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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.

Recent Comments

Comments 36201 to 36250:

Razo at 08:36 AM on 3 June 2014

Models are unreliable

Hey KR. Thank you.

I wanted to point out to Dikran Marsupial, that the point of my post 706 was that the model that includes man made forcings only seems to be reducing the large error of the natural forcing only model in the 1850s when they are combined. this is about the figures 1 a, b, and c in the rebuttal on the intermediate page.

So KR I have a couple questions: 1) Is the common base the measured values or the ensemble mean? 2) does it make a difference to the results if you change the baseline dates?

KR at 07:29 AM on 3 June 2014

Models are unreliable

Razo - I would point out that the reference you made here to "Can climate models explain the recent stagnation in global warming" is to an un-reviewed blog article.

The published peer-reviewed literature on global models, on the other hand, states something quite different, such as in Schmidt et al 2014. This is discussed in some detail here on SkS. Climate model projections are run with forcing projections, and that includes the CMIP3 and CMIP5 model sets discussed by the IPCC. And each model run represents a response to those projected forcings.

When (as per that paper) you incorporate observed, not projected, forcings, it is clear that the models are quite quite good.

KR at 07:13 AM on 3 June 2014

Models are unreliable

Razo - Baselines are not complex in the least. Simply put, you take two series, and using a baseline period adjust them so that they have the same mean over that period -in order to see how they change relative to one another.

For example, comparing GISTEMP and HadCRUT4 without adjusting for the fact that they use different baselines:

And by setting them to a common baseline of 1980-1999:

A common baseline is really a requirement for comparing two data series.

scaddenp at 07:09 AM on 3 June 2014

Models are unreliable

Razo, climate modellers explicitly state that climate models have no skill at decadal level prediction. You seem to think from your experience as a numerical modeller, that they should be able to predict the trade winds (aka ENSO cycle), but then have tried predicting weather beyond 5 days? Weather prediction (and ENSO prediction) are initial values limited by chaos theory. Climate prediction is a boundary value problem where internal variability is bounded energy levels. (by analogy, you might get warm days in winter, but the average temperature for a month is going to be lower in winter than in summer). Climate models are trying to predict what will happen to 30 year averages. Got a better way of doing it?

They are incredibly useful tools in climate science, but if you are wanting to evaluate the AGW hypothesis, then please do it properly rather making uninformed stabs at things you havent understood. Perhaps the IPCC chapters on the subject where everything is referenced to the relevant published science as a starting point?

Razo at 06:58 AM on 3 June 2014

Models are unreliable

I wasn't think that calibrating means curve fitting or trend.

I know there are different opinions. Some, which are not deniers, appear to agree with me.

I can appreciate baseline study is a little more complex. I think the topic of my post 706 is not effected by this.

This is what I found for what a baseline climate is for. Amoungst other things, they do say its used for calibration.

http://www.cccsn.ec.gc.ca/?page=baseline

''Baseline climate information is important for:

-characterizing the prevailing conditions under which a particular exposure unit functions and to which it must adapt;

-describing average conditions, spatial and temporal variability and anomalous events, some of which can cause significant impacts;

-calibrating and testing impact models across the current range of variability;

-identifying possible ongoing trends or cycles; and

-specifying the reference situation with which to compare future changes.''

Timothy Chase at 06:48 AM on 3 June 2014

2014 SkS Weekly News Roundup #22B

The moderator responded to 10:

[JH] Sicnetists typically use commonly accepted defintions of terms. "Climate change" and "Global warming" are no exceptions. The commonly accepted definitions of these two terms were developed by the IPCC and WMO. Those definitions are in the SkS Climate Science Glossary.

From the glossary:

... in its Article 1, defines climate change as: ‘a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods’. The UNFCCC thus makes a distinction between climate change attributable to human activities altering the atmospheric composition, and climate variability attributable to natural causes. See also Climate variability; Detection and Attribution.

I would have assumed that "climate change" refers to a change in the "climate system that persists over an appropriate span of time". However, as such, I would not simply focus on the atmosphere or land or ocean surface, but the ocean at various depths, including temperature, circulation, salinity, and more broadly, chemistry. The chemistry would be particularly significant when it comes to the carbon cycle. And obviously, if you have a calcium carbonate shell, you might likewise be concerned with ocean acidity just as surely as you are with the temperature and salinity that also affect ocean circulation.

