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Use and abuse of climate simulations

Some of you may be interested in Gavin's Schmidt's forthcoming talk  at Exeter University. It's hard to deny his expertise in the area.

Climate change is now a constant presence in the media with many stories about the latest records in global heat, Arctic ice loss, sea level rise, or the potential for changes in extreme weather. But many people still have questions about how scientists study the Earth system, where the dramatic predictions of future change come from, and how credible they are.

In this talk Dr Schmidt will discuss the use and abuse of climate simulations, how they are used to attribute changes in the past and what they suggest for the future. He will specifically discuss how global society now has to choose its own adventure and what the implications of these choices will be.

Details here.

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Reader Comments (186)

There is a troll at WUWT who call himself "Griff" who could be Phil's twin, in style, bad faith, deceptive cut-n-paste, religious zealotry and ignorance just received a definitive schooling that is quite memorable. My smart phone makes links rather difficult, so please just peruse the recent Polar bear thread, if you have not yet done so. As I consider PC, he is not as clever as Griff has been and is clearly less capable. PC relies even more on the true believer tactics than did Griff. His obsession with McIntyre seems both personal and based on deceptively misquoting Steve, for instance. But here we can just watch PC demonstrate how fanatics deal with their failing belief systems.

Dec 15, 2016 at 12:24 PM | Unregistered Commenterhunter

'Griff' got mercilessly savaged by the inmates at WUWT for musing

BTW: does Susan [Crockford] actually have any qualifications to speak about bear populations?

She does not research or publish (scientifically) about bears, nor is she involved in the biology of arctic populations, so far as I know.

Which seems odd as the lady herself, who holds a PhD in dog evolution, concedes that I am a different kind of polar bear expert than those that study bears in the field but having a different background means I know things they do not and this makes my contribution valuable and valid.

And her list of peer-reviewed studies includes a number on polar bear populations that approximates to none.

I think Griff may have a point.

Dec 15, 2016 at 2:08 PM | Unregistered CommenterPhil Clarke

Exactly, Hunter. Phil Clarke likes to attack the person, not their research. In the case of polar bears, it is easy to see why; They have increased dramatically in numbers since we stopped shooting them in numbers. They are doing quite well, thank you very much. Susan Crockford is a qualified zoologist, and people can decide for them selves by reading her website:

She is at least as well qualified to talk about her subject as most self-styled "climate scientists", who generally appear to claim to be experts on everything under the sun, whether they specialised in it or not.

Dec 15, 2016 at 2:17 PM | Unregistered Commentermichael hart whit, Gavin Schmidt, who trained as a mathematician, in which he may well have some skill. But that doesn't stop him being lauded as a climate-guru.

Now I believe people can indeed achieve expertise outside of their original speciality, but climate propagandists don't like to concede this when confronted by valid criticisms from technically qualified people who are outside of their little clique...

...and a little clique it is, when you compare the climate field to the rest of science that is being tarred with the climate toilet-brush.

Dec 15, 2016 at 2:23 PM | Unregistered Commentermichael hart

Dec 15, 2016 at 2:36 PM | Unregistered CommenterPhil Clarke

"it is not trivial – but neither is it hugely important."

This should be quoted whenever a scientist tries to convince us that he or she is not being political. This is the greatest non-answer answer in the history of fudging answers.

Dec 15, 2016 at 5:57 PM | Unregistered CommenterCaligula Jones

Dec 15, 2016 at 2:08 PM | Phil Clarke

You do know that one of the skills sets that a professional polar bear counter is supposed to have is the ability to fly over open water and count white things in the water that may, or may not be, dead polar bears, right?

Dec 15, 2016 at 6:06 PM | Unregistered CommenterCaligula Jones

My favorite, by far, cameo of Schmidt is him refusing to be seen on the same TV stage with Roy Spencer. Worth looking that little gem up and linking it.

Dec 14, 2016 at 1:18 AM | Unregistered Commenterkim

You're welcome, Kim. TV presenter John Stossel had Roy Spencer vs Gavin Schmidt on his program, but Gavin Schmidt only appeared with the proviso that he didn't actually have to sit next to Roy Spencer and debate science with him.

This is the kind of “scientist” that Exeter University is inviting to give a presentation. Donald Trump takes office about nine days after this talk. In the unlikely event that any of his advisers ever read Bishop Hill, they might wish to take this into consideration.

Dec 15, 2016 at 7:36 PM | Unregistered Commentermichael hart

Peer Reviewed Climate Science is consistently wrong, as McIntyre has demonstrated (without thanks or payment from the Peer Reviewers or Climate Scientists, who all seem to know each other's work quite well) Trump may be seeking advice on which bits of Climate Science are worth keeping.

I expect he will ask Myron Ebell for advice.

President Obama appointed John Holdren has his Science and Technology Adviser, and has caused many of the problems in Science and Technology that Trump now has to deal with. Back in the 1970s, John Holdren contributed to work on the Ice Age scare, that Climate Science now pretends never happened.

Dec 15, 2016 at 9:46 PM | Unregistered Commentergolf charlie

The Impending Collapse Of The Global Warming Scare?

