I know that. My personal gut bet is what the ARF4 said: ~3C of change by 2100 with the gut part being +/- .5C. But saying that it’s not a huge drop is like saying moving the top end 4.5 to 5 wouldn’t be a huge lift or that it wasn’t a big deal in the AR4 when it went from 1.5 to 2 in the first place.
As you keep saying. And, yet, our little sector of the world is doing fantabulous in regard to shrinking our impact, going from 20t/person in 1990 to 17t/person in 2012. And we are getting betterer.
We should consider it on the proper course of action. What should we do as a globe to obstinate nations like India or China that aren’t under our government’s umbrella?
Hm. I wonder if the History Channel would bring the reality show “Climate Wars” for our troops taking over Asia…
On the topic of further reduction (although on the massively expensive side) could we install electric rails in the roadways with something like RFID chip technology that will dispense electricity to registered RFID users? That way we can skip the toxic batteries on EVs (or at least have them be optional or rented when going long distance) and also let people have the freedom to do both tool around town and also drive out to middle-of-nowhereville to meet their families? Hopefully someone around here has actual electric rail experience and could tell me how wrong an idea this is.
I noticed the ARF4 on preview. I just couldn’t change it. Climate Science for Dogs!
We are, but as others have pointed out, it can be better still, much better. Again, the more one does on that front the less of a worry and less money that we will need to spend in the future.
There is a lot to do in the hybrid and electrical cars and engines front as **San Stone **reports. As for other countries following, one thing to consider is that we will be one of their biggest customers still, and once we do clean up our act the future businesses will demand more of what we are using to reduce our emissions. Companies in China and India that insist on doing the old will be left behind thanks to market pressure, regulations and trade restrictions for the ones that do not comply or change.
The point to press to the ones that do not comply is that it is more likely that chronic pollution and vulnerability to natural disasters will increase in many of those countries that think that ignoring the emissions that they are making will not affect them too.
As the UNDP concluded, failing to address climate change will affect human development progress in the world’s poorest countries and that progress would come to a halt or even reverse.
I know that you believe this, but I don’t see how it’ll happen. Not unless this world suddenly joins hands and sings kumbaya and devote themselves to environmentalism and sacrifice.
The trajectories of things like Hybrids and EVs are hard, technologically, to move faster than they are. Hybrids are deploying to vehicle line after vehicle line in the automakers’ fleets. Outside of mandating that holes be installed in all non hybrid engine blocks, how would we make this move faster? Perhaps by my question posed above, but that’s not cheap in any way shape or form (And part of it may not be feasible - RFID-for-power part).
One of the big ways that wouldn’t be very expensive are the SMRs that Sam brings up. These, individually, are relatively cheap (compared to other power sources) and easily distributable. But outside of that, most energy sources are very expensive. Wind power needs a lot of subsidy. Moving to nuclear would solve a lot of these issues, but the the current reactors generate waste and the new reactors with significantly less waste and the possibility of reconstitution are 10-30 years off (Depending on which tech and which estimate you look at).
These, though, could be brought forward faster, but I already advocate for stiff funding increases - and even a 1950’s style gangbusters testing method of putting all the reactor designs in a place like underneath the Sahara where environmental affects would be limited to duke it out for bestest design and then start producing those.
There is a bit of a problem with this thought and it’s the problem with the “green energy builds jobs!” thought that has been pushed for 20 years: America is a leaky sieve. If we were to design a magical 100% efficient solar panel tomorrow, we would get it built in China. And the Chinese, owning half or 51% of all of the companies, would have access to those designs and other firms would produce those designs to compete with the original American firm.
In order for us to flex our muscles in the way you describe, we’d have to first interrupt free trade like we do with “sensitive” technologies so that they couldn’t be dispersed in that way and exclusively build stuff like that within the US. They wouldn’t so much “buy it from us” as “sell our own stuff back to them.”
But there’s an additional problem with that: Moving fast means we want this economy of scale. You want China to produce a knockoff 95% panel for pennies on the dollar because it’s heads and shoulders above the rest, and then we get to the further problem in this web of happy: Where the political back pressure comes in. We paid to design it but they get to knock it off and sell the knock off back to us. This sends us straight to “OUR JERBS” country.
To add in additional difficulty, what would China say and how protectionist to their own economy would they suddenly become if we even tried to restrict this sort of manufacturer work to on-shore plants? If they really wanted to get pissy they could jack up the prices of darn near everything to just the US and/or start making even more coal-powered inroads to the other third world countries that are starting to get a leg up.