As I understand the nature of definitions, oftentimes there will be broader and narrower definitions that make use of different criteria and consequently have either different ranges or domains of applicability, where context might suitably determine what distinctions become significant, and thus context may determine which definition is in use, or alternatively, one may use a more specific term to indicate which definition is in use. "Climate sensitivity" is one such term, where one could be referring to either the Charney Climate Sensitivity that includes only the fast feedbacks (e.g., water vapor, clouds, sea ice and changes to the lapse rate) or the Earth System Sensitivity that includes both fast and slow feedbacks (e.g., ice sheets and the elements of the carbon cycle).

In my view, these are not different concepts but different yet closely related senses of the same concept. It becomes necessary to distinguish between them only once a distinction between fast and slow feedbacks is made.

Similarly, under local thermodynamic equilibrium conditions it may make sense to speak of only temperature, but under non-local thermodynamic equilibrium conditions one distinguishes between the kinetic temperature of matter and the Maxwell temperature of radiation since they are no longer strongly coupled. Moreover, under non-LTE conditions one may also distinguish between the temperatures of different quantum modes of molecular excitation due to the rate of collisions being insufficient to result in the equipartition of energy.

MThompson at 06:33 AM on 3 June 2014

2014 SkS Weekly News Roundup #22A

Mr. Chase,

Thank you for your comment and research on the use of "sheeple" at other blogs.

I followed your suggestion to spend some time on the “WattsUpWithThat” website. As you reported, there were far more references to “sheeple” than on the present blog. While didn’t see the value of attempting a statistical analysis of the detailed usage of the term (it would be too subjective to be meaningful) , I did get quite a few chuckles from some of the other posts and comments. Perhaps higher web traffic would account for some of increased frequency of usage, but I see your point.

Perhaps I need to become a little more tolerant of this lack of civility so often encountered on the web. My hope is that the SKS blog will be more conducive to the open sharing of ideas, and the “regulars” will challenge those few bad actors to keep our discourse substantive. The television is quite sufficient for mindless entertainment.

Dikran Marsupial at 06:28 AM on 3 June 2014

Models are unreliable

Razo, none of the examples of the use of "calibration" you provide are referring to baselining, which kind of makes my point, you are not using the term in the ususal sense in climatology. There is a difference between baselining (which was the cause of the phenomenon you were describing) and calibration (a.k.a. tuning) in the sense of those three quotes. The models are not affected in anyway by baselining, it is a method used in the analysis of model output and is not part of the model in any way.

Please, do yourself a favour and try and learn a bit more before making assertions or criticisms (or at least pay attention to responses to your posts, such as mine at 711).

Dikran Marsupial at 06:22 AM on 3 June 2014

There's no empirical evidence

Razo can models be reasonably expected to predict the stagnation of temperatures over a 15 year period? The answer is essentially "no, but hey can be expected to predict that such stagnations will happen evey now and again (but not when)" and indeed they do, see Easterling and Wehner.

michael sweet at 06:16 AM on 3 June 2014

Models are unreliable

Razo,

In the second question at Real Climate's FAQ on Global Climate Models they say:

"Are climate models just a fit to the trend in the global temperature data? No. Much of the confusion concerning this point comes from a misunderstanding stemming from the point above. Model development actually does not use the trend data in tuning (see below). Instead, modellers work to improve the climatology of the model (the fit to the average conditions), and it’s intrinsic variability (such as the frequency and amplitude of tropical variability). The resulting model is pretty much used ‘as is’ in hindcast experiments for the 20th Century. - See more at: http://www.realclimate.org/index.php/archives/2008/11/faq-on-climate-models/#sthash.EiXtCir9.dpuf"

You say in reply to me: "If its just blind physics, it is improbable that the spread of the results would behave so differently in this time period." It appears to me that you are saying that the results are too good to be based on just the physics.

I am not an expert in this area, but it seems to me that you are confusing your definations of tuning and calibration for these models because you have not read the background material. This is very common and most of the experienced posters have seen this many times. As I understand Tamino's reference to baselining, they are aligning the data from 1980-2000 for comparison, they did not use that data to tune the models. Perhaps the alignment you referred to above is from how the data are graphed for comparison. Read the above Real Climate reference.

In your post at 712, your first and second references are to Regional Climate Models, not Global Climate models. They are not done the same way. You need to clear up in your mind what you want to discuss. Since you mentioned the "hiatus", it previously appeared that you were discussing Global Climate models.

Hans Von Storch is a respected scientist, but there are many different opinions on how well Global Climate Models are performing. Tamino states at the end of the post you linked above "The outstanding agreement holds not just for the 20th century, but into the 21st as well — putting the lie to claims that recent observations somehow “falsify” IPCC model results." (my emphasis) That was in 2010, but Tamino still feels that climate models are holding their own.

