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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

Recommended supplemental reading:

Climate Change Denial: the Lysenkoism of the present-day Republican Party by Dr. Kevork N. Abazajian, 314 Action, Apr 5, 2017

CBDunkerson at 21:39 PM on 6 April 2017

Sea ice falls to record lows in both the Arctic and Antarctic

On those PIOMAS numbers... it looks like the yearly max volume now is roughly equivalent to where the yearly min volume was in 1980. Meanwhile the minimum has dropped ~80% and is now approaching zero.

Which would mean that a continuing linear trend, let alone the accelerating decline which has actually been going on, would result in the Arctic being nearly ice free year round by ~2060.

Jim Hunt at 16:51 PM on 6 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

John @5 - You are certainly not the only one:

http://AFWetware.org/2017/03/20/a-letter-from-wonderland/

Reality is now more surreal than the imaginative writers of previous eras could conceive?

Jeff @7 - I watched the whole show live, and I agree with you (and Tom) that Michael Mann was not the best choice in all the circumstances. Another option advocated by retired Rear Admiral David Titley was a boycott of such hearings by climate scientists:

Should Climate Scientists Boycott Congressional Hearings?

In the past, the science community has participated in these hearings, even though questioning the basics of climate change is akin to holding a hearing to examine whether Earth orbits the sun.
Enough!

Would such action get the message across more effectively? Or not?

Jim Hunt at 16:27 PM on 6 April 2017

Sea ice falls to record lows in both the Arctic and Antarctic

In addition the PIOMAS Arctic sea ice volume numbers for March 2017 have just been released:

http://GreatWhiteCon.info/2017/04/facts-about-the-arctic-in-april-2017/#Apr-4

As expected Arctic sea ice volume is still by far the lowest in the PIOMAS record, and seems certain to result in another "minimum maximum" this year.

Volume on March 31st 2017 was 20.398 thousand km³. The previous lowest volume for the date was 22.129 thousand km³ in 2011.

Tom Curtis at 14:51 PM on 6 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

Jeff T @7, I have not watched the testimony, and so cannot comment on the relative merits of each performance. I agree with you that Michael Mann should not have been the witness chosen by the Democrats (if he was in fact chosen by them). It is very clear that the chair wanted to stack the deck. Essentially the 97% of climate scientists who agree with the consensus got represented by Michael Mann. The 1% who are uncertain got represented by Roger Pielkie Jr and Judith Curry, and the 2% who are definite "skeptics" were represented by John Christy. Whilst the chair insists on an effective gag on the vast majority of climate scientists, the Democrats should invite a different climate scientist to each such hearing. Over time, this will highlight that the Republicans always invite the same people because they really do not have that many to choose from.

Jeff T at 13:55 PM on 6 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

The hearing was (or should have been) an embarrassment to most participants. Michael Mann was a poor choice for the Democrats' invitee. He's much too combative to sway any fence-sitter in his direction. Yes, he was the object of a political witch hunt and has received a great deal of vitriol, but those facts aren't effective arguments for his scientific positions. Judith Curry was her usual we-don't-know-enough-to-say-anything-about-anything self.

An especially telling exchange occurred at 1:08 in the recording. Rep. Brooks said that sea level ought to fall in response to global warming. John Christy avoided the awkward moment by deferring to Curry, who hemmed and hawed about East and West Antarctica. Isn't she a big fan of satellite data? Not wanting to cross her sponsors, she missed an opportunity to educate them and gave Mann the chance to mention that we have good data showing that Greenland and Antarctica (as a whole) are both losing ice mass. That was Mann's best moment.

I'm not a fan of his, but I thought Roger Pielke, Jr came out best. He kept quoting IPCC, mostly stayed out of the "you attacked me before I attacked you" conversation, and managed to contradict his sponsors.

Bob Loblaw at 10:25 AM on 6 April 2017

We're heading into an ice age

I remember as an undergrad in the 1970s that an open Artic Ocean was thought to be one possible way of creating enough precipitation to initiate the growth of continental ice sheets - i.e. initiate a glacial period.

