“The greenhouse effect is here.”
– Jim Hansen, 23rd June 1988, Senate Testimony
The first transient climate projections using GCMs are 30 years old this year, and they have stood up remarkably well.
We’ve looked at the skill in the Hansen et al (1988) (pdf) simulations before (back in 2008), and we said at the time that the simulations were skillful and that differences from observations would be clearer with a decade or two’s more data. Well, another decade has passed!
How should we go about assessing past projections? There have been updates to historical data (what we think really happened to concentrations, emissions etc.), none of the future scenarios (A, B, and C) were (of course) an exact match to what happened, and we now understand (and simulate) more of the complex drivers of change which were not included originally.
The easiest assessment is the crudest. What were the temperature trends predicted and what were the trends observed? The simulations were run in 1984 or so, and that seems a reasonable beginning date for a trend calculation through to the last full year available, 2017. The modeled changes were as follows:
- Scenario A: 0.33±0.03ºC/decade (95% CI)
- Scenario B: 0.28±0.03ºC/decade (95% CI)
- Scenario C: 0.16±0.03ºC/decade (95% CI)
The observed changes 1984-2017 are 0.19±0.03ºC/decade (GISTEMP), or 0.21±0.03ºC/decade (Cowtan and Way), lying between Scenario B and C, and notably smaller than Scenario A. Compared to 10 years ago, the uncertainties on the trends have halved, and so the different scenarios are more clearly distinguished. By this measure it is clear that the scenarios bracketed the reality (as they were designed to), but did not match it exactly. Can we say more by looking at the details of what was in the scenarios more specifically? Yes, we can.
This is what the inputs into the climate model were (CO2, N2O, CH4 and CFC amounts) compared to observations (through to 2014):
Estimates of CO2 growth in Scenarios A and B were quite good, but estimates of N2O and CH4 overshot what happened (estimates of global CH4 have been revised down since the 1980s). CFCs were similarly overestimated (except in scenario C which was surprisingly prescient!). Note that when scenarios were designed and started (in 1983), the Montreal Protocol had yet to be signed, and so anticipated growth in CFCs in Scenarios A and B was pessimistic. The additional CFC changes in Scenario A compared to Scenario B were intended to produce a maximum estimate of what other forcings (ozone pollution, other CFCs etc.) might have done.
But the model sees the net effect of all the trace gases (and whatever other effects are included, which in this case is mainly volcanoes). So what was the net forcing since 1984 in each scenario?
There are multiple ways of defining the forcings, and the exact value in any specific model is a function of the radiative transfer code and background climatology. Additionally, knowing exactly what the forcings in the real world have been is hard to do precisely. Nonetheless, these subtleties are small compared to the signal, and it’s clear that the forcings in Scenario A and B will have overshot the real world.
If we compare the H88 forcings since 1984 to an estimate of the total anthropogenic forcings calculated for the CMIP5 experiments (1984 through to 2012), the main conclusion is very clear – forcing in scenario A is almost a factor of two larger (and growing) than our best estimate of what happened, and scenario B overshoots by about 20-30%. By contrast, scenario C undershoots by about 40% (which gets worse over time). The slight differences because of the forcing definition, whether you take forcing efficacy into account and independent estimates of the effects of aerosols etc. are small effects. We can also ignore the natural forcings here (mostly volcanic), which is also a small effect over the longer term (Scenarios B and C had an “El Chichon”-like volcano go off in 1995).
The amount that scenario B overshoots the CMIP5 forcing is almost equal to the over-estimate of the CFC trends. Without that, it would have been spot on (the over-estimates of CH4 and N2O are balanced by missing anthropogenic forcings).
The model predictions were skillful
Predictive skill is defined as the whether the model projection is better than you would have got assuming some reasonable null hypothesis. With respect to these projections, this was looked at by Hargreaves (2010) and can be updated here. The appropriate null hypothesis (which at the time would have been the most skillful over the historical record) would be a prediction of persistence of the 20 year mean, ie. the 1964-1983 mean anomaly. Whether you look at the trends or annual mean data, this gives positive skill for all the model projections regardless of the observational dataset used. i.e. all scenarios gave better predictions than a forecast based on persistence.
What do these projections tell us about the real world?
Can we make an estimate of what the model would have done with the correct forcing? Yes. The trends don’t completely scale with the forcing but a reduction of 20-30% in the trends of Scenario B to match the estimated forcings from the real world would give a trend of 0.20-0.22ºC/decade – remarkably close to the observations. One might even ask how would the sensitivity of the model need to be changed to get the observed trend? The equilibrium climate sensitivity of the Hansen model was 4.2ºC for doubled CO2, and so you could infer that a model with a sensitivity of say, 3.6ºC, would likely have had a better match (assuming that the transient climate response scales with the equilibrium value which isn’t quite valid).
Hansen was correct to claim that greenhouse warming had been detected
In June 1988, at the Senate hearing linked above, Hansen stated clearly that he was 99% sure that we were already seeing the effects of anthropogenic global warming. This is a statement about the detection of climate change – had the predicted effect ‘come out of the noise’ of internal variability and other factors? And with what confidence?
In retrospect, we can examine this issue more carefully. By estimating the response we would see in the global means from just natural forcings, and including a measure of internal variability, we should be able to see when the global warming signal emerged.
