I received this presentation of the “Bjerknes Lecture” that Dr. James Hansen gave at the annual meeting of the American Geophysical Union on December 17th. There are the usual things one might expect in the presentation, such as this slide which shows 2008 on the left with the anomalously warm Siberia and the Antarctic peninsula:
Source: James Hansen, GISS
Off topic but relevant, NASA has recently “disappeared”updated this oft cited map showing warming on the Antarctic peninsula and cooling of the interior:
There is also some new information in Hansen’s presentation, including a claim about CO2 sensitivity and coal causing a “runaway greenhouse effect”.
Hansen makes a bold statement that he has empirically derived CO2 sensitivity of our global climate system. I had to chuckle though, about the claim “Paleo yields precise result”. Apparently Jim hasn’t quite got the message yet that Michael Mann’s paleo results are, well, dubious, or that trees are better indicators of precipitation than temperature.
In fact in the later slide text he claims he’s “nailed” it:
He adds some caveats for the 2xCO2 claim:
Notes:
(1)
It is unwise to attempt to treat glacial-interglacial aerosol changes as a specified boundary condition (as per Hansen et al. 1984), because aerosols are inhomogeneously distributed, and their forcing depends strongly on aerosol altitude and aerosol absorbtivity, all poorly known. But why even attempt that? Human-made aerosol changes are a forcing, but aerosol changes in response to climate change are a fast feedback.
(2)
The accuracy of our knowledge of climate sensitivity is set by our best source of information, not by bad sources. Estimates of climate sensitivity based on the last 100 years of climate change are practically worthless, because we do not know the net climate forcing. Also, transient change is much less sensitive than the equilibrium response and the transient response is affected by uncertainty in ocean mixing.
(3)
Although, in general, climate sensitivity is a function of the climate state, the fast feedback sensitivity is just as great going toward warmer climate as it is going toward colder climate. Slow feedbacks (ice sheet changes, greenhouse gas changes) are more sensitive to the climate state.
Hansen is also talking about the “runaway” greenhouse effect, citing that old standby Venus in part of his presentation. He claims that coal and tar sands will be our undoing:
Hansen writes:
In my opinion, if we burn all the coal, there is a good chance that we will initiate the runaway greenhouse effect. If we also burn the tar sands and tar shale (a.k.a. oil shale), I think it is a dead certainty.
That would be the ultimate Faustian bargain. Mephistopheles would carry off shrieking not only the robber barons, but, unfortunately and permanently, all life on the planet.
I have to wonder though, if he really believes what he is saying. Perhaps he’s never seen this graph for CO2 from Bill Illis and the response it gives to IR radiation (and thus temperature) as it increases:
It’s commonly known that CO2’s radiative return response is logarithmic with increasing concentration, so I don’t understand how Hansen thinks that it will be the cause of a runaway effect. The physics dictate that the temperature response curve of the atmosphere will be getting flatter as CO2 increases. Earth has also had much higher concentrations of CO2 in past history, and we didn’t go into runaway then:
Late Carboniferous to Early Permian time (315 mya — 270 mya) is the only time period in the last 600 million years when both atmospheric CO2 and temperatures were as low as they are today (Quaternary Period ).
There’s lots more in this paper to behold in wonderment, and I haven’t the time today to comment on all of it, so I’ll just leave it up to the readers of this forum to bring out the relevant issues for discussion.
I’m sure Steve McIntyre at Climate Audit will have some comments on it, even though his name is not mentioned in the presentation. My name was mentioned several times though. 😉
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Richard Sharpe
December 23, 2008 8:37 pm
Joel Shore says:
I don’t see how looking at absolute temperatures rather than anomalies will help you and it will just introduce other severe problems. There is a reason why people have chosen to look at anomalies.
A comparison between Young Earth Creationists and warmists, like Joel:
Sitting here in my armchair I can’t see how evolution could happen.
and:
Sitting here in my armchair I can’t see how the models could be wrong.
the Arctic sea ice extent reached its lowest ever extent for Dec 20 and remains below the already remarkably low 2007../John Philip
Even if true, who cares? That is, unless we’d much rather be warmer than cooler. Especially given that sea ice area has remained unchanged over 30 years and the Antarctic is cooling. In that light, I’d view your claim as a positive! Is that your point?
Graeme Rodaughan
December 23, 2008 9:58 pm
Mike Bryant (18:53:42) :
Where’s the
Ha Ha.
Graeme Rodaughan
December 23, 2008 10:01 pm
My text just disappeared.
Supposed to be “sarc off” …
Graeme Rodaughan
December 23, 2008 10:04 pm
Mike Bryant (21:01:53) :
Interesting data Mike – all from official, i.e. Government sources?
Thanks. G
J. Peden
December 23, 2008 10:22 pm
There is a reason why people have chosen to look at anomalies.
Right, perhaps because anomalies are not “normal”?
CodeTech
December 24, 2008 12:33 am
Trust me, I’m laughing… the whole time.
Yep – kinda reminds me of the days when I, too, believed. I just couldn’t imagine what mental aberration these “skeptics” were suffering from. I mean, it’s self evident, right?
Watching someone defend the indefensible can be entertaining 🙂
old construction worker
December 24, 2008 1:41 am
Joel Shore (20:23:07)
‘At any rate, I have a standing challenge to anyone who actually wants to argue that the models are wrong on this point…….’