I also remember that the 1970s was a period where much of the knowledge of glacial geology in Canada's Arctic was being re-written. Flynn's (?) massive single Laurentide Ice Sheet idea was losing to the idea of several ice domes and much more complex movements. (I was a lowly field assistant working in Canada's Keewatin District, on the west side of Hudson's Bay, on research that helped definitively establish the Keewatin Ice Divide as a long-standing feature, not the late glacial feature that it had been claimed to be.)

So, the idea that moisture from the Arctic Ocean could lead to glacial periods was a serious idea at the time. Knowledge of the systems and causes are much greater now.

Tom Curtis at 10:10 AM on 6 April 2017

We're heading into an ice age

scaddenp @374, I was, and apologies to both ladies.

scaddenp at 09:49 AM on 6 April 2017

We're heading into an ice age

Tom, I think you are confusing Betty Friedan (author idea that open arctic might trigger ice age), with Anne-Marie Blackburn (Sks author of Milankovich article).

Tom Curtis at 08:45 AM on 6 April 2017

We're heading into an ice age

DaveMartsolf @372, adding to scaddenp's comment, I would note that Flanner et al (2011) measured the albedo feedback from snow and ice between 1979 and 2008 (see here for discussion). As can be seen from the second panel of the figure below, the only month in which the albedo feedback had increased over that period was October, and that by a very small amount. It in no way compensates large increases from March through to July:

A more recent review finds a global Snow Albedo Feedback of 0.1 W/m^2 per degree K, but that is significantly increased over spring, amounting to a 1% decrease in surface albedo per degree K over spring.

In either case the effect of a more open Arctic sea has been to decrease the snow albedo effect, resulting in further warming. That has been despite some indications of a thicker snowpack in the depths of winter, particularly January. The increased snow depth in winter has minimal impact because winter days are much shorter in the relevant latitudes, and the sunshine weaker durring those days. Despite the thicker snow pack, however, it continues to melt earlier, just as the sunshine strengthens and the days lengthen. The result is an overall increase in albedo. There is minimal effect in the late summer because by that time nearly all the snow pack, except at high altitudes, has already melted.

Overall, Anne-Marie Blackburn's idea, as described by you, is an interesting one, but appears to be failing the empirical test. It also contradicts the current understanding of the causes of glacials and the end of interglacials. In relation to the later, and as shown by the Vostock and Epica C ice cores, declines from interglacials to glacials tend to be long drawn out affairs (unlike the very rapid transitions from glacial to inter glacials). That is the opposite of what would be expected if Blackburn's idea had merit:

Leto at 08:29 AM on 6 April 2017

A Perfect (Twitter) Storm

"Obviously, condescension is a one way street on this site."

JF. Don't blame Tom and Rob for my comment. They have been very patient.

I'll leave you guys to it.

Moderator Response:

[DB] Mr Fornaro has recused himself from further participation in this venue, finding the burden of complying with the Comments Policy too onerous.

scaddenp at 07:52 AM on 6 April 2017

We're heading into an ice age

Dave, I have a couple of objections to idea that ice-free arctic would trigger an ice age.

Firstly, an historical look (something not known in 50s). Last time we had 400ppm of CO2 and open water was Pliocene and we didnt have an ice age cycle then (but still have milankovich cycles).

But why?

A warming world will certainly have more precipitation and for cold, wet parts of the globe it will certainly mean heavier snow falls. However, an open arctic ocean is still freaking cold so the contribution to water in the atmosphere from arctic basin is small compared to the warmer oceans elsewhere. An open arctic isnt going to be trigger point.

But could thick snows more than offset the albedo loss from having dark water instead of ice in the summer arctic ocean? The forcing of the ice ages from Milankovich cycles implies that critical factor is persistance of snows around 65N through summer. In cold part of the cycle, there is not enough radiative heat to surface to melt the snow. The summer extent is more important for global albedo than winter. Summer extent continues to decrease implying there is more than enough heat to melt the winter snows even as they get heavily.