The shading in the figure (showing results from the CMIP5 GISS ModelE2), is a 95% confidence interval around the “all natural forcings” simulations. From this it’s easy to see that temperatures in 1988 (and indeed, since about 1978) fall easily outside the uncertainty bands. 99% confidence is associated with data more than ~2.6 standard deviations outside of the expected range, and even if you think that the internal variability is underestimated in this figure (double it to be conservative), the temperatures in any year past 1985 are more than 3 s.d. above the “natural” expectation. That is surely enough clarity to retrospectively support Hansen’s claim.
At the time however, the claim was more controversial; modeling was in it’s early stages, and estimates of internal variability and the relevant forcings were poorer, and so Hansen was going out on a little bit of a limb based on his understanding and insight into the problem. But he was right.
Misrepresentations and lies
Over the years, many people have misrepresented what was predicted and what could have been expected. Most (in)famously, Pat Michaels testified in Congress about climate changes and claimed that the predictions were wrong by 300% (!) – but his conclusion was drawn from a doctored graph (Cato Institute version) of the predictions where he erased the lower two scenarios:
Undoubtedly there will be claims this week that Scenario A was the most accurate projection of the forcings [Narrator: It was not]. Or they will show only the CO2 projection (and ignore the other factors). Similarly, someone will claim that the projections have been “falsified” because the temperature trends in Scenario B are statistically distinguishable from those in the real world. But this sleight of hand is trying to conflate a very specific set of hypotheses (the forcings combined with the model used) which no-one expects (or expected) to perfectly match reality, with the much more robust and valid prediction that the trajectory of greenhouse gases would lead to substantive warming by now – as indeed it has.
References
- J. Hansen, I. Fung, A. Lacis, D. Rind, S. Lebedeff, R. Ruedy, G. Russell, and P. Stone, "Global climate changes as forecast by Goddard Institute for Space Studies three‐dimensional model", Journal of Geophysical Research: Atmospheres, vol. 93, pp. 9341-9364, 1988. http://dx.doi.org/10.1029/JD093iD08p09341
- J.C. Hargreaves, "Skill and uncertainty in climate models", WIREs Climate Change, vol. 1, pp. 556-564, 2010. http://dx.doi.org/10.1002/wcc.58
Victor@82, your wrote
Look up Occam’s razor for why this is a non-scientific argument.
I’ve been doing some research on Hansen’s notorious West Side Highway prediction, prompted by indignant claims that this story has been misunderstood, exaggerated, unfairly hyped. According to the original report, he predicted, in 2008 or 2009, that this portion of Manhattan Island would be under water “in 20 years,” an alarmist prediction if there ever was one. After several years went by with no sign of anything unusual, the story got changed. Apparently it was 40 years, not 20. Now that the 40 year mark is fast approaching, we get another update on the story: Hansen now claims his prediction was based on the doubling of CO2 levels. Which is, of course, still a long time off — getting Hansen off the hook. Really?
Well, first of all, I see no reason to dismiss that first report. The reporter was not hard of hearing, nor was he suffering from early onset Alzheimer’s. He heard “20 years” and reported “20 years.” Looks to me like Hansen had second thoughts as it became increasingly clear that his prediction was going nowhere, so he managed to convince the reporter to modify the story to 40 years. In other words, I think he might have bullied the guy. Then, as the 30 year mark approached with no sign his prediction was even close to actually happening, Hansen once again may have bullied this guy to suddenly recall, “Oh yeah, now I remember. He qualified it by including that bit about CO2 doubling.”
Now this is ONLY my opinion. And maybe I’m being unfair. But considering the extreme amount of bullying and browbeating we see on a regular basis in this field (including so many of the comments on this blog), and considering Hansen’s almost fanatical tendency to predict the most extreme and alarming outcomes, one can’t help but wonder. Underwater in 20 years sounds a lot like the kind of thing he’d have said and it rings true, as far as I’m concerned.
OK, so much for speculation. Let us now get closer to the facts. Even if we’re willing to accept Hansen’s insistence that he said “40” and not “20,” and even if we accept that he qualified that by including the bit about CO2 doubling, it is now clear that, whatever he had in mind, he was not only wrong, but devastatingly so. If there was anything at all to his prediction we would certainly have seen signs of it by now, and the signs would be alarming. Yet we see no such sign whatever. I very much doubt that anyone residing in Manhattan over the last 40 or 50 years would have noticed any difference in sea level during his or her time of residence. And I don’t mean any “significant” difference, but literally any difference at all. Which is not to say that there hasn’t been a difference — sea levels have risen –only that it’s so minuscule as to be easily overlooked.
As in literally all the other cases exposed by Tony Heller, Hansen was dead wrong on the future of the West Side Highway, probably his most spectacular attempt to amaze and alarm.
Victor, explain me how this timeline works in your little theory that Hansen bullied Reiss into changing his story:
a) the Salon article that mentions 20 years (no further caveats) is from 2001
b) the Salon article was an interview about Reiss’ book “The Coming Storm”
c) the book, which was written before the interview, mentions 40 years AND the caveat of doubling of CO2
Oops. Timeline broken.