See what I mean about “kumbaya”? And that’s without even getting started on things like actual sacrifices to living. Americans don’t want to sacrifice and neither do the Chinese that have gotten a taste of a better life.
So, while you believe “it can be better” - I would say “Show me a plan that’s better than what we are doing and we can actually get even one country to agree on.” This is why I say we are doing a pretty good job. We are making changes that hasn’t had the electorate raise up and replace our legislature with members of “Tea Party 2: This time it’s about climate stuff.” And after the ACA passed and this exact thing happened, you can bet that it would happen again if we decided that everyone was walking from now on.
I honestly don’t think this. Even if you assume that some how, Navi will pop out and go “HEY! You’re only warming 1.5 C for the next 100 years magicwave” it will still cost them if they do nothing. Even if you believe that all catostrophic talk is bupkiss, changes are coming. They know and understand what’s coming. I’d even hang a wild-assed guess that our North Korean despot even knows and comprehends.
But China wants a free pass. Either the rest of the world cash infuses their economy and pays for their non-CO2 infrastructure to some high percentage, they are just going to do it on whatever time scale they feel like.
And this is what Sam Stone was talking about with the SMRs. If we deploy those, they can do a huge amount of development without CO2 introduction and in Western societies, we could use them to replace the coal infrastructure we have with something better than natural gas. We need to be doing less navel gazing about hybrids and other such things and actually pick up as leaders of the world and begin elevating other portions of the globe. Not just China/India, but the entirety of Africa and the middle east, too. Plant as much production and work squarely on the shores of the US as possible and then partner with political frenemies like China and Russia as well as actual friends like Western Europe and move a process like this forward.
I think you misunderstand, the items I mentioned assume that there will be no kumbaya. Some unwelcome (by them) pressure will be needed. As I pointed before, in the case of China, if they do think that they have a timeline that they can arbitrarily choose, then I can see the end on the rule of the communist party in China.
And I would welcome that BTW.
But I think it is more likely that China will, as one Republican congressman (!) once said, eat out lunch when alternate technologies will increase in demand and reach.
For humanitarian reasons and such I agree with ending communism. But In this context, I would wonder if we (or by itself) toppled the Communist control, would it end up setting back any progress we might have made within China for several years if not a decade? The Soviet fall into Russia was politically tumultuous…And is still kinda, 20 years later.
I do not understand what it means to say “what must be done” when what must me done cannot be done and will not be done.
Lowering CO2 output over the next 20 or 30 years from current levels cannot be done.
It is not possible to swap out enough of the energy grid in that timespan. Consider the 12 years it has taken to get Cape Wind where it is so far, and extend that general process to a nuclear plant, for example.
It is not possible to get the world’s population to live at consumption level that will lower energy use enough to allow renewables to actually replace fossil fuel.
It is not possible to muster enough political will in the developed world to scale back economic growth enough to reduce their carbon footprint.
It is not possible to muster enough public support in the developed world to scale back personal lifestyle voluntarily, nor elect politicians who will enforce such scaling back.
It is not possible to get the developing world to substitute enough renewables in time to lower CO2 output over the next two or three decades.
There are ACC Denialists who deny that science predicts the climate will change based on anthropogenic forcing.
There are also ACC Denialists who deny the reality of this world. Pretending that CO2 production can actually be diminished from current levels within the next two or three decades is either remarkable ignorance, naivete, or denialism.
So what I am wondering is, what do you think the CO2 output could be reduced to in a best case scenario 20 years out? And I’m quite serious: if either you or GIGObuster posts a best guess, I’ll bow out of this and every other AGW/ACC thread.
I am genuinely curious about what goals the “anti-Denialists” think are actually reachable for this world for CO2 output relative to today’s output. And I’m patient enough to wait 20 years to re-post in an ACC thread on the SDMB.
Personally, I don’t think you have a clue, and personally I don’t think you want to guess, anymore than some guy screaming about the population Time Bomb in 1968 wants to guess what the population would be 45 years hence and what the consequences would be. We just didn’t know, nor did we have any viable answers on how to address the catastrophic consequences of too many people on this earth.