Dec 15, 2016 at 9:50 PM | Unregistered CommenterDave Salt

Dec 15, 2016 at 9:50 PM | Dave Salt

Excellent link! A neat summary of the hole that climate scientists have dug for themselves.

Dec 15, 2016 at 10:31 PM | Unregistered Commentergolf charlie

Mere ground preparation for early excuses to the hysterical over-reaction of a very obvious el-nino driven 'hottest ever' year (in reality a dead heat with 1998) prior to the coming la-nina cooling which will be prove to be highly embarrassing.

Yes global society indeed has to choose between the comfort and prosperity (and perhaps even a little benign & beneficial global warming) brought about by cheap energy and the new dark ages of energy scarcity that the hypocritical, ivory-tower new romantic luddites are determined to foist on us all. Gee I wonder what they'll choose.

Dec 16, 2016 at 1:31 AM | Unregistered CommenterJamesG

Dec 15, 2016 at 2:08 PM | Phil Clarke

Phil Clarke, why is it that Susan Crockford is right about Polar Bear numbers, when all those Polar Bear experts trying to spread panic are wrong? Why do you constantly criticise and attack those that can do maths, when Climate Science's approved experts can't?

There is not going to be much left of anything connected with Climate Science once it has all been subjected to proper Auditing, so it is going to be quicker and cheaper for Trump to discard 100%, not just 97%.

Dec 16, 2016 at 7:04 AM | Unregistered Commentergolf charlie

American mid west to experience the coldest wind chill for several years when Winter storm passes over.
Jaysus American weather is so naturally extreme...

Dec 16, 2016 at 10:53 AM | Unregistered CommenterThe Dork of Cork

DoC, your comment, "American weather is so extreme" is spot on. But it is true for nearly everywhere on our stormy planet. That it has always been so is what the climate change movement has tricked people into forgetting.

Dec 16, 2016 at 11:59 AM | Unregistered Commenterhunter

"Rashit Herimentov at Climate Audit. Rashit is a distinguished field dendrochronolgist"

How can a tree driller be seen as 'distinguished'?

Dec 16, 2016 at 2:53 PM | Unregistered CommenterCapell

"Which seems odd as the lady herself, who holds a PhD in dog evolution, concedes that I am a different kind of polar bear expert than those that study bears in the field but having a different background means I know things they do not and this makes my contribution valuable and valid."

Well, it appears Crockford can also count bears, a skill that seems to elude many, such as PC.

Dec 16, 2016 at 2:57 PM | Unregistered CommenterCapell

Capell, whether it involves polar bears, or drilling trees, or reading thermometers etc, in Climate Science, "Distinguished" indicates an inability to count, or do simple sums to within +/- 100% accuracy.

Many Climate Scientists are Highly Distinguished, and have received special awards and commendations for their lifetime records of innumeracy.

Dec 16, 2016 at 3:18 PM | Unregistered Commentergolf charlie

What Gavin & gang's use of climate models really proves is that climate change really is caused by human activity. In the same way that any work of fiction is created by human activity.

Dec 17, 2016 at 12:33 PM | Unregistered Commenterhunter

hunter, what Gavin and the Hockey Teamsters have just realised is that CliSciFi went out of fashion in 2016. 97% of people don't believe in it anymore.

Unlike Father Christmas and the Tooth Fairy, there is no point in anyone continuing to encourage belief in Climate Science.

Dec 17, 2016 at 4:04 PM | Unregistered Commentergolf charlie

Unfortunately for dear Gav his faith in climate models is misplaced.

Dec 18, 2016 at 9:16 AM | Unregistered CommenterANH

Phil Clarke:

One can always find some reason to disbelieve any source of information or paper. Susan Crockford may receive a small amount of funding from the Heartland Institute, but the funding for most of those who study polar bears in the field depends on the perception that there may be a catastrophic decline in polar bear population. Russia was in financial difficulty after the fall of Communism and default in 1998, so Rashit Herimentov desperately needed funding for fieldwork from CRU. As a retired mining analyst with decades of experience auditing mining data for potential investor, Steve McIntyre has no need for funding, but still possesses the right skill set for auditing the statistical analyses of paleo-climatologists. However, McIntyre discourages or deletes speculation about people's motivations at his blog, because he believes such speculation is a waste of time. The important thing is the data and whether it was analyzed correctly. McIntyre addressed Rashit's complaints that you cited above. Did you read his answer - to which Rashit doesn't appear to have replied?

McIntrye acknowledged having some data on Yamal from Rashit in the early 2000's. What he didn't have was the PRECISE DATA SET used by BRIFFA to create the Yamal chronology (with extraordinary warming in the late 20th-century). That chronology was used in most reconstructions of MWP temperature, because it showed the greatest warming in the late 20th century. Auditing Briffa's work (as he had done with Mann's hockey stick) required access to the data Briffa used and then refused to provide for almost a decade. When a journal editor finally demanded that the raw data be shared (a normal scientific requirement for publishing in many journals), the world learned that the extraordinary warmth in the late-20th century found at Yamal had been calculated from far fewer trees than normal, and that only ONE tree showed extraordinary warmth in the late 20th-century. (The post you cited involved other sites near Yamal, where Briffa found additional trees showing warmth in the late 20th century - and McIntyre found other trees nearer Yamal that didn't.)