Victor @102 says “According to the original report, he (Hansen) predicted, in 2008 or 2009, that this portion of Manhattan Island would be under water “in 20 years,”….Well, first of all, I see no reason to dismiss that first report. The reporter was not hard of hearing, nor was he suffering from early onset Alzheimer’s. He heard “20 years” and reported “20 years.”
Yes of course the media are always accurate and so reliable, never lie, twist things or take them out of context, (heavy sarcasm).
Hansen has also long predicted that the antarctic ice sheets could become unstable due to the ice shelf issue, and evidence for this along with a significant acceleration in the melting of antarctic ice has been detected this year and reported in the media. So Hansen has been right about most things.
https://www.washingtonpost.com/news/energy-environment/wp/2018/06/13/antarctic-ice-loss-has-tripled-in-a-decade-if-that-continues-we-are-in-serious-trouble/?noredirect=on&utm_term=.43f52be0c147
Victor @ 102 says:
If I recall, what happened below 49th st. along the West Side Highway during Hurricane Sandy, would fall under the category of at least somewhat ‘alarming’.
Of course I moved from Manhattan to Miami before that event and feel much safer now that sea level rise, storm surges, kingtide flooding and increased hurricane intensity will no longer affect me… /sarc
You might want to read this paper: http://www.pnas.org/content/112/41/12610
Increased threat of tropical cyclones and coastal flooding to New York City during the anthropogenic era
BTW, even if Dr. Hansen was off by 50 years there is still a significant probability that NYC will have to deal with more frequent flooding due to sea level rise in the relatively near future, probably before the end of this century.
To keep things in perspective, with regards the time frames over which a somewhat analogous event to our current ongoing anthropogenic climate change and sea level rise took place, you could also read up on climate change during The Paleocene–Eocene Thermal Maximum.
With regards the big picture, the relevant orders of magnitude of the rates of change, make quibbling over whether or not someone was off by a few decades in their predictions pretty much irrelevant.
It’s kind of like arguing that Newton’s law of universal gravitation had suddenly ceased to be useful as a model when Einstein came along with his theory of General Relativity. We now know that both those models are incomplete but given his resources at the time, Newton was phenomenally accurate!
Bob Reiss: “When I interviewed James Hansen I asked him to speculate on what the view outside his office window could look like in 40 years with doubled CO2.”
James Hansen: “Reiss asked me to speculate on changes that might happen in New York City in 40 years assuming CO2 doubled in amount.”
AB: That pretty much settles it, eh? The reporter and Hansen both said Hansen said that if CO2 doubled immediately (or over 40 years, I suppose) then 40 years later a highway would be under water. Of course, Victoresque doesn’t care about caveats. He’s into attention. Oops. (You’re welcome, Vic.)
This is a BIG THANK YOU to Tamino (on his website), Al Rodger, Hank Roberts, Susan Anderson, jgnfld, etc., for finally identifying Victor AKA DocGee to me. I believe Hank had mentioned that Victor was an academic, so I had deduced incorrectly that he was Victor Venema from Variability Blog / U Bonn, who also posts here occasionally. I couldn’t understand why Dr Venema had such a totally split intellect, and where did Dr Venema (obviously not retired) find the time to post such … a lot of … words. My apologies to Dr Venema.
IMHO the best place for Victor is the borehole.
Why am I thinking of Ann Elk?
Victor @102
Oh my, more poppycock from Victor who has gone from just questioning the science, science he is admittedly completely clueless about, to full blown denialism.
From Skeptical Science:
So it was the actual questioner who clarified that he brought up the 40 year time frame not Hansen and, more importantly, that the assumption would be that CO2 levels had doubled. Hansen concurred. No one changed the story except the denialante.
Got that? Assuming doubling has occurred.
It hasn’t, so you cannot proclaim Hansen’s casual prediction to be wrong.
Steven Emmerson @101
LOL. Victor believes that these unknown natural drivers ARE the simpler explanation. To him it doesn’t matter that they are unknown or that there is no known possible physical explanation of how such a driver could work creating heat within the boundaries of the well understood physical laws of thermodynamics and heat transfer theory. The possibility of such is the simpler explanation just because Victor says so. Natural variation! Simpler! Damned the physics or the evidence. Doesn’t matter. Simpler! Why? Because Victor with no formal training in the hard sciences says so.
Victor, #102–
I think you are being unrealistic. Reporters deal with unhappy interviewees all the time; the notion that one is going to fold on a professional matter due to supposed (and purely speculative)’bullying’ seems pretty silly. For that matter, so does the idea that Hansen is so invested in defending a casual comment that he would bother to harass a reporter in the first place–for this was never a scientific prediction in any real sense; it was on the face of it a speculative answer to an invitation to speculate.
I think the WUWT post supports that interpretation; in 2009 Anthony Watts called the comments “little known”, yet Bob Reiss had already agreed that the correct conditions for the speculation were 40 AND an assumed doubling of CO2.
https://wattsupwiththat.com/2009/10/22/a-little-known-but-failed-20-year-old-climate-change-prediction-by-dr-james-hansen/
(Oh, and by the way, your “research” didn’t happen to consist entirely of Googling up the WUWT piece, did it? I certainly don’t see anything you say that wasn’t already in that 2009 article.)
“We,” Kimo Sabe?