I believe that most people who look at this issue beyond simply mentally masturbating over it come to the conclusion that it’s highly unlikely we will change our CO2 output until such time as we run out of fossil fuels. And that keeps getting extended. We want all the energy from all sources until we can all live like Al “Strawman” Gore. (Sorry; had to do that one more time in case you or Gb actually come up with a best guess for where CO2 outputs will be in 20 years. For some reason Gb thinks Al Gore is a “strawman” so I try to save him the time of pointing it out.)
Gb, please put the blame on me and not the legislators I elected.
I want to live well, and I find myself living well even though I know if I could reduce my carbon footprint to that of a Tanzanian, I would do my 1/7Billionth bit for humanity.
But I have no confidence the other 7 Billion will join me, and a lot of them live very crappily compared with me.
It isn’t “the lawmakers.” Government is me, and what they are worried about is who I will vote for should they require me to sacrifice severely.
Cutting CO2 until we swap out the grid will require severe sacrifice, and I’m not willing to do it. I’ll pay some lip service. Since I’m reasonably well off, I’ll even cough up for what little renewable energy there is. But that’s about it, and I’ll draw the line at actually living less well.
Acid rain didn’t cost me First Class on United, or my personal jet. It didn’t mean I had to use public transportation instead of my limo. It didn’t mean I had to downsize my house(s), my cars and limos, my golf clubs, my vacations overseas, my preference for the Ritz over Motel 6 nor any of the other niceties I can afford. And if legislators start legislating that away, I’m not voting them back in.
What I need to even think about it is an estimation by you on how much money, spent which way, will reduce the world’s CO2 output by what percent over what period of time, and because of that ameliorate which consequences to what extent for which populations.
If all of that is just a WAG from you, then I think I’m just going to muddle through and see what happens. I’m not denying it might happen; I’m just not moved to action.
This is getting ridiculous, and somewhat amusing. Your statement was: “It has recently been shown that greenhouse gas sensitivity is significantly lower than it was calculated in the 90’s and 00’s”. You might now wish to retract that. Except for AR4 it has been estimated since the first IPCC report in 1990 to be in the range of 1.5 to 4.5. That’s still where it is. Therefore your statement is wrong. Period. It’s totally mind-boggling how the hell you can conclude from this that we have now corrected some grossly inflated previously held value. (BTW, I stand corrected about what I said about the Third Assessment range of 2 to 4.5 – it was indeed 1.5 to 4.5 in all of them except the AR4 – a consistency which actually makes your claim even more ridiculous).
Now with that in mind, let’s move on to some of your other points.
Yes, I understand what ECS means. Frankly you don’t seem to.
First of all it wasn’t a “big deal” that the lower range went to 2.0 in the AR4, and if you think it was, you don’t understand how subjective that is and how little it really means – this is why ECS is represented as a probability density function in the first place. Who was making it a “big deal”? It certainly wasn’t me, and it wasn’t the IPCC. The only claim being made about ECS at that time was that for the first time, the probable range was less of a guess and better substantiated than it had been in the Third Assessment, not that it had changed in any significant way, because it hadn’t.
Likewise, it didn’t change in any significant way in the AR5 when it went back to the old range. If you look at Box 10.2 Fig. 1(a) in the old AR4, there are plenty of distributions spanning below 1.5 – as a matter of fact, every single one of them, with only one exception.
And if you think a change of 0.5 degrees in a subjectively determined cutoff point in the assessed likely limits of dozens of different probability distributions is “significant”, then you clearly have no idea how ECS is being determined and assessed. And if you honestly think that you can calculate the percentage by which any such parameter has increased or decreased from the fringe of a probability distribution like some of your ridiculous pronouncements about how this implies -50% or +80% changes – even if we had such an integrated distribution – then I’m sorry to say you don’t appear even to understand basic statistics.
No need, you can see the results from all the most reputable papers in Fig. 10.20(b) in the Attribution chapter of AR5 WG1. And if you actually stayed up on the science, you would know what the most common prevailing estimates are. They’re all there. Forgive the Statistics 101 again but the important thing to look at, if you’re going to focus on any single number for each PDF, is the median below the curves and not the mode of the distribution, because, again, most of these are extremely skewed distributions.
I don’t care what you’ve been reviewing, I care about the incorrect statement that you made about what we were supposedly estimating back in the 90’s and 00’s.
No they don’t, and no it isn’t. If that was believed to be the probable range they would say so.
Amazing – so the more money we put into research, the vaguer the results! Maybe we should save our money and improve our knowledge!