So how does one know WHAT to believe about a scientific mess like this one. Well, one can look at Briffa's actions. One can also learn that the tree line at Yamal during the MWP was FURTHER NORTH than it is today - qualitative, but not quantitative, information about relative temperature. (We don't know how long it takes for a tree line to move north in response to warming.) One can read in the scientific literature about the "divergence problem", a well known phenomena where many trees at the northern tree line are known to have NOT grown wider tree rings in the warmer late 20th-century. When you have a reasonable background, you can then compare what ClimateAudit and RealClimate have to say on these subjects and decide what to believe. However, if you simply read one side of the issue at highly politicize blogs that don't really go into the scientific evidence in depth, all you will know is what highly politicized blogs want you to know. In that case, don't waste your time commenting here.

As for the bottom line about polar bears, orbital mechanics (the apparently driver of ice ages) caused the northern Arctic to be extraordinarily warm during the Holocene Climate Optimum" 7000-5000 years ago. The passage below is from Wikipedia.

The Holocene Climate Optimum warm event consisted of increases of up to 4 °C near the North Pole (in one study, winter warming of 3 to 9 °C and summer of 2 to 6 °C in northern central Siberia).

It was so warm that the northern tree line was the Arctic Ocean, far north of where it is found today.. Polar bears and the Greenland Ice Sheet obvious survived these two millennia of warmth, though the subpopulations of bears living furthest south may not have survived. Today, polar bears thrive from the northernmost islands in the Arctic all the way to the southern Hudson Bay and Labrador. This suggest that they can adapt to a wide variety of climate. If any populations are declining, climate change may not be the cause. This doesn't mean that a half-century or more from now that the polar bears might only survive at the northern end of their current range and that some of the GIS won't have melted. However, CURRENT changes are not catastrophic and future changes depend on climate sensitivity, which even the IPCC recognizes is highly uncertain.

Dec 18, 2016 at 10:01 AM | Unregistered CommenterFrank

Frank, your excellent thoughtful summary is likely wasted on the addressee of your post. Fanatics seldom want thoughtful replies.

Dec 19, 2016 at 10:19 AM | Unregistered Commenterhunter

"Beth, You are a deluded, McIntyre-worshipping, unsceptical, selectively-quoting idiot."

Beth, please ignore. Phil Boy is a classic example of a rude & unpleasant little boy growing up into a rude and unpleasant 40-something.

I'm sorry you were insulted here. PC will never apologise to you, but I'm afraid that such is the way with half-baked fanatical onanists such as him.

Dec 19, 2016 at 12:47 PM | Unregistered CommenterJerryM

More of the same here: as WUWT records, the NYT sees healthy, well fed polar bears scavenging food at a rubbish tip during a season when polar bears are usually cited as not normally having food available (little baby seals, in the spring).

It takes the special kind of global-warming intelligence to assert that this is because these healthy, well-fed polar bears must have come from somewhere else where they were starving. As late as the ~1960s, these five polar bears would probably only have been counted, somewhere else first, with five pieces of lead. The change in hunting laws is why we now get to see such bears feeding on rubbish tips. Nothing to do with global warming. The bears are not stupid (compared to global-warmers, at least) and, like many intelligent mammals, can feed on a variety of food sources, depending on availability and the laziness of any given bear.

And since this thread was supposed to be about Gavin Schmidt, before Phil Clarke went off about polar bears, here's an article from more than 6 years ago about Gavin Schmidt, the mathematician, neither Phil Clarke nor zoologist, lecturing his peers about polar bears (lol, with peers like that...). Funnily enough, many of the links have now gone dead, so Gavin Schmidt's Arctic wisdom may be forever lost to later generations.

Dec 19, 2016 at 2:20 PM | Unregistered Commentermichael hart

edit "...more than five years"

Dec 19, 2016 at 2:22 PM | Unregistered Commentermichael hart

Another tell that indicates "climate change" is politics dressed up with science is how the alleged scientists leading the opinions pontificate on the policies of "climate change".

Dec 19, 2016 at 2:54 PM | Unregistered Commenterhunter

michael hart

Thanks. This article appeared below 'your' one

NASA’s Dr. Gavin Schmidt goes into hiding from seven very inconvenient climate questions

Guest essay by Dr. Roger Pielke Sr.

WUWT readers probably remember when the now head of NASA GISS, Dr. Gavin Schmidt, could not stand to be seen on the same stage with Dr. Roy Spencer. Gavin decided to hide offstage while Dr. Spencer had finished his interview with John Stossel, rather than be subject to some tough questions Dr. Spencer might have posed in a debate with him on live TV. Gavin knew he’d lose, so he acted like a child on national TV and hid from Dr. Spencer offstage. It was one of the truly defining moments demonstrating the lack of integrity by mainstream climate scientists.

