that the IPCC report cycle drives. (Note that it’s prognostication and not prediction; all of the climate models of the future are predicated on CO2 concentration scenarios, which in turn depend on 1) human behavior and 2) carbon cycle feedbacks; there’s no way around the first part at least.)
How reliable these prognoses are is not better than the scatter among them, which is large. It may be worse than that, because there may be some unconscious bias toward producing a “typical” result among the modeling centers. However, it is difficult in practice to imagine how such biases might operate.
So it is a bit of a quandary.
The less you believe the models, the more vigorously you should support carbon mitigation. I feel compelled to come out and say this on occasion, since most people get it backwards. The weaker you think the science is, the bigger the risk you believe we are taking, and hence the more effort you should put into avoiding the worst cases. The cost of overreacting to benign climate change scenarios has to be balanced against the much larger cost of overreacting to catastrophic ones. The cost of the catastrophes increasingly dominate the more uncertainty you place upon the estimates.
It is also important to take note of the fact that despite enormous motivation to do so, nobody has been able to build a model that reasonably represents contemporary climate that has a greenhouse gas sensitivity different from the model consensus by a factor of greater than two.
The models continue to fail to represent local changes well enough to rely upon for local policy. Whether they can be improved enough to do so remains an open question. I think it is too soon to give up, but late enough to start exploring alternative design methodologies. That is a topic that is worthy of a real scientific debate.
Your question whether we “can accurately model the entire atmosphere” depends very much on what sort of accuracy you are looking for. The models produce storms that go where storms go and, as of recently, hurricanes that go where hurricanes go. The gulf stream goes where the gulf stream goes, and so does the Kuroshio and the Antarctic current. The sea ice grows and shrinks at roughly the right times and rates. The intertropical convergence zone and the El Nino, however, remain wretched. Make of this what you will. (I make of it a living, myself.)
But the climate sensitivity to CO2 is essentially known. There’s very little evidence that would place it far from 3 degrees C per CO2 doubling, and a great deal that puts it near that quantity. Models agree with other evidence on this matter. It’s not really an open question; any scientist proposing a dramatically different value at this point would have an awful lot of ‘splainin’ to do.
J.C.Hsays
“…while someone (admittedly not me) may fully understand a model I just question the idea that you can accurately model the entire atmosphere of a planet. …” – PhilC
As long as we’re mixing things, a prediction of the weather to be on Thursday morning requires a degree of accuracy akin to threading the eye of a tiny needle; hitting the broad side of a barn 200 years from now doesn’t.
RE PhilC,
Any person should question the idea that you can model the atmosphere of a planet… but then, assuming that’s the question of interest (and not, how can I inject doubt into scientific discussions of climate in order to prevent governments from taking action?) then you’d want to look at weather models, and how climate models are derived from weather models, and how ocean circulation and heat transport is modeled, and how ocean models are coupled to climate models… and so on. You’d want to compare past model predictions to reality (see for example https://www.realclimate.org/index.php?p=148 “Planetary Energy Imbalance”)…and then you’d realize that the models do a pretty good job.
Of course, there’s always something that might be missing, but that’s true for any model – a model of air flowing over an airplane wing, a model of a bridge. That’s why comparing models to observations matters; if there’s a persistent discrepancy it can tell you about what your model is missing (for example, early models didn’t include aerosol effects). That’s how science is done.
If you ignore the facts after they’re presented to you and persist with the same discredited arguments, as Lindzen et al do, then you simply lose all credibility.
PhilCsays
re# 86
“As long as we’re mixing things…. hitting the broad side of a barn 200 years from now doesn’t.”
What am I mixing?
The current models seem to predict different ‘barns’ depending on who’s running the model (i.e. different temperatures and climate effects etc) – how come they differ so much if they are essentially accurate.
PhilCsays
re #81
“The model sensitivity is significantly less for any one scenario. See the SPM for details. – gavin]”
Gavin, could you let me know what the SPM is?
Many thanks
Phil
[Response:Sorry. Summary for Policy Makers from IPCC – discussed (and directly linked to) here. Look at Figure SPM-5 – gavin]
Hank Robertssays
Mark, that’s the difference between what you see and what you get (grin).
You old enough to remember the 48-star flag? I’m still flying mine, it hasn’t worn out yet — it’s a grid (stars aren’t offset), six rows. You don’t see all eight columns in the WSJ Editorials picture.
Trust me, that’s the flag from before the upstart Alaska and Hawaii Territories intruded themselves into the country (and the current staggered-to-fit-fifty star layout became the official flag).
Aw, you knew that, I’m such a sucker for a good troll sometimes. Gulp.
