You did said to brazil84 “Not quite! Look, I’m no warmist. I accept that it’s entirely possible for Nature to produce a temperature upswing of the kind we’ve seen ALL ON HER OWN.”
And one of the natural bits mentioned by you early was the AMO, I’m just saying that an answer like that has a lot of baggage (like the term warmist) and it is very clear where it comes from, but once again, I do see you on a better light as an skeptic, deniers like brazil84 are not doing good even with skeptics like you.
It is just that one has to say that you are catching discredited labels to apply on others and there is also an unnecessary increase on the doubts when it is even doubtful that the deniers have a point by talking about the AMO. I mean, just by looking elsewhere on the IPCC and RealClimate it is clear that scientists already looked at it and they are highlighting the fact that most of the recent warming is global in scale and the AMO? Not driving things so much, like Tamino reported.
Never said that you did, I’m only using logic, as you already mentioned, you do look at sources like WUWT, the IPCC in reality is mentioning the AMO to point at the fact that they did take a look and reported that currently the AMO is not the main driver of the recent warming, when you reply to braiz84 to his comment that
“For example, what caused the Little Ice Age? Nobody knows. So it’s reasonably likely that there are important forcings and interactions which are simply unknown.”
With:
I have to see where do you get that “understanding” as mentioned even by you now if “it averages out to zero in the long term” then this business of implying that we can throw the AMO in with the unknowns is not the complete picture, so I’m just saying.
Yes, and I stand by that. I don’t think it’s possible to prove that the current warming is unprecedented, nor do I think it’s important either way. As I said in page one of this very thread, in fact.
Yes, I mentioned the AMO earlier. E.g. in post 242, where I linked to the IPCC4 page on it and said “Note that those IPCC graphs are NOT showing global warming - they are showing a long-period oscillation in Atlantic temperatures that is on top of global warming. The North Alantic shows an additional upward swing of about 0.7 deg. over the period 1970 - 2007 - about 0.19 deg. per decade over that time that is purely an energy oscillation and not a warming trend at all!” I doubly emphasised that the AMO is a cycle and not a trend, even back then.
I mentioned my dislike of the polarisation of this matter into “sides” very early in this thread, and my first use of the phrase “warmist” was in quotes in post 406, in response to a question which incorporated the term. I’m not a big fan of “denier” either, which you seem more than happy to use freely. As I said, I’m in a dialogue and I sometimes answer questions in the same terms that they are framed in.
Tamino didn’t report anything, he performed a circular “analysis” that basically subtracted the AMO from itself. The AMO doesn’t drive anything - it produces cyclic bumps and dips on the Atlantic temperature record, and since the Atlantic is a fair chunk of global area those bumps and dips feed through into the global temperature record. Tamino may not like AMO, possibly because subtracting it from the temperature record makes the late 20th Century warming less severe, but if we lose the AMO then we also lose an explanatory factor for the early 20th century warming, as indicated by my realclimate cite. Your realclimate cite is basically a gripe about NOAA not attributing increased hurricane activity to AGW, and emphasises that the Atlantic sees both AGW plus the AMO - it’s not an either-or. It doesn’t support Tamino’s position that the AMO is an artefact.
I’m not saying the AMO is an unknown at all. I’m saying it was an unknown before 1994 which is comparatively recent, and it is entirely possible that we will discover other things we didn’t know about before we’re really on top of what’s happening.
That does throw away the evidence gathered to calculate how sensitive climate is to changes, and the National academy of sciences reported on Mann’s work that:
I’m just saying that we needed to clarify this, and you did, these clarifications are very important as long as you want to play fair to deniers (and even scientific organizations do call them that way)
There is a big difference from an skeptic that does not ignore science like you from a denier that discusses for several posts that he is worried about the water vapor feedback, ignores the latest evidence on the water vapor, and then goes back to even denying that there is any valid evidence for the non feedback CO2 warming physicists expect.
And then one has to still clarify further, even 2 degrees of increase is not without problems, as the IPCC is reporting that we will very likely get by a doubling of the CO2 in the atmosphere. As uncertainty goes both ways, it is not responsible to not tell others that the high end of the predictions from the IPCC are higher than that. “Best estimate for a “high scenario”[13] is 4.0 °C with a likely range of 2.4 to 6.4 °C (7.2 °F with a likely range of 4.3 to 11.5 °F)”
Your selective quote says what Mann’s 1998 and 1999 reconstructions implied, NOT what the National Academy of Science says about those reconstructions! From your very own cite:
**"3. It can be said with a high level of confidence that global mean surface temperature was higher during the last few decades of the 20th century than during any comparable period during the preceding four centuries. This statement is justified by the consistency of the evidence from a wide variety of geographically diverse proxies.