PluviAL at 06:45 AM on 6 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

I don't think you can comment about this article without being political, and you should not. This is politics; the intention is to discredit the scientific evidence because the objective is to mislead. The job is not up to scientists, it is up to politicians and political leaders to get us on the right road.

What we need is a vision of where we want to go and how to get there. That is what is lacking. I feel that the Trupm distortion is leading to a certain debacle, the sooner, and the bigger the better, so as to project us in some direction.

The direction we want to take is solutions:

a) reduce carbon, and shift to renewable sources

b) Re-fit cities and social orders

c) Develop truly new solutions (what I work toward)

You will go crazy trying to make sense out of words and deeds that are meant to mislead and obfuscate.

DaveMartsolf at 05:00 AM on 6 April 2017

We're heading into an ice age

The first hyperlink above was mistyped and should be Milankovitch Cycles. The second link to "The Coming Ice Age" is not directed properly and I don't know how to fix it. The Harpers URL works only sporadically, so to those interested in this bit of ancient history I can only suggest Googling a term such as "The Coming Ice Age Harpers" and look for the link in the search results. My apologies for this inadequacy. Another good book for detailed descriptions of Blackburn's original response submission is the book The Ice Chronicles by Paul Mayewski et. al., 2002.

Rob Honeycutt at 04:28 AM on 6 April 2017

A Perfect (Twitter) Storm

Thanks, Tom. It strikes me that JF is potentially trying to focus on an element of #6 to make an "incontrovertible" argument of persuasion, and is actually looking for the opposite. My suspicion is that he's purposefully creating a straw man argument by ignoring all the other elements that are actually incontrovertible.

"My question will not be answered, and I know why" is a strong indication that he's been persuing a specific answer all along.

DaveMartsolf at 04:16 AM on 6 April 2017

We're heading into an ice age

Thanks JH and PS. This topic appears to be the most relevant to my question, and my apologies as a newbie if it has already been debunked somewhere in the past 360-odd comments.

I am familiar with the arguments against a new ice age coming any time soon submitted by Anne-Marie Blackburn (the discussion of the <href="https://www.skepticalscience.com/Milankovitch.html">Milankovitch Cycles and the CO2 emissions override to which Daniel Bailey added the effects of solar insolation contained in the header's Intermediate tab.

My idea comes as old memories from research I made in preparation for my 7th grade geography class term paper on the ocean floor in 1962. At that time I had read a 1958 article published in Harpers written by Betty Friedan called "The Coming Ice Age" that proposed that an open water Arctic Ocean could essentially jump-start a new ice age by saturating the usually very dry Arctic air with moisture that would in turn increase winter snowfalls to the point that increased albedo from snowpack in the northern hemisphere would create a feedback loop that would continue the snowfall throughout the year in these latitudes.

Of course, if you read that entire article you can poke holes in all manner of the supportive evidence since the science at that time was just in its formative years. But, I wonder about the central premise because the catalytic state of an ice-free Arctic Ocean is soon to be achieved. And, just as one releases the choke on one's snowblower after getting it started, I wonder if the world's now-underway switch from fossil fuels to renewables (turning off the choke) will remove the CO2 threat over the next century just at the time when it would be helpful to mitigate against the snow cycle about to come. I would appreciate your views on this idea.

Tom Curtis at 03:04 AM on 6 April 2017

A Perfect (Twitter) Storm

Rob Honeycutt @90, excellent summary. I woud add that we have a far firmer idea of the low end of possible sea level rises (mostly determined by thermal expansion of sea water) than we do of the high end. We also have some reasonable empirical and model based estimates of the final (equilibrium) sea level rises due to increased temperature, with 7 meters or more for the 2 C that current policy aims at, and 20-50 meters for the likely range of end century temperatures with BAU. What is not known is how long it will take to reach that equilibrium level. From those estimates it follows that a low rate of sea level rise in the 21st century means a longer period to reach equilibrium (which is good news), but it does not mean we will not be dealing with 7 plus meters of sea level rise in the long run.