Chuck Boothsays
Philc,
Michael Tobis (#87) was correct – I was using “ignorant” and “ignorance” to describe your apparent lack of knowledge about global climate models. Had I intended to disparage you personally, I would have chosen some other term (and the comment would surely have been deleted by the RC moderators).
As others have pointed out on this and other RC threads, computer models used to make forecast are commonly run mutiple times using different starting values to account for the known (or expected) variability of the input parameters (i.e., the assumptions on which the model is based). The result is a range of possible output values (predictions/prognostications, whatever you want to call them). Yes, the predicted magnitude of global warming is a range of temperature values – usually these predicted values are assigned some degree of certainty akin to confidence limits in statistics. It will take some time to verify the accuracy of these predictions, but the fact that they all predict global warming should be alarming to everyone – keep in mind that one degree C is almost two degrees F, and a rise in global mean temperature of even 1 degree C over a couple of decades could be expected to have very serious implications for sea level rise, animal and plant survival, disease outbreaks, etc.
Don’t go there (grin). Hardly the sort of link you want to have Google think is a recommended one, eh? Sourcewatch is good on “SEPP” info.
David B. Bensonsays
Re #37: Richard Ordway — My understanding of the LGM to Holocene temperature increase of 6–8 K is that only about half of that can be attributed to so-called greenhouse gases. (My amateur attempt only supplies about 2 K.) The rest of the temperature increase might be due to albedo changes?
Mitch Goldensays
Re #45: PhilC:
There’s a mathematical way to understand why it might not run away: The positive feedback is smaller than the initial kick. So, if we take the initial kick as having one unit of strength (in other words, call it 1), the positive feedback could be 3/4 the size. Then that 3/4 causes a feedback 3/4 the size of that one, etc:
1 + 3/4 + (3/4)*(3/4) + (3/4)*(3/4)*(3/4) + …
This is what is called in mathematics a “convergent” series, which adds up to 4. So the final effect is that the change is 4 times as big as the original effect.
Plus, there could be a time delay as it takes effect. So, for example, the solar change that kicks it off happens at time t=0, but then t=100 years later the initial 3/4 takes effect. Then at t=200 years the next 3/4 takes effect, etc. What you’d see is the CO2 rise trailing the climate change in precisely the observed way.
It is possible that the feedback was bigger than the initial kick, say 1.2. Then the series is:
1 + 1.2 + (1.2)*(1.2) + (1.2)*(1.2)*(1.2) + …
This series is called “divergent” – it never stops growing. I have heard that it is believed that this is what happened on Venus. (Of course, in any physical system you eventually get cut off – you run out of carbon, for example.)
Aaron Lewissays
What we really need to fix is our science education.
The final vote of the debate was really a notice that society is not going to make a determined effort to restrict ghg emissions until our infrastructure is flooded, and we are living in a tent on Mt Ararat. Noah did, and so can we. I have lived in a tent and herded sheep, it is not so bad â?? if you have those skills.
In only a 150,000 years, the waters will recede and we can reclaim places like New York City, Houston, London, Istanbul, Bombay, and Shanghai. Not to mention every major refinery in the world. Of course, without those refineries, even inland cities could no longer function.
We have a society that does not understand science: not climate science, not economics, and not geography.
fieldnorthsays
Piers Corbyn, the meteorologist that supplies long range forecasts for industry says the IPCC in fairness should include a temperature record going back to the end of the last ice along with the CO2 record of the same period. Do you agree with him?
[Response: Umm… sure. If such a thing existed. But we don’t even have good data for the global mean back before 1000 years ago (and Mr. Corbyn would probably dispute that also), so how we can have it going back 15,000 years is a little odd. The graph he uses appears to a very rough copy of one of the Greenland ice cores, but that is hardly typical, and certainly not a global mean. – gavin]
re. 45 Phil writes:
…re. why CO2 disappears natually.
“Once this process (co2 being incresed naturally -RO) starts – what stopped it from running completely out of control in the past?”
Again anyone step in. Here is a simplified explanation. There are several processes (can be called negative feedbacks) which stop the Co2 (on Earth…not poor Venus)from going “runaway” (“runaway greenhouse effect”).
The first is, is that rocks (silicate rocks), in the long term, remove the CO2 out of the air with a reaction with rain.
The warmer it gets, the more these chemical reactions increase (because it rains more when it gets warmer-ooops, what does that mean is happening now?).
Now this solution flows to the sea and dumps CO2 into the sea. in other words to paraphase from your high school chemistry that you were required to take: CaSiO3 + 3H2O + 2CO2 turns into Ca2+ + 2(HCO3- ) + H4SiO4).
Notice how the CO2 disappears. This is called the chemical weathering process and is part of the “carbon cycle.” In the ocean, types of animals absorb the carbon out of the water to make shells…they die and sink to the bottom of the ocean.