Less confidence can be placed in large-scale surface temperature reconstructions for the period A.D. 900 to 1600. Presently available proxy evidence indicates that temperatures at many, but not all, individual locations were higher during the past 25 years than during any period of comparable length since A.D. 900. The uncertainties increase substantially backward in time through this period and are not yet fully quantified.
Very little confidence can be assigned to statements concerning the hemispheric mean or global mean surface temperature prior to about A.D. 900."**
Additionally, I posted links to Mann’s 2008 work in the first page of this thread, showing that much of the historic variation invisible in his 1998-1999 work is now back in his latest proxy reconstruction. I also showed where, by eliminating some of his proxies in his supplementary work, Mann himself produced a reconstruction where the MWP exceeds current temperatures. Since the proxy reconstructions tell different stories depending on what what proxies you pick, I have lost confidence in them being able to tell us much.
I’m sorry but on what you are basing that it is not the academy who is **not **telling us that:
BTW, less confidence does not mean that Mann was wrong, that “less confidence” item referred to some areas of the reconstruction, and this also does not mean that then one should have no confidence at all. The conclusion that was posted early comes after your quote, so lets not change the order of when the Academy is telling us that we should not trust any of those researchers.
Still, what it needs to be said here is that it goes both ways, and that was the original beef I had with guys like brazil84, increasing the lack of confidence **also **means that there should be less confidence on the medieval warm period, really, the more one wants to dispose or discredit the paleoclimate evidence the more then one should doubt items like the medieval warm period, it **should **be dismissed then. I still have to see a denier (or should I have to include an skeptic like you on this item?) that has not ever stopped to notice the contradiction and reflect on the nonsense they are pushing.
As long as skeptics do insist on bringing the medieval warm period as a way to seed doubts on the reasons for the current warming, they do so by also relying on the same paleoclimate data sources that scientists are using to tell us that the current warming is unprecedented for the precious 900 years and likely to be unprecedented for the previous 2000 years.
The academy is giving a mixed message. Highlighting the part you like and leaving the rest out changes the appearance of that message.
Um, sure. So is it alright that I have less confidence in proxy evidence, especially the further back we go?
Where did I “change the order” of anything? Do you think the order determines which bits they really mean and which bits they don’t? How about numbered points - should they take priority?
Good grief. In my previous post I said “Since the proxy reconstructions tell different stories depending on what what proxies you pick, I have lost confidence in them being able to tell us much.” That’s what I wrote. That’s what you quoted. What does that tell you about what I think of proxy reconstructions?
The 2000 year figure refers to local proxy indicators rather than global temperature reconstructions, but as for the rest of it: see above. I don’t think proxies can tell us much and I think trying to prove current warming is unprecedented, or otherwise is pointless.
I gave Mann credit for the pioneering nature of his work on the first page of this thread. That said, I’m convinced that the proxy data can only give the general shape of the historic temperature trends at best and is probably fairly distorted. It’s Mann’s work that convinced me of this, as I explain below.
The supporting information also lists the proxies used: 105 dendro (tree ring) proxies, 81 non-dendro reconstructions including the 4 Tiljander sediment series, 19 historical temperature records and 71 “composite” reconstructions. It shows in figure S7 what happens if you take out the 105 dendro proxies - not too much. And then in figure S8 what happens if you take out the seven possibly problematic non-dendro series mentioned in the text (the four Tiljander plus three others known to be contaminated after 1870, 1870 and 1940 respectively) and there is very little difference - not surprising since it is only 7 series out of 270-odd. But later he released what happens if you take out the dendro and the 7 together (the cyan line here: http://www.meteo.psu.edu/~mann/supplements/MultiproxyMeans07/NHcps_no7_v_orig_Nov2009.pdf) and it makes a big difference - the variance has increased dramatically and the MWP spikes up to around current temperatures. Do I believe the MWP was warmer than today? I don’t know and don’t think we can know. Mann’s data using 160-odd non-dendro records says yes, and changes to no again if you add in seven “problematic” records. Or another way to look at it is, if you remove the “problematic” seven then the dendro and non-dendro don’t match anymore. What are we to make of that?
I would go for what NASA accepts, they have not gotten rid of Mann nor his conclusions, the point here is that
The point here is that if you are more correct than Mann and others, then it should be easy on this current political environment to denounce outfits like NASA for following bad science, but somehow, I do not think that NASA nor the National Academy of Sciences would agree with the idea that they just posted a mixed message or told Mann that he is still wrong, if that was the case then it should be easy to find cites from the Academy complaining to Mann for continuing to misinterpret them or they reporting that Mann is continuing to doing it wrong.
Your world is incredibly black and white, is all I can say. You really think academia is so polarised that there’s no variety of opinion within it? That being unconvinced by the paleo approach is the same as thinking Mann’s science is bad? That NASA is a monolithic body which makes endorsing or rejecting research its business?
Since I’ve basically been reiterating stuff I said in the beginning of the thread for the last few posts, I think we’ve started to go in circles so I’m done for now.
