Bishop Hill Reacting to Rose
Mar 18, 2013 Climate: Models Climate: Surface Climate: sensitivity In the wake of David Rose's Mail on Sunday article yesterday, Piers Forster tweeted that he was unimpressed with the article. I asked him if he would be willing to set out why in a bit more detail and this is his response:
It's fine to say that current models overestimate the last decade of warming. They clearly do, and as I say in my quote I think we can rule out some high sensitivity values because of this. But to do a far comparison you need to remove the effects of variability. Note also that some model runs also get the temperature evolution pretty right - although the majority don't. Even with a suggested ECS of around 2.5 C or so we can end up with a very significant climate change by 2100 if we don't do something - therefore I think the tone of the article in terms of its implications for the IPCC, climate science and the climate itself are all wrong.
He also sent the full quote that he gave Rose for his article, which gives some context.
Basically, the climate sensitivity has always been very uncertain. > estimates have put it somewhere between 1 to 5 C for a doubling of CO2. The IPCC best estimate has been around 3C. The fact that global surface temps haven't risen in the last 15 years, combined with good knowledge of the forcing terms changing climate over the satellite era: greenhouse gases, volcanoes, solar changes and aerosol is beginning to make the high estimates unlikely. Given this, i would put the best estimate using this evidence around 2.5 C. There are still uncertainties though particularly in heat going into the ocean, but climate sensitivities above 3.5C or so don't seem to fit. Keep in mind that this is only one line of evidence for quantifying climate sensitivity. Other lines of evidence have been able to firm up the bottom end. We now have good observational evidence for a positive water vapour feedback and even clouds, which have always been the largest headache in climate change, are beginning to be understood and a positive cloud feedback is looking more likely. This line of evidence helps rule out climate sensitivities below 2C. So I see it very much as a positive story that careful science ( and time) is helping to reduce the most significant uncertainty in climate science.
This thread will be tightly moderated for tone and relevance.
Reader Comments (187)
Mar 19, 2013 at 2:14 PM | Richard Betts
The amount of times that the politicians have publicly stated that the policy is correct because the science says so is immeasurable.
I don't recall any of your fellow scientists at the MO releasing statements at the News Blog publicly defending the science from being mis-represented by those advocating closure of coal operated energy plants because CO2 is going to plunge the world into disasterous climate change making millions homeless and food scarce.
Now that climate sensitivity is ever falling it's not good good enough to wander off saying that 'we' didn't set the policy. The policy WAS determined by scientific advice and if that advice was embelished to meet political ends the science is still complicit by the silence that followed those desicions.
Betts, Forster, et al....
How can you make a case for the 'science' when the 'science' relies, for example, (in the papers that you yourselves cite) on correlations which are indistinguishable from 0.0 (i.e. no correlation whatsoever)? (This is in the Dessler 2010 Science paper, which is absurd).
This is not science! If this were a drug company trying sell a medicine or vaccine they would be laughed at, and they persisted they would be locked up. How you can pretend that there is any firm science behind climate sensitivity is beyond comprehension. We simply do not understand this at present. Please do not cite another 'clump' of faulty papers - this is obfuscation - simply prove your case.
(see http://geotest.tamu.edu/userfiles/216/dessler10b.pdf).
(See Figure 2)
@Entropic Man
Please explain how you think Engelbeen's remarks - which are exclusively about the origin of the increased CO2, represents proof of the proposition
'that the recent warming was due to man-made CO2 rather than natural climate variability?'
It doesn't even address the point at all.
Mar 19, 2013 at 7:27 AM | Latimer Alder
Regarding warming, nothing at all. I was responding to Schrodingr's Cat's request for evidence that the increasing CO2 came from anthropogenic, rather than natural sources.
Well said Roger Pielke Jr
The Dessler paper(s) failed at climateaudit:
http://climateaudit.org/2011/09/06/the-stone-in-trenberths-shoe/
http://climateaudit.org/2011/09/08/more-on-dessler-2010/
http://climateaudit.org/2011/09/23/the-dessler-2011-regression/
http://climateaudit.org/2011/09/21/troy-dessler2010-artifact-of-combining-two-flux-calculations/
Piers Forster wrote:
Have they actually accepted that they are wrong?