Seems like the city has ‘noticed’:
http://www.dec.ny.gov/energy/45202.html
Seems like builders, citizens and media have all ‘noticed’:
https://www.technologyreview.com/s/603527/new-york-city-is-building-for-a-future-of-flooding/
Oh, and *all* of New York certainly noticed during Sandy:
http://www.businessinsider.com/sea-level-rise-new-york-city-economic-2017-8
I’ve seen one estimate that without SLR to date, about 60,000 fewer New Yorkers would have lost their homes due to Sandy.
But if we look to solid, empirical data, here’s what things look like just up the coast in Boston:
https://tamino.wordpress.com/2017/07/24/boston-sea-level/
Hmm, 10 cm or so since Dr. Hansen’s prediction. No wonder all those folks are ‘noticing.’
But Boston isn’t New York. Luckily, NOAA has the tide gauge data online. What does it say for the Battery?
https://tidesandcurrents.noaa.gov/sltrends/sltrends_station.shtml?id=8518750
Yeah, by eyeball 8-10 cm since ’88.
And all of that has happened with an increase of about 40% CO2 above pre-Industrial–*not* the 100% increase posited in the conditions of speculation.
So, Victor–do you feel a little silly, having your blatant denial of sea level rise exposed? Your eye is supposed to be fabulously good. How come all of this is apparently invisible to you?
Because I think we all ‘noticed’ the gap between your blindness and reality–not to mention your unsavory indulgence in slander based on nothing but pure speculation. That was truly despicable.
You should be ashamed–but I suspect ‘should’ is the operative word.
Could we elevate the discussion? An article about Hansen has now become about fakery because people can’t resist responding to a hot air merchant. Surely we all can do better.
My oh my. Where to begin?
Well, last things first: let’s start with Hansen’s W. Side Highway prediction.
Sample objection, from my old “pal,” CCHolley:
CC: So it was the actual questioner who clarified that he brought up the 40 year time frame not Hansen and, more importantly, that the assumption would be that CO2 levels had doubled. Hansen concurred. No one changed the story except the denialante.
Got that? [in bold:] Assuming doubling has occurred.
It hasn’t, so you cannot proclaim Hansen’s casual prediction to be wrong.”
I’m not quite ready to accept that Hansen didn’t fudge things by adding the CO2 doubling bit later, and getting the reporter to agree, retrospectively. It sounds much more dramatic, thus more characteristic of Hansen, to simply predict the sea level change — adding that CO2 doubling caveat would have weakened the effect. Nonetheless, it’s just a suspicion, I certainly have no way of proving it, so am perfectly willing to put it aside.
The heart of the issue is not whether Hansen said “20” or “40” or whether he included CO2 levels, but the fact that there has been little to no noticeable sea level rise on the Manhattan coast since the time Hansen made that prediction, all of 30 years ago. Meanwhile, CO2 levels, while not yet having doubled, have continued to soar. If Hansen were right, we’d expect to have seen signs of rapidly accelerating sea levels below the W. Side Highway by now, regardless of any doubling, but nothing of the kind has happened. NY sea levels have continued to rise at more or less the same glacial pace as 30 years ago, and there is no sign that they are about to suddenly undergo a growth spurt. Unless we see such a spurt over the next 10 years (doubtful), Hansen was wrong.
For reference, here’s the link to Tamino’s initial article, complete with the graphs to which I referred above: https://tamino.wordpress.com/2014/01/30/global-temperature-the-post-1998-surprise/
His more up-to-date graphs look somewhat different now, thanks to the temperature runup due to the recent El Nino, but evidence of the leveling after 1998 remains.
110 Kevin McKinney knocks himself out with a whopper of an indignant post, offering all sorts of reasons why my take on Hansen’s W. Side Highway prediction is all wet (notice the pun!). After the dust clears, however, the inconvenient truth remains: after 30 years, NO evidence whatsoever to support Hansen’s prediction.
We know Victor’s response, which amounts to “La la la la la I can’t HEAR you …”
https://www.dec.ny.gov/energy/45202.html
http://journals.sagepub.com/doi/abs/10.1177/0959683616683263
#114, Victor–IOW, not only is the Victorian eye unable to spot evidence in a lineup, it can’t even spot that evidence when, metaphorically, it slaps Victor across the face and challenges him to pistols at 20 paces.
Victor @112
Of course not, Victor is never wrong. Even when he has been shown to be wrong. In this case as shown by the timeline of events and the statements of those involved. Victor is wrong (as usual), nevertheless.
Of course Victor conveniently forgets that Hansen clearly said assuming CO2 doubles just as he was asked (even with the bold Victor doesn’t get it). Currently CO2 levels are up about 130 ppm with another 150 ppm needed for the doubling. We are not even 50% there. Hanson did not make the prediction that doubling would occur in 40 years, Reiss did. It was a hypothetical. Hanson made the sea level prediction based on the hypothetical doubling. We aren’t even close and fortunately current projections are for that to occur sometime after 2050. So come back in 2050 when CO2 levels have doubled and tell us how Hansen’s prediction turned out. No way today to say Hansen was wrong, but easy to say Victor is wrong.
Victor as usual is being completely disingenuous and deceitful.
Victor @113
Nope. His trend line is based on the years 1975 through 2000. All the years after fall within two standard deviations of that trend line regardless of the el Nino event. There is zero evidence of a leveling off after 1998. It’s pure statistics and true regardless of baseless proclamations by the self proclaimed statistics expert Victor. What a clown.