In the AR4 WG2 SPM, the impacts were summarized in a single small table taking up a single page, Fig. SPM.2. In the AR5, the impact and vulnerability assessment summary table now spans Assessment Box SPM.2 Table 1, Tables SPM.1 and SPM.A1 covering over ten pages, with far more detailed descriptions of the same phenomena, including water stresses, crop reductions, pests, diseases, economic losses, floods, heat mortality, coastal destruction, wildfires, and other fun stuff. It must be all that “vagueness” that caused this explosion of new threat information. :rolleyes: The text includes such highlights as “substantial species extinction, large risks to global and regional food security” (page 14) I suppose just to point out how insignificant it all is.
It doesn’t seem likely to me that “market pressure” will have much effect. Sort of like bemoaning WalMart but the Mom and Pops are still gone.
“Regulations and trade restrictions” occur at a government level and are fairly tricky to effect unilaterally.
China’s CO2 footprint per capita is less than half that of the US, and even that is because they are making stuff for the rest of the world. In effect the CO2 pollution footprint assignment shifts to them although they are not the ones actually consuming the stuff (be it solar panels, golf clubs or Christmas trinkets).
China’s air is filthy with particulate matter. When I was in Chongqing a few years back the haze was so bad I could barely see across the river.
Life for the average guy in China kind of sucks.
OK…if you were the Chinese government, wouldn’t you more or less have the following perception (and I have no idea if they do or not, as I know very little about China)? :
The West has no high ground on which to stand in terms of telling us what to do with CO2 production. They have achieved a great lifestyle, and now want us to be the ones sacrificing.
Our priorities of cleaner air (particulate) and a better life for our citizenry rank above GHG emissions.
We have dammed the Yangtze (in the face of a fair amount of environmental opposition) and we think we might have the capacity to build out 25 more nuclear plants but we are already close to the limit of what we can do for CO2 reduction without sacrificing economic growth.
Come back and talk to us when you (the West) have your economic house in order and your CO2 footprint is close to ours.
So let me explain. The beauty of discussing the issue in terms of RCPs is that it’s a purely objective scientific approach that decouples the discussion from exactly the kinds of arguments that you like to make. It lets us dispassionately examine where we end up under four different plausible mitigation circumstances, and lets us perhaps decide that certain outcomes would not be acceptable. The requirements to move to a less harmful pathway then become “must-do”, which turns out to be a remarkably pliable concept once the motivation is there. This is a work in progress as at this time we’re not sure what RCP we will be tracking, but at least we have a yardstick. And we also have a warning, because at this point in time we appear to be tracking the worst possible one.
I agree, with that point and the other three. This is the Catch-22 that the West and the developing countries each use against each other, each justifying their own inaction. That’s why my belief is that the West – and the US in particular because Europe isn’t quite so intransigent – needs to take a leadership role and not only gain the moral high ground but be pretty aggressive about international negotiations and the trade consequences of non-compliance.
I read that as “damned Yankees”, which is probably pretty close to what the Chinese are thinking!
Ah. I see, now. I was wrong. It should have been “from the AR4”. I apologize for getting it wrong, and now I’m far less baffled about your arguments. I don’t think the venn diagram of the arguments we were having touched at all.
Since I was only arguing in your general direction, as per above, I’m going to step this back:
The ECS range itself (the 1.5-4.5) is the expected warming based on doubling CO2 in the atmosphere. This is the direct sensitivity. E.g. If it was just Carbon Dioxide (and feedbacks either didn’t exist or were aggregate neutral) the maximum warming we could get is 1.1 C. So if your ECS is simply “4.4C” that means that the warming from each unit of CO2 is quadrupled (or 4x or 400%). This range is informed both by historical statistical calculations and the climate models.
Even though this is, as you note, subjective, this change is important not only because it follows the scientific reasoning but it’s the range given to policy makers along with a “Best guess” estimate of what the IPCC considers the likely warming based on certain scenarios as they are run through the climate models. Their current guesstimate is 3C based on the statistical series that you believe is most important. If that’s the case, why give the ECS range at all? Politicians would love a single number. Sound bites are how they run for office, after all. Or, heck, even two numbers: 3C on our current course and 2C if we reduce emissions to X mmt a year.
I’m sorry, but I can’t get on board with that. If the IPCC gives it out, not only in their technical documentation but as part of what politicians should know, then it’s not as worthless as you say it is.