You may not like what they say but they do make some strong points that you and the IPPc needs to address. http://www.ncpa.org/pub/st/st308
“Problems with Climate Models. Researchers who have examined long-term climate forecasts have concluded they are based on nothing more than scientists’ opinions expressed in complex mathematical terms, without valid evidence to support the chosen approach.11”
“For example, when computer simulations project future global mean temperatures with twice the current level of atmospheric CO2, they assume that the temperature forecast is as accurate as a computer simulation of present temperatures with current levels of CO2.12 Yet it has never been demonstrated that temperature forecasts are as accurate as simulations of current conditions based on actual temperature data. Indeed, there are even serious questions surrounding model simulations of current temperature with current CO2 levels. According to the models, the earth should be warmer than actual measurements show it to be, which is why modelers adjust their findings to fit the data.”
foinavon
December 24, 2008 3:03 am
Will Nitschke (18:11:52) :
Will, let me address just a couple of general points before addressing more specific points if I have time later (it’s XMas Eve, in case you didn’t know – I’d hunt down a link to inform you of that if I had time)
You said on your mistake re the Santer paper: The number I typed should have been 9 not 8. My mistake.
But actually your initial mistake was stated thus: Secondly, Santer ends his study in 1998 at the height of the super el nino. A little convenient perhaps? The cherry picking being done here is breathtaking.
So it wasn’t a typo. You seemed to think that Santer’s study ended in “a super el nino” (and not a La Nina year). I’m not trying to “nail you” but this highlights a real problem with information, which might be that if you source information from sites designed to misrepresent the science, you are very likely to get the wrong end of the stick more generally.
For you later state with respect to my straightforward higlighting of the profound errors in the graphic representations in the introductory “article” to this thread: Could you provide some links please on published criticisms of this data? As long as the criticism have at least made it into published journals and have at at least some form of review as a starting point, then they do need to be taken on board and considered fairly by all sides of the debate.
But surely you can interpret the graphs in the same way that I can. I’ve described the problems in detail (I provided an equation for determining the temperature rise for a given CO2 concentration….I provided references to a detailed review on contemporaneous paleoCO2 and paleoT data together with around 10 further papers that address the issue further since the review was written and so on).
Its a profound problem if you can only assess the science after it’s been “filtered” through some dodgy web site somewhere! Your going to end up with someone elses “view” of the science and they may have some rather smelly fish to fry….
…and of course that attitude unwittingly politicises what should be an issue of science…a “beauty contest” in which you “choose” who has the most “convincing” propaganda on some web site…
Better to focus more directly on the science (use Google Scholar..visit .edu sites and so on, email authors for copies of their papers, download papers from government funded organisations like NASA; go to your local Uni library). My “evasive” remark was in respect to your ability to express a lot of opinion (not knocking it, I’m always interested in opinions) but your inability to point to any credible science to back it up in the form of links.
And yet I’ve provided equations, I’ve made interpretations with justifications, I’ve quoted at length from scientific papers and I’ve provided citations to dozens of scientific papers. Yet you describe my apparent “inability to point to any credible science to back it up..” Go figure!
As for: However, I do find it a little hard to swallow that you or Joel are “agnostic.”
I can’t speak for Joel, but I get the impression from reading his excellent posts that he is “agnostic” on this issue as I am. Speaking personally, I consider that it’s all about the science, which is all about the evidence. If the tropical tropospheric data, for example, becomes sufficiently validated to be confident that there isn’t the predicted warming in the tropopical troposphere then that will be just dandy. We will be that bit better informed and can reassess our view of that element of the climate system and its repsonse to greenhouse gases accordingly.
Until then there’s no point in turning it into a cause celebre for denialism. We’ve been here before, of course (e.g. tropospheric water vapour). There are always areas of uncertainty and we should be rather more relaxed about these. An area of uncertainity doesn’t willy nilly mean that the science is wrong and the whole edifice is tumbling. It’s actually rather delightful since it provides a nice focus for directing research effort. And in case you might be one of those that disvalues “models”, the uncertainty around the rather specific area of tropospheric temperature in the tropics highlights one of the real value of climate models…
Syl
December 24, 2008 4:48 am
Mike D
“Syl, this is going to blow your mind so hang on to your chair, but people have been living in rain forest for thousands of years, and burning them, and deforesting them, and farming them. Humanity has had a huge impact on the Amazon and and all the other rainforests on Earth for millennia, and yet the rain forests are still there and the oceans have not boiled away! Imagine that! Creation still exists!!!”
Well, you surely have me pegged wrong. Not difficult since I post very little. I’m no alarmist, have no fear of carbon and am what one might call a luke-warmer. I quite firmly believe the earth will be much better off when/if it warms.
I was quoting from a page I ran across and found it very interesting. I have no idea if their figures stand up to scrutiny. These people seem to be activists in their own way (which means other factors aren’t taken into account when they make their claims), but I find the claim that the loss of the carbon sink by tropical deforestation far outweighs the additional CO2 supposedly pumped into the atmosphere by human sources a bit eye-opening. Which means that even if humankind by some miracle ended all our carbon emissions, it would make little difference. This is merely another way of viewing the picture.
As for the deforestation itself, of course the rate has increased in the last few decades. What the long term impact may be, I know not, but I doubt it will be nothing. We still have so much to learn.