Rob Honeycutt at 02:43 AM on 6 April 2017

A Perfect (Twitter) Storm

JF... Let's think of this another way, in terms of scientific confidence and risk.

1) Global mean temperature is rising: High level of confidence.

2) Rising CO2 is the primary factor in rising temperature: High level of confidence.

3) Rising CO2 is due to human activities: High level of confidence.

4) Rising global temperature will cause ice sheets to lose mass: High level of confidence.

5) Ice sheet losses will lead to sea level rise: High level of confidence.

6) Rate/pace of ice sheet losses: Low level of confidence.

From this you can easily determine that (a) sea levels will rise as we continue to add CO2 to the atmosphere, (b) we don't know exactly how quickly the sea level rise issue will play out. There is virtually no doubt this is occurring. The evidence is already incontrovertible. There is significant risk that this will play out faster than models are telling us.

John Mason at 02:04 AM on 6 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

Does anybody else share the feeling that they've gone to bed at night, only to awake the next day and find themselves in the middle of Alice In Wonderland?

Rob Honeycutt at 01:54 AM on 6 April 2017

A Perfect (Twitter) Storm

JF... When you use a terms like "scalar transformation" and "abscissa" it implies that you're working with actual data rather than a graphic representation of data. So, far I've seen no evidence of this.

"At what point can we measure sea level rise and point to that rise as incontrovertible evidence that one or more of these models is accurately predicting sea level rise?

My question will not be answered, and I know why."

Excellent! That must mean you now grasp that the question is irrelevant.

It's rather like asking when you can measure the impact of the speeding train as it crashes into your body instead of measuring the speed it's approaching you ahead of time.

As has been repeated many times over, sea level rise is a function of ice sheet dynamics. That is the entire story.

Look, JF. There is no magic bullet here. There is no one graph that you're going to create that is going to convince people who don't want to be convinced. There is an abundance of compelling graphical representations of the science on climate change out there. Any one graph (sea ice retreat, global mean temp, CO2 levels, ocean heat content, sea level rise, changes in animal migration patterns, seasonal patterns for plants, storm intensity, etc, etc) should be enough to give any rational person pause to think about this, and collectively should convince anyone that this is real and very serious.

The problem is that the people who refuse to believe it are doing so because of other reasons. No graph, no matter how incontrovertible, is going to fix that.

I have a suspicion that's not what this conversation is actually about for you, though.

MA Rodger at 00:50 AM on 6 April 2017

A Perfect (Twitter) Storm

JohnFornaro @87.

The question you pose is:-

"At what point can we measure sea level rise and point to that rise as incontrovertible evidence that one or more of these models is accurately predicting sea level rise?"

We can measure sea level with enough accuracy to plot a global value for Sea Level Rise. We can therefore check whether the SLR projected by "these models" are consistent with the measured values. I would assume that when you talk of "these models" you refer to the graphical representations of SLR presented @40 and @39. Note that these projections of SLR derive from work carried out in 2012 or 2013. That is, the graph presented @40 is sourced from Horton et al (2014), a paper submitted in 2013. And that presented @39 derives from Bamber & Aspinall (2013) submitted in 2012. This means SLR data measured after "these models" were completed includes data beginning from mid-2013. Thus the SLR data as graphed @73 already includes three years of such data, a length of period you have suggested would be adequate.

Assuming all this conforms to the intention of your question, the only part of the question remaining outstanding is whether 3 years of SLR data would be adequate for the establishment of "incontovertible evidence" that "these models" are "accurate." As I made plain @77, I'm not sure what it is you are attempting to establish 'incontrovertibly', what particular aspect of "these models" you hope to estabish as "accurate" but 3 years doesn't seem long enough for anything useful to be learned given the lumpy nature of global SLR data.

JohnFornaro at 23:01 PM on 5 April 2017

A Perfect (Twitter) Storm

Leto @ 85: "...scalar transformation is fine..."

Of course it is. Rather than discuss data, I'm being criticized for scaling the data to present the information to a policymaker in an easier to understand fashion, because persuading policymakers is the fundamental task at hand.