Hank Roberts “We know Victor’s response, which amounts to “La la la la la I can’t HEAR you …”
Or possibly la la la I don’t want to hear you. I have vested a lot in this denialism, and its too late to back down and admit I have got it wrong, so I’m in this “for the long haul”, and anyway I like the attention.
Susan Anderson. I agree entirely that its annoying when things distract from the original article.
However its human nature to respond to people who write nonsense like Victor. I did a couple of years in quality assurance, and so I tend to react to nonsense, and deceptive nonsense really, really annoys me for some reason. And ignoring nonsense can be interpreted by many as TACIT APPROVAL, or an inability to prove it wrong.
I think it’s up to the moderators to borehole more stuff from Victor, and this will reduce the problem.
“I’m not quite ready to accept that Hansen didn’t fudge things by adding the CO2 doubling bit later, and getting the reporter to agree, retrospectively.”
Victor, why did you ignore my comment @103?
Victor, did you even read that Tamino article, or subsequent ones? There is no evidence of a pause or even a slow down. I notice you haven’t mentioned Tamino’s debunking of your claim that there is no evidence of a long term warming trend. Why do you bother posting here when your arguments are continually torn apart? Are you simply trying to waste the time of others? If so, well done, mission accomplished.
123 Mike Roberts says:
Victor, did you even read that Tamino article, or subsequent ones?
V: Yes, of course I read it. And I wrote a response, but it was consigned to the bore hole.
MR: There is no evidence of a pause or even a slow down.
V: Tell that to the long list of climate scientists who have acknowledged the existence of a hiatus and gone to great lengths to explain it.
Victor (@86) I’ve had my say about Hansen and your sad attempt to discredit him. Honestly, if you think demonstrating that he got some minor, regional calls wrong would have any impact, then you need to think a little harder.
What irks me is that you have taken up accusing scientists of “cooking” data (presumably something akin to “cooking the books”) and, less importantly, me of “fiddling” with the numbers. Sorry charlie, you need to look to your buddy Heller for that kind of dishonesty.
Victor @borehole (where he belongs–always, IMHO)
The stupidity of Victor knows no bounds.
Natural variation does not drive anything. It is simply the redistribution of heat between the oceans and atmosphere and cannot account for significant heating or cooling of surface temperatures. This is because *natural variation* is neither the creator of energy nor a consumer of energy. Heat flows from hot to cold per the second law of thermodynamics therefore natural variation must vary about the driven mean equilibrium temperature based on the energy into the system versus energy out. Natural variation does not change the energy in or energy out therefore cannot account for long term heating or cooling, it is physically impossible. Victor has been told this simple fact a thousand times but cannot grasp it. Or refuses to grasp it. When looking at long term heating as observed since the 1970s *natural variation* can never be the *null hypothesis*. Never never ever. It is NOT a driver.
Perhaps Victor means variability of the natural drivers of climate, i.e. natural forcings, but if he does, he should learn the definitions of the terms he is using if he expects to have an intelligent discussion on the science. However, that is probably far to much to expect from Victor as Victor seems to refuse to learn or simply ignores anything that might upset his world view.
So if Victor actually does mean natural drivers, those that have driven the temperature since the origin of the earth and that we do not seem to need evidence for, then he needs to explain which of those natural drivers is the default natural driver for his null hypothesis and why. Or perhaps it is all of them. Simple, right? The problem with this is that we know what the natural drivers are and we have a very good idea how they have varied over time so we know what their possible contribution is. And furthermore, if we know what their contribution is and that the contribution cannot account for the warming how can they be the default? They cannot. It is a silly notion. Claiming such is NOT science, it is the stupidity that science is meant to counter.
So since the natural drivers cannot explain the warming and cannot be the *null hypothesis* we need theories as to what did cause the warming. What is the default? Victor says *natural variability*, but that is silly because natural variability is not a driver and cannot account for the large increase in temperatures. So what’s left? um CO2. CO2 doing what physics says it will do and what the evidence shows. It IS the simplest explanation that fits the evidence per Occam’s Razor.
However, Victor wouldn’t recognize evidence or a null hypothesis if it slapped him in the face.
Heres the “pause”. Victor likes “eyeballing” graphs:
https://en.wikipedia.org/wiki/Instrumental_temperature_record#/media/File:Global_Temperature_Anomaly.svg
A tiny flattening in the red trend line of about 6 years from about 2004 to 2010. Not significant, and clearly natural variation.
nigelj @127
What Victor cannot comprehend is that it has been well established that due to natural variability it takes 30 years to establish a trend in the temperature record. A short period of what appears to be flat temperatures does not constitute a change in the trend. This is exactly what Tamino showed. The period following the strong 1998 el Nino may appear to be flat and a pause in temperature rise, but that does not mean that there is any pause in the overall trend. This because these temperatures fall within the range of variability of that trend.
To establish that the long term trend in temperature rise had actually stopped or slowed, you would need thirty years of data to confirm it, or at least you would need some of the temperatures falling out of two standard deviations of the established trend. This has not occurred. Subsequently, we’ve had 2014, 2015, and 2016 all being record temperature years with 2017 also remaining quite high. Although high, these years all still fall within two standard deviations of the established trend thus help confirm further that the trend from 1975 to present has continued at the same rate and that despite the earlier observed slowdown, there has been no slowdown in the overall rising trend.