And, yet, the IPCC felt that they were certain the range of 1.5-1.99_ could be ruled out as a sensitivity and now that same range is back on the table.
It works for 18 year olds. Why can’t it work for us?
Yes, they migrated the anticipated effects from the technical documents of AR5 to the Summary in, oddly enough, a summary form. The summary segment of AR4 was very brief. The only way it could have been shorter would have been to say “Bad stuff will happen. Move along to the WG3 SPM, please.”
No worries, but the central point here that got me going was your implication that there was a sense in the AR5 that things weren’t as bad as we thought. This is the really egregious misconception that I was trying to correct because it’s just not so. Whether it’s the allegation that climate sensitivity had been “significantly” reduced in the WG1 or the allegation that the WG2 was much more laid back about the impacts – neither of those things is true. More below.
I never said the range is “worthless”. On the contrary, the range – or more precisely, a set of probability distributions – is all we have, and indeed the AR5 now declines to give a single “most likely” value at all. What I’m saying is that the argument that the range has changed in any significant way since the AR4 is without merit. If it had merit, I would happily say so – I’m not selling anything here!
As I mentioned before, virtually all of the PDFs in the AR4 ECS estimates extend back below 1.5, but the range was still given as 2 to 4.5 with a most likely value of 3. The AR5 looks much the same, but a “most likely” value is no longer given, and the low range reverted back to prior values. The mean of all model results in the AR4 was around 3.2, and ironically (in view of the alleged “reduced” sensitivity) the mean in the AR5 was actually ***higher ***(around 3.4, IIRC) – this is from memory and the numbers may be slightly off. Here is a nice high-res version of Figure 10-20(scroll down for 10-20(b), which is the ECS PDFs from the AR5 mentioned before) which helps to illustrate just how non-straightforward and subjective these aggregate combined assessments can be. What’s worse, the IPCC in their wisdom decided to remove the AOGCM model results entirely from the chart (they were present in the earlier drafts, and are discussed elsewhere) leaving only the relatively smaller observationally derived estimates. Suffice to say that if they were present, you would see the CMIP5 results trending higher than the older CMIP3, mostly clustered just below 3 and a larger cluster around 4.
BTW, the reason I keep mentioning to look at the median and not the mode when looking at graphs like Fig. 10-20 is because the eye naturally looks at the peaks of these curves, but since they are mostly very skewed with long tails on the high end, the peak (mode) is deceptive and doesn’t represent the most probable value – since these are probability density functions, it’s really the area under the curve that represents the likelihood of finding the correct value. This is also why extending the fringe at either end of what is basically a bell curve has little effect on the probable value. The medians are the solid dots on the horizontal lines below the PDFs.
Absolutely not! As you can now (I hope) see from the above, there was never any “certainty” in the AR4 that 1.5 to 2 could be eliminated because the evidence has never been anywhere close to being that definitive. As a matter of fact not only the probability distributions but the narrative text specifically talks about the lower value probabilities, mentioning for instance that it’s “very unlikely” to be below 1.5, pretty much the same as what the AR5 says.
If you still believe the AR5 WG2 is “less alarming” than the AR4 despite what I pointed out, you might be interested in this minor kerfuffle that occurred when one of the WG2 authors, an economist who is admittedly a bit of a strange bird and who among other things is a consultant to the Global Warming Policy Foundation, a denialist lobby group, publicly accused the WG2 of being too alarmist! From the above link:
I still disagree. The range is very important in public debate and a low side 50% sensitivity drop, while not anything like a “smoking gun of alarmism’s death!” like you seemed to think I was saying, is huge.
Which is actually one of the things that makes it “less alarming.” Take off your statistics hat and think like a politician:
2007 - best estimate 3C, low 2 high 4.5; very unlikely less than 1.5, unlikely [inferred from “Cannot be excluded”] greater than 4.5.
2013 - range: low 1.5 high 4.5; extremely unlikely less than 1 and very unlikely greater than 6.
Note, that I didn’t say “Oh, we can all go back and just forget about all of this stuff” as both you and Gigo jumped up to decry. Compare the two WG2s. The actual the impacts given, all of it are in terms that are less alarming and lots more fuzzy when compared to what the WG2 of AR4 said. Specific points were given, as I pointed out earlier, of specific events, anticipated severities, and such. Now those far more specific projections have been backed off and the general range of effects are given. This is all in a language that is a lot less alarming than “The Himalayas will melt by the 2030s” that was in the AR4.