There are several posters here that are more experienced that I am. They seem to be holding back. Perhaps if you make less statements about the Physics being too good people will be more friendly.

You frequently make sweeping statements and confuse apples and oranges. For example, your confusion of Regional and Global climate models above. This makes you appear hostile. Dikran Marsupial is very knowledgable and can answer your questions if you pose them in a less hostile tone.

knaugle at 05:30 AM on 3 June 2014

2014 SkS Weekly News Roundup #22B

I noticed on the wattsupwiththat.com blog that Meteorologist Joe Bastardi (on 5-23-2014) claims that NOAA predicts above average sea ice extent for August. Yet I cannot find this directly, except for cryptic links to plotted data, and NSIDC seems to be showing below average trends. Given the skeptical/denier nature of WUWT I am not surprised, but was curious if anyone knows more about where JB got his data?

Razo at 05:13 AM on 3 June 2014

There's no empirical evidence

I have posted this link elsewhere, but I post it here to show that others share my critism of climate modeling not predicting recent stagnation in global warming. Also he considers the stagnation to be a 15 year period from 1998 to 1012.

http://www.academia.edu/4210419/Can_climate_models_explain_the_recent_stagnation_in_global_warming

Razo at 04:50 AM on 3 June 2014

Models are unreliable

Well here are a few examples of the use of the word 'calibration' or synonyms in climate change literature, found by simply googling 'calibration climate change model'. I think my use of the term and the idea are reasonbly inline with the scientific community. Where am I going wrong on this? I have not read each of these exhustively. I am only showing showing the use of the expression.

1)http://www.iac.ethz.ch/groups/schaer/research/reg_modeling_and_scenarios/clim_model_calibration

This is a Swiss institute for atmospheric and climate science:

''The tuning of climate models in order to match observed climatologies is a common but often concealed technique. Even in physically based global and regional climate models, some degree of model tuning is usually necessary as model parameters are often poorly confined. This project tries to develop a methodological framework allowing for an objective model tuning with a limited number of (expensive) climate model integrations.''

http://journals.ametsoc.org/doi/abs/10.1175/2011BAMS3110.1

American meteriological society

''Calibration Strategies: A Source of Additional Uncertainty in Climate Change Projections''

3)http://www.academia.edu/4210419/Can_climate_models_explain_the_recent_stagnation_in_global_warming

An article titled ''Can climate models explain the recent stagnation in global warming?''

''In principle, climatemodel sensitivities are calibrated by fitting the climate response to the known seasonal and latitudinalvariations in solar forcing, as well as by the observed climate change to increased anthropogenicforcing over a longer period, mostly during the 20th century. It would be difficult to modify the modelcalibration significantly to reproduce the recent global warming slow down while still satisfying theseother major constraints.''

villabolo at 04:08 AM on 3 June 2014

2014 SkS Weekly Digest #22

@2 Magma,

Good question.

Pope Francis and Pope Benedict.

Dikran Marsupial at 03:17 AM on 3 June 2014

Models are unreliable

BTW Razo, baselining and calibration are not the same thing. Yes, the variability in the baselining period should be expected to underestimate the true variability of the model projections, even if the model physics is 100% correct.

Dikran Marsupial at 03:11 AM on 3 June 2014

Models are unreliable

Razo writes "When I make a mistake, people expect me to have a PHD in GCM. "

and yet on another thread, (s)he writes " I am not in the climate field, but I do have experience with numerical modelling. I simply think GCM should be able to predict trade winds and ocean warming."

where (s)he is explicitly claiming to have a background that provides a position to criticise GCMs. As it happens the criticism shows a fundamental lack of understanding of what GCMs are designed to do and what can be expected of them. Razo, you need to understand first and then criticise. Asking questions is a better way of learning than making assertions or criticism, especially when you are not very familiar with the problems. Your tone is not "reasonably passive" as the quote above demonstrates.

Magma at 03:00 AM on 3 June 2014

2014 SkS Weekly Digest #22

Why is a Catholic or Anglican bishop included in the cartoon, considering that both those churches publicly recognize the reality and the seriousness of AGW?

mperkel at 02:56 AM on 3 June 2014

Venus doesn't have a runaway greenhouse effect

I'm not convinced of Venus having a runaway greenhouse effect. With 92X atmosphere than Earth - and if Venus has a radioactive heat source like Earth that the insolation effect, as well as some solor heat trapped in the atmosphere - would be keeping the planet from cooling off.