Dr. Schmidt seems to be hiding from those inconvenient questions again, as Dr. Roger Pielke Sr. writes below

Dec 19, 2016 at 2:56 PM | Unregistered Commenteresmiff

Hunter: I agree that my thoughtful answer is probably a waste on PC, but it helps me sort out the real issues. What are the thoughtful reasons for being a skeptic or a supporter? How do I know I'm not being "brainwashed" hanging around blogs like this one or the ones PC visits? Believing my position is the right one simply because I prefer believing in it is religion and too many people on both sides are behaving like religious zealots.

Dec 19, 2016 at 8:00 PM | Unregistered CommenterFrank

Frank, Michael Hart, esmiff & hunter + others

As a country bumpkin, with some understanding of tree rings and variable growth, the Dendrochronology of Mann's Hockeystick was something I felt comfortable about trusting, as it was "science" laid out in graph form, set out by nature, not computers.

I trusted the science, and did not believe that the world's top climate scientists could possibly have selected, fiddled and abused the raw data.

I was wrong. I admit it. I have no reason to trust those that have abused my trust. There is no way I am going to make the mistake of trusting anyone who fails to denounce Hockey Stick science, or any of the Hockey Teamsters, who continue to profit from the Hockey Stick.

I would not trust them to sit the right way on a lavatory seat, but have no desire to check, so I now simply assume they can't. Of course, if they say they do know which way round to sit on a lavatory seat, why should anyone trust them not to lie?

Cutting off their funding, is a mild punishment, considering their crimes against humanity.

Dec 20, 2016 at 1:12 PM | Unregistered Commentergolf charlie

Golf Charlie: I agree that most temperature reconstructions of the last millennia or two based mostly on TRWs have been a "scientific swamp that needs to be drained" (though Trump isn't capable of making that judgment). TRW's are a lousy temperature proxy, and have been abused for political reasons: the relative temperature of the MWP and CWP. Nevertheless, a few researchers in this field are gradually confronting their problems and are making some progress. One paper I saw showed a dramatically cleaner response of C13 in tree rings compared with TRW or MXD to temperature. That paper clearly showed what a lousy temperature proxy TRWs really are - by showing how much better C13 isotope effects were.

Nevertheless, NONE of the conventional theory of CAGW depends in any way on TRWs or reconstructions of MWP temperature. Scientifically, it would make NO DIFFERENCE if unambiguous evidence of a MWP warmer than today were discovered and every earlier paper were retracted or considered obsolete. The key issue will still be CLIMATE SENSITIVITY. If climate sensitivity is high, then 21st century temperatures will soon be warmer than MWP temperature - if they aren't already! And then much warmer. All Holocene variability looks trivial compared with what high climate sensitivity could bring without dramatic emissions reductions.

The MWP is only important for understanding natural and/or unforced variability in temperature: How likely is it that the 20th century could have warmed as much as it did without a substantial contribution from GHGs? That is mostly a political issue that began with an inappropriate graph in FAR. 20th century warming places few limitations on the range of climate sensitivity - the only scientific issue that really matters. Lewis and Curry find ECS of roughly 1-4 K/doubling and the IPCC's projections are based on models with ECS averaging 3.3 K.

The other thing that "really matters" is the credibility of the scientists that are reporting on ECS. By not "draining the paleoclimatology swamp", IMO they have hurt their credibility on the most important issue, ECS. However, their credibility or lack thereof doesn't change ECS. The feedbacks that control ECS will amplify the warming from radiative forcing by some amount and scientific credibility won't change that amount.

Dec 20, 2016 at 6:23 PM | Unregistered CommenterFrank


We went through a period of more than 10 years where CO2 massively increased and temperature didn't. No amount of moving the goalposts baloney will take away the significance of that.

CLOUD experiment sharpens climate predictions - October 1016

This is a huge step for atmospheric science,” says lead author Ken Carslaw of the University of Leeds, UK. “It’s vital that we build climate models on experimental measurements and sound understanding, otherwise we cannot rely on them to predict the future. EVENTUALLY, when these processes get implemented in climate models, we will have much more confidence in aerosol effects on climate.”

Dec 20, 2016 at 7:04 PM | Unregistered Commenteresmiff

Frank: and if ECS is zero (or irrelevant), what then?

Dec 20, 2016 at 7:19 PM | Registered CommenterRadical Rodent

There are two different worlds.

There is Buddy and his honest, climate model elf pals, noses to the grindstone, plugging numbers into Santa's big computer and coming up with their best estimate of climate sensitivity.

Then there is the world in which liars like Mann, Schmidt and Guardian journalists make dire predictions about the future as if these Legoland models were Newtonian equations.

Dec 20, 2016 at 7:51 PM | Unregistered Commenteresmiff

If climate sensitivity is high, then 21st century temperatures will soon be warmer than MWP temperature - if they aren't already! And then much warmer. All Holocene variability looks trivial compared with what high climate sensitivity could bring without dramatic emissions reductions.[..]
Dec 20, 2016 at 6:23 PM | Unregistered CommenterFrank

That, IMO, still remains the crux of the issue. It was claimed, several decades ago, that global warming disaster would soon be upon us. I took the view that disaster seemed highly unlikely, but we would at least soon find out. Disaster didn't happen. But the alarm got louder, developed into screaming, and started affecting government policies. I thought "another 10 years will surely settle this discussion, one way or the other". Those 10 years have passed, and still disaster shows no sign of appearing above the horizon. Yet hysteria volume is now turned up to 11.