"I was responding to Schrodingr's Cat's request for evidence that the increasing CO2 came from anthropogenic, rather than natural sources"
That darn cat. When you look at his question it changes. Then you answer one that was not asked.
@Mar 19, 2013 at 5:01 PM | Richard Betts
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Richard
I fully accept your flip point.
As you say matters are uncertain and I would regard your point with respect to possible dangers as having particular weight, if there were only two choices, namely (1) to mitigate so as to avoid the possibility that dangers may come to fruition, or (2) to do nothing on the basis that the dangers are nothing more than mere possibilities and to take the risk that the dangers do not come to pass. However, we have a third option, namely adaption.
In an uncertain world (ie., one which we do not know whether climate change will lead to dangers, or will be neutral, or will in practice turn out to be beneficial), I am of the view that the sensible course would be to wait and see what happens and then to adapt to meet what ever dangers may in fact be visited on us. Obviously, this would not be prudent if we were unable to adapt to meet the dangers, but to date no one has suggested that adaption is not possible.
As I see matters, the real risk is that any action undertaken fails to be effective. The real disaster scenario is that we spend trillions of dollars mitigating only to find out that the steps taken to mitigate are unsuccessful and the climate continues to change and that change turns out to be dangerous. We may decarbonise but if CO2 is not the driver of climate change (suppose for moment global warming is all natural, or perhaps due to changes in land use) then decarbonising will not be the cure.
It is important to appreciate that IF despite decarbonising the climate continues to change in an adverse manner, we then encounter a problem that we did not initially face, namely we have bankrupted developed nations so they no longer have the financial wherewithal to meet the costs of adaption, we have de-industrialised the developed nations so that they can no longer mobilise the industrial might necessary to meet the chanllenges of adaption, and the developing world neither has the financial wherewithal nor the industrial capacity, know how and technology to meet the needs of adaption.
In short if we spend trillions on mitigating and if the mitigation is unsuccessful, we may not be in a position to spend trillions on adapting. That is a risk that needs to be thrown into the melting pot, and in my opinion, this risk is not being addressed.
Additionally, one has to consider the prospect that climate change may in practice be beneficial, not harmful. It may be that the research into the dangers is flawed, and that a warming of 3 or 4 or 5 or 6 degrees would be a net positive. The history of the advent of civilisation (including the onset of the bronze age, iron age etc) suggests that warmth is beneficial. Man has flourished in warm times and cold climates have always hindered development. Bio diverity is greater in warm wet environs than in cold arid environs. Given uncertainties, it is possible that climate change would be a net benifit for mankind and biodiversity in general. That possibility cannot be ruled out.
Once again, adaption is the better option. Would it not be unfortunate for us to take steps to prevent a warmer world only to find out that had we permitted the world to warm by say 3 or 4 or 5 degrees that warming would in practice have been a good thing? If instead of mitigating, we adapt, we do not lose out on this possble advantageous scenario.
Further, unlying all of this is the error of the global nature of warming. In reality, climate change is a local phenomena not a global one. Some parts of the globe are warming, some are not warming and some parts are if anything cooling. Materially, the effects of climate change are felt on a local basis. Many countries would benefit greatly from a warmer climate. For example, it is probable that Canada would significantly benefit and It is difficult to envisage why climate change would not be net beneficial for the UK. Even sea level rise is not a global problem, for example it does not impact upon Switzerland.
Once again, adaption would appear the better option since it can be more surgically targetted to deal with the dangers where the dangers materialise, and yet at the same time enable countries that would benefit from climate change to reap those benefits.
The upshot of the above is that I consider that there needs to be a more detailed study and debate dealing with the risks and benefits of climate change, and with the correct response. Personally, I consider the mitigation approacj to be misguided, and to be based upon a false appreciation of the precautionary principle (the real danger is that steps taken to mitigate will be unsuccessful since we are incorrect as to the cause of the present warming). I consider that adaption makes more sense; in my opinion it is the win win option. But I accpet that all of this is a matter for open and objective debate.
@entropic maan
'I was responding to Schrodingr's Cat's request for evidence that the increasing CO2 came from anthropogenic, rather than natural sources.'
Here is SC's request
'Can anyone produce evidence to prove that the recent warming was due to man-made CO2 rather than natural climate variability?'
It is for evidence about the cause of warming, not about the origin of CO2.