Please, point your alarmist-peashooter elsewhere. Thanks.
foinavon
December 24, 2008 4:57 am
Will (18:11:52)
The notion that sentences need “deconstructing” is rather sad! You brought this up in relation to a totally neutral statement of Joel’s. Since you addressed this to me let me address it here: Here’s what you said: Now let’s deconstruct a couple of statements to illustrate my concern:
Joel:
“It hardly seems miniscule when we have already raised the level of XXX over 35% and will likely more than double it by the end of the century.”
(I’ve replaced CO2 with XXX to make the statement more neutral.)
Is the above statement true or false?
Well it depends. If we’re talking about nitrogen then that is a major constituent of our atmosphere so a 35% change would be enormous. If we were talking about some rare trace gas, then 35% of almost nothing is still nothing.
How are statements such as these in any way neutral? You argue like this when you’re trying to win a debating contest, or a court case before a jury. You don’t argue like this if you’re trying to get to the truth.
1. Joel’s statement is a pretty neutral one incorporating the fact that CO2 levels have increased by over 35% since pre-industrial times…
100%*(386-280)/280 = 37.85%
…and the truism that even if CO2 emissions weren’t to accelerate at all in the future but would level off at current rates, we’d reach a doubling of pre-industrial levels by 2100:
emission rise of 2 ppm per year over 91 years = 182 ppm.
386 + 182 = 568 ppm.
2. A 35% increase in nitrogen would still be 35%. Of course that’s meaningless, since we’re not interested in nitrogen. We’re considering the greenhouse effect, and therefore we ignore non-greenhouse contributions and focus on greenhouse contributions. That’s obvious surely.
CO2 is the dominant independently variable greenhouse gas, and we happen to be ramping its concentrations up massively. Nitrogen is a homo-diatomic molecule, and thus like oxygen cannot under a change in its dipole moment upon molecular vibration and so doesn’t significantly absorb electromatic radiation in the infrared (or visible thankfully!). So although these gases constitute the vast proportion of the atmosphere we essentially ignore them with respect to the greenhouse effect, at least in terms of their absorption properties.
3. So considering the gases relevant to the greenhouse effect (in terms of absorption of longwave IR radiated from the earth’s surface and “trapped and re-emitted” in the atmosphere), a 35% increase in atmospheric CO2 is very large indeed.
4. But we don’t need to rely on qualitative statements. We can calculate the effect of raising atmospheric CO2 according to our best understanding of the earth’s temperature response to raised CO2. Bill Illis’s graph in the introductory post, however misleading with respect to relevant CO2 concentrations, illustrates the large warming that CO2 provides. You can use the equation in my post [21.12.08 – (12:52:53)] to calculate the effect of the 35% increase in atmospheric CO2 or the effect of doubling it (according to a climate sensitivity of 3 oC).
5. So joel’s statement contains within it some completely straightforward and non-controversial, and essentially neutral science.
It’s the science we should be addressing…it’s a waste of time and rather futile to feel that one has to “second-guess” what individuals might be “meaning”. After all, if one wishes clarification on any point, one could always re-address the science inherent in the statements (as I’ve done here), or ask for clarification…
Syl
December 24, 2008 5:18 am
Joel Shore
“The reason that one can cherrypick is because one is looking at too short a period.”
LOL
That’s just plain false. One can cherry-pick when looking at longer periods as well.
come on. What are you afraid of?
Real temperatures please.
No sooner had I said that Hansen’s prediction had been good enough that there was an industry dedicated to distorting it than you provide a perfect illustration of this! Hansen published three predictions based on future forcing scenarios (manmade emissions as well as whether or not there was a major volcanic eruption). If you look at which forcings scenario we have followed, it is close to Scenario B; in fact, apparently our forcings are a little below those of Scenario B. Yet, the comparison in that link is only to the highest forcing Scenario A, which is considerably different. See here: http://www.realclimate.org/images/Hansen06_fig2.jpg
(Hansen’s climate model from 1988 also had a climate sensitivity that is at the upper end of current IPCC estimates…so we better hope that temperatures do not rise as fast as his model predicted. As it is, only in the past few years has the real world temperature deviated a bit low of his Scenario B and I don’t think the deviation is as of yet statistically significant.)
John Philip
December 24, 2008 5:33 am
the Arctic sea ice extent reached its lowest ever extent for Dec 20 and remains below the already remarkably low 2007.
Even if true, who cares? …
Well, our kind host seems to take an interest, writing posts headed Ice Reality Check: Arctic Ice Now 31.3% Over Last Year, and Arctic sea ice continues rebound earlier this year.
Now that the ‘31% lead’ has evaporated (or should that be melted) and in fact gone negative perhaps we can expect a post on the new reality?
Merry Christmas to those of all beliefs and of none.
Mike Bryant
December 24, 2008 6:06 am
“Interesting data Mike – all from official, i.e. Government sources?”
Isn’t it funny how you can make graphs scary if you want?
Why does our government have to present common data in the most alarming possible light?
hunter
December 24, 2008 6:34 am
John Phillip,
You are implying Arctic ice has melted. Please post a link showing that anyone talking about the Arctic ice at this time claims it is melting at this time, other than yourself. The change in the thermal characteristics of water would certainly be worth noting further.
hunter
December 24, 2008 7:11 am
And by the way, the pictures still do not lie, although it would appear taht AGW faithful do play with the algorithms and probably by this point, the actual raw data, when ever they get access to it.