Was there a pause in temperature rise? …Yes, perhaps.
Was there a pause in the rising temperature trend? …Absolutely not.
@vic124
For someone who likes to invoke “natural variation” so much, it ought to be confusing that vic willfully ignores a perfectly good example of it in action in, for example, the period of a few years after 1998 (among many other places in the record).
But it isn’t confusing in the least. It’s just another example of vic’s will to deny at all costs.
As for the “long list of acknowledgers”, show us a real list and what said “long list” of them actually said. Many people have studied that period trying to drill down into what exactly caused the natural variation of the time–e.g., a string of repeated la Ninas–just as many study el Ninos. But this is NOT an “acknowledgement of a pause” in overall warming any more than studying el Ninos is an “acknowledgement of sudden natural warming”. It is an attempt at a deeper level of explanation, an attempt to parcel out some portion of the error term into a described factor. Some think the attempt is worthwhile, others think not so much. NONE of this has anything to do with a “pause” in the action of the greenhouse warming effect. Nada. Zilch.
Added: We see vic’s “reasoning” as well in deniers who try to argue that every slight uptick in the downward trend of arctic ice as a “recovery”. Oddly, sea ice spends about 50% of the time “recovering”. Yet still extent plummets. How can this be? Oh yeah…natural variation.
Jut a note of clarification for Victor’s reference. The Bob Reiss book, The Coming Storm was first published on September 5, 2001. It was obviously written well before the Salon interview, in fact, the Salon interview was held in October of 2001 because of its release. Sorry, book clearly came first.
See the Publisher’s Weekly review dated July 23, 2001.
https://www.publishersweekly.com/978-0-7868-6665-6
131 CCHolley says:
“Jut a note of clarification for Victor’s reference. The Bob Reiss book, The Coming Storm was first published on September 5, 2001. It was obviously written well before the Salon interview, in fact, the Salon interview was held in October of 2001 because of its release. Sorry, book clearly came first.
See the Publisher’s Weekly review dated July 23, 2001.”
My apologies. I was wrong. The date I provided (see the Bore Hole) was based on information gleaned from Amazon (https://www.amazon.com/Coming-Storm-Extreme-Weather-Terrifying/dp/0756777917/ref=sr_1_1?s=books&ie=UTF8&qid=1530738041&sr=1-1&keywords=reiss+the+coming+storm), where I found the following line in Product Details: Publisher: Diane Pub Co (April 1, 2004)
Thanks for the correction, CC. I nevertheless find it difficult to understand why Reiss would include that bit about CO2 doubling in the book, yet omit it when being interviewed. Wonder what the first edition of the book actually says.
Regarding Hansen’s supposed prognostication of a submerged West Side highway (which I can see from my office): I think THAT is a good instance to use Occam’s Razor. (unlike, say, instances when we have actual known physical relationships and quantitative methods to choose between options…)
Which seems more straightforward? That a highly trained scientist made a serious (because if if wasn’t serious, why do we care?) yet outlandish prediction, diverging MASSIVELY from any published research of his or anyone else of that era. Or that something might have been lost between his statement in an interview and what ended up on paper.
The former would require him to be running some model unknown to anyone else and take it seriously enough to talk about its results publicly. The latter happens all the time.
V: “wonder what the first edition … actually says”
You claim there’s more than one edition, and that explains your confusion?
https://www.google.com/search?q=Why+is+ISBN+important%3F
https://books.google.com/books?q=editions:ISBN0786866659&id=gsARAQAAIAAJ
Victor @132
Simple. Weiss stated that when he wrote the book he referenced his notes from his discussion with Hansen many years prior; however, his interview with Salon was strictly from memory and his memory failed him. I think you’ve been told this already.
And, BTW, the first publication by Hyperion says exactly what the second publication in 2004 by Diane says. It is not a revised addition, it is strictly a reprint. The book sold well, Hyperion also published a paperback edition in 2004.
CCHolley @128, your commentary is always very informative.
I understand what you are saying about the pause, and your technical definition of a pause, but there’s a real problem because the general public definitely see any slowdown of more than about two years in the temperature record as a ‘pause’, and one can undertand why: It’s just commonsense application of the english langauge. So we actually have a lot of confusion out there, and it makes it look like climate scientists are trying to deny the obvious, because clearly temperatures did at least flatten for a few years.
I suppose the only antidote to the confusion is to do what you have done to explain the technical definition of a pause. But I suggest at least also acknowledge the obvious, that temperatures slowed for about 6 years, and then explain that its due to natural variation cycles etcetera. Because I’m telling you if you try to suggest there was no slowdown, or you downplay it, it comes across very badly.
And we know this slowdown is easily explained by natural variation related to relatively short term ocean and sunspot cycles, and does not in any way mean the underlying warming trend from CO2 has stopped. The jump in temperatures after 2015 clearly showed how the slowdown was temporary and insignificant.
The public also define natural variation as anything not caused by humans, so therefore solar cycles, volcanoes, orbital cycles, etc, and again they dont know your technical distinctions. I suggest bear that in mind.
Another point on Bob Weiss and The Coming Storm.