Additionally - I object to comparing Venus to Earth in this regard because the fact is that you can't compare a planet with 92X atmosphere and being closer to the Sun and having different atmospheric chemestry as being similar.

And - since almost no light makes it to the surface of Venus all solar energy is absorbed in the atmosphere. Therefore if a solar heating event is happening then the atmosphere would have to be hotter than the surface and heating the whole planet by convection and conduction. But the atmosphere is not hotter than the surface so that tends to disprove the runaway greenhouse idea.

The simplier and more plausable explanation is that like Earthg Venus was molten and because of 92X atmosphere it never cooled off, as opposed to the idea that it used to be cool and was heated up.

I'm not buying it.

Timothy Chase at 02:43 AM on 3 June 2014

2014 SkS Weekly News Roundup #22A

MThompson wrote:

I performed two searches. One was for sheeple in Skeptical Science, the other for sheeple in WattsUpWithThat, both using Google.

site:skepticalscience.com sheeple returned 9 webpages

site:wattsupwiththat.com sheeple returned 501 webpages

Now before you think I am responding with a "they do it too" or "they do it more often" I should also let you know that I looked at the 9 instances at Skeptical Science.

There was the reference to the cartoon the response to the reference to the cartoon, neither of which was in a context specific to the acceptance or dismissal of climate science, one reference to the "uneducated masses" who don't get climate science. In this case the comment was posted by someone calling himself "actually thoughtful" who isn't a regular, just passing through. The 6 other webpages contained references by those who are pro-science refering to those who are pro-science — mocking the use of the term itself.

I will let you discover for yourself how the term gets used at Watts Up With That.

Timothy Chase at 01:45 AM on 3 June 2014

2014 SkS Weekly News Roundup #22B

MThompson wrote:

Now, based on the theme of Ms. Flam's missive, I wonder how the IPCC in 1988 settled on the name of their august panel. Was there a consensus some 25 years ago that rejected IPGW as the moniker of the most important international body for the future of earth? I'm sure that within the vast experience range of SKS commenters someone can provide interesting history about this divisive nomenclature.

Personally, I have thought that "climate change" is better because it is the wider term, which is also probably part of the reason why they chose it. In my view, the more important issues won't be heat waves but droughts and flooding. Climate change is also wide enough to encompass ocean acidification, which has the same root cause and, like droughts, will greatly impact our ability to feed our people. In fact, if we could do this over again, I would prefer the term "industrial climate disruption" as "industrial" is suggestive of both the cause and scale and "disruption" alludes to the how we are leaving the relatively stable Holocene Epoch, during which agriculture was developed and civilization flourished, for something that appears a great deal less stable.

However, "global warming" appears to be the term that the public find it easier to grasp, perhaps because it is less abstract, something that they can more easily relate to the perceptual level. It is a bit like communicating abstract ideas through metaphor, I suppose. And it is probably best to stick to one phrase or the other. Otherwise one is likely to confuse.

Moderator Response:

[JH] Sicnetists typically use commonly accepted defintions of terms. "Climate change" and "Global warming" are no exceptions. The commonly accepted definitiobns of these two terms were developed by the IPCC and WMO. Those definitions are in the SkS Climate Science Glossary.

Razo at 01:43 AM on 3 June 2014

Models are unreliable

Micheal Sweet, I think my tone is reasonably passive to suggest I'm open to correction. I am not a denier, I present myself as an educated skeptic, and I am here to learn. When I make a mistake, people expect me to have a PHD in GCM. I think the point of calibration can be a little subtle, but it doesn't take away from my post.

I did read about AR4 models:

http://web.archive.org/web/20100322194954/http://tamino.wordpress.com/2010/01/13/models-2/

Here they say

''But there’s a sizeable spread in the model outputs as well (especially in the early 20th century, since these results are set to a 1980-2000 baseline).''

In this case the spread is very little in the 1980-2000 period. If its just blind physics, it is improbable that the spread of the results would behave so differently in this time period.

Also in the rebuttal above, the basic section, they say models use hindcasting. So if they test with hindcasting, and it doesn't work, one tries to improve thier model. So this is what I call calibrating. Am I wrong on this?

I think I see the word 'calibrate' has a charged meaning, becasue deniers use it. Well I didn't know that. LOL. Anyway, I presented my definition of calibrate. Please note the above question mark indicating a question--you invited me to ask.

michael sweet at 00:40 AM on 3 June 2014

Models are unreliable

Razo,

You say "The model aslso shows a great match around the 80s and 90s, which is probably what it is calebrated to." This is fundamentaly not how climate models work. You are coming in from another line of work and incorrectly applying your modeling methods to climate. The climate models are designed from the ground up using basic physics principls and are not "calibrated" to any period. If you wish to continue posting on an informed board you need to do your homework and stop making baseless assertions.