If in fact currents and winds are piling up the ice deeper and in a smaller area, the apocalypse believers should be even more concerned: This leaves more open ocean to radiate more heat longer, losing even more latent heat so that when the ice does form, it will last even longer than last year’s increase. Since this time of year sees very little solar input, it is the ability of water to cool uninsulated by ice that is likely more significant.
But enough popping AGW dogma. What is actually happening?
Clearly people, like all life on Earth, influence the environment. And like all life that takes up a lot of space and changes its environment, we can influence the climate. Climate forcings will ahve positive and neative directions. Changes in vegetation, urbanization, power generation, brning of transportation fuels, changes in river basins, all make an impact.
What seems clear from the evidence is that the climate is not easily changed, and that the atmosphere and ocean interactions are far more complex and of a vastly larger scale than anything we are able to move around very much.
After all of Hansen & co.s hysteria, what do we actually have?
Practically nothing. Temperature movements over the past 100 years are nearly flat. It is very reasonable to point out that the ‘big’ changes claimed by the apocalypse promotion industry are not really outside the margin of error of instrument accuracy. And when that lack of accuracy is compounded with the normal range of variation in climate, it is clear not much bad is happening at all.
We do know from satellite imagery that biomass is up, http://svs.gsfc.nasa.gov/vis/a000000/a003400/a003451/index.html
And that would be a good thing.
What would have been a better use of the billions spent on promoting a non-existant climate apocalypse woud have been to work towards a world standard on burning coal that yields less soot and toxins.
Joel Shore
December 24, 2008 7:34 am
Syl says:
LOL
That’s just plain false. One can cherry-pick when looking at longer periods as well.
The fact is that once you go back 12 years or so, which year you choose to start from or whether you use Hadcrut or NASA GISS data set makes only a little difference in the trendline slope that you get. Once, you get out to about 18 years, the difference gets really tiny. I can see that because I have a graph in front of me that I made that shows me the linear trend as a function of start year. (I made this for the end year being 2007 but there is little reason to believe that the story will change when we make the end year 2008.)
Joel Shore
December 24, 2008 7:46 am
Will Nitschke says:
Joel:
“It hardly seems miniscule when we have already raised the level of XXX over 35% and will likely more than double it by the end of the century.”
(I’ve replaced CO2 with XXX to make the statement more neutral.)
Is the above statement true or false?
Well it depends. If we’re talking about nitrogen then that is a major constituent of our atmosphere so a 35% change would be enormous. If we were talking about some rare trace gas, then 35% of almost nothing is still nothing.
I agree with the very good points that foinavon made above. In particular, the two major constitutes of our atmosphere, nitrogen and oxygen, are essentially transparent to IR radiation, so trace gases that actually do absorb IR radiation play a very important role in the climate. Of course, the largest contributor to the natural greenhouse effect is water vapor…but CO2 and the other trace gases play an important role and together all the greenhouse gases, although making up less than 2% of the concentration of the atmosphere on average, keep the temperature about 30 C or so warmer than it would be if they were absent (assuming the earth had the same albedo as it does…which it wouldn’t exactly if the absence of water vapor was taken to mean that clouds were absent too).
foinavon
December 24, 2008 8:45 am
A general point about raised CO2 concentrations in the past. Several posters have brought this up in relation to the effects of raised CO2 concentrations in Hansen’s somewhat scary predictions about what would happen were we to return all the CO2 locked away in coal and tar shales back into the atmosphere.
Have a look at the sketch of paleotemperature and paleoCO2 in the introductory post. Disregarding it’s rather ludicrous nature, one might look at the very high levels of CO2 in the Paleozoic, for example, and ask the question: If CO2 levels were apparently so high in the past, what’s the problem of sending them back up there in the near future?
The answer has a lot to do with what the sun has done in the intervening 1/2 billion years or so. It’s got a lot hotter (Joel has alluded to this previously too).
So, remembering that the greenhouse effect is a product of the greenhouse gas levels and the sun, we need to take both into account in determining the radiative forcing. In other words just as the world gets hotter if greenhouse gas levels rise at constant insolation, so the world gets cooler if the sun reduces its insolation while greenhouse gas levels remain constant.
So, surprising as it may seem, the radiative forcing (CO2 + solar contribution) was very likely higher during the Mesozoic (CO2 levels around 1000-2000 ppm) than during the Paleozoic (CO2 levels 4000 ppm and above)[*****].
How can this be?
It’s because the sun was rather cooler in the Paleozoic than the Mesozoic (and it’s continuing to get hotter…we probably all know that at some time several billions of years in the future the oceans really are going to boil away!).
How much cooler was it?
If one starts from around 500-ish million years ago, the solar luminosity was around 94.5% of present day values. It increases roughly linearly through time.
Is that a little or a lot?
It’s quite a lot. The 11 year solar cycle encompasses an intensity range between around 1366.6 Wm-2 (solar max) to 1365.5 Wm-2 (solar min). That’s around 0.08%. We hardly notice this (perhaps 0.1 oC at the surface and 0.2 oC in the troposphere from max to min), but that’s partly because the variation is cyclic and the Earth doesn’t really have a chance to “keep up” with what is quite a rapid cycle.