I now recognise that the hysterical alarmism about global warming is simply not going to end. Not his decade. Not the next decade. Not ever. It will be poisoning our political and economic discourse long after I am dead. It is a theory/complaint that cannot be dismissed in one human's life-cycle. That is what the proponents like about it.

And that is a good enough reason for electing a US President like Trump, despite his failings.

Dec 20, 2016 at 9:32 PM | Unregistered Commentermichael hart

Esmiff wrote: We went through a period of more than 10 years where CO2 massively increased and temperature didn't. No amount of moving the goalposts baloney will take away the significance of that.

If you understood anything about chaos and unforced variability, you would know that a single decade is unimportant - weather rather than climate. The trend in the surface record over the last 40 years is 0.18 K/decade (0.16-0.18) and more over land. There is a 10-year period with negligible warming, 0.02 K/decade (I think +/-0.10) that is statistically significantly different from the past 40 years, but the 2015/6 El Nino has restored significant warming (0.10 K/decade or more) for all periods such as 2016-end - today and for the next several years. The Pause is over.

Climate has shifted modestly throughout the Holocene. A decade when temperature "should have" risen 0.2 K (but didn't) is totally MEANINGLESS given the historical record of variability. (I did exposure the over-confidence of the IPCC and the inability of their models to create realistic variability.)

I strongly recommend that you read a short paper by Lorenz, the discoverer of chaotic behavior in weather. The paper was written in 1991, before the hysteria about CAGW. It discusses the challenge of DEMONSTRATING the existence of GHG-mediated warming (attribution) by observing changes on our chaotic planet. The challenge of disproving the existence of GHG-mediated warming from observations is exactly the same. Only the last two pages are critical, the rest simply illustrates the behavior of relevant chaotic systems. If you believe this paper, the IPCC has been over-confident in attribution (because there models are tuned to match the historical record) and many skeptics are over-confident about the meaning of a single decade (or even two).

"Chaos, spontaneous climatic variations and detection of the greenhouse effect"

Dec 20, 2016 at 9:38 PM | Unregistered CommenterFrank


We were lead to believe that CO2 was a greenhouse gas which had a direct effect on global temperature, that one could see in temperature graphs. Up and up they climbed due to human CO2. Unless you can come up with a reason for this (15 year) 'natural' pause, I will choose to apply Occam's principle and attribute it to the fact that climate sensitivity is insignificant.

Dec 20, 2016 at 9:50 PM | Unregistered Commenteresmiff


You might want to read this.

"Questions put to Professor Phil Jones (Director of the Climatic Research Unit (CRU) and a Professor in the School of Environmental Sciences at the University of East Anglia)

Do you agree that according to the global temperature record used by the IPCC, the rates of global warming from 1860-1880, 1910-1940 and 1975-1998 were identical?

An initial point to make is that in the responses to these questions I've assumed that when you talk about the global temperature record, you mean the record that combines the estimates from land regions with those from the marine regions of the world. CRU produces the land component, with the Met Office Hadley Centre producing the marine component.

Temperature data for the period 1860-1880 are more uncertain, because of sparser coverage, than for later periods in the 20th Century. The 1860-1880 period is also only 21 years in length. As for the two periods 1910-40 and 1975-1998 the warming rates are not statistically significantly different (see numbers below).

I have also included the trend over the period 1975 to 2009, which has a very similar trend to the period 1975-1998.

So, in answer to the question, the warming rates for all 4 periods are similar and not statistically significantly different from each other. "

Dec 20, 2016 at 9:52 PM | Unregistered Commenteresmiff

Frank: you do give an interesting slant to the discussion, but I do find it odd that you should dismiss a ten-year trend (though many would argue that it is a longer trend than that), yet attribute great significance to a one-year spike. You might have missed the point that the largest fall in temperatures yet recorded that has occurred in the aftermath of the 2015-16 el Niño; perhaps you agree that this should be dismissed as “weather” brought on by la Niña. But, then, perhaps the “pause” is not as over as you suggest.

I do hope that the “pause” (though I always preferred it described as a plateau) is over, and warming can resume. As I get older, and my income becomes tighter, the prospect of warmer winters becomes very attractive – while I welcome years without winter, I dread years without summer.

Dec 20, 2016 at 11:33 PM | Registered CommenterRadical Rodent

Michael Hart wrote: "That, IMO, still remains the crux of the issue. It was claimed, several decades ago, that global warming disaster would soon be upon us. I took the view that disaster seemed highly unlikely, but we would at least soon find out. Disaster didn't happen. But the alarm got louder, developed into screaming, and started affecting government policies. I thought "another 10 years will surely settle this discussion, one way or the other". Those 10 years have passed, and still disaster shows no sign of appearing above the horizon. Yet hysteria volume is now turned up to 11.