You would be much better served by asking questions about how climate models work, which you obviously do not understand, than incorrectly complaining that those models do not work properly. Real Climate has several basic links on how climate models work.

chriskoz at 00:01 AM on 3 June 2014

Global warming and the vulnerability of Greenland's ice sheet

wili@6,

I checked AR5 Table 4.6 and found out that my previous IPCC numbers were the last 18y average IS loss trends. Because IS melt is accelerating, the more recent trends - last 6y - are higher:

Period Ice sheet loss (mm yr–1 SLE)
Greenland
2005–2010 (6-year)   (0.63 ±0.17)
1993–2010 (18-year) (0.33 ±0.08)
Antarctica
2005–2010 (6-year)    (0.41 ±0.20)
1993–2010 (18-year) (0.27 ±0.11)
Combined
2005–2010 (6-year)   (1.04 ±0.37)
1993–2010 (18-year) (0.60 ±0.18)

So, AR5 latest 6-year trend is consistent with (McMillan 2014), no surprise here. The AR5 combined 1.04mm/y value constitutes about 1/3 of current total SLRR of 3.2mm/y.

But the question when we are going to see IS contribution emerging as dominant factor is still too hard to tell. You can check AR5 chapter 4 summary e.g. in Bamber presentation: Look esp. at Figure 4.25 on page 12 and try to extrapolate... Or, with Hansen's fastest doubling every 7y, you'll arrive at 8mm/y by early 2030s... But with more realistic IMO doubling every 10y+, you'll arrive at 2mm/y by 2020s which still less than other contributions, and 4mm/y (a dominant contribution) by 2030s.

Composer99 at 23:44 PM on 2 June 2014

2014 SkS Weekly Digest #22

Regarding the Skeptical Science Highlights:

Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows. by Howard Lee received the most comments of the articles posted on SkS during the past week once again reflecting how many people are interested in geolgical extinction events.

One thing that struck me about the comment thread of this post has been the overall high quality of the comments. It's not the case that someone started spouting re-hashed rhetoric which others have been forced to step in and debunk - instead the commenters have been sharing perspectives and papers.

It's the kind of comment thread that I suspect every science blog aspires to have all the time.

Composer99 at 23:07 PM on 2 June 2014

2014 SkS Weekly News Roundup #22A

MThompson:

I don't think it's going out on a limb to say that, when someone links to an XKCD comic mocking the "wake up, sheeple!" thing (*), it's not serious.

I might add that the impression I have from posts here at Skeptical Science which (a) detail the authors' direct experiences with working in developing countries around the world, or (b) share links to news agencies and various organizations, that the majority of people living in developing countries are generally quite aware of how AGW is affecting their day-to-day lives - at least, more aware than too many in affluent countries who allow themselves to be blinded.

(*) Does anyone actually use the term sheeple in a non-ironic way anymore?

Leland Palmer at 22:35 PM on 2 June 2014

Rapid climate changes more deadly than asteroid impacts in Earth’s past – study shows.

On the other hand, the high salt methane hydrates could be quite significant and could be a major piece of the puzzle of how these past mass extinction events occurred. The high salt hydrates could also be crucial to predicting how our manmade extinction event will proceed, and what the eventual outcome will be.

From an earlier thread on Skeptical Science:

Such high salt methane deposits may be fairly common, according to authors including Maria Torres and Miriam Kastner:

OCCURRENCE OF HIGH SALINITY FLUIDS ASSOCIATED WITH MASSIVE NEAR-SEAFLOOR GAS HYDRATE DEPOSITS

CONCLUSIONS
Massive gas hydrate and chloride brines in near- seafloor sediments along continental margins are not at all uncommon, and may represent a significant carbon reservoir, which is susceptible to oceanographic perturbations....
Preliminary estimates suggest that there is approximately 125 x 10-3 Gt of carbon trapped in the Ulleung Basin brine patches. If we assume that there are 200-500 such locations sites worldwide, this will represent a ~25 to 62.5 Gt carbon, which is 0.25 to 12% of the total carbon thought to be sequestered in gas hydrate deposits globally.

The existence of these deposits may be the answer to the disconnect between the geological evidence of past methane catastrophes and our current lack of understanding of how these mass extinction events occurred.