A second process to stop co2 from growing , is that the warmer it gets (the ice-covered lands disappear and the more trees and plants appear. They absorb more CO2 from the air and transfer it by roots deep in the soil where it combines with water to make an acid “carbonic acid” which disolves calcium silicate in rock to to make calcium carbonate (notice the word carbon in carbonate).
The calcium carbonate (carbon) is then transported in solution to the oceans where it can be dumped out as limestone.
Okay, those are the two basic processes. Otherwise, co2 gets reduced during ice ages when the Earth’s orbit changes the amount of sun energy hitting at least the northern hemisphere during the summer in regular (pretty regular) three cycles of about 26,000 years, 41,000 years and 100,000 years (Milankovitch cycles).
You know the routine: Cool the air. Cool the oceans which can hold more co2 in solution (think of your cold versus hot pop bottle). Now increase the ice on Earth. This makes higher winds by air coming over ice, rapidly sinking and making winds. With an ice age, more dusty land is exposed as sea levels drop as water becomes ice. This carries more dust. Dust has iron. More iron feeds more plankton in the oceans. More plankton (plant variety) eats more co2 and sinks.
In ice ages, the ocean currents often also get more active because of a bigger difference in temperatures between the poles and the equator and this allows even more co2 to be absorbed (subducted).
That is a simplified expanation that leaves a lot out.
RE#45, This was discussed from many perspectives at the “Swindled” thread; my attempts can be viewed at #150, #202, #291, but to quote one of the moderators:
“Response:AFAIK, people don’t know exactly why CO2 stopped at 280 in interglacials and 180 in glacials. It doesn’t have to be feedbacks: there could simply be some reservoir that is exhausted. Also, thats for the previous 4 interglacials: before then, EPICA shows 250. This again is unexplained – William”
If you look at http://news.mongabay.com/2005/1124-climate.html , you can see a graph of the ice core CO2 record (halfway down the page). We know that CO2 stops increasing – why is uncertain.
Once again (as with the solar issue, see Nigel Weiss’s comments above) you have contrarians using one-sided distortions of scientific uncertainties to support their views.
RE#32 – I’ve just read the Independent article someone linked to after my post on Hardarker & Co.
From the article http://news.independent.co.uk/environment/climate_change/article2368999.ece
‘Some confusion surrounded the views of the RMS scientists yesterday after Prof Hardaker told the IoS that he could not think of a case where a scientist had overstated the position. He did however mention a statement by the American Association for the Advancement of Science that described an “intensification of droughts, heatwaves, floods, wildfires and severe storms” as “early warning signs of yet more devastating damage to come”.
He said he did not disagree with any of this, but thought the AAAS should have made it clear what could be justified by the scientific evidence and what was based on judgement. He pointed out that he and his colleague were not experts on climate change. ‘
So after all this fuss, he did not disagree with any of the statement, and ‘he and his colleague were not experts on climate change’. Strange, since the BBC Today website still has the interview http://www.bbc.co.uk/radio4/today/listenagain/ram/today2_climate_20070317.ram with the headline ‘Two of Britain’s most senior climate researchers have told the BBC that scientists have been overplaying the message on climate change.’. Still, if you wanted to get lots of pulicity for outfit like Sense about Science (who have some slightly dodgy links to the RCP/Spiked crowd), then this nonsense would have done you no harm…
I’ve been following the “pro” and “cons” for a while now and still can’t get to some conclusion of it all. On questions I have for instance is: The CO2 we are releasing now is that not previously free CO2 that have been captured at some time in history? And if so, are these volumes not already in the climate system and we are actually not adding anything that did not exist before?
/Br. Rob
Re #35, climate change is relative is the answer. Today millions of people live along the coasts of the world, when the seas rise due to climate change they will be in trouble, it does not matter that 50 million years ago the earth was 5 degrees hotter and the seas 70 meters higher does it as it did not impact anyone ?
It is all about forcings or which the earths albedo and vegetation is the strongest followed by greenhouse gases. Both do not need to be high for warming to occur either can cause warming or cooling for that matter. 10,000 years ago the earths natural cycles (known to us as miltankovitch cycles) starting to bring us out of an ice age and hence the albedo effect was the cause of this warming. As you have been told it takes some 800 years of warming before albedo and vegetation had been effected enough although RC tell us that it may not have been this long. Anyway the source of the CO2 is most likely the oceans which absorb CO2 when it is cold and release it when it is warmed and it is this released CO2 that then causes further warming of the atmosphere.
In the modern world 280 ppm seems to be the earths natural limit and we are not at 390 ppm due to industrial burning. Further burning will cause steadily increasing CO2 levels and hence further warming.
Re #47 Earth’s atmosphere (Rob)
Yes, most CO2 we are producing at present was at some point in history captured and converted to fossil fuels, which then remained safely underground (and outside the climate system) until we recently started re-releasing it into the atmosphere.