I now recognise that the hysterical alarmism about global warming is simply not going to end. Not his decade. Not the next decade. Not ever. It will be poisoning our political and economic discourse long after I am dead. It is a theory/complaint that cannot be dismissed in one human's life-cycle. That is what the proponents like about it."

Brilliant analysis - of the political situation. In an effort to convince policymakers to act, alarmists exaggerated what portion of the science was settled and minimized the role of unforced (chaos) and natural (sun volcanos) variability. They didn't properly discuss the uncertainties associated with AOGCMs. Every projection should begin with, "If our climate models are correct, the ..."

The alarmists don't deserve your trust.

Nevertheless, CO2 is still a GHG. As it accumulates in the atmosphere,1} radiative cooling to space must slow and 2) the retained radiation/heat must warm the planet. 1) The physics of the interaction between GHGs and radiation was worked out beginning a century ago in laboratories - before alarmism about CAGW. 2) Warming is a consequence of conservation of energy. The S-B eqn tells us that dW/dT for a simple blackbody near 255 K (or a gray-body at 288 K with an emissivity of 0.61) is -3.76 (or -3.33) W/m2/K. If we take the reciprocal of these values and multiply by 3.7 W/m2/doubling, you get a no-feedbacks climate sensitivity of 0.98 (or 1.11) K/doubling. This is simple physics.

How will the planet respond to this warming? Where liquid water is in equilibrium with water vapor (near the surface of the ocean and in rising cloudy air), the amount of water vapor - a GHG - must increse and it could rise elsewhere. Rising humidity will decrease the lapse rate, but the reduction in radiative cooling (warming) almost certainly dominates the cooling from lapse rate change. From space, satellites have monitored the large increase in radiative cooling to space associated with seasonal warming (3.5 K) that occurs every year. We know that radiative cooling through clear skies increases by only 2.3 W/m2/K, less than expected for a blackbody. The combined WV+LR feedback in the OLR channels is unambiguously positive - at least in response to SEASONAL warming, bringing climate sensitivity up to 1.6 K/doubling. High climate sensitivity requires strongly positive cloud feedback in the SWR channel. Seasonal warming isn't a great model for understanding feedback in the SWR channel in response to global warming. Climate models disagree significantly with EACH OTHER and with observations about SWR feedback in response to seasonal warming, There is no reason to trust their predictions about global warming.

Tsushima and Manabe, PNAS (2013)

Radical Rodent asks "Why can't ECS be ZERO? An ECS of zero means that dW/dT is very large in magnitude and negative. That way a negligible change in temperature can negate the forcing (dW) from doubling CO2. A negative cloud feedback of about -4 W/m2/K will make ECS around 0.5 K/doubling. -10 W/m2/K will lower ECS to 0.24 K/doubling. -33 W/m2/K will lower ECS to 0.1 K/doubling. There is no way to get to zero. If cloud feedback were this negative, twentieth century warming would have produce 100% cloud cover by now. Climate sensitivity much below 1 K/doubling is probably impossible.

Remember, the deep ocean is composed of a massive amount of polar water that sank with a temperature of only a few degC. When more of that cold water upwells than usual, the surface cools (La Nina). When upwelling slows, the surface warms (El Nino). These phenomena occur chaotically every few years. The PDO, AMO, LIA?, MWP? could also involve such changes - or natural variability in the sun or volcanos. Climate models don't produce much unforced or natural variability, so they have been tuned (perhaps unintentionally) to attribute all observed warming to man. So models didn't predict the recent Pause, nor the 1960's Pause (without excess cooling from aerosols) or the warming ending around 1940.

IMO, the trustworthiness of IPCC scientists doesn't have any impact on the science I discussed above. The seriousness of GW depends on climate sensitivity and the Pause is no guarantee that it will be low. Cloud feedback is critical and uncertain. To minimize the effect of unforced variability, look at the longest warming trends in response to significant forcing. Those trends are between 0.15 and 0.20 K/decade for surface warming, and about half as much for satellite troposphere measurements. Argo is also up.

Dec 21, 2016 at 10:22 AM | Unregistered CommenterFrank

Esmiff and RR: I addressed most of your issues responding to Michael Hart.

RR criticized my analysis of the 15/16 El Nino and the Pause. Perhaps this criticism is valid. I recently spend a long time with Nick Stoke's and Sheldon's trend viewers looking at the confidence intervals for warming over various periods. Was there a statistically significant change during the Pause. Absolutely, but we expect 5% of periods to look statistically significantly different "by chance". Trend viewers make it easy to cherry-pick, one reason I distrust them.

In that process, I was astounded by how much effect the 15/16 El Nino had on trends beginning around 2000. According to linear regression, warming was almost negligible ending in 2013 and is above 0.10 K/decade now. We are still 0.2? K above the plateau in the 2000's. The 15/16 peak will increase any linear regression trend that has this event near the end. In another five years, it will be in the middle of a decade-long trend and not matter at all, but the confidence interval for decade-long trends is very wide, especially with a large El Nino in the middle. As best I can tell it will be a long time before we can have another period with negligible warming and with a narrow enough confidence interval to be meaningfully different from the long term trend of 0.15-2.0 K/decade.