MThompson at 22:24 PM on 2 June 2014

2014 SkS Weekly News Roundup #22A

I for one find it abhorrent that posters to this blog refer to a group of humans as "sheeple." I infer from this that the writers use the term to indicate disdain for the relatively uneducated and impoverished peoples of the earth. Most people have no way to understand how the issues of the carbon cycle affect them. They are fighting day-to-day for food and energy to survive. All this while the erudite sit in air conditioned abodes on high munching carrots from vertical gardens perched on balconies with panoramic views. But I suppose that many readers of this generally insightful blog will relish the humor of such posts.

If my inference was too hastily drawn, then please accept my heart-felt apology, and keep up the good work!

Dikran Marsupial at 20:19 PM on 2 June 2014

There's no empirical evidence

Razo wrote "I also do criticize global models for not capturing decade long cooling intervals very well"

Criticising models for not being good at something they are not designed to do and for which they do not claim a high degree of skill suggests that you have not put much effort into finding out what models do and how they work. I criticise them for not being able to predict volcanic eruptions. This is about as meaningful a criticism as Razo's ;o)

Razo at 19:28 PM on 2 June 2014

There's no empirical evidence

scaddenp, I must confess to not reading it thouroghly enough. I seem to remember it differently, or was relying on journalists interpretations too much. For that I apologize. But nevertheless Fig 1 does describe cooling over part of the last decade

"Observations of global average surface air temperature (SAT)
show an unequivocal warming over the twentieth century1,
however the overall trend has been interrupted by periods
of weak warming or even cooling (Fig. 1)."

I also do criticize global models for not capturing decade long cooling intervals very well, and not predicting trade winds. I am not in the climate field, but I do have experience with numerical modelling. I simply think GCM should be able to predict trade winds and ocean warming.

Moderator Response:

[JH] Your "experience with numerical modeling" is nor a substitute for doing your homeowork on GCMs before proceeding to critique them. Please stop flying blind and look before you leap.

Glenn Tamblyn at 18:26 PM on 2 June 2014

2014 SkS Weekly News Roundup #22A

Non-Scientist.

No, not yet. The Sheeple may be fractious and disturbed, filled with an ill-defined disquiet. But not awoken, not yet.

It would take a ..... WHAT IS THAT SMELL?......

.... A Stinking mix of dung and lanolin.....

.... Those SCREAMS.... Just like the sound of Shearers dying.....

Nobody panic.... JUST NOBODY PANIC.....It's just a few sheep!

Oh My God!!! Billions of Sheep. And they aren't smiling!

wili at 14:35 PM on 2 June 2014

Global warming and the vulnerability of Greenland's ice sheet

chriskoz @#3: Thanks for your insights. But the last bit leaves me confused: "IS will not become dominant contributor for another 20y or so, even according to somewhat overestimated prediction by Hansen"

Your numbers for GIS and total Antarctic contributions (if I understand them correctly) add up to (.45mm/yr + .33mm/yr =) .78mm/yr, about the same as that from all glaciers, by your numbers, and about 80% of the contributions from thermal expansion.

If we take Hansens fastest doubling time (which, I agree, seems...ambitious) of 7 years, we would be getting about 6mm/year from ice sheets alone in about 20 years. Are you expecting the other factors to grow even faster during this period? If not, how is it that you say IS contributions would not be 'dominant'?

scaddenp at 14:26 PM on 2 June 2014

There's no empirical evidence

Razo, did you actually read the England et al papers that you quote? How come you have changed a slowing in the rate of warming into a cooling trend?

From the first "Here we show that a pronounced strengthening in Pacific trade winds over the past two decades—unprecedented in observations/reanalysis data and not captured by climate models—is sufficient to account for the cooling of the tropical Pacific and a substantial slowdown in surface warming through increased subsurface ocean heat uptake."

and the second...

"A variety of mechanisms have been proposed to account for this slowdown in surface warming" and "This hiatus could persist for much of the present decade if the trade wind trends continue, however rapid warming is expected to resume once the anomalous wind trends abate."

The papers conclusions do not appear to match your perception.

Non-Scientist at 12:33 PM on 2 June 2014

2014 SkS Weekly News Roundup #22A

Re: "It's an angry beast that we've awoken".

Perhaps.

But have we awoken the Sheeple?

http://xkcd.com/1013/

Moderator Response:

[PS] Fixed link

Tom Curtis at 11:47 AM on 2 June 2014

There's no empirical evidence

Razo @203:

1) I did not put words into your mouth. I quoted you verbatim.