In researching for the book, Reiss travelled the world over multiple years interviewing many top scientists, not just Hansen, to get their views on what the future holds due to global warming. That was the book’s theme. It shouldn’t be a surprise that he wouldn’t remember the exact details of each interview, that’s why one takes notes, nor would it be a surprise that from the top of his head he wouldn’t remember exactly what he wrote about each one.
The whole idea of some kind of coverup conspiracy here is preposterous. The fact that Victor works so hard to cling to such a possibility is telling that he only wants to believe what he wants to believe.
nigelj @137
Good points. Thank you.
It can certainly be confusing. That’s because as you state the temperature record tells us what is going on with *surface* temperatures and not the whole climate system. Most people obviously do not understand the distinction. So yes, we can say that there was a slight pause or slowdown in surface temperature rise while asserting that there was no pause in the warming of the system, but the distinction must be made clearly. Explaining it all is easier said than done, though. I’ll keep working on it.
On the “pause”:
It was not a pause after 1998, it was a SPIKE after 1996 followed by a reversion to the trend. Semantics is critical. Call it what it was as opposed to what deniers claim it to have been.
Determined to get to the bottom of the W. Side Highway prediction story, I headed for the library and found Reiss’s book. And sure enough, I found the passage we’ve been discussing, on p. 30. Here’s the money quote:
“. . . the reporter would ask the scientist whether, if he was right, and carbon dioxide in the atmosphere really doubled, anything down there would look different because of it by 2030.”
So my suspicions were unfounded, the question did involve a doubling of CO2 levels after all, a detail Reiss must have forgotten during the interview, unfortunately. It’s possible also that he got his dates mixed up, confusing the year 2030 with 20 or 30 years.
I owe Hansen an apology.
From NASA, 2014: In the 21st century, greenhouse gases have continued to accumulate in the atmosphere, just as they did in the 20th century, but global average surface air temperatures have stopped rising in tandem with the gases. The temperature of the top half of the world’s oceans – above the 1.24-mile mark – is still climbing, but not fast enough to account for the stalled air temperatures. https://www.nasa.gov/press/2014/october/nasa-study-finds-earth-s-ocean-abyss-has-not-warmed/#.VUJ7G9Izbs1
From Scientific American, 2014: The [deep ocean] study set off a furious debate among scientists and oceanographers studying climate change. The world’s surface temperatures have risen at a slower rate over the past 15 years than at any time since 1951, according to the Intergovernmental Panel on Climate Change. Some scientists have tied the phenomenon, called the global warming “pause,” to the deep oceans’ taking up more heat. But the NASA study suggests that may not be the case. . .
The study was called “deeply flawed” by Kevin Trenberth, a climatologist at the National Center for Atmospheric Research. He faulted the authors’ choice of data and sampling methodology.
The challenge goes to a key problem in climate science today. Sea surface temperatures over the last decade have essentially been at a standstill, which is a problem, since the ocean warms from the top down. So, it would appear, global warming has “paused.”
Trenbeth and others have used simulation-based studies to suggest that the ocean is continuing to warm, but [according to Trenbeth] the deeper layers have been warming up more in the last decade.
Willis’ study suggests this is not the case.
from Nature, 2014: “Climate change: The case of the missing heat
Sixteen years into the mysterious ‘global-warming hiatus’, scientists are piecing together an explanation”: For several years, scientists wrote off the stall as noise in the climate system: the natural variations in the atmosphere, oceans and biosphere that drive warm or cool spells around the globe. But the pause has persisted, sparking a minor crisis of confidence in the field. Jeff Tollefson — https://www.nature.com/news/climate-change-the-case-of-the-missing-heat-1.14525
From the journal Atmospheric and Climate Sciences, 2014:
The question whether human activities seriously affect climate is asked with increasing voice these days. Quite understandable since the climate appears to be out of control with the significant global temperature increases already seen during the last three decades and with still heavier temperature increases to come in the future according to prognoses, among others, in the recent comprehensive IPCC reports [1]. However, the most recent climate data [2], show global temperature development levelling off or even turning negative since 2001 in contrast to the anticipated course related to the steady increases in the concentration in the atmosphere of green-house gasses, primarily carbon dioxide and methane [1]. http://www.scirp.org/journal/PaperInformation.aspx?PaperID=41752
Need I continue?
Of course, as might be expected, most of the above authors present a theory as to why temps have leveled off, but in all cases they have been forced to admit that for whatever reason, there HAS been a significant hiatus from roughly the turn of the century until 2014. This remains a widely recognized issue that can’t easily be erased from the record.
@142
Can you READ???
https://www.nasa.gov/press/2014/october/nasa-study-finds-earth-s-ocean-abyss-has-not-warmed/#.VUJ7G9Izbs1 “Scientists at NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, California, analyzed satellite and direct ocean temperature data from 2005 to 2013 and found the ocean abyss below 1.24 miles (1,995 meters) has not warmed measurably. Study coauthor Josh Willis of JPL said these findings do not throw suspicion on climate change itself.