JF @ 53: "As a technical point, this graph [ http://sealevel.colorado.edu/ ] is in millimeters, and the graph @40 is in meters.

If policy is to be changed by effective persuasion, then it would be requisite to paint all the graphical pictures at the same scale. Scott Adams may not have any good knowledge about the climate, but he does have good knowledge about persuasion."

The objection made was this: "...if our elected representatives cannot cope with the mental difficulty of understanding a change in scale, there is no hope of persuading them of the actual science and it implications."

JF @ 56: "I pasted the colorado.edu graph mentioned above over the graph @40, squeezed it down to about the right scale at least on the abscissa. The ordinate of the colorado.edu graph should be flattened even more. 1 cm barely registers."

Then the objection became: "In other words, whether squashing (or "squeezing", as you originally termed it) two data series together is more persuasive is irrelevant."

I clarified by mentioning scalar transformation.

Then the objection became: "No, merely squashing a chart down is not — in any way, shape or form — a substitute for real analysis."

Then the argument became "'Squeeze' was your original term, not mine." Of course I used "squash", but hey.

My question [@ 42] is pretty simply stated:

At what point can we measure sea level rise and point to that rise as incontrovertible evidence that one or more of these models is accurately predicting sea level rise?

My question will not be answered, and I know why.

Persuasive evidence, measured in the real world, such as, for only one example, a 4cm rise in sea level in only three years, is not necessary, personal criticism is.

Leto: "Just keep in mind that you are conversing with people who understand this material better than you do."

JH: "Your [JF's] condescending tone is neither warranted nor welcome."

Obviously, condescension is a one way street on this site.

Moderator Response:

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Jim Hunt at 22:51 PM on 5 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

My own thoughts on last Wednesday's events:

The House Science Climate Model Show Trial

Some highlights from my Transatlantic perspective:

The denialosphere is of course now spinning like crazy attempting to pin something, anything, on Michael Mann.

not to mention:

Why on Earth Judith chose to repeat the “CAI” allegation is beyond me.

and:

Given our long running campaign against the climate science misinformation frequently printed in the Mail on Sunday it gives us great pleasure to reprint in full the following extract from [Mann’s] written testimony:

I'm currently doing battle with Steve McIntyre and other "skeptics" on Twitter over his assertion that "the CV contradicts his lie" regarding Mann's alleged CAI "affiliation/association".

I can only assume that Mr. McIntyre has neglected to watch the above video of the proceedings. I even managed to persuade one of Judith Curry's "denizens" to take on board my point of view about that contentious issue!

ubrew12 at 20:59 PM on 5 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

I think the persistence of people like Smith, Pruitt, and Inhofe is a sign of the corruption of our democracy by 'dark money'. Anyone familiar with the climate 'debate' knows that if the money went away, or shifted to prefer climate action, action would begin tomorrow. It is still shocking, however, to learn in just how many ways 'dark money' has permeated every branch of 'our' government, as Bill Moyers recently wrote about concerning 'plain vanilla' Supreme Court candidate Neil Gorsuch.

Glenn Tamblyn at 13:25 PM on 5 April 2017

Elevator Pitches - Chapter 02 - Radiative Gases

Interesting find Tom.

And thus maybe rotational isn't a factor in the IR bands for CO. Interesting however that it is a factor for H₂O - another feature to add to waters status as a really 'interesting' molecule.

chriskoz at 10:22 AM on 5 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

bjchip@1,

They SHOULD be going to jail.
Lamar brings his politics to dictate his science. His ignorance is simply a symptom of the destruction of our democracy.
(comment policy violating emphasis original)

I note that rep. Lamar Smith is the democratically elected senator in TX. So he (or his ignorance) is the actual product (rather than destruction) of US democracy. And that democracy is working fine to date: e.g. takeover of Congress seats at each term, takeover of WH by successive administrations; all happenning peacefuly according to Constitution, without any hint of voter fraud. I'd add from myself, that the system is working amazingly well, given its recent absurd outcome of installation the biggest imaginable Moron-In-Chief and Psychopath-In-Chief in WH. Rep. Smith is trying to follow the WH example in his absurd denial of climate science but I think he does not quite match the WH lead because it other aspects of life he may be more reasonable and less disconnected from reality.