Look for example in Wikipedia:
http://en.wikipedia.org/wiki/Earth%27s_atmosphere#Evolution_of_the_Earth.27s_atmosphere
But regardless of where that CO2 was in history, the trouble now is that all that CO2 in the atmosphere will have rather unpleasant consequences.
re#49
if, at some point, it was all in the atmosphere why have the “unpleasant consequences” (runnaway greenhouse I presume) not been seen in the historical record.
[Response: Who says “runaway greenhouse”? -William]
Re #49 Earth’s atmosphere (Dick V)
I should maybe start by stating that I recognize the fact that earth is warming… And with that out of the way… After considering your answer I still don’t understand why many claim that the CO2 levels have never been this high when evidently “all” the CO2 we’re releasing must have been around some point in time. I understand the consequences at present and future time for mankind but in the history of earth (and I’m thinking rather recently) there must have been worse situations than the one that is proposed to be?
/Br. Rob
Rob…the problem is I think pre-Industrial Revoluton levels of CO2 were 270ppm with a very small population and now C02-equivalent levels are way over 400ppm with a population heading towards 9.5 billion by 2050. These people need to be fed, housed, clothed, and have access to clean water and good sanitation. If extreme weather events increase and the temperature gets hotter, then this has severe implications for that larger population. If there were still less than a billion people in the world and the temperature rose naturally rather than being forced there wouldn’t be such a problem. Isn’t this what we are all really worried about?
Re #50 Worries (Philip M)
Exactly, we should worrie about the consequences of a warmer world rather than try to rectify something that we might or might not be able to influence. Is it not so that a very high percentage agrees and recognize that the world is getting warmer (independent of source)? And are we also not on agreement that this warming will continue for a long time regardless of any action taken to prevent that? If so, shouldn’t the prudent way of the humankind (as history have told us) be to adapt?
/Br. Rob
Re #47, #50 Earth’s atmosphere (Rob)
The claim about “CO2 levels never been this high” is made (as far as I know) for the last 650,000 years (this is found from analysing air bubbles in ice cores).
With a little googling I found this temperature graph: http://www.scotese.com/climate.htm which has several maxima at ca 22 deg C global T, for example in the Cretaceous some 100 million years ago (currently we’re at 15-16 deg C). Presumably CO2 concentrations were also higher then (but I am no paleoclimate expert).
However, as people have often pointed out in the hockeystick discussion, whether CO2 levels were higher at some time in the past is really not the issue*). Even if we had no clue whatsoever about the climate before 1800 there is plenty of evidence that the theory of global warming is sound and we’re involved in a dangerous global experiment.
*) Of course I don’t mean to deny the importance of paleoclimatology. It it is a good thing to have the complete picture, and to check our theories wherever we can.
Rob,
“…I still don’t understand why many claim that the CO2 levels have never been this high when evidently “all” the CO2 we’re releasing must have been around some point in time.”
Bear in mind that the coal / oil deposits we’re burning through weren’t laid down overnight. The CO2 we’re re-releasing WAS all in the atmosphere in the past, but not necessarily all at the same point in time (unless you go billions of years back, before life on the planet).
[[You don’t explain why there’s global warming on Mars, Jupiter, Triton and Pluto. ]]
All we know about Mars is that one of its polar caps has shrunk a bit in the past three years. That proves exactly nothing relevant to the overall thermal balance of Mars.
Jupiter is not undergoing global warming. Where did Lindzen get that idea?
Triton? Where is Neptune in its orbit just now? Ditto Pluto. Neither Triton nor Pluto has an atmosphere worth speaking of, but they do have summer and winter. Is Lindzen aware that Pluto takes 248 years to go around the Sun, and therefore that its seasonal change in any direction will last a lot longer than on Earth?
Different Kind of Debate
Coming up at 10am on C-SPAN, another episode of “Stop Interfering with My Research.” Today, the big boys go at it. The CEQ head’s name is actually James Connaughton, a fairly important policymaker on climate change, but who is seldom seen or heard. C-SPAN usually repeats these hearings, so check the schedule.
Global Warming Research
Rep. Henry Waxman (D-CA) chairs an Oversight and Gov’t Reform Cmte. hearing on claims of poli-
tical interference with government scientists & their research on climate change. Witnesses include James Hansen, Dir., NASA Goddard Inst. for Space Studies; John Connaughton, Council on Environmental Quality & others.
thanks for the replies so far – I do appreciate the time people take to put forward information but…
All of this started off in the 1970’s with the simple idea that Co2 warms the atmosphere. This has developed so that now ice coverage, methane, CO2 etc all contribute. Throw in solar and cosmic activity and I’d say you have a very, very complex system youâ��re trying to model. Anyone who is willing to take a firm stand on any prediction being right is a brave sole.