‘The sea level is still rising,” Willis noted. “We’re just trying to understand the nitty-gritty details.’ ”
From Scientific American, 2014:
“Now, as the global-warming hiatus enters its sixteenth year, scientists are at last making headway in the case of the missing heat. Some have pointed to the Sun, volcanoes and even pollution from China as potential culprits, but recent studies suggest that the oceans are key to explaining the anomaly. The latest suspect is the El Niño of 1997–98, which pumped prodigious quantities of heat out of the oceans and into the atmosphere — perhaps enough to tip the equatorial Pacific into a prolonged cold state that has suppressed global temperatures ever since.”
From the journal Atmospheric and Climate Sciences, 2014:
“The solar activity is now at the lowest level seen in the
past 100 years and could not go much lower. Thus, the
observed global temperatures may soon resume the steady
rise observed from around 1980 to 2001. If solar activity
starts increasing then the global temperatures may rise
even steeper than that seen over the past three decades.”
Need you continue??? I think yes.
V: Need I continue?
You don’t seem to come up with anything new, so why bother? You’re just refighting old battles with old information.
That’s from Berkeleyearth’s FAQ “warming stopped?” page.
http://berkeleyearth.org/faq/#stopped
The graphic link is broken. I’ve emailed them about the broken link.
Victor @ 142 says:
Surely you jest? One could, should one be so inclined, go so far as to characterize that, as, highly refined Mongolian Yak Dung.
https://www.scientificamerican.com/article/no-pause-in-ocean-warming/
The article also contains a 5 min embedded video explanation by Zeke Hausfather at the University of California at Berkeley.
https://www.youtube.com/watch?v=hnyX32nkYBs
Victor @142
Let’s look at the more recent research based on the Argo Float system. Seems that the heat has gone into the oceans as expected by the climate models for the so called *hiatus* period. No missing heat. The slowdown in surface temperature increases after the large el Nino event was due to natural variability with the shift being more heat into the oceans rather than the atmosphere.
As such, the warming trend continued through this period even though there was a slow down in the increases in surface temperatures.
Stephen C. Riser, et al, “Fifteen years of ocean observations with the global Argo array” Nature Climate Change, volume 6, pages 145-153 (2016), DOI: 10.1038/NCLIMATE2872
As noted, a number of observation-based studies have concluded that the upper layers of the global ocean have warmed in recent decades, or even over a longer period. Yet it is the change in heat storage by the ocean (essentially the vertical integral of temperature change) that is likely to be directly related to the planetary radiation imbalance. It seems that the observed increase in ocean heat content in the upper 700 m over the past 40 years, inferred from Argo and hydrographic observations, is the dominant term in the global inventory of heating changes, with over 90% of the excess heat in the climate system being stored in the oceans. Without Argo, it is unlikely that such a conclusion could have been drawn. The data have also allowed temporal spatial variations in ocean heat content to be discerned, suggesting that most of the increase in heat content in the past decade has occurred in the Southern Ocean (which was poorly sampled before Argo); it has also been noted that ENSO variability in the tropical Pacific has for now somewhat obscured the global increase in sea surface temperature. Some of these ideas have been tested using Argo data alone (Fig. 5), by examining the change in heat content of the upper 2,000 m of the ocean in three latitudinal bands from 2006 to the present time; during the Argo era it can be seen that the ocean is warming, mostly south of 20 °S. In Fig. 5 the Argo-only plots (inset) are only for the years 2006–2014, the period when global coverage from Argo exists. So these short plots are overlaid on a plot of heat content estimates for 0–2,000 m depth for the period 1955–2010. The Argo estimates show a very similar trend. It is a crucial result in making an assessment of the ocean’s role in climate change, one that would have probably been impossible before Argo. Indeed, a recent detailed and systematic analysis of the change in ocean heat content and our ability to observe it concludes that estimates of the upper-ocean heat content based on data collected before Argo systematically under-estimate the amount of heat content change, mostly due to under sampling of the Southern Hemisphere ocean; with the advent of a significant amount of Argo data becoming available around 2004, the estimates are greatly improved and are in better agreement with climate models.
http://www.aoml.noaa.gov/phod/docs/nclimate2872.pdf
Gee, Weaktor, a study from 2014–just before we had 3 years running of record surface temperatures. Those sure are juicy cherries!
“Need I continue?” asks the moron Victor Grauer of Pittsburg PA. I think a pause is required to consider the four cited items and what the moron concludes from them. Cetainly the moron’s quotes are more ‘cherry-pick’ than ‘precis’ suggesting the moron has failed to understand the messages set out in his citations. The first three citations (1), (2) & (3) are not primary science but journalists reporting sceince. The fourth is an astro-physicist chancing his arm so not really climatology. If the moron hopes these four sources demonstrate climatology discussing the ‘hiatus’, they are less than convincing.
But there are people, indeed actual climatologists, discussing the ‘hiatus’. Even the IPCC AR5 Ch9 Box 9.2 discusses “Climate Models and the Hiatus in Global Mean Surface Warming of the Past 15 Years”(My bold). There is no question that there is a period where successive annual global temperatures, in the words of the IPCC AR5, show “a much smaller increasing linear trend.” Yet such discussion of a so-called ‘hiatus’ does not undermine in any way the scientific basis for AGW. Yet the intent of the moron Victor Grauer of Pittsburg PA is exactly that, to misuse such discussion of a so-called ‘hiatus’ by suggesting the discussion proves the existence of a Victor-type ‘hiatus’ which ever disproves AGW.