Once again, being unconvinced implies that somewhere that research is wrong, The point here is that it should not be too hard to get the best skeptical minds on the subject to let NASA and others on the reasons why Mann is unconvincing, somehow I do think that groups like NASA also asked around before accepting Mann’s research. You see, I originally approached this issue from an historical perspective, there is this little item called the march of science in it.
Currently the best available science is telling us something that many people do not like.
As Feynman could say, it does not matter how great or neat the idea that this is pointless or mixed so much is, if the evidence says otherwise this idea that it is pointless is wrong. The fact is that climate centers are using Mann’s research, his research would by now be dismissed if it had not been confirmed by others.
**
I appreciate what you are doing against deniers here, but one can not ignore the “squik” ideas like the “pointless” one are still coming out.**
The latest squik item is 100% related to the OP and the research that Mann is involved with. But we have to go back in time a little: The first reconstruction of past climate came with a huge medieval warm period, it was that early reconstruction published by the IPCC the one that was grabbed by skeptics to tell others that everything was alright, the warming of today can be explained as being entirely natural as like in the past.
Going to the present (as an aside, I have noticed before how peculiar are conservatives that politicize this issue, they also have trouble dealing with the march of time) There are 3 problems by ignoring the current research and sticking with the early reconstruction.
One problem is that it needs to deny that new data could be gathered and new reconstructions made, then it has to deny that new data does change the graph that one should get as a result. And then it has to deny that there is now better evidence that enables scientists to understand and better model the many different states of the climate system that have existed in the past.
Skeptics had more support back in the recent past to remain skeptics, data and sources not being readily available, tree rings having an already pointed out problem in the recent decades, etc. But those issues were deal with in the latest research and one has to notice that the latest 2008 research by Mann is still being criticized by using the mild criticism made by the National Academy of his research from 1998-2001.
What you are calling “black and and white” I just call it the result of the progress scientists have achieved so far, when I look at history (and the very recent one) what I see is a progression from the climate change denial side to become like creationists when they tell others that there is a huge controversy on virtually all aspects of evolution, but just like talkorigins.org pointed out, it is in academia and the research world where these pontifications of “lack of confidence” on an issue are being constantly verified by the experts on the field. As talkorigins put it recently: “sure you want to teach the controversy, so where is it?” It had been years since people like Behe had published his “definitive” book against evolution and a look at the academic sources showed how pathetic his footprint or influence in academia was really after 10 years, but this is not an exercise on popularity, research would by now had supported many of his ideas against evolution, but the only thing we got was even more evidence that evolution was and is real.
Of course, I do not see that disregard of evidence from skeptics like you matt, however there are still very peculiar items on your skepticism and if the evidence and history does not match an important item you are referring to then it is important to clarify where we are. After a process of decades, researchers like Mann are getting better data and getting more confidence on the ranges that then other climate researches use.
The research of Mann is only one piece of the whole effort to understand the current global warming and the most likely effects humanity will encounter if nothing is done.
(1) By at least roughly 10% up or down, and possibly more. All for reasons unknown.
(2) We know very little about the other factors, but we do know that they can cause 10% changes in mileage.
Can you answer the question now?
Those are not warmist predictions. As I have repeatedly pointed out, warmists predict that global surface temperatures will increase substantially more than what would be predicted by this type of simple calculation. Warmists predict that there are second order effects which will cause greater increases. You have admitted this yourself.
No it is not, because it also requires you to make assumptions about other second order effects. Besides, if it were simply a matter of physics, there wouldn’t be disagreement about sensitivity among warmists.
I doubt there is enough empirical data to evaluate sensitivity in this way. It goes back to the problem of unknown forcings, which clearly exist.
Well if you like, I will assume nothing, not even a modest warming in response to CO2 increases. Now the full burden is on you.
Well this is just semantics, but it’s reasonable in my opinion to characterize second order (and third order) responses as “feedback.”
Well that means you are confident that whatever factor caused warming in the first half of the twentieth century substantially diminished in the second half.
No they do not. Observation does not since there are unknown factors at work. “Physics” has the same problem as well as the problem of disagreement. “Modelling” does not either since none of the simulations have been tested and validated. Further, there is excellent reason to believe that the simulations are simply tuned to fit history. Last, I’m not sure what you mean by paleohistory, but it seems to me this has the same problem as observations, combined with the problem of actually estimating temperatures and other factors, which makes the picture only fuzzier.
And like clockwork there is brazil84 still insisting after all these years that there is no testing or validation, this point is not correct at all.
As he will not pay attention to this, IIRC he likes to denigrate that testing by claiming that it is not Independent Verification and Validation (IV&V), contrarians like him are doing so by ignoring how inappropriate that kind of verifications is in this case. *
Or maybe they do know what it leads to and are pushing for it as yet another attempt at delaying research, this becomes obvious after reading more of the post from this computer expert.