2) I am astonished that you do not know the meaning of "prima facie". As you do not, you need to learn it as it is a useful concept in understanding the practise of science. Of course, your intention was a rhetorical trick to allow you to criticize the OP without substance, so it may not help you.

3) Your precise words were:

"It also been all over the news now that temperatures have not risen in the last 15 years."

The paper for which you provide a link discusses the so-called "hiatus" since 2001, ie, the last 13 years. Thank you for indirectly confirming that you were exagerating the length of time involved. Further, to that, it is irrelevant how frequently a paper is echoed in the press.

Tom Curtis at 11:24 AM on 2 June 2014

2014 SkS Weekly News Roundup #22B

grindupBaker @6, Wally Broecker's 1975 article only includes the term "global warming" in the title, and as such contains no definition of global warming. Further, the term was in use before 1975. The earliest use I have found was in 1972 (used three times in the article, but again without definition). However, I have no reason to think that was the earliest use.

The IPCC does not have a definition of "global warming". They do, however, define deglaciation as follows:

"Deglaciation/glacial termination Transitions from full glacial conditions
(ice age) to warm interglacials characterized by global warming
and sea level rise due to change in continental ice volume."

The warming in deglaciation is more strongly characterized by reduced albedo than by increased greenhouse forcing. Given that, the use of the term here is inconsisent with the NASA definition.

The WMO defines global warming as follows:

"Global warming is an observed or projected increase in global average temperature."

The EPA defines it as follows:

"Global Warming
The recent and ongoing global average increase in temperature near the Earths surface."

This is again inconsistent with the IPCC usage in that it is restricted to recent warming.

I consider the WMO definition to be best. It does not seem redundant to me to talk about recent global warming (as it would be with the EPA definition). Nor is it apparent that somebody claiming that the sun is the cause of recent global warming is contradicting themselves (as opposed to merely being in error) as they would be with the NASA definition.

The problem arises, however, that meanings are defined by usage. If the most common usage is of cases which are recent, and driven by anthropogenic green house gases, it is not clear the definition is not restricted to that use. It may be that the NASA or EPA defenitions are good descriptive accounts of the common meaning of "global warming". They are poor prescriptons for that meaning, however. Further, they are poor descriptive defenitions of my usage (which may only mean that I am idiosyncratic), or that by the IPCC or WMO.

scaddenp at 08:22 AM on 2 June 2014

Models are unreliable

Razo - these diagrams are from TAR, based on Stott et al 2000. I would agree there is an issue and I would hazard a guess the cloud-response to sulphate aerosols is exaggerated at low concentrations.

If you look at the corresponding diagram in FAQ 10.1, Fig 1 in latest report you will see that neither the CMIP3 nor CMIP5 model ensembles have this issue.

Razo at 08:20 AM on 2 June 2014

There's no empirical evidence

Hey Tom,

You're just putting words in my mouth. You wanna critisize me for not being exact, just Relax. FYI I do have a degree in a scientific field, I have bben published, and I didn't know what prima facie means.

Anyway, this is the article I was reffering to

http://www.nature.com/nclimate/journal/v4/n3/full/nclimate2106.html

They say they found a cooling trend. And is was in all the papers around February 10, 2014, such as

http://www.nature.com/nclimate/journal/v4/n3/full/nclimate2106.html

Thank you for the information about methane.

Moderator Response:

[JH] Pease tone down the rhetoric.

Please note that posting comments here at SkS is a privilege, not a right. This privilege can be rescinded if the posting individual treats adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.

Please take the time to review the policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.

[PS] fixed links

chriskoz at 08:16 AM on 2 June 2014

2014 SkS Weekly News Roundup #22B

grindupBaker@6,

NASA's definition:

Global warming: the increase in Earth’s average surface temperature due to rising levels of greenhouse gases.

(Broecker 1975) abstract:

If man-made dust is unimportant as a major cause of climatic change, then a strong case can be made that the present cooling trend will, within a decade or so, give way to a pronounced warming induced by carbon dioxide. By analogy with similar events in the past, the natural climatic cooling which, since 1940, has more than compensated for the carbon dioxide effect, will soon bottom out. Once this happens, the exponential rise in the atmospheric carbon dioxide content will tend to become a significant factor and by early in the next century will have driven the mean planetary temperature beyond the limits experienced during the last 1000 years

Note that (Leiserowitz 2014) definition questioned by yourself, agrees 100% with NASA's definitiond. So, do you implicitly argue that NASA's definiton is also "poor"? What do you find in Broecker's definition that makes it "better" than the other two ? Maybe a context "beyond the limits experienced during the last 1000 years"? Admittedly, a smart statement by Broecker, given it was written 22 years before (Mann et al 1997) - the hockey stick paper. But does the omition of that (now implicit in everybody's mind) context makes other definitions "poor"?

villabolo at 07:11 AM on 2 June 2014

2014 SkS Weekly News Roundup #22B

@Moderator, #4.