Dec 21, 2016 at 10:48 AM | Unregistered CommenterFrank

Well argued, Frank, though I do feel it is flawed – for instance, by saying that the ECS is around 1.0, you are effectively stating that increasing CO2 has to result in increasing temperatures. So, what happened from 1945-75, when the CO2 continued its rise, yet temperatures fell – and fell to such a degree that we were led to believe that we were heading into another ice age (caused, ironically, by rising CO2 – and a scientific blunder that is frantically being erased from history)? Can you see why there are so many not entirely convinced that CO2 has anything to do with global temperatures or climates?

You also mentioned “unforced variability”; an odd concept, I would have thought, if you were to take on of Newton’s (still valid) laws into account – to paraphrase: there can be no change in state without an external influence; in other words, for there to be variability there has to be some “forcing” (a dreadful term, IMO) to effect such variability. So, do we having “forcings” or do we not?

Personally, I think that there are other influences involved which have yet to be discovered or identified, or are being ignored. While I do not dismiss the role of CO2 out of hand, I feel that it is being given undue credence (and there still has been no strong evidence to support that theory), as we have yet to explain why we have had the observed cycle of heating and cooling over the past few thousand years other than by your rather wishy-washy concept of “unforced variation” – which, if it exists, would be a more realistic explanation of the present situation than just blaming human-produced CO2. Wait! Don’t tell me – ’cos this time, it is humans wot are doing it!

What would you say, should global temperatures start to irrefutably fall?

Dec 21, 2016 at 11:04 AM | Registered CommenterRadical Rodent

Frank, Radical Rodent, esmiff, & michael hart,

as a non-climate scientist, and someone who found Physics the least inspiring of my 3 science "O" Levels, it amazes me that all these equations can be calculated, but everything still depends on the magic "X" factor of fudge, which could range from 0-4.5.

If climate science is based on pure Physics, as certain self proclaimed experts maintain, it just seems strange that ECS is NOT better defined.

Hockey Teamsters take exceptional outrage to the likes of Curry and Lewis, plus others, querying ECS assumed values, therefore I am inclined to agree with Curry and Lewis plus others. It is logical, since Climate Science has never admitted a mistake.

Obviously ECS does not cause La Nina/El Nino and that seems to be the biggest climate control knob.

Dec 21, 2016 at 4:20 PM | Unregistered Commentergolf charlie

Here's a podcast that has an interview with Prof. Curry...
...which reflects much of what Frank has highlighted.

Thank you Frank for taking the time to prepare such thoughtful contributions to this thread. You neatly summarized my understanding and concerns with 'climate science', or at least the version of it that activists would have the general public believe is the absolute 'truth'.

Dec 21, 2016 at 7:38 PM | Unregistered CommenterDave Salt

Frank, the consensus science which you retail is tainted by the CAGW meme.

Dec 21, 2016 at 7:42 PM | Unregistered CommenterBudgie

Radical Rodent: The discovery of chaos destroyed the idea that Newton's laws could be used to predict the future evolution of many systems whose physical laws are known. (Chaos wasn't taught when I took college physics.) From Wikipedia:

"Small differences in initial conditions (such as those due to rounding errors in numerical computation) yield widely diverging outcomes for such dynamical systems, rendering long-term prediction of their behavior impossible in general. This happens even though these systems are deterministic, meaning that their future behavior is fully determined by their initial conditions, with no random elements involved.[4] In other words, the deterministic nature of these systems does not make them predictable.] This behavior is known as deterministic chaos, or simply chaos.

The theory was summarized by Edward Lorenz as: Chaos: When the present determines the future, but the approximate present does not approximately determine the future".

Please read the last two pages of the Lorenz paper I cited above. In this paper, Lorenz speculated about what could be conclude if temperature rose for another decade given what we know about unforced variability. He believed we would not be able to draw any conclusions from warming alone. As it turned out, we got that decade of warming and it was followed by the Pause! Then he discussed whether climate models could be used to attribute warming to an enhanced GHE: Not if the models are tuned to match the historical trend!

When our climate or weather varies, the explanation does not have to be a change in the net flux of radiation to and from space; it can be due to a chaotic fluctuation in fluid flow exchanging heat between the deep ocean the surface. We call former "forced variability" (anthroopogenic, GHGs and aerosols; natural: volcanos, sun, aerosols) and the later "internal or unforced variability". El Nino is a complicated phenomena, but slowing of upwelling of cold water off South America is a key component. Before April, no one is able to look at the current state of the Pacific and predict whether an El Nino will develop the following winter. Nor can we forecast the weather 20 days into the future.

Most climate scientist assume that the LIA and MWP and similar periods of variation were "naturally forced" by changes in the sun or volcanic eruptions, but I include "unforced variability" as a possible cause. ENSO, AMO, PDO, etc are assumed to be unforced variability.