A computer model of this would have to take account of every contributing factor in exactly the right amount for its predictions to have any chance of being right. Not only the initial conditions but also the exact nature of how everything interacts with everything else. Should any of these be out (or some other as yet unrecognized factor be missed altogether) then after a few interations the model would bare no relation to how the world’s real climate will change.
Perhaps this is why the GW predictions I read range from �not too bad� to �the end of life as we know it�.
Other theories like relativity or quantum mechanics stand or fall on very definite predictions. The predictions from GWT have such a wide variation that the theory itself seems very under-developed.
Re:63
Perhaps Lindzen is suggesting Earth’s orbit is as eccentric as Pluto and Neptune. This seems an unusually amateurish attempt at baiting and misdirection.
[[I watched the program and read the rebutals but still cannot for the life of me understand if CO2 levels lag behind the temperature by 800 years how CO2 causes the temperature to change. ]]
Try reading the past posts in the blog. RealClimate and posters have covered this many, many times.
We know more CO2 in the air raises the temperature of the ground. That’s basic radiation physics which goes back at least to Arrhenius in 1896. If any temperature increase for another reason raises CO2, the CO2 will raise the temperature further. It can’t be avoided unless there’s some counteracting factor, and no one has ever found one despite diligent search for many decades.
[[If I understand this correctly, an initial rise in temperature causes an increase in CO2 which then causes an increase in termperature which would cause another rise in CO2.
Once this process starts – what stopped it from running completely out of control in the past? ]]
The math governing it is essentially a converging series — each increment is smaller than the last, so the total comes to some finite sum. Compare the series 1 + 1 + 1 … which diverges to infinity, with 1 + 1/2 + 1/4 … which converges to 2.
[[I’ve been following the “pro” and “cons” for a while now and still can’t get to some conclusion of it all. On questions I have for instance is: The CO2 we are releasing now is that not previously free CO2 that have been captured at some time in history? And if so, are these volumes not already in the climate system and we are actually not adding anything that did not exist before?]]
Most of the carbon on Earth is not in the climate system, but in sedimentary rocks on the ocean floor. It does eventually get recycled to the air, but the process takes millions of years.
You’re right that the total amount of carbon is fixed — mass is conserved in any non-nuclear reaction. But what’s happening now is that carbon is being released from the rocks — fossil fuels — and dumped into the atmosphere faster than natural recycling can handle it.
[[I should maybe start by stating that I recognize the fact that earth is warming… And with that out of the way… After considering your answer I still don’t understand why many claim that the CO2 levels have never been this high when evidently “all” the CO2 we’re releasing must have been around some point in time. I understand the consequences at present and future time for mankind but in the history of earth (and I’m thinking rather recently) there must have been worse situations than the one that is proposed to be?]]
There have been times in geological history when CO2 was much higher and the world was much warmer, and life survived. It will survive now. But the transition to that warmer state will be faster than our agriculture and our economy can handle. In the Jurassic when the sea level was higher, there were no cities built on the coastline. There are now.
Re #65, PhilC
The model problems are not so severe as you make them out to be.
1. Some factors are less important than others, so it doesn’t matter whether we know them accurately, as long as we’re in a reasonable range. There are also some statistical ‘tricks’ to deal with uncertainty, as they do in the ClimatePrediction project.
2. Some important factors (what CO2, CH4 etc do with radiation) are well known from independent experiments.
3. It gives A LOT of confidence that the models reproduce measurements fairly well, not only over time, but also in space: temperature and rain distributions over the globe for example.
There is the matter of lacking knowledge of ice dynamics (melting) of course, but from what I gather this will probably make matters worse than better.
And what’s the alternative? Just ignore the best predictions science has to offer?
re. 54. Rob wrote:
“On questions I have for instance is: The CO2 we are releasing now is that not previously free CO2 that have been captured at some time in history?
And if so, are these volumes not already in the climate system
and we are actually not adding anything that did not exist before?”
My over-simplified explanation was too simplified on how Earth’s systems keep CO2 in check. I named only two general processes.
There is at least a third important process at work that keeps the CO2 naturally in check…sometimes known as biological sequestering or a biological pump. This is also part of the carbon cycle.
This third process is approximately as follows (again very simplified)… the CO2 levels rise, Earth’s average surface temperatures rise.
Now trees, plants, algae (in comparatively now stagnant oceans and lakes-[algae are plants]…think scum on a summer pond surface) and swamps and bogs spread massively.
Oceans often become more stagnant during long warm periods because of fewer temperature differences between the poles and the equator.
The warmth spreads to almost the poles. Palms and ferns grow at the equivalent of the artic circle area…ie most of the Earth’s land surface now becomes covered by swamps and the oceans by algae.