My point here is that your logic is wrong in labeling Rep. Smith "a symptom of the destruction of our democracy". Rather, if people follow your calls to sue him and throw him to jail; or "a march, [...] a general strike", and domestic violence is to ensue, then Rep. Smith may be the reason of the "destruction of our democracy".

Moderator Response:

[PS] Your point on democracy is well made but while this thread is a necessarily about politics, your characterizations are over the line on comments policy.

bjchip at 08:30 AM on 5 April 2017

Inconceivable! The latest theatrical House 'Science' committee hearing

Without putting too fine a point on it, Lamar and his fellow travellers are committing treason, damaging the future of the nation for their personal financial gain. That it looks like politics-as-usual is a measure of the degree that the Overton Window has shifted in the USA. They are traitors to the human species.

They SHOULD be getting sued. They SHOULD be getting impeached. They SHOULD be going to jail.

...and that is not happening and not likely to happen until Mother Nature opens up her can of whup'@55 and lays in all of us in about a decade or so, for their hubris and for permitting our hands to be tied by such as them. That will be unmistakably happening by 2030 and we're going to be in dire straits by then.

The alternative is perhaps not a march, but a general strike, possibly the first such in the history of the Nation. The government is in this one specific way, entirely wrong by adopting ignorance as a sacrament.

We HAVE to make it clear that a majority of Americans voted for revolution, not for this ignorance, and that we want them to be draining the swamp instead of importing bigger Alligators. Not just a march now.

What is necessary is something that kicks them hard enough to actually get their attention. To get the attention of the media too. To shift the Overton window on this back somewhere in the vicinity of where we actually live. A serious threat of secession of some regions of the country could also be appropriate. Lamar brings his politics to dictate his science. His ignorance is simply a symptom of the destruction of our democracy.

Moderator Response:

[JH] The use of "all-caps" constitutes shouting and is is prohibited by the SkS Comments Policy. If you want to emphasize a word or words, the use of bold font is acceptable.

DaveMartsolf at 05:25 AM on 5 April 2017

We're heading into an ice age

From the time-stamp history of the past 368 comments I see a drastic slow-down in discussion of this topic in the last 4 years. Is there a better "Arguement" topic in which to post regarding this topic?

Moderator Response:

[JH] Enter "Ice Age" in the search engine and take your picks among the articles that are listed.

[PS] All threads remain open. Regulars use the "Comments" item to view comments so anything added to any thread is visible. If this article has the content you wish comment on then go ahead here, but be sure to read and abide by the comments policy.

John Hartz at 00:48 AM on 5 April 2017

A Perfect (Twitter) Storm

NASA has just updated it's Sea Level Facts webpage. It contains two charts. The first chart tracks the change in sea level since 1993 as observed by satellites. The second chart, derived from coastal tide gauge data, shows how much sea level changed from about 1870 to 2000.

Click here to access this NASA webpage.

Nick Palmer at 22:33 PM on 4 April 2017

Dear Mr President 2.0: the discovery of the Greenhouse Effect - in Tweets

Superb satire

KR at 21:17 PM on 4 April 2017

CO2 lags temperature

malpeli - Long story short with Humlum: if you remove the trend before analysis, then claim from what's left that the trend doesn't exist, you have done your analysis incorrectly. I won't speculate on why his analysis is so poor, but I'll point out that Humlum has a history of similar errors.

Leto at 08:59 AM on 4 April 2017

A Perfect (Twitter) Storm

JF: If you want to keep using the colloquial terms "squash" or "squeeze", as a short hand for a scalar transformation of the ordinate of a graph, that's fine with me.

RH: Squeeze' was your original term, not mine.

JF: " 'Squeeze' was your original term, not mine." Do you have a point? A scalar transformation of either the ordinate or the abscissa in any graph is a fair math move.

