Models(4) Iconic Figure:

By: Dr. Ricky Rood , 4:42 AM GMT on February 13, 2008

Models(4) Iconic Figure:

Of the figures that I consider the Iconic Figures of climate, there is one based totally on models. A recent version of this figure from the IPCC 2007 is given here.

Figure 1: Observations and simulation of the past century from the IPCC 2007 Technical Summary (Working Group 1) (largish PDF).

This is a figure of, approximately, the last century. In this figure there are three traces. One of traces, the black one, is of the observed, globally averaged surface temperature record. In the bottom figure is a blue curve, which is a model simulation that does not include anthropogenic (human-related) forcing. That is, it is “natural” forcing. In the top curve there is a red curve that is a model simulation that includes both natural and anthropogenic forcing. The point of this figure is that both natural and anthropogenic forcing is important, and that the recent warming requires the inclusion of anthropogenic forcing to simulate the recent observed temperature increase.

Forcing: For the purpose of this figure, “forcing” are those things that change the ability of the Earth to absorb or reflect radiative energy. Another “forcing” is the radiative energy that comes from the Sun. “Natural” forcing starts with the variability of the Sun. Of special importance in the realm of natural forcing is the impact of volcanic eruptions. Large volcanic eruptions put aerosols into the atmosphere. Aerosols above the Earth’s surface can reflect more solar radiation or they can absorb radiation in the atmosphere. These help cool the surface of the Earth. Aerosols also impact the infrared radiation; that is, the radiation emitted by the Earth back to space. Other natural forcings include water in the atmosphere, in all phases, and carbon dioxide. In general, these model experiments assume that the amount of carbon dioxide in the atmosphere prior to, about, 1850 is “natural.” Of course, the amount of solar radiation that is reflected by the surface is also included – ice and land.

In contrast to “natural” forcing is anthropogenic or human-related forcing. This is change in the forcing relative to the natural forcing. The most important of the anthropogenic forcings is due to carbon dioxide, which is calculated as the additional forcing due to the increased amount of carbon dioxide relative to the “pre-industrial” amount of carbon dioxide. Pre-industrial forcing is linked to about the year 1850. There are other greenhouse gases like methane, nitrous oxide, and the chlorofluorocarbons. Nitrous oxide increases are largely related to use of synthetic fertilizers. Other anthropogenic changes in the radiative balance of the Earth are related to changes in reflection at the surface due to how we use land.

The Plot: Here is my description of this plot. The dark red and the dark blue lines are averages from many model simulations. The light lines that surround the dark lines are all of the individual simulations. Prior to 1950 the natural and anthropogenic simulations are not much different from each other. After 1960 only the plot with anthropogenic forcing follows the temperature observations. Perhaps more importantly, the natural and anthropogenic curves diverge from each other as time goes along.

The light lines surrounding the dark lines give some idea of model variability. It is notable that, for the most part, this variability covers the range of variability in the observations. The models do not follow, point by point, the shorter scale variability in the observations, for example between 1920 and 1930. The models have variability, such as the El Nino – La Nina and North Atlantic Oscillation. The spread of the models suggests that the model variability covers this range of variability, but the models are not tracing this variability on an event-by-event basis. The comparable spread in the models and the observations also serve as a sanity check that the models represent variability in the same range as the Earth’s climate.

The simulations do show the impact of several large volcanic eruptions. The volcanoes do cause cooling of the globe. Volcanic eruptions, and especially the well observed Mount Pinatubo eruption in 1991, provide opportunities to evaluate processes in models.

It is also of interest to examine where the models and the observations do not agree. A most interesting period is from 1935-1940, a period when the planet was warm. (Thanks to crucilandia for pointing a reference to get me started.) A substantial literature is developing that examines this period. It seems to be associated with substantial Arctic warming. It is a period that demands more study. The cooling that all of the models calculate about 1915 is also interesting.

An important take away message from these simulations is that there are factors other than carbon dioxide that cause temperature variability. Hence, carbon dioxide and temperature are not necessarily correlated on shorter scales of variability. (This is a like my wave metaphor on this blog. )

Conclusions: This is a figure open to interpretation. Personally, I find this figure compelling. I know how difficult it has been to develop the models and to specify the forcing. There is also a huge depth of analysis at different levels of detail and averaging that support the conclusion that it is only with increasing carbon dioxide forcing that the recent temperature increase can be explained.

Others can look at this plot, and come to a different conclusion. One issue that many raise is what about the treatment of aerosols? This is a process in models which has substantial uncertainty in its quantification.

Looking forward to the comments.