Trees, plants, algae and other single-celled animals absorb CO2. They die and are covered by newer trees, plants and algae in this stagnant wet swamp/bog/ocean envriroment.
They sink (in swamps, bogs and oceans) and are covered my more plants and trees. After a while (millions of years) this is turned by pressure and heat…into coal, oil and gas full of…carbon.
It basically stays this way…unless we humans suddenly dig it up and release it to the atmosphere by burning oil, coal and gas. This carbon now combines with oxygen to form…co2 when you burn it.
Guess what one of the biggest geological ages was called when this “biological sequestering or biological pump” was occurring about 300 million years ago…the “Carboniferous age” (note the word carbon).
That is a third major process that keeps co2 in check…and has severe implications for today and the future. In short…”this ain’t natural.”
PhilC @ #65 – all of this started a long time ago, long before the 1970’s. I was curious and found this timeline:
http://www.aip.org/history/climate/timeline.htm
on the American Institute of Physics website. Arrenhius’ (1896) prediction was that for a doubling of CO2 there would be roughly 5degree increase in temperature, I believe the current estimate for this sensitivity is a little lower.
I wonder if he intended for us to test his prediction experimentally?
For those who’d rather not install RealPlayer to listen to BBC programmes (those that aren’t podcast), Google “Real Alternative” for an, er alternative.
RE SomeBeans #73 see the top “Science Links” link on the RHS side bar for the full history.
AHHH, if only you guys were 1/10 as diligent and skeptical of the info in Inconvemient Truth…
the entire TGGWS is now on YOuTube: http://www.youtube.com/watch?v=XttV2C6B8pU
Here’s the latest hit piece from the WSJ from the dropout John Fund.
http://www.opinionjournal.com/diary/?id=110009804. He quotes Milloy!
Re # 65 So, because you don’t fully understand the computer models of global climate, you assume everyone else is a ignorant as you?
I frequently warn my students about the logical fallacy of arguments based on ignorance.
The Waxman hearings are on now on C-Span. The Souder from Indiana is particularly vile and hostile to Hansen.
re #71
1.. “The model problems are not so severe as you make them out to be.”
you can only know how severe they are by waiting until the predictions have come true – or not. If it turns out to have even a slightly different effect that you origianlly thought your model can be way off.
2. “Some important factors (what CO2, CH4 etc do with radiation) are well known from independent experiments.”
experiments that actually show their overall effects on the real climate, or do they just extrapolate an effect in the laboratory.
Am I wrong in thinking that the different models report widely varying predictive effects (between 1-6 degree temperature changes for example)
How can they be accurate yet produce widely differing at the same time
[Response: There are two parts to making a projection. The first is the scenario that is used that determines how much CO2 etc. might change, and secondly, the physical model is to project the change in the climate. The range you quote is for both sorts of uncertainty, and most of it is related to the different scenarios, not the different models. The model sensitivity is significantly less for any one scenario. See the SPM for details. – gavin]
Mark, did you notice, on the website, the age of the flag next to that WSJ opinion piece? 48 stars on it.
Chuckle.
Re #72
Richard – an amplification.
Carbon trapped in limestone deposits is returned to the atmosphere when the limestone is subducted during a plate collision. It can then react with silicate rocks
and the CO2 is expelled, through volcanoes funnily enough (so much for the assertion that volcanoes emit CO2 – it’s often fossil atmosphere anyway).
And of course, the organic stuff can be returned when their strata are eroded and the material is then oxidised.
But of course, all this happens very slowly.
#76 [[AHHH, if only you guys were 1/10 as diligent and skeptical of the info in Inconvemient Truth…]]
The above shows little understanding of how science works.
Scientists were harsh of the climate disaster movie the 2004 Day After Tommorow’s science.
http://www.msnbc.msn.com/id/5058474/
Scientists also critiqued and thought the science was generally sound for “An Inconvienient ruth.”…although they were quick to nitpick a few scientific points.
https://www.realclimate.org/index.php?p=299
re#79
“So, because you don’t fully understand the computer models of global climate, you assume everyone else is a ignorant as you?”
while someone (admittedly not me) may fully understand a model I just question the idea that you can accurately model the entire atmosphere of a planet.
But it didn’t take long for the name calling to start :)
I’ve been busy & need to catch up, so this might be off topic, but several posts ago Chris Mooney raised the issue of Al Gore being incorrect on something in AIT, and how that might damage credibility or something.
If Gore underestimated GW, then that is a bad mistake & morally reprehensible (if done purposely). If he overestimated the harm, then that is perfectly okay.