The decreased solar luminosity 500 million years ago is equivalent to the sun’s luminosity dropping more than 50 times the solar cycle range and staying there.
That’s why we should be concerned about the effects of a really gung-ho effort at burning every last bit of fossil fuel we can lay our hands on!
[*****]Data and analysis from Figure 2 of:
D. L. Royer (2006) CO2-forced climate thresholds during the Phanerozoic
Geochimica et Cosmochimica Acta 70, 5665-5675.
Peter
December 24, 2008 9:06 am
Joel Shore:
The reason for this is that, at the end of the day, the earth equilibrates to a new level of greenhouse gases by raising the temperature at the effective level it radiates from
Are you sure you’ve got that right?
Surely if you increase the temperature at the effective level it radiates from, it will radiate more energy into space?
Or am I missing something?
Mike Bryant
December 24, 2008 9:21 am
Lucia said this about Hansen A, B and C:
“Main Observation:
When comparing Scenario projections A, B & C, to land-ocean type data, it appear Hansen et al. 1988 over-predicted the real world warming that occurred in years following publication of his paper. This is the main observation based on this data. The remaining discussion are details for those who wish to know more.”
This was back in January perhaps she would like to chime in. As I understand it Lucia is a warmer, but a real sweet one that bakes brownies.
Mike Bryant
Joel Shore (05:21:06) :
Mike Bryant said:
Those early modelers were real good: http://climate-skeptic.typepad.com/.a/6a00e54eeb9dc18834010535b4046b970b-pi
No sooner had I said that Hansen’s prediction had been good enough that there was an industry dedicated to distorting it than you provide a perfect illustration of this! Hansen published three predictions based on future forcing scenarios (manmade emissions as well as whether or not there was a major volcanic eruption). If you look at which forcings scenario we have followed, it is close to Scenario B; in fact, apparently our forcings are a little below those of Scenario B. Yet, the comparison in that link is only to the highest forcing Scenario A, which is considerably different.
This graph is a well known distortion of Hansen’s data by Michaels who tried to portray the data scenario A as if it was the most likely (contrary to the statements in the paper) and exclude the data described as the most plausible (Scenario B). Not only that he did it ten years later when he knew that the emissions trajectories necessary for Scenario A had not occurred!
Peter
December 24, 2008 9:59 am
Foinavon:
If one starts from around 500-ish million years ago, the solar luminosity was around 94.5% of present day values. It increases roughly linearly through time.
Then how come ice ages are relatively recent events in geological time? When the solar luminosity was low the earth was ice-free.
Clearly, there are larger forces at work.
Joel Shore says:
A comparison between Young Earth Creationists and warmists, like Joel:
and:
Is 28 years long enough to see a trend? This one looks pretty scary:
http://junkscience.com/GMT/NCDC_absolute.gif
And this one too:
http://i224.photobucket.com/albums/dd137/gorebot/co2-2000.gif
Those early modelers were real good:
http://climate-skeptic.typepad.com/.a/6a00e54eeb9dc18834010535b4046b970b-pi
Bush is leaving the world cooler than when he took office. I am afraid Obama will do the same.
the Arctic sea ice extent reached its lowest ever extent for Dec 20 and remains below the already remarkably low 2007../John Philip
Even if true, who cares? That is, unless we’d much rather be warmer than cooler. Especially given that sea ice area has remained unchanged over 30 years and the Antarctic is cooling. In that light, I’d view your claim as a positive! Is that your point?
Mike Bryant (18:53:42) :
Where’s the
Ha Ha.
My text just disappeared.
Supposed to be “sarc off” …
Mike Bryant (21:01:53) :
Interesting data Mike – all from official, i.e. Government sources?
Thanks. G
There is a reason why people have chosen to look at anomalies.
Right, perhaps because anomalies are not “normal”?
Trust me, I’m laughing… the whole time.
Yep – kinda reminds me of the days when I, too, believed. I just couldn’t imagine what mental aberration these “skeptics” were suffering from. I mean, it’s self evident, right?
Watching someone defend the indefensible can be entertaining 🙂
Joel Shore (20:23:07)
‘At any rate, I have a standing challenge to anyone who actually wants to argue that the models are wrong on this point…….’
You may not like what they say but they do make some strong points that you and the IPPc needs to address.
http://www.ncpa.org/pub/st/st308
“Problems with Climate Models. Researchers who have examined long-term climate forecasts have concluded they are based on nothing more than scientists’ opinions expressed in complex mathematical terms, without valid evidence to support the chosen approach.11”
“For example, when computer simulations project future global mean temperatures with twice the current level of atmospheric CO2, they assume that the temperature forecast is as accurate as a computer simulation of present temperatures with current levels of CO2.12 Yet it has never been demonstrated that temperature forecasts are as accurate as simulations of current conditions based on actual temperature data. Indeed, there are even serious questions surrounding model simulations of current temperature with current CO2 levels. According to the models, the earth should be warmer than actual measurements show it to be, which is why modelers adjust their findings to fit the data.”
Will Nitschke (18:11:52) :
Will, let me address just a couple of general points before addressing more specific points if I have time later (it’s XMas Eve, in case you didn’t know – I’d hunt down a link to inform you of that if I had time)
You said on your mistake re the Santer paper:
The number I typed should have been 9 not 8. My mistake.