Here are the previous blogs on models.
Uncertainty and Types of Models
Models (1) Assumptions
Models (2) Forgotten Layers
Models (3) Predictable Arguments

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139. SteveBloom
8:05 AM GMT on February 17, 2008
Re #133: Sull, I hadn't realized you were that young. That causes me to give you a bit more credit since I suspect your main exposure to the issue has been through this site, which like most weather sites is a bit of a nest of denialists. I have to say the thing that makes you seem most close-minded is the disdain you express toward climate scientists such as the RC authors. Try to fix that before you start school.
138. sullivanweather
3:02 AM EST on February 17, 2008

I don't run a global warming blog. I run a Northeast weather blog. Why would I allow my blog to be contaminated with such hatred spewed by those that believe the world is coming to an end and if I don't agree I should be hung at the stake?
Member Since: March 8, 2007 Posts: 273 Comments: 12612
137. sullivanweather
2:51 AM EST on February 17, 2008

Perhaps you view them as 'denialist'. I view them as contributing factors.

If there's several factors contributing to the warming of the climate, such as increased TSI, warm phases of oceanic oscillations and the like they would most certainly contribute to the temperatures currently being experienced compared to what had previously been documented during the late 19th and beginning of the 20th century.

To flat out deny that they have any effect is severely short-sighted. Otherwise we would've had a flat climatic scheme over many thousands of years, which has been proven to be false.

A denialist comment would have been 'It snowed in the Middle East, therefore global warming doesn't exist'

Thre's nowhere in my comments where such words were uttered. I simply called what was happening as 'weather'.

Also, simply requesting a paper written about natrual variability in climate isn't denialist either. It's called a request for information. I don't know how you can rationalize to yourself that it is 'denialist'. Perhaps you're a denialist to natrual variability of climate and you believe that everything that happens is of direct result of global warming, which is also as short-sighted as believing that global warming doesn't exist.
Member Since: March 8, 2007 Posts: 273 Comments: 12612
136. Fshhead
7:56 AM GMT on February 17, 2008
Hey Sully & MLC,
THANX for the compliments to me!!!!!!!!
Member Since: November 19, 2005 Posts: 9 Comments: 9960
135. quasigeostropic
2:51 AM EST on February 17, 2008
"Regardless of how you slice it, modern solar forcing cannot account for temperature variations since about 1950."

Well, my slice says you cannot just "minimize it" just because you can't account for temperature variations. Like others and I have said, faulty and inaccurate data collection will result in poor analysis......night.

Member Since: November 20, 2007 Posts: 21 Comments: 192
134. SteveBloom
7:49 AM GMT on February 17, 2008
Re #122/5/6: Sull, when I suggested you carry on the denialist discussions elsewhere, I meant on one of the many other blogs on WU. Yours, for example.

OK, I looked at your site and reviewed your prior comments in this thread. The site is very nice, although long-term climate issues seem a little beside the point for a blog of that sort (nor did I see any discussed). Of the comments, only 10, 11, 28, 31, 38, 50, 52, 60 and 73 were what I would call denialist. A couple of your "Six Degrees" remarks mught have been as well, but I passed on those since I haven't seen it.

BTW, you're a bit behind the times on the solar stuff. Scroll down and read the SORCE meeting posts. Take-home point: "Regardless of how you slice it, modern solar forcing cannot account for temperature variations since about 1950."

Regarding the paper you were asking for in #60, it should be simple to find using Google Scholar. It may be that you'll have a difficult time finding one with no reference to AGW, though, since IIRC the scientists who discovered the PDO and all the current leading researchers are nasty warmists. Just like nearly every climate scientist.
133. sullivanweather
2:29 AM EST on February 17, 2008
Thank you for your kind comments, Cowboy! They are much appreciated!

I think Bloom will come around...eventually.

One day he'll realize that this is a community blog site and learn to not be so harshly critical of those who disagree with his opinions.

Eventhough Ricky runs a very scientifically orientied blog, the members of this site aren't scientists and are mostly lay folks. I try my best to understand the technical stuff despite not having yet gone to college. I do read my fair share of technical papers that I'm able to access on my limited budget and while I may not have the most technical understanding of some studies, I have a very good instinctual understanding of weather and climate.

I'm sure my blogging abilities will increase many fold once I begin college in the fall at Albany. Until then, I will continue to try and do my best at forecasting weather and learn as much as I can about climate. For being self-taught in the field I feel as though I know enough info to be able to carry on a scientific conversation with most. There's plenty of things that are still above me but I don't allow myself to be closed off to any subject and try my best to encompass the great wealth of information that's out there.
Member Since: March 8, 2007 Posts: 273 Comments: 12612
132. moonlightcowboy
7:24 AM GMT on February 17, 2008
I look forward to it, Sully! I remember a
conversation last year one night, late
recalling our first experiences with weather.
I've respected you since then!