John. If you do not understand RH's comment that 'squeeze' was your original term, consider this. Your first comment I have quoted above sounds as though you have disdain for folksy types who write 'squeeze' when they mean scalar transformation, but you will condescend to converse with them on their folksy level. It sounds like a conversational gambit to make onlookers perceive you as the mathematically sophisticated one. RH countered that the folksy term came from you. You then disowned your own rhetorical gambit, even as you dropped in "abscissa", which sounds like another attempt to portray yourself as mathematically elite. (None of us care, really, what terms are used, and scalar transformation is fine; the issue is simply tangential to the discussion.)

Maybe you did not mean it that way, but that is how it reads. On the other hand, I find it folksy and unsophisticated to consider the atempt to validate or invalidate a model based on ridiculously short time spans, such as 4 years.

Just keep in mind that you are conversing with people who understand this material better than you do.

Tom Curtis at 08:20 AM on 4 April 2017

A Perfect (Twitter) Storm

JohnFornaro, I have just taken a expanded image of the IPCC projections, and the upper limit of the likely range shows a 100 mm increase relative to 1986-2005 levels by 2020. Taking the midpoint of the baseline period, that requires a 100 mm increase relative to 1995, or a mean rate of 4 mm per year. The rate since 1995 has been approx 3.3 mm per year, for a total increase of approximately 69 mm since then, leaving a 31 mm increase or 7.75 mm per annum to reach the upper limit of the likely range. We have already exceded the lower limit of the likely range, and effectively reached median estimate for 2020. That suggests we are currently running between the median and upper likely limit of the AR5 projections, and on the upper likely limit of the AR4 projections. Unfortunately, that tells us the IPCC projections are running low for sea level rise other than from large scale ice sheet events, which will be lumpy and hence unlikely to show up over short periods early in the century. That is, on current evidence 2100 sea level will be in the upper range of the IPCC projection plus an unknown further amount from large scale ice sheet collapse.

I am not sure where you got the 4 cm expectation between now and 2020, but suspect it may be because you have not correctly baselined the IPCC projections.

chriskoz at 08:06 AM on 4 April 2017

Elevator Pitches - Chapter 02 - Radiative Gases

Tom@24, Glenn@23,

Rotational energy quants at the molecular level are smaller than the vibrational. The result is that molecular rotation produce spectral lines in the radio part (some 100MHz or less), therefore not playing a mejor part in greenhouse effect (radiation in radio frequency constitutes a miniscule part of an outgoing body radiation at Earth temperature). That's probably why most GHE textbooks talks about virbational energy quants as the main phenomenon of interest.

But I suspect, in combination with vibrational changes, rotational changes may result in broadening of virbational spectral lines since the comination of two quants of a magnitude difference (if allowed) would produce a quant slightly shifted. However that's only my intuition as I'm not an expert in this field.

HK at 04:33 AM on 4 April 2017

CO2 lags temperature

A big problem with Humlum’s claim is the period from 1940 to 1975.

Using SkS’s trend calculator I find the trend in this period to be -0.024^oC/decade with data from NASA-GISS and -0.015^oC/decade with data from Berkeley Earth, plus/minus some uncertainty for both.
In the same 35 year period the global mean CO₂ concentration increased from 311 to 331 ppm. Where did those 155 gigatonnes of extra CO₂ come from when both land and sea surface temperature trends were close to zero or slightly negative?

michael sweet at 02:20 AM on 4 April 2017

A Perfect (Twitter) Storm

John,

We do not expect sea level rise to change much in the next four years. According to your graph at 72, from the middle of 2012 to the middle of 2016 (the last four years of data) sea level rose about 20 mm. Why are you so focused on the next four years? We already have the data you seek in the last four years. Sea level rise was in the range of 1-4 cm you indicate. Over time we expect the sea to rise faster.

Short time periods have much more noise than long time periods. El Nino's tend to have faster rise and La Nina's slower rise. If the next four years are mostly La Nina (through random chance) sea level may rise more slowly. That would mean nothing. From 2005 to 2011 we see this effect. From 2011 to 2016 we see faster rise as there more El Nino's. You need to adopt a longer time frame to eliminate the noise.