But actually your initial mistake was stated thus:
Secondly, Santer ends his study in 1998 at the height of the super el nino. A little convenient perhaps? The cherry picking being done here is breathtaking.
So it wasn’t a typo. You seemed to think that Santer’s study ended in “a super el nino” (and not a La Nina year). I’m not trying to “nail you” but this highlights a real problem with information, which might be that if you source information from sites designed to misrepresent the science, you are very likely to get the wrong end of the stick more generally.
For you later state with respect to my straightforward higlighting of the profound errors in the graphic representations in the introductory “article” to this thread:
Could you provide some links please on published criticisms of this data? As long as the criticism have at least made it into published journals and have at at least some form of review as a starting point, then they do need to be taken on board and considered fairly by all sides of the debate.
But surely you can interpret the graphs in the same way that I can. I’ve described the problems in detail (I provided an equation for determining the temperature rise for a given CO2 concentration….I provided references to a detailed review on contemporaneous paleoCO2 and paleoT data together with around 10 further papers that address the issue further since the review was written and so on).
Its a profound problem if you can only assess the science after it’s been “filtered” through some dodgy web site somewhere! Your going to end up with someone elses “view” of the science and they may have some rather smelly fish to fry….
…and of course that attitude unwittingly politicises what should be an issue of science…a “beauty contest” in which you “choose” who has the most “convincing” propaganda on some web site…
Better to focus more directly on the science (use Google Scholar..visit .edu sites and so on, email authors for copies of their papers, download papers from government funded organisations like NASA; go to your local Uni library).
My “evasive” remark was in respect to your ability to express a lot of opinion (not knocking it, I’m always interested in opinions) but your inability to point to any credible science to back it up in the form of links.
And yet I’ve provided equations, I’ve made interpretations with justifications, I’ve quoted at length from scientific papers and I’ve provided citations to dozens of scientific papers. Yet you describe my apparent “inability to point to any credible science to back it up..” Go figure!
As for:
However, I do find it a little hard to swallow that you or Joel are “agnostic.”
I can’t speak for Joel, but I get the impression from reading his excellent posts that he is “agnostic” on this issue as I am. Speaking personally, I consider that it’s all about the science, which is all about the evidence. If the tropical tropospheric data, for example, becomes sufficiently validated to be confident that there isn’t the predicted warming in the tropopical troposphere then that will be just dandy. We will be that bit better informed and can reassess our view of that element of the climate system and its repsonse to greenhouse gases accordingly.
Until then there’s no point in turning it into a cause celebre for denialism. We’ve been here before, of course (e.g. tropospheric water vapour). There are always areas of uncertainty and we should be rather more relaxed about these. An area of uncertainity doesn’t willy nilly mean that the science is wrong and the whole edifice is tumbling. It’s actually rather delightful since it provides a nice focus for directing research effort. And in case you might be one of those that disvalues “models”, the uncertainty around the rather specific area of tropospheric temperature in the tropics highlights one of the real value of climate models…
Mike D
“Syl, this is going to blow your mind so hang on to your chair, but people have been living in rain forest for thousands of years, and burning them, and deforesting them, and farming them. Humanity has had a huge impact on the Amazon and and all the other rainforests on Earth for millennia, and yet the rain forests are still there and the oceans have not boiled away! Imagine that! Creation still exists!!!”
Well, you surely have me pegged wrong. Not difficult since I post very little. I’m no alarmist, have no fear of carbon and am what one might call a luke-warmer. I quite firmly believe the earth will be much better off when/if it warms.
I was quoting from a page I ran across and found it very interesting. I have no idea if their figures stand up to scrutiny. These people seem to be activists in their own way (which means other factors aren’t taken into account when they make their claims), but I find the claim that the loss of the carbon sink by tropical deforestation far outweighs the additional CO2 supposedly pumped into the atmosphere by human sources a bit eye-opening. Which means that even if humankind by some miracle ended all our carbon emissions, it would make little difference. This is merely another way of viewing the picture.
As for the deforestation itself, of course the rate has increased in the last few decades. What the long term impact may be, I know not, but I doubt it will be nothing. We still have so much to learn.
Please, point your alarmist-peashooter elsewhere. Thanks.
Will (18:11:52)
The notion that sentences need “deconstructing” is rather sad! You brought this up in relation to a totally neutral statement of Joel’s. Since you addressed this to me let me address it here: Here’s what you said:
Now let’s deconstruct a couple of statements to illustrate my concern:
Joel:
“It hardly seems miniscule when we have already raised the level of XXX over 35% and will likely more than double it by the end of the century.”
(I’ve replaced CO2 with XXX to make the statement more neutral.)
Is the above statement true or false?
Well it depends. If we’re talking about nitrogen then that is a major constituent of our atmosphere so a 35% change would be enormous. If we were talking about some rare trace gas, then 35% of almost nothing is still nothing.
How are statements such as these in any way neutral? You argue like this when you’re trying to win a debating contest, or a court case before a jury. You don’t argue like this if you’re trying to get to the truth.
1. Joel’s statement is a pretty neutral one incorporating the fact that CO2 levels have increased by over 35% since pre-industrial times…
100%*(386-280)/280 = 37.85%
…and the truism that even if CO2 emissions weren’t to accelerate at all in the future but would level off at current rates, we’d reach a doubling of pre-industrial levels by 2100:
emission rise of 2 ppm per year over 91 years = 182 ppm.