And I think this is where you are getting lost in my statement: Technically, I’ll agree with you. But the language is less alarming (“more neutral” a better phrasing, perhaps?) than how all of this was phrased back in AR4.
Note that the rest of my post was in relation to a specific quote about the costs relating to the RCS models and was a different topic about how to proceed. (You might also note that I copied the wrong piece into that post but didn’t notice until much later. We need a longer edit window. Like…two days. )
Which is your opinion and obviously not the opinion that held during the IPCC’s assemblage of AR4WG2. I’m sorry, but I’m giving the IPCC’s assessments the higher priority. While I don’t consider them perfect by any stretch, they are supposed to be giving us the data we need to make appropriate choices and even with the 5 or 10 non-critical technical and process errors that cropped up with AR4 I haven’t seen anything that says they are failing at their job.
Of course, I could always go “ZOMG! Ancient Aliens was right! The IPCC is the earth wing of a space crypto nazi cult! Prai’thor, our new evil overlord, is going to work us to death in the acid mines all because of the IPCC!”
Yeah…I glanced over a news report or two when that happened late last week or earlier this week. I didn’t search, but did he give useful specific details that were “too alarming” or was he simply giving generics and playing with the presses’ attention? I tend to ignore this stuff and wait to read the report myself so I didn’t pay much attention to him.
As for his political views - Should we ask a Righty Right Republican if welfare is too socialist and/or liberal? That’s why I’d prefer specifics instead of media sound bites. But, as I said…I haven’t bothered to look for anything.
Edit: Actually, wasn’t that glacier thing one of the technical errors of AR4?
Edit -2147467259: Yes, it was. I probably should drop that from my examples of specificity, then.
Well, I’m looking at more of a 30 year time frame, and perhaps it would take longer than that, but ~90% of the world’s power could be supplied by solar. Cite. The work is already a little dated- its assumptions are based on concentrated solar power, but other works cite this paper as applying to PV very similarly because of “nearly identical overall land use efficiencies”. I’m not sure how that translates exactly to reduction in CO2, but ITSM it would do the trick.
CSP, or what is a variant of Ivanpah’s solar thermal, has been showing some downsides:
Birds are being burned, Pilots are being blinded, and apparently we destroyed a chunk of desert tortoisehabitat to build it. And, while Ivanpah was built with a closed loop water system, it still uses a decent bit of water, which is a scant resource in deserts. Though I am not ultimately familiar with other forms of CSP. They may be less intensive than the solar thermal variant.
Sending our poor environmental effects to the middle of nowhere I don’t agree with. We can do a lot of good using PVs on buildings, even on the glass of buildings. This would be especially useful in the sun saturated areas(so places like Seattle should be last to receive these upgrades ). This means less destruction of as-yet untouched wilderness. If we start subsidizing it first in suburban areas and then move into rural and urban areas along a pathway of sun saturation, we can generate a lot of our energy without having to take over the deserts.
I would like to see a better PV cell or a way to use CSP without stretching ourselves into deserts.
OK, just a few last things, because for some reason you’ve obviously got your mind made up that there was some huge change in the AR5 ECS estimates and obviously nothing I can show you is going to change that perception. All I can say to wrap that up is that it should be obvious (but apparently it isn’t to you) from all those different scattered probability density functions (and around 25 more non-probabilistic estimates from the climate models) that the ECS range has been – and continues to be – scattered across a wide range of values, with each set of estimates coming with its own strengths and its own uncertainties. Because of the different baseline assumptions, there is not even a reliable formal way to statistically combine them. So what you really have is a committee that looked at the set used for AR5 and decided that 1.5 would be a reasonable “likely” bottom limit – and, incidentally, not even the same committee that estimated 2 for the AR4.
But even worse, and the most significant thing of all, is that it’s at the tapering fringe of a bell curve. So sure, 1.5 is 25% less than 2.0 (I don’t know where you get 50%) but to suggest that such a percentage meaningfully represents anything at all is the worst kind of statistical fakery. It’s 25% less in a region where nothing is likely to be found anyway! I’m probably not explaining it very well. Maybe somebody who teaches statistics might have a useful analogy. All I can think of is that if you have a normal distribution of IQ scores and somebody revises it with new data that pulls the low tail end of it say half a standard deviation further down, it doesn’t mean that your entire population is suddenly 50% stupider! Most likely, it hardly means anything at all. To be fair, when the IPCC gives a simple range, the underlying probability distribution isn’t immediately obvious. That’s why the background information is so important.
I’m not sure what you’re referring to here. The climate sensitivity estimates are in WG1 and we were talking about AR5WG1. On that basis, let me just say that at no point – ever – did the WG1 report claim that their ECS range was “significantly” different from the AR4. So go ahead and trust the IPCC – I do! They’re saying the same thing that I’m saying.
It’s not just that guy, although I thought it was funny that a report that you claimed “wasn’t alarming” he claimed was so excessively alarmist that he disowned his authorship in it! But it was also NPR’s assessment of it, and that of many other media. Obviously this is a subjective matter, but I thought it contained a lot of worrying specifics, and a lot of the media seems to agree. That’s all that was about.
Now that you mention it, that Himalyan glaciers thing became famous because it was an actual, real case of an IPCC error, one that wasn’t fabricated by denialists. The fact that such hoopla was made in the denialist wackosphere out of something of so little importance says a lot about how few actual errors they have really been able to find among the thousands of pages of each IPCC assessment. For your interest and anybody else’s, here’s what I remember of it, with the caveat that this is from memory.
First of all the error occurred in the WG2, not the WG1 science report which tends to be generally more rigorous. It concerned high-altitude glaciers about which there was very little observational data, so really very little was known about them. One of the WG2 authors took information about the alleged glacier melt from what appeared to be (IIRC) a paper in an Indian scientific publication, which turned out not to have been properly peer reviewed. It fell through the cracks because it was an incidental factoid of no great relevance, and although it became a bit politically embarrassing for the IPCC, that is certainly not how they typically source their information, and certainly not on major issues. Of course the delighted denialist wackosphere exploded in allegations that it meant exactly that.
So…we shouldn’t trust the IPCC committee in AR4 because they weren’t in consensus with 3 and 5? :dubious: I’m trying to get your point here, really. Each committee looked at the underlying data and decided on the ECS range. According to you, they could have gone with 1.5 and they instead went to 2. I believe it’s because the committee decided that was what was most scientifically secure and not, as some arguments I’ve seen in the past either say or imply, that they were being “alarmist”.
Here is a better way to look at it:
Take a simple Bayesian distribution to an IQ chart that has a tail from the low end and give a simple axis range of 75-125. The mode is 112 the mean is 100. Simple?
Leave the rest the same and change the axis to 75-150. It’s a tiny change and overall the chart doesn’t change, but there would be an underlying dataset change to go with that, in this case you probably have more 150 IQs than, say 70 IQs and you wished to capture that. (Assume altruism and that they aren’t manipulating IQs to make people feel better about themselves…Or to strip funding from schools.)
Now to relate this back to the AR4 vs AR5 - yes it is significant because they thought the data in 4 was sufficient to say that 1.5 shouldn’t be in the chart for consideration. In AR5 after six more years of study, they thought it should be brought back in. That’s a change in the effect that CO2’s influence on the climate is potentially less than what the data leading up to 2007 indicated. More data = betterer. And I still think the change (both in 2007 and now) is a big one.
To be fair, at best we are both attributing our thoughts to what they haven’t stated.
Oo. Specifics! I’ll go Google News that guy, then. From what you read, did you think he had valid complaints?
That’s pretty much what happened. The IPCC went through their processes between 4 and 5 to iron out their editing to better vet the science and language of the detail going into the ARs.
After reading your link and some others, he complaint is basically “This isn’t accurate because people will adapt!” which is true, as are his points about crop yields declining probably not being true because of technological advances. But…we need those adaptions to start going into place all over the world, not just in the rich kids’ countries. As some have said in this very thread, getting the African continent and Indian nation to industrialize on non-CO2 technology would be a huge boon towards these efforts. And we will most certainly adapt crops with as-yet undiscovered technology and/or methodologies. But crystal balling that sort of thing is incredibly difficult.
For example, will Monsanto make a drought-thriving wheat stalk tomorrow? In 2050? In 2255? How long will it take to implement into society once they make it? 2 years? 5 years? 100 years? Will the variety that Monsanto makes tomorrow be fully mobile, have a taste for human brains, and wipe us out by 2023? How will we shoot zombie plants in the brain? And so forth.