The only debate in my view is between the scientists, avoiding false positives (not making a claim re GW unless they are extremely sure), and the environmentalists (and everyone else), avoiding false negatives (being cautionary in assuming and trying to prevent the worst). So, the skeptics and contrarians and denialists are all in the “avoid the false positive” camp, with only the scientists having a morally valid reason to be there.
So any mistake on the “assuming the worst & trying to prevent it side” is a non-problem. It’s perfectly okay. That’s were everyone, except the scientists, should be.
re #85, #79;
You needn’t take offense, Phil, the word “ignorant” was used in its literal rather than pejorative sense.
You do have a point. Climate models have a lot of utility in investigating climate, but the boundaries between their uses and abuses are complex and controversial. It’s not especially easy or obvious what we should trust about them and what not to.
The public and much of the scientific community focuses on the conceptually simple use of prognostication that the IPCC report cycle drives. (Note that it’s prognostication and not prediction; all of the climate models of the future are predicated on CO2 concentration scenarios, which in turn depend on 1) human behavior and 2) carbon cycle feedbacks; there’s no way around the first part at least.)
How reliable these prognoses are is not better than the scatter among them, which is large. It may be worse than that, because there may be some unconscious bias toward producing a “typical” result among the modeling centers. However, it is difficult in practice to imagine how such biases might operate.
So it is a bit of a quandary.
The less you believe the models, the more vigorously you should support carbon mitigation. I feel compelled to come out and say this on occasion, since most people get it backwards. The weaker you think the science is, the bigger the risk you believe we are taking, and hence the more effort you should put into avoiding the worst cases. The cost of overreacting to benign climate change scenarios has to be balanced against the much larger cost of overreacting to catastrophic ones. The cost of the catastrophes increasingly dominate the more uncertainty you place upon the estimates.
It is also important to take note of the fact that despite enormous motivation to do so, nobody has been able to build a model that reasonably represents contemporary climate that has a greenhouse gas sensitivity different from the model consensus by a factor of greater than two.
The models continue to fail to represent local changes well enough to rely upon for local policy. Whether they can be improved enough to do so remains an open question. I think it is too soon to give up, but late enough to start exploring alternative design methodologies. That is a topic that is worthy of a real scientific debate.
Your question whether we “can accurately model the entire atmosphere” depends very much on what sort of accuracy you are looking for. The models produce storms that go where storms go and, as of recently, hurricanes that go where hurricanes go. The gulf stream goes where the gulf stream goes, and so does the Kuroshio and the Antarctic current. The sea ice grows and shrinks at roughly the right times and rates. The intertropical convergence zone and the El Nino, however, remain wretched. Make of this what you will. (I make of it a living, myself.)
But the climate sensitivity to CO2 is essentially known. There’s very little evidence that would place it far from 3 degrees C per CO2 doubling, and a great deal that puts it near that quantity. Models agree with other evidence on this matter. It’s not really an open question; any scientist proposing a dramatically different value at this point would have an awful lot of ‘splainin’ to do.
“…while someone (admittedly not me) may fully understand a model I just question the idea that you can accurately model the entire atmosphere of a planet. …” – PhilC
As long as we’re mixing things, a prediction of the weather to be on Thursday morning requires a degree of accuracy akin to threading the eye of a tiny needle; hitting the broad side of a barn 200 years from now doesn’t.
Hank I only counted 36.
RE PhilC,
Any person should question the idea that you can model the atmosphere of a planet… but then, assuming that’s the question of interest (and not, how can I inject doubt into scientific discussions of climate in order to prevent governments from taking action?) then you’d want to look at weather models, and how climate models are derived from weather models, and how ocean circulation and heat transport is modeled, and how ocean models are coupled to climate models… and so on. You’d want to compare past model predictions to reality (see for example https://www.realclimate.org/index.php?p=148 “Planetary Energy Imbalance”)…and then you’d realize that the models do a pretty good job.
Of course, there’s always something that might be missing, but that’s true for any model – a model of air flowing over an airplane wing, a model of a bridge. That’s why comparing models to observations matters; if there’s a persistent discrepancy it can tell you about what your model is missing (for example, early models didn’t include aerosol effects). That’s how science is done.
If you ignore the facts after they’re presented to you and persist with the same discredited arguments, as Lindzen et al do, then you simply lose all credibility.
re# 86
“As long as we’re mixing things…. hitting the broad side of a barn 200 years from now doesn’t.”
What am I mixing?
The current models seem to predict different ‘barns’ depending on who’s running the model (i.e. different temperatures and climate effects etc) – how come they differ so much if they are essentially accurate.
re #81
“The model sensitivity is significantly less for any one scenario. See the SPM for details. – gavin]”
Gavin, could you let me know what the SPM is?