Your assertion that you were responding to his request is incorrect.
Mar 19, 2013 at 5:14 PM | nTropywins
"I hope Richard Betts will field this one."
He won't. Nor will he explain why the positive feedbacks can be capped, which is probably the most important of the two questions. Once you've postulated that there will be a positive feedback you have opened a can of worms if you can't say why it won't be a runaway positive feedback, every electrical engineer knows that. If you have an amplifier, e.g. the sensitivity, and you take some of the output, e.g the temperature and feed it back into the input of the amplifier you'll increase the output by the sensitivity plus the extra input and so on, unless there is some mechanism to dampen the output being fed back into the input. I don't understand why the climate would do that. What stops the feedbacks at 2.5, or 535 for that matter?
Richard appears to be going through some sort of mid-crisis crisis. He's now telling us that a rise of 5C won't necessarily be catastrophic, and that the scientists shouldn't be the only ones to decide policy. On the first point, we all know that anyway, humans will adapt to whatever climate comes along, there will be no catastrophes, the only place uninhabitable for humans is the Antarctic, we have adapted to temperatures from the Arctic to the Gobi desert. The whole catastrophe thing is the tool for environmentalists to get control of our lives by frightening the bejasus out of us into to doing what they tell us to do. As for scientists not making policy, agreed, but not by his colleagues in the Met Office, just see how they'd react publicly if the government was to say, "It's all bollocks, we're not going to do anything to mitigate CO2." Richard mentioned the "barbecue summer" fiasco. This arose during a time when the Met Office thought that global warming would bring, well, warming. Accordingly, all their quarterly forecasts were about hot summers and mild and wet winters. And all wrong of course. Last year we had rain all year, so up pops Julia Slingo, Propogandist-in-Chief and tells us that this is what we're going to get from a warming world. Cold wet weather? Well it appears that any sort of weather is now indicative of AGW according to the climate science community, and nothing can disprove the theory of AGW, in fact every datum is further proof.
Of course the reason for this is that, unscientifically, they've espoused a theory that CO2 emissions will cause increases in temperature on the basis of the only correlation to be found in the history of the Earth between CO2 and temperature that occurred between 1980 and 2000. I'm not denying CO2 will cause temperatures to rise, but as Julia Slingo now says, when temperatures rise rainfall will increase. If rainfall increases then clouds must increase, mustn't they? And who knows what effect clouds have on the climate? Nobody apparently.
Does anyone know what's meant by "lines of evidence", I know it first appeared in the Charney Report, but in fact it has no meaning. A "line of enquiry" produces evidence but I've never understood what a line of evidence could be, evidence is data isn't it?
From another thread:
"AVOID is a research programme that provides key advice to the UK Government on avoiding dangerous climate change brought on by greenhouse gas emissions."
AVOID seems to be a branch of the Met Office propaganda generating machine, with some of the propaganda generation outsourced and all funded by DECC so far as I can see [ie paid for by by you and me].
http://www.metoffice.gov.uk/avoid/avoid-team/jason-lowe
Mar 20, 2013 at 8:12 AM Martin A
Like many others, my gut tells me that given the fact that planet Earth has survived for some 4.5 billion years notwithstanding the varied and extreme changes that it has encountered during this period and has come out of all of this in a benign form, the net feedback in the climate system must be negative not positive.
Of course, one's gut is not proof of anything, but I do consider the positive feedback assertion to be a particular suspect part of the AGW 'theory'. If feedback is positive, there is no ready explanation why we did not see runaway warming in past epochs when Earth had high levels of CO2 and/or high temperatures.
We know as undisputable fact, that runaway warming never took place in these conditions (Earth is not similar to Venus), and this requires the AGW 'theory' to put forward a convincing explanation to explain why runaway warming did not occur in these past epochs when CO2 levels were very high and/or temperatures were very much warmer than today if feedback is positive.
nTropywins, Geronimo,
I don't think we've had periods in the historical past which are as warm as expected for later this century, so I don't think the periods you mention are useful analogies. (As far as I can see, the debate over the MWP is whether it was warmer than present-day or not, as opposed to being warmer than temperatures projected for end of the 21st Century).
The other reason people are concerned is the rate of change projected for this century, not just its magnitude.
Your assertion that you were responding to his request is incorrect.
Mar 20, 2013 at 5:22 AM Latimer Alder
I think this can be explained as being due to quantum mechanical effects involving the cat and an as-yet unopened box.
But, seriously, this illustrates that you cannot take EM seriously.
"The other reason people are concerned is the rate of change projected for this century, not just its magnitude."
And why is this a problem? The rate of change in any given day or week may be far more. Several degrees in a few minutes. How is the rate of change in the global temp average going to affect anybody more than that? As Lindzen pointed out at the Oxford Union, nobody lives in the global average temperature anomaly.
Let's turn it on its head for comparison. What if the Marcott paper was right? What would be the global temp given no 20th century uptick? Would this be better or worse? I can't think who it would be better for. I know it would be worse for billions. Who wants it colder? I'd put 'warm is better' as a null hypothesis. No, not even 'stasis is better', which is the fake alternative warmists seem to lean towards.
Richard Betts
"the rate of change projected for this century"
From the "impeccable" data source that is HadCRUT4 using the WMO Standard 30 yr rolling trend the maximum rate of change so far recorded is +0.199C/Decade = +2C/Century.
This was recorded in Dec 2003, since then it has been in a steady decline and is now some 20% lower than it was in Dec 2003.
So at our present rate of change we cannot achieve the much vaunted 2C that must be avoided?
If the projection for the latter stages of this century is that we will exceed the 2C target when do you expect the rate of change to break through the previously recorded high of 2C/century?
TIA
Edit: Sorry, not clear but "WMO Standard 30 yr rolling trend" is a rolling monthly trend. 360 months.
Richard : "I don't think we've had periods in the historical past which are as warm as expected for later this century, so I don't think the periods you mention are useful analogies. (As far as I can see, the debate over the MWP is whether it was warmer than present-day or not, as opposed to being warmer than temperatures projected for end of the 21st Century)."
I may have this wrong, so correct me if I do, my understanding was that a doubling of CO2 would give rise to an increase of around 1C and that the sensitivity in the climate would increase this to 3C+/-1.5C. giving rise to a large number of catastrophes as outlined in IPCC AR4. Now it seems to me that it is entirely plausible that either of the MWP, Roman or Minoan Warm Periods could easily have been at 1C above the 1970 to 2001 anamoly, and hence would kick in the positive feedbacks. Or am I talking the usual rubbish?
Who sort of advice was Ed Milliband getting with statements tempertures were 'accelerating' back in 2007..
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Today’s report by the Intergovernmental Panel on Climate Change (IPCC) shows that global temperatures continue to rise and that there has been an ACCELERATION in the rate of changes observed over the last few decades.
Mr Miliband added:
“The report confirms our concerns that the window of opportunity to avoid dangerous climate change is closing more quickly than previously thought. ,It is another nail in the coffin of the climate change deniers and represents the most authoritative picture to date, showing that the debate over the science of climate change is well and truly over.
“What’s now urgently needed is the international political commitment to take action to avoid dangerous climate change. This has been absent so far. If we are to succeed, we will require the engagement not just of environmental ministers but heads of state, prime ministers and finance ministers. This first report by the IPCC, and others to follow later this year, can provide a strong evidence base needed to move the prospects of agreement closer.
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ie - 'aceleration'
the rate of change was increasing...
when in fact the rate of change was decreasing..
where were the scientists!!!
Oh and that was in a DEFRA ! press release..... I guess they were all asleep.
http://web.archive.org/web/20080330091524/http://www.defra.gov.uk/news/2007/070202a.htm
"I don't think we've had periods in the historical past which are as warm as expected for later this century, so I don't think the periods you mention are useful analogies. (As far as I can see, the debate over the MWP is whether it was warmer than present-day or not, as opposed to being warmer than temperatures projected for end of the 21st Century)...." see: Mar 20, 2013 at 8:53 AM | Richard Betts
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Richard
The positve feednack issue is not limited to the 'historical' past but rather to the geological past.
If feedback is positive, how did planet Earth come through periods when CO2 was perhaps 6,000 to 10,000ppm and/or temperature of about 10 degrees C or more above today's temps?
I fully accept that evidence of long ago events is uncertain, but that said there is strong evidence to suggest that in the past CO2 levels were more than an order of magnitude greater than today, and that temperatures (not necessarily coinciding) were substantially more than 6 degC warmer than today (consider the period say 50 to 550 miilion BC).
Due regard nneds to be had to this on a geological time scale not simply a 'historical' scale.
Your views on this would be appreciated.
In January 2011, Phil. Trans. R. Soc. A published a glossy magazine, entitled:
Theme Issue 'Four degrees and beyond: the potential for a global temperature increase of four degrees and its implications' compiled and edited by Mark G. New, Diana M. Liverman, Richard A. Betts, Kevin L. Anderson and Chris C. West.
January 13, 2011; 369 (1934)
Here is the contents page:
Just have a look at the first Article:
Beyond ‘dangerous’ climate change: emission scenarios for a new world.
Kevin Anderson1,3 and Alice Bows2,*
1 Tyndall Centre for Climate Change Research,
2 Sustainable Consumption Institute, School of Earth, Atmospheric and Environmental Sciences, University of Manchester, PO Box 88, Manchester M60 1QD, UK
3 School of Environmental Sciences and School of Development, University of East Anglia, Norwich NR4 7JT, UK
--------------------------------------------
The authors are well known to readers on BH.
Our Kev, who made a complete ass of himself before the numpties last December, and Alice, now a grand fromage at New Left Project, recently ridiculed on Unthreaded last week.
However, they chose the word "dangerous" and the word is spread throughout the paper. Also, it must have passed the panel of compilers and editors, which includes Richard Betts.
How far up the scare scale, on a 1 to 10 basis, is "dangerous" relative to "catastrophic" in the lexicon of the Team and the Met Office.
geronimo (11:19 AM) -
The ~1 deg C is the no-feedback sensitivity of global average temperature to a doubling of CO2. Judith Curry had an interesting post on the topic. With climatic feedbacks, the sensitivity was claimed to be in the 2.0-to-4.5 degree C range in IPCC AR4 WG1, although more recently lower estimates have surfaced (e.g. Nic Lewis, which IIRC was in the range of 1.5-2.0). [Edit: just checked AR5 WG1 second-order-draft, and it reiterates the 2.0-to-4.5 range. It must be difficult to change a compromise assessment such as that -- lots of entrenched opinions.]
The observed warming in any historical warm periods includes climatic feedback. So if, for example, the temperature was 1 degree above mean in the past, and sensitivity were 2 deg per doubling, the effective forcing would have been equivalent to half a CO2 doubling, or about 3.7/2=1.85 Wm-2. [That's a simplification because climate does not respond instantly, and the sensitivity is *equilibrium* climate sensitivity, so consider this only a hand-waving approximation.]
@Richard Betts
thanks for your response.
It is my understanding that Greenland was settled for 2 centuries during the MWP. So this was a prolonged warm period. The Little Ice Age is recorded in the historical records. Temperature has fluctuated significantly without any help from mankind over the last several hundred years.
We know that the rate of increase in global average surface temperature between 1975 and 1998 was similar to the rates of increase between 1860 and 1880 and between 1910 and 1940 (approximately 0.16 C° per decade). I think it is accepted that the increase in temperature in the 1860-1880 period and the 1910-1940 was due to natural variability. We are asked to believe that there was something unusual about the warming between 1975 and 1998. If that warming really was driven by increasing CO2 would we not expect the rate of increase to have been greater than the earlier periods? Is it not a fact that we simply do not have the data to rule out other possible causes of warming during this period (as in the earlier periods) such as changes in albedo or cloud cover or stratospheric water vapour or who knows what else? Do we know how much insolation actually reached the land and the oceans during this period? What is the real world evidence that the 1975-1998 warming was different from the earlier warming? What is the real world evidence that any part of it was caused by CO2?
There has been no statistically significant warming since 1998. The projections of your own Met Office are that there will be no warming for the next 5 years. So I have to ask how could anyone be anything other than extremely skeptical of your assertions that the rate and magnitude of temperature rise to the end of this century are reasons for concern?
Re: Mar 20, 2013 at 8:53 AM | Richard Betts
"I don't think we've had periods in the historical past which are as warm as expected for later this century, so I don't think the periods you mention are useful analogies. (As far as I can see, the debate over the MWP is whether it was warmer than present-day or not, as opposed to being warmer than temperatures projected for end of the 21st Century).
The other reason people are concerned is the rate of change projected for this century, not just its magnitude."
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RIchard,
I fail to see why we should be at all concerned about 'projections' or are you actually talking about 'predictions'
- it seems the Met Office use these terms interchangeably!!!
Whatismore the models used for these 'projections' tend to be based on subjective (ie 'characteristic of or belonging to reality as perceived') rather than objective ('Uninfluenced by personal prejudices') assumptions.
And as we all know
our climate system is both incredibly complex and chaotic
http://wattsupwiththat.com/2012/01/21/the-ridiculousness-continues-climate-complexity-compiled/
so that one can sympathise with our climate modellers as to the difficulties of deciding which parameters / criteria to include and of course on the quality of the 'data' on which they are working.
http://wattsupwiththat.com/2009/11/25/climategate-hide-the-decline-codified/
It seems to me that whether we are talking of 'projections' or 'predictions' the quality of either is highly suspect!!!
Let me ask a question usually attributed to Roger Longstaff. What are the criteria for excluding output for a model run, or terminating that run unfinished? Could it be possible that runs showing a decrease in temperature are filtered out, consciously or otherwise, before the confidence limits are calculated? Or do we see all the runs, warts and all? Are these things published or must we accept the judgment of the modellers?
Marion
I'm not telling you whether you should be concerned or not - that's entirely up to you. I'm stating a fact that many people are concerned about what the future rates of change may be - whether predicted, projected, expected, it doesn't really matter what word is used, the point is that there is a case that the climate may change in the future and some people are concerned about how fast this may be.
Rhoda
I don't particularly think that either warming or cooling are in themselves intrinsically good or bad (within limits - clearly we don't want to be in another ice age or have the climate of Venus!). It's more about the fact that we tend to be adapted to the current climate. If this changes, we can probably adapt in many cases, especially if the change is not too rapid. Natural systems can also adapt to some extent, although there are probably limits for individual species. In the long term, adaptation may become quite costly, and that's where it becomes an economic argument about whether it is better to spend money early on mitigation or later on adaptation (or some combination of the two). This in itself is a value judgement as the benefits of any kind of action, whether mitigation or adaptation, depend on what level of risk is thought to be acceptable.
On your other question, yes we can use comparison with observations to rule out some model runs, see Ed Hawkin's blog post.
Richard, thanks for the response. I'm not convinced by the rate of change case, given rates within past limits. If you are saying the rate may be faster than ever seen, that might be something to think about, if the suggestion had justification. Effects on flora and fauna are inevitable at any rate of change, but just as there is no right CO2 ppm or global temp, there is no right number of warthogs or anopheles mosquitoes. There will be effects on species which cannot move.
On the models, Ed explaIns that results are tempered by observation. I didn't really ask that, but how the runs are filtered in the 'prediction' part of the regime. Basically I wonder whether the Met chucks away results which do not suit the institutional bias. Whether a model running cold is more likely to be cut than one running hot. Yes I know that would not be a good thing to do and no honest scientist would suggest such a thing, but I also know how easy it is to fool oneself when making objective judgments.
I'm also wondering why the Rose article's graph, all recognised model output and Hadcrut4, looks as it does if Ed is throwing away runs which don't match observations. Surely the high side predictions are just plain wrong? Or is the Christmas eve graph an acknowledgment of that?
Re: Mar 20, 2013 at 5:19 PM | Richard Betts
" I'm not telling you whether you should be concerned or not - that's entirely up to you. I'm stating a fact that many people are concerned about what the future rates of change may be - whether predicted, projected, expected, it doesn't really matter what word is used, the point is that there is a case that the climate may change in the future and some people are concerned about how fast this may be."
Strange Richard, I would have thought that your scientific background would have necessitated a far greater accuracy in word usage - perhaps not in the case of climate 'science' - no matter, I shall refer you to your colleagues at the CRU, they are a little more careful than yourself it would seem -
"Scientists tend to apply very specific meanings to words that are more freely used in everyday life. And confusingly, terms like prediction may be used differently in different scientific communities. In the study of climate, meteorology and oceanography, prediction is used mostly in the same way as forecast.
A prediction is the most probable outcome of future developments – in terms of a number, an interval or a category. A prediction is constructed using statistical or dynamical models, which process the knowledge given by an initial state or given by predictions of major steering components.
Another approach to envisage futures is to construct scenarios. These are descriptions of alternative possible, plausible, internally consistent, but not necessarily equally probable futures. In climatology, this is done by simulating in climate models the implications of factors such as changing land use and changing atmospheric compositions (increases in greenhouse gases). Thus scenarios are, technically, conditional predictions – i.e., conditional on the assumptions made about the future evolution of greenhouse gases and so on."
So ... back to 'assumptions' that are by definition subjective (ie 'characteristic of or belonging to reality as perceived') rather than objective ('Uninfluenced by personal prejudices').
And what confidence can we have that the 'scenarios' chosen don't display the same warm bias that was evident in the Met Office winter forecasts which resulted in our local councils being so badly prepared in their grit stocks.
http://www.eureferendum.com/blogview.aspx?blogno=71486
So yes Richard I AM concerned but rather that with massively escalating power bills we will be inadequately prepared for the likelihood of a cooling climate and as for your statement that
"the point is that there is a case that the climate may change in the future" - I'd be very surprised if it didn't change, it has done so since time immemorial!!!
Link for "Predictions and Projections"
http://www.cru.uea.ac.uk/projects/ensembles/pus/CLIMATE%20MODELS/Prediction.html
"...I also know how easy it is to fool oneself when making objective judgments...."
Mar 20, 2013 at 7:47 PM Rhoda
Haha
I missed that Martin. Rhoda, you little rascal.
Rhoda and Marion
what's the trick to get Richard Betts to respond to you? Do I have to change my name to Sara?
nTropywins
I ask specific questions on science rather than policy. No gotcha questions, I hope. I don't expect Richard to be the flak-catcher for the whole Met or IPCC especially their leadership. He doesn't have to come here. And he is probably quite busy in his day job, which is quite important as he is influencing policies which will affect us all. Of course I try to be polite and not put in sneaky digs. I try, I really do.
Rhoda
mine was a bit of a rhetorical question but thanks for responding
I knew it was rhetorical. No. I did. Really.
You should, however, change your name to Sara. Saves that awkward case shift inside the name. Because my fat fingers always hit capslock too.
My worry is that there is no - or as little or as much - for an 'unknown feedback factors' as there is for an 'unknown separate driver'
That is if we strip out all the knowns, we are left with a 'temperature anomaly'
No one denies there is one.
This is where the logic goes atsray.
IF we assume that the only DRIVER is CO2, then we do the (possibly spurious) calculations on CO2 effect and we get a formula of the firm An = p * CO2.
Where p is a constant derived from the 'physics' that nets out to IIRC about 0.4C for every doubliing of CO2..
That doesn't account for temperature rises between 1970 and 1990., so the big error is to intrioduce the lambda factor and make the equation:
An = p * CO2 * λ.
where λ represents unknown FEEDBACK.
There is absolutely no justification in doing this. You might just as well write the equations as
An = p * CO2 + q* λ.
Here the unknown FEEDBACK is replaced by and unknown DRIVER. This would in fact fit the real world data better.
The problem with this is not scientific or mathematical: its with what it MEANS.
It means that CO2 is almost irrelevant in climate change, and whatever λ represents, its totally independent of CO2. .
It might be for example cloud level modulation by Svensmark's cosmic rays, dust, industrial pollution, or simply an anomaly to do with weather stations being encroached upon by urban heat islands. Whatever.
But if adopted it would mean a total end to CO2 alarmism, and a multi-billion industry that hangs off the tit of The Great Climate Of Fear.
And a lot of people would lose their jobs....
Richard Betts should find pause for his concern about rapid rates of change in the relief of the temperature record of the last decade and a half. Perhaps he already has, to some degree. I expect his concern will be further ameliorated by a rise in concern for the madness of the most extreme advocates of alarmism.
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Interesting .... I missed this when it first came out, being out of the country at the time with no access to internet. A revised Met Office 'decadal' forecast.
http://tallbloke.wordpress.com/2013/01/05/major-change-in-uk-met-office-global-warming-forecast/
Tell me, Richard, does that downward tick keep on going down for the following five years, is that why the Met Office only produced the first five years of its 'decadal' forecast?
http://bobtisdale.wordpress.com/2013/01/06/ukmo-lowers-5-year-global-temperature-forecast-and-omits-the-second-5-years-of-the-decadal-forecast/