Sea level rise experts are people who have devoted their lives to learning about glaciers and the ocean. The partisans are absent from the scientific debate.

If you can provide the data about exactly how much CO2 will be emitted for the next 80 years the scientists can give you a better projection. You ask more than can be known.

There are many questions about how the great ice sheets will behave. 20 years ago scientists thought that the great ice sheets might grow from more snow. They learned that the sheets melt from below from a warming ocean. A few years ago scientists thought that there was no possible mechanism for greater than 2 meters of sea level rise before 2100. A mechanism for the disintegration of the West Antarctic ice sheet has now been discovered (3-4 meters of rise). It is not yet known exactly how that mechanism will affect the next 80 years. We have to go with the best science that we have today. That is reflected in the graphs you have posted.

Exact predictions of the future are hard. There is no doubt that AGW is causing the sea to rise and will continue to rise. If you think there is an issue with that, buy land in Miami.

Rob Honeycutt at 02:05 AM on 4 April 2017

A Perfect (Twitter) Storm

JF... I'd suggest that "persuasion" is merely Scott Adams favorite dog whistle. I'd also say that, no, altering a graph just for the purposes of persuasion is not appopriate.

A good example is with climate deniers. It seems to be persuasive to many when they take a temperature graph of the holocene and change the Y-axis to start a 0°C. Like here. That is persuasive for those who are not inclined to look any deeper into the matter.

The problem is, for every piece of incontrovertible evidence there is another anti-science meme produced by someone out there designed to cast doubt on the science. Google any climate topic out there and see what comes up. It's a smattering of both real science and conspiracy addled fake science, and for most people it's hard (sometimes impossible) to tell the difference.

I am curious about this statement, though.

"The "climate experts" have no idea by what amount the sea levels might be rising, and they have no idea of how much sea level rise would be non-partisan, incontrovertible proof of sea level rise."

Climate experts actually do have a strong idea of how much sea levels are rising. They also understand the uncertainties and the variability within the data. So, I'm not clear how you justify that statement.

And the second half of that statement just doesn't make sense to me. "Non-partisan, incontrovertible proof" (evidence would be a better word) doesn't seem to describe anything since science is, by nature, non-partisan.

JohnFornaro at 01:21 AM on 4 April 2017

A Perfect (Twitter) Storm

Rob Honeycutt @ 79:

"'Squeeze' was your original term, not mine."

Do you have a point? A scalar transformation of either the ordinate or the abscissa in any graph is a fair math move.

From:

https://support.office.com/en-us/article/Change-the-scale-of-the-vertical-value-axis-in-a-chart-05973661-e56a-4486-a9f3-f9ce41df0021

"You can customize the scale to better meet your needs."

For example, one might want to make a flat line look like a sharply rising line. One might want to misinform shallow thinking politicians, always a fair move in principle.

I'm studying whether or not one to four cm of sea level rise, if observed and measured accurately by 2020, three years from now, would be incontrovertible evidence that the graphs of the two models that I studied have accurately predicted sea level rise. I guess not.

The "climate experts" have no idea by what amount the sea levels might be rising, and they have no idea of how much sea level rise would be non-partisan, incontrovertible proof of sea level rise. The issue continues to be persuasion.

Nice chatting tho.

Moderator Response:

[JH] Your condescending tone is neither warranted nor welcome.

MA Rodger at 01:01 AM on 4 April 2017

Breathing contributes to CO2 buildup

Grumpymel @93.

Your argument only works if you assume that an apple (or other plant-matter that would grow and decay in its stead) somehow does not emit CO2 when it decays. An apple contains carbon and oxygen so as it decays, what happens to the carbon and oxygen? Is it only humanity that by eating apples and other food breath out CO2?

Tom Curtis at 00:12 AM on 4 April 2017

Elevator Pitches - Chapter 02 - Radiative Gases

Glenn Tamblyn @23, evidently so (scroll down to figure 4.14).

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