I'm out, at least for now, waiting and dreading
the severe weather headed this way a bit later
this morning!

Again, thanks, Sully! Always appreciate your efforts!

Member Since: July 9, 2006 Posts: 184 Comments: 29682
131. sullivanweather
2:18 AM EST on February 17, 2008
Huuricane season is right around the corner as well, which is when my other strong points in weather forecasting will be realised.

I'll be issuing my 2008 seasonal forecast on the 25th of this month, if I can get it done in time. I have no doubts that I won't.

I have all my info down. Now it's a matter of putting it all together.
Member Since: March 8, 2007 Posts: 273 Comments: 12612
130. moonlightcowboy
7:09 AM GMT on February 17, 2008
I've really enjoyed reading, listening,
learning and discerning from several here on
Ricky's blog and others. In the beginning I was
very open-minded on the subject of AGW, but
since then I've been able to discern certain
truths - some of which I believe are science
related and others non-science related. And,
sometimes I think it takes someone away from
and outside of science and politics to see
truths, especially in the absence of
verifiable, repeated processes.

Have a good sleep, Sully!

Member Since: July 9, 2006 Posts: 184 Comments: 29682
129. moonlightcowboy
7:15 AM GMT on February 17, 2008
128. sullivanweather 6:59 AM GMT on February 17, 2008
Civility is a wonderful thing when practiced.

...that's the kind of statement I expect to
come from you, Sully! Well said, thanks! And
aside from your great knowledge of weather,
especially "winter" weather up there -
certainly, you've been able to advance yourself
in part due to your civility, I'm sure! And,
well done, too, I might add!
Member Since: July 9, 2006 Posts: 184 Comments: 29682
128. sullivanweather
1:57 AM EST on February 17, 2008
I simply don't understand Blooms' arrogance.

I seriously think, since he's a smart guy, that he'd be able to convince some folks here that global warming does exist. But pounding someone's opinions into a bloody pulp when they don't agree with him is not the way to get it done.

Civility is a wonderful thing when practiced.
Member Since: March 8, 2007 Posts: 273 Comments: 12612
127. moonlightcowboy
6:48 AM GMT on February 17, 2008
Fish is a great example of how to get along and
respect those with differing opinions! I really
like his blog and learn a great deal there!

Bloom's prolly not a bad guy either-when he's
sleeping! LOL - he's just one of those types that
hasn't ever learned the meaning of respect!
My children learned that at two years old!
Member Since: July 9, 2006 Posts: 184 Comments: 29682
126. sullivanweather
1:31 AM EST on February 17, 2008

Thank you for having my back.

I think I've handled myself quite well while debating Bloom. He has yet to disprove anything I've posted on this site. Since most of his posts are full of outright disdain for most bloggers here that he calls denialists, I have yet to be swayed in my opinion of the global warming subject.

Maybe Bloom should concentrate on trying to provide useful science information for others to read rather than berating those that don't agree with him. I have no respect for those that hold themselves, and their opinions, in such high regard that other people's opinions are beneath them. However, I would like to point out that respect from my end can be easily won.

I'll use Fshhead as an example as he did run the original climate change/global warming blog on this site and we have become good friends here. He never chastised me for my opiniion, nor I his. We simply discuss the issues and went from there. I highly suggest Bloom do the same since this is a community blog site.
Member Since: March 8, 2007 Posts: 273 Comments: 12612
125. sullivanweather
1:17 AM EST on February 17, 2008

How abouts you go and read my blog and tell me what you think.

Since I'm reviewing the month of January in my current entry there's a bunch of climate info in there for the previous month. You can read it and see that I take an objective, rather than subjective, view to what's happening.

Perhaps you can write to Dr.Masters and tell him to take me off the featured bloggers list since I don't buy into your version of global warming. Or maybe you can go to Tamino's site or Real Climate to complain about my so-called 'denialist' view of global warming on the WUG site.
Member Since: March 8, 2007 Posts: 273 Comments: 12612
124. quasigeostropic
1:17 AM EST on February 17, 2008
I do believe in natural variability and a short term "global warming" episode caused primarily by the sun(sun spots and the such)....But this sort of science is very little known. I respect people who believe in Co2(man-made) induced GW even though I dont believe in man-made GW.....I actually agree with sullivan, that "hyping up" the science is very premature.....
Member Since: November 20, 2007 Posts: 21 Comments: 192
123. moonlightcowboy
6:22 AM GMT on February 17, 2008
That-a-boy, Sully! You tell him, but we've got your back on this one! NO worries!
Member Since: July 9, 2006 Posts: 184 Comments: 29682
122. sullivanweather
12:47 AM EST on February 17, 2008

First of all, I'm a featured blogger here. Why would I take my conversations elsewhere?