Spencer Weart's book is titled "The Discovery of Global Warming."

Moderator Response:

[JH] My bad. Thank you,

grindupBaker at 04:42 AM on 2 June 2014

2014 SkS Weekly News Roundup #22B

Can somebody provide Wallace S. Broecker's 1975 definition of "global warming" because the definition given by Yale University researcher Anthony Leiserowitz, PhD in subject social-science paper "Global warming refers to the increase in the Earth’s average surface temperature since the Industrial Revolution, primarily due to the emission of greenhouse gases from the burning of fossil fuels and land use change" is a poor definition which renders much of the sks discussions a bit silly, even the ones that are excellent on the real topic, tautological at best. I'm going to stop using the phrase "global warming" entirely and invent a sensible one for myself unless somebody can provide Wallace S. Broecker's 1975 definition and I find it workable for the science. Thanks.

Razo at 04:19 AM on 2 June 2014

Models are unreliable

I find Fig. 1 of the respone curious.Figure 1a, the natural forcings, shows quite bad match with the climate model, especially for the 1850s. Fig 1b, the man made forcings, shows a great match in the 1850s, which is flat around zero. The model aslso shows a great match around the 80s and 90s, which is probably what it is calebrated to. In 1c, the combination of the two, the match is pretty good.

Even though its agreed that there is little effect of human activity in the 1860s, there is a significant correction in the model 1c at these dates. The poor modelling of natural forcing, doesn't say much for the model. This may best describe the error of the model, say .2C.The choice of calibration date appears to have a large effect on the results. I don't think AR4 models 'perturbate' calibration dates.

Its hard to understand the model to such detail, but it does appear that the models seem to only be able to predict recent warming.

DSL at 01:38 AM on 2 June 2014

2014 SkS Weekly News Roundup #22B

MThompson, I'd guess that the current name was settled on because the assessment targeted climate change and not simply the primary driver of that change--global warming. The "IPCC" designation allows assessment of impacts and mitigation/adaptation.

MThompson at 22:16 PM on 1 June 2014

2014 SkS Weekly News Roundup #22B

Regarding "Global warming vs. climate change" by science journalist Faye Flam:

Here is yet another article stimulated by the Yale publication that I have found objectionable and commented upon elsewhere in this prestigious blog. At least this time the author rightfully presses the responsibility of connotation upon journalists and not upon scientists.

Moderator Response:

[JH] The all-volunteer SkS team has a lot on its platter right now. You can probably find the answer you are looking for by perusing Spencer Weart's History of Global Warming. Also take a look at Wikipedia's entry for the "IPCC."

chriskoz at 20:30 PM on 1 June 2014

2014 SkS Weekly News Roundup #22B

A bit of sad news from Auastralia. A bitter comment written by a young engineer who sees no future for himself is his home country:

Science going back to dark ages

I note that it was written n May 28 but published on 20140531, per the link format.

chriskoz at 20:22 PM on 1 June 2014

2014 SkS Weekly News Roundup #22B

U.S. Bishops call for reduction on carbon pollution

That news is a direct consequence of what Pope Francis said just a week ago: Causing Climate Change Is a "Sin", which itself should not be surprising to those who remember that Pope-emeritus Benedict expressed the same worry earlier.

It's worth noting that traditionally catholic church was very conservative, taking new science very cautiously. This latest news, especially Francis' latest statement, leaves no question as to where they stand with their preachings.

That leaves the conservative politicians in US and AUS on a very foolish position of not just science denial, but increasing alienation in their denial, as more and more influential organisations - traditional supporters - are not fooled anymore.

scaddenp at 20:07 PM on 1 June 2014

Models are unreliable

Well models from 30 year ago have been remarkably accurate. The Manabe model used by Broecker in the landmark paper 39 years ago nailed 2010 temperatures remarkably well. However, the model is too primitive to deal with much more than energy balance which is reasonably well understood. The inner workings of climate internal variability, regional difference etc are not captured at all. What exactly do mean by the comment?

That all models are wrong is trivial. The question is, are they skillful? Ie do they allow you to make better predictions of the future than doing it without a model. How would you make a prediction for future temperatures without a model.

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