386 + 182 = 568 ppm.
2. A 35% increase in nitrogen would still be 35%. Of course that’s meaningless, since we’re not interested in nitrogen. We’re considering the greenhouse effect, and therefore we ignore non-greenhouse contributions and focus on greenhouse contributions. That’s obvious surely.
CO2 is the dominant independently variable greenhouse gas, and we happen to be ramping its concentrations up massively. Nitrogen is a homo-diatomic molecule, and thus like oxygen cannot under a change in its dipole moment upon molecular vibration and so doesn’t significantly absorb electromatic radiation in the infrared (or visible thankfully!). So although these gases constitute the vast proportion of the atmosphere we essentially ignore them with respect to the greenhouse effect, at least in terms of their absorption properties.
3. So considering the gases relevant to the greenhouse effect (in terms of absorption of longwave IR radiated from the earth’s surface and “trapped and re-emitted” in the atmosphere), a 35% increase in atmospheric CO2 is very large indeed.
4. But we don’t need to rely on qualitative statements. We can calculate the effect of raising atmospheric CO2 according to our best understanding of the earth’s temperature response to raised CO2. Bill Illis’s graph in the introductory post, however misleading with respect to relevant CO2 concentrations, illustrates the large warming that CO2 provides. You can use the equation in my post [21.12.08 – (12:52:53)] to calculate the effect of the 35% increase in atmospheric CO2 or the effect of doubling it (according to a climate sensitivity of 3 oC).
5. So joel’s statement contains within it some completely straightforward and non-controversial, and essentially neutral science.
It’s the science we should be addressing…it’s a waste of time and rather futile to feel that one has to “second-guess” what individuals might be “meaning”. After all, if one wishes clarification on any point, one could always re-address the science inherent in the statements (as I’ve done here), or ask for clarification…
Joel Shore
“The reason that one can cherrypick is because one is looking at too short a period.”
LOL
That’s just plain false. One can cherry-pick when looking at longer periods as well.
come on. What are you afraid of?
Real temperatures please.
Mike Bryant said:
No sooner had I said that Hansen’s prediction had been good enough that there was an industry dedicated to distorting it than you provide a perfect illustration of this! Hansen published three predictions based on future forcing scenarios (manmade emissions as well as whether or not there was a major volcanic eruption). If you look at which forcings scenario we have followed, it is close to Scenario B; in fact, apparently our forcings are a little below those of Scenario B. Yet, the comparison in that link is only to the highest forcing Scenario A, which is considerably different. See here: http://www.realclimate.org/images/Hansen06_fig2.jpg
(Hansen’s climate model from 1988 also had a climate sensitivity that is at the upper end of current IPCC estimates…so we better hope that temperatures do not rise as fast as his model predicted. As it is, only in the past few years has the real world temperature deviated a bit low of his Scenario B and I don’t think the deviation is as of yet statistically significant.)
the Arctic sea ice extent reached its lowest ever extent for Dec 20 and remains below the already remarkably low 2007.
Even if true, who cares? …
Well, our kind host seems to take an interest, writing posts headed Ice Reality Check: Arctic Ice Now 31.3% Over Last Year, and Arctic sea ice continues rebound earlier this year.
Now that the ‘31% lead’ has evaporated (or should that be melted) and in fact gone negative perhaps we can expect a post on the new reality?
Merry Christmas to those of all beliefs and of none.
“Interesting data Mike – all from official, i.e. Government sources?”
Isn’t it funny how you can make graphs scary if you want?
Why does our government have to present common data in the most alarming possible light?
John Phillip,
You are implying Arctic ice has melted. Please post a link showing that anyone talking about the Arctic ice at this time claims it is melting at this time, other than yourself. The change in the thermal characteristics of water would certainly be worth noting further.
And by the way, the pictures still do not lie, although it would appear taht AGW faithful do play with the algorithms and probably by this point, the actual raw data, when ever they get access to it.
If in fact currents and winds are piling up the ice deeper and in a smaller area, the apocalypse believers should be even more concerned: This leaves more open ocean to radiate more heat longer, losing even more latent heat so that when the ice does form, it will last even longer than last year’s increase. Since this time of year sees very little solar input, it is the ability of water to cool uninsulated by ice that is likely more significant.
But enough popping AGW dogma. What is actually happening?
Clearly people, like all life on Earth, influence the environment. And like all life that takes up a lot of space and changes its environment, we can influence the climate. Climate forcings will ahve positive and neative directions. Changes in vegetation, urbanization, power generation, brning of transportation fuels, changes in river basins, all make an impact.
What seems clear from the evidence is that the climate is not easily changed, and that the atmosphere and ocean interactions are far more complex and of a vastly larger scale than anything we are able to move around very much.
After all of Hansen & co.s hysteria, what do we actually have?
Practically nothing. Temperature movements over the past 100 years are nearly flat. It is very reasonable to point out that the ‘big’ changes claimed by the apocalypse promotion industry are not really outside the margin of error of instrument accuracy. And when that lack of accuracy is compounded with the normal range of variation in climate, it is clear not much bad is happening at all.
We do know from satellite imagery that biomass is up,
http://svs.gsfc.nasa.gov/vis/a000000/a003400/a003451/index.html
And that would be a good thing.
What would have been a better use of the billions spent on promoting a non-existant climate apocalypse woud have been to work towards a world standard on burning coal that yields less soot and toxins.
Syl says:
The fact is that once you go back 12 years or so, which year you choose to start from or whether you use Hadcrut or NASA GISS data set makes only a little difference in the trendline slope that you get. Once, you get out to about 18 years, the difference gets really tiny. I can see that because I have a graph in front of me that I made that shows me the linear trend as a function of start year. (I made this for the end year being 2007 but there is little reason to believe that the story will change when we make the end year 2008.)
Will Nitschke says:
I agree with the very good points that foinavon made above. In particular, the two major constitutes of our atmosphere, nitrogen and oxygen, are essentially transparent to IR radiation, so trace gases that actually do absorb IR radiation play a very important role in the climate. Of course, the largest contributor to the natural greenhouse effect is water vapor…but CO2 and the other trace gases play an important role and together all the greenhouse gases, although making up less than 2% of the concentration of the atmosphere on average, keep the temperature about 30 C or so warmer than it would be if they were absent (assuming the earth had the same albedo as it does…which it wouldn’t exactly if the absence of water vapor was taken to mean that clouds were absent too).
A general point about raised CO2 concentrations in the past. Several posters have brought this up in relation to the effects of raised CO2 concentrations in Hansen’s somewhat scary predictions about what would happen were we to return all the CO2 locked away in coal and tar shales back into the atmosphere.
Have a look at the sketch of paleotemperature and paleoCO2 in the introductory post. Disregarding it’s rather ludicrous nature, one might look at the very high levels of CO2 in the Paleozoic, for example, and ask the question:
If CO2 levels were apparently so high in the past, what’s the problem of sending them back up there in the near future?
The answer has a lot to do with what the sun has done in the intervening 1/2 billion years or so. It’s got a lot hotter (Joel has alluded to this previously too).
So, remembering that the greenhouse effect is a product of the greenhouse gas levels and the sun, we need to take both into account in determining the radiative forcing. In other words just as the world gets hotter if greenhouse gas levels rise at constant insolation, so the world gets cooler if the sun reduces its insolation while greenhouse gas levels remain constant.
So, surprising as it may seem, the radiative forcing (CO2 + solar contribution) was very likely higher during the Mesozoic (CO2 levels around 1000-2000 ppm) than during the Paleozoic (CO2 levels 4000 ppm and above)[*****].
How can this be?
It’s because the sun was rather cooler in the Paleozoic than the Mesozoic (and it’s continuing to get hotter…we probably all know that at some time several billions of years in the future the oceans really are going to boil away!).
How much cooler was it?
If one starts from around 500-ish million years ago, the solar luminosity was around 94.5% of present day values. It increases roughly linearly through time.
Is that a little or a lot?
It’s quite a lot. The 11 year solar cycle encompasses an intensity range between around 1366.6 Wm-2 (solar max) to 1365.5 Wm-2 (solar min). That’s around 0.08%. We hardly notice this (perhaps 0.1 oC at the surface and 0.2 oC in the troposphere from max to min), but that’s partly because the variation is cyclic and the Earth doesn’t really have a chance to “keep up” with what is quite a rapid cycle.
The decreased solar luminosity 500 million years ago is equivalent to the sun’s luminosity dropping more than 50 times the solar cycle range and staying there.
That’s why we should be concerned about the effects of a really gung-ho effort at burning every last bit of fossil fuel we can lay our hands on!
[*****]Data and analysis from Figure 2 of:
D. L. Royer (2006) CO2-forced climate thresholds during the Phanerozoic
Geochimica et Cosmochimica Acta 70, 5665-5675.
Joel Shore:
Are you sure you’ve got that right?
Surely if you increase the temperature at the effective level it radiates from, it will radiate more energy into space?
Or am I missing something?
Lucia said this about Hansen A, B and C:
“Main Observation:
When comparing Scenario projections A, B & C, to land-ocean type data, it appear Hansen et al. 1988 over-predicted the real world warming that occurred in years following publication of his paper. This is the main observation based on this data. The remaining discussion are details for those who wish to know more.”
This was back in January perhaps she would like to chime in. As I understand it Lucia is a warmer, but a real sweet one that bakes brownies.
Mike Bryant
Joel Shore (05:21:06) :
Mike Bryant said:
Those early modelers were real good:
http://climate-skeptic.typepad.com/.a/6a00e54eeb9dc18834010535b4046b970b-pi
No sooner had I said that Hansen’s prediction had been good enough that there was an industry dedicated to distorting it than you provide a perfect illustration of this! Hansen published three predictions based on future forcing scenarios (manmade emissions as well as whether or not there was a major volcanic eruption). If you look at which forcings scenario we have followed, it is close to Scenario B; in fact, apparently our forcings are a little below those of Scenario B. Yet, the comparison in that link is only to the highest forcing Scenario A, which is considerably different.
This graph is a well known distortion of Hansen’s data by Michaels who tried to portray the data scenario A as if it was the most likely (contrary to the statements in the paper) and exclude the data described as the most plausible (Scenario B). Not only that he did it ten years later when he knew that the emissions trajectories necessary for Scenario A had not occurred!
Foinavon:
Then how come ice ages are relatively recent events in geological time? When the solar luminosity was low the earth was ice-free.
Clearly, there are larger forces at work.