Secondly, Can you point out any post where I went about denying global warming, let alone it's cause? I think in prior conversations we've had I did tell you that a double of CO2 would create an enhanced greenhouse effect and even posted a link to a well known study that proves this. I simply don't buy into the alarmist version of catastrophic global warming of 5-6C of warming on top of today's current levels and put a little more emphasis on natrual variability in climate rather than a man made global warming dominated climate. Since you cannot prove that the catastrophic global warming scenario will play itself out let's simply call this subject a draw.

Thirdly, You should stop by more often to actually READ THE THREADS. I believe I've asked Ricky a plethora of questions here. Perhaps more so than other of the other bloggers that visit his blog. They've never been answered, but hey, maybe he simply doesn't know the answers or doesn't have the time to reply.

Additionally, I find it ironic that everytime you take time out to post here you're usually dumbing down the others that visit this blog then have the nerve to say that my comments are 'slapping the blog author in the face'. Perhaps you should go back and read some of your own comments. It is your comments, my friend, that are a slap in the face to the blog author since you fill them with such disrespect for the others that post here.
Member Since: March 8, 2007 Posts: 273 Comments: 12612
121. quasigeostropic
12:56 AM EST on February 17, 2008

So you think this blog should have ZERO "denialist" comments? What if I happen to not believe man-made GW? This is what debate is about. Having two sides to an argument...And just because some dont believe it the way the tax-hungry interest groups would want us to believe doesn't make us any less intelligent.
Member Since: November 20, 2007 Posts: 21 Comments: 192
120. moonlightcowboy
5:48 AM GMT on February 17, 2008
Well, Steve, if we did as you suggest,
all you AGW advocates would have the room all
to yourselves. No varying opinions, thoughts
and discussion. Even you wouldn't like that
because you wouldn't have anyone to patronize!

I mean, isn't your opinion the only one that
really counts? And, don't you want us all to
know that you're the only one that has an
opinion that is right? That's what I thought!
So, if you must stay and suffer through it like
the rest of us, being polite would be nice.
Certainly, us AGW skeptics have mostly been
civil and nice to those in with which we
disagree. Why not try it? You might find people
willing to be more open-minded to your opinions
less the associated cynicism.
Member Since: July 9, 2006 Posts: 184 Comments: 29682
119. SteveBloom
5:43 AM GMT on February 17, 2008
Re #107 etc.: Sull, it is very odd that your little group has selected a climate blog run by a climate scientist to have your denialist conversations. Hardly any of you ever have a question for Ricky, which I suppose is unsurprising since there's no point to learning about the details of something that you think is a fraud on a large scale. As well, I think your presence discourages others from commenting or asking questions. In any case, why here rather than some other blog where you wouldn't be slapping the blog author in the face with every other comment you make?
118. SteveBloom
5:34 AM GMT on February 17, 2008
Re #110: Also, you might want to double-check on those cloud stats. It's been noted that the ISCCP database isn't really suited for those sorts of global stats, so there have been some false interpretations floating around. What does the AR4 say?
117. SteveBloom
5:28 AM GMT on February 17, 2008
Re #110: Low clouds cool, high clouds warm (one of the reasons why albedo doesn't quite tell you everything you need to know), so they really have to be considered separately. I wouldn't know about the middle ones.
116. SteveBloom
5:28 AM GMT on February 17, 2008
Re #111: Those are slanted questions, jer, but I'll answer them (this once, anyway). I won't stop to check sources, so this is a chance for me to see if I can answer these off the top of my head. Hopefully Ricky will let me know how I did.

"Do you believe that climate models that project future climate conditions are scientific fact?"

Are the *projections* scientific fact? No. In that sense they're similar to a weather forecast for a week ahead, although one that doesn't try to specify the weather on individual days (instead the approximate end conditions and the range of variability on the way to it).

"Or would you agree that such models at best are a theory yet to be proven by actual observations."

No. See the graphic in Ricky's post, e.g. As well, there are a number of discrepancies between the models and observations that have been resolved in favor of the models (e.g. tropical lower troposphere temperatures).

"If CO2 increases are supposed to cause an increase in global temperatures over time, why is Jan. 2008 .36 degC cooler than Jan 1983? That is a quarter of a century, why is it colder? BTW I'm using GISS figures here."

Consider that with no AGW there's a baseline amount of climate variability that AGW isn't going to cancel. Indeed, AGW theory says that variability ought to increase. This means that at the relatively early stage we're at now, we can still see some relatively cold years. Things will eventually warm enough that years this cold will no longer occur, but I would expect that won't be real soon. What we can expect is an increasing number of hot years and a decreasing number of cold years, with "normal" years that are a bit warmer. Imagine a standard bell curve which then gets shifted in the warm direction and has its "tails" extended in both directions (but bear in mind that this assumes a smooth warming that likely will not hold indefinitely since with enough warming climate patterns like ENSO will begin to change). Note also that if you go back before 1982 you start seeing lots of colder Januaries, and don't forget January 2007 (as perhaps not a bad indicator of increased variability when taken together with this January, although last January was rather more extreme -- compare them).

"Would you admit that a relatively strong La Nina coupled with fairly docile sun have conspired to put a hitch in the get along of the climate models?"

No. Generally the models don't forecast ENSO or the conditions of individual years, although last year the Hadley Center did a GCM forecast for the very first time. They of course knew the timing and magnitude of the solar low, and I think by then there was reason to expect a strong La Nina. Plugging that information into their model, they predicted a cool 2008/9 followed by fairly sharp warming for the following several years. Predicting a cool 2008 was perhaps not so amazing, so we'll see how they do for 2009/10.

115. LowerCal
6:13 PM PST on February 16, 2008
#108) Buster, you're looking at water vapor as a "brick wall" for it's specific wavelengths of infrared. It's more like a picket fence. A packet of the radiation has to hit a water molecule to be absorbed. Also once it is absorbed it can be reradiated.

Take a look at the graphic in Ricky's previous blog.
Water, Water, Water (2): Water Vapor Feedback
The skinny red arrow on the left could represent infrared radiation from the surface going directly into space. The fat red arrow pointing up is infrared radiated from the surface absorbed by water vapor in the atmosphere. Some of that is reradiated and propogates downward (the fat red arrow pointing to Earth). Some is reradiated upward (the fat pink arrow pointing to space). Actually the absorption and reradiation can take place many times in random directions before a packet of energy eventually reaches the surface or space.

The BTU's can (and do) get out.
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111. sebastianjer
7:17 PM EST on February 16, 2008
Steve and or Ricky:

I'll ask the question I asked earlier which received no reply.

Do you believe that climate models that project future climate conditions are scientific fact?

Or would you agree that such models at best are a theory yet to be proven by actual observations.

If CO2 increases are supposed to cause an increase in global temperatures over time, why is Jan. 2008 .36 degC cooler than Jan 1983?
That is a quarter of a century, why is it colder? BTW I'm using GISS figures here.

Would you admit that a relatively strong La Nina coupled with fairly docile sun have conspired to put a hitch in the get along of the climate models?


Member Since: August 26, 2005 Posts: 1030 Comments: 11197
110. crucilandia
12:07 AM GMT on February 17, 2008
cloud typically decreases, enhancing the warming

this is false. Mid clouds and high clouds has been increasing for a decade
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109. quasigeostropic
6:43 PM EST on February 16, 2008
which BTW I'd have more of were it not for all the trash that gets posted here by the usual suspects

Mr bloomy boy, if we dare disagree with you why dont you ask the admin if you could be the police then you could arrest all these "denialists".....This is a logical argument. No one knows what the past holds anymore than what the future holds. Models are ALL biased by those that program them. No graph or paper can prove man-made GW........You can believe what you want, but we have opinions too, they are NOT trash. The media and mainstream thinking taught you well to be intolerant of anyone else's opinions......
Member Since: November 20, 2007 Posts: 21 Comments: 192
107. sullivanweather
4:32 PM EST on February 16, 2008
It would appear as though the only trash that gets posted here is by you, Bloom.

There's usually civil conversation here until you show up and proceed to call everyone's posts trash.

Perhaps you'd be better received if you weren't so cumbersome to the other bloggers here. You should practice some civility once in awhile.
Member Since: March 8, 2007 Posts: 273 Comments: 12612
106. latitude25
9:27 PM GMT on February 16, 2008
105. SteveBloom 9:26 PM GMT on February 16, 2008
I have an actual question for Ricky (which BTW I'd have more of were it not for all the trash that gets posted here

Then stop doing it.

Member Since: August 24, 2007 Posts: 0 Comments: 3654
105. SteveBloom