If the temperature were to fall 1 degC over the next decade without a major eruption or change in solar output, I would assume that unforced variability would be the cause and that rising CO2 is still warming the planet at 0.15-0.20 K/decade as it appears to have done for the last 40 years. I presume that ARGO would tell us where all the cold water was coming from that cooled the surface (without a change in the planet's energy balance). Nevertheless, my confidence would decrease. However, the minor warming in 1920-1940 and the Pauses in 1960s and 2000s are don't shake my confidence at all. They appear to be are relatively common. Whatever their cause, LIAs and MWP of 1 degC are precedented. If ECS is high, CAGW will be unprecedented in the Holocene. (Which brings us to the big problem of ice ages - which I won't discuss except to say little global forcing is involved.)

My assumption is that climate models have been tuned (intentionally or unintentionally) to attribute roughly all warming to anthropogenic forcing and little to unforced variability. They produce little unforced variability, not enough to explain the Pause or 1920-1940. Early models didn't produce an ENSO, now they show something resembling an ENSO. Early models didn't show a QBO (a change in wind direction in the stratosphere every OTHER year), but adding more and smaller grid cells to the stratosphere produced models with a QBO. The GFDL model produces more unforced variability than others. IMO, the Pause has invalidated models to the extent that I can say models produce too much warming OR too little unforced variability.

Dec 21, 2016 at 8:24 PM | Unregistered CommenterFrank

Golf Charlie: "If climate science is based on pure Physics, as certain self proclaimed experts maintain, it just seems strange that ECS is NOT better defined."

In addition to physics, AOGDMs rely on adjustable parameters to describe the physics of phenomena that occurs on too small a scale to model in a grid cell: condensation, precipitation, and turbulent mixing. Saying climate science based on pure physics may be the worst deception of the consensus.

Lewis and Curry are not the only ones to have recognized that observed warming and forcing agree with 3 K as the best estimate for ECS ("energy balance models"). Lewis and 11 authors from the Chapter of AR5 on ECS published an earlier paper (Otto 2013) discussing the same subject. Because of the disagreement between AOGCMs and energy balance models, AR5 did not offer a best estimate for ECS - unlike all earlier reports. And their projections for the next few decades are for only modest warming (0.3-0.7 K). Nevertheless, the rest of the report ignored these problems and offer only projections from AOGCMs without explaining that other evidence suggests that the low end of their range is more likely than the bottom. More deception from the climate science consensus. However, the disagreement between AOGCMs and energy balance models is the subject of ongoing research and controversy.

ENSO is obviously a control knob from year to year. Your weather varies chaotically from day to day. Seasonal changes in your weather vary with the angle of the sun above the horizon. What is the control knob of your environment? Imagine January 1 was 1900 and today is now March 1 (slightly warmer) and these two months are the only experience we have had with seasonal warming. Some scientists predict that when the sun is at its highest point in June, it will be 1.5 to 4.5 K warmer than it is today. Others say 3-9 K warmer. Fundamental physics says the angle of the sun (like radiative forcing from CO2) is critical to energy balance and future warming. Others say it is colder when the wind comes from the north and warming from the south - that is the main control knob.

Dec 21, 2016 at 8:55 PM | Unregistered CommenterFrank

Frank, thank you for the further explanation, and added question marks about climate science.

I am not qualified or experienced in climate science, but it just gets more unsettled. I have been involved in trouble shooting after things have gone wrong, and the more confident "experts" are, about why they were not wrong, the more suspicious I get.

97% of Climate Scientists have been consistently incapable of finding fault in their own peer reviewed work, and will remain incapable whilst they remain in outright Denial that they ever got anything wrong. This actually makes it simple for Trump and his appointed officials in determining which Climate Scientists represent value for money, and have scientific reasoning that is logical, and worth further funding.

is there a scientific and/or experimental way of narrowing the range of ECS, even if a precise number can not be determined? Were the extreme scenarios and scaremongering all dependent on a high value of ECS, in which case, all the scary scenarios can be scrubbed from the tabloid science reporting that has proved so lucrative for 97% of Climate Scientists, but so damaging and expensive for everyone else.

Dec 22, 2016 at 12:04 AM | Unregistered Commentergolf charlie

Computers cannot model the earth's climate or forecast the future. It's a ludicrous idea with current knowledge.

In 1998 (circa Kyoto), we were told were were standing on the cusp of catastrophe, a thermal tipping point. In the 15 plus years following, CO2 hugely increased and temperature did not increase at all. That was climate science's only chance of credibility and it fell on its face. Then there was Climategate.


The article above that clearly states models are inadequate

It’s vital that we build climate models on experimental measurements and sound understanding, otherwise we cannot rely on them to predict the future.

Freeman Dyson

Phil Jones demonstrating that the alarmist's favourite period (1975-1998) , the one that allegedly showed hugely faster increase in temperature is no different from 1860-1880 or 1910-40

Dec 22, 2016 at 1:07 AM | Unregistered Commenteresmiff

Budgie wrote: "Frank, the consensus science which you retail is tainted by the CAGW meme."

And if I wrote the same comments at another web site, equally close-minded there people would say "the skeptical science you retail is tainted by Denial".

Both are meaningless responses in a scientific discussion.

Dec 22, 2016 at 4:33 AM | Unregistered CommenterFrank

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