Many thanks
Phil
[Response:Sorry. Summary for Policy Makers from IPCC – discussed (and directly linked to) here. Look at Figure SPM-5 – gavin]
Mark, that’s the difference between what you see and what you get (grin).
You old enough to remember the 48-star flag? I’m still flying mine, it hasn’t worn out yet — it’s a grid (stars aren’t offset), six rows. You don’t see all eight columns in the WSJ Editorials picture.
Trust me, that’s the flag from before the upstart Alaska and Hawaii Territories intruded themselves into the country (and the current staggered-to-fit-fifty star layout became the official flag).
Aw, you knew that, I’m such a sucker for a good troll sometimes. Gulp.
Philc,
Michael Tobis (#87) was correct – I was using “ignorant” and “ignorance” to describe your apparent lack of knowledge about global climate models. Had I intended to disparage you personally, I would have chosen some other term (and the comment would surely have been deleted by the RC moderators).
Re your comments in #91:
You seem to be confusing precision with accuracy – if so, these links might be helpful in clarifying the difference:
http://www.flatsurv.com/accuprec.htm
http://www.chem.tamu.edu/class/fyp/mathrev/mr-sigfg.html
http://en.wikipedia.org/wiki/Accuracy_and_precision
As others have pointed out on this and other RC threads, computer models used to make forecast are commonly run mutiple times using different starting values to account for the known (or expected) variability of the input parameters (i.e., the assumptions on which the model is based). The result is a range of possible output values (predictions/prognostications, whatever you want to call them). Yes, the predicted magnitude of global warming is a range of temperature values – usually these predicted values are assigned some degree of certainty akin to confidence limits in statistics. It will take some time to verify the accuracy of these predictions, but the fact that they all predict global warming should be alarming to everyone – keep in mind that one degree C is almost two degrees F, and a rise in global mean temperature of even 1 degree C over a couple of decades could be expected to have very serious implications for sea level rise, animal and plant survival, disease outbreaks, etc.
Now I’ve seen everything.
http://ff.org/centers/csspp/docs/20070316_monckton.html
Don’t go there (grin). Hardly the sort of link you want to have Google think is a recommended one, eh? Sourcewatch is good on “SEPP” info.
Re #37: Richard Ordway — My understanding of the LGM to Holocene temperature increase of 6–8 K is that only about half of that can be attributed to so-called greenhouse gases. (My amateur attempt only supplies about 2 K.) The rest of the temperature increase might be due to albedo changes?
Re #45: PhilC:
There’s a mathematical way to understand why it might not run away: The positive feedback is smaller than the initial kick. So, if we take the initial kick as having one unit of strength (in other words, call it 1), the positive feedback could be 3/4 the size. Then that 3/4 causes a feedback 3/4 the size of that one, etc:
1 + 3/4 + (3/4)*(3/4) + (3/4)*(3/4)*(3/4) + …
This is what is called in mathematics a “convergent” series, which adds up to 4. So the final effect is that the change is 4 times as big as the original effect.
Plus, there could be a time delay as it takes effect. So, for example, the solar change that kicks it off happens at time t=0, but then t=100 years later the initial 3/4 takes effect. Then at t=200 years the next 3/4 takes effect, etc. What you’d see is the CO2 rise trailing the climate change in precisely the observed way.
It is possible that the feedback was bigger than the initial kick, say 1.2. Then the series is:
1 + 1.2 + (1.2)*(1.2) + (1.2)*(1.2)*(1.2) + …
This series is called “divergent” – it never stops growing. I have heard that it is believed that this is what happened on Venus. (Of course, in any physical system you eventually get cut off – you run out of carbon, for example.)
What we really need to fix is our science education.
The final vote of the debate was really a notice that society is not going to make a determined effort to restrict ghg emissions until our infrastructure is flooded, and we are living in a tent on Mt Ararat. Noah did, and so can we. I have lived in a tent and herded sheep, it is not so bad â?? if you have those skills.
In only a 150,000 years, the waters will recede and we can reclaim places like New York City, Houston, London, Istanbul, Bombay, and Shanghai. Not to mention every major refinery in the world. Of course, without those refineries, even inland cities could no longer function.
We have a society that does not understand science: not climate science, not economics, and not geography.
Piers Corbyn, the meteorologist that supplies long range forecasts for industry says the IPCC in fairness should include a temperature record going back to the end of the last ice along with the CO2 record of the same period. Do you agree with him?
http://www.weatheraction.com/index.php?option=com_content&task=view&id=14&Itemid=37
[Response: Umm… sure. If such a thing existed. But we don’t even have good data for the global mean back before 1000 years ago (and Mr. Corbyn would probably dispute that also), so how we can have it going back 15,000 years is a little odd. The graph he uses appears to a very rough copy of one of the Greenland ice cores, but that is hardly typical, and certainly not a global mean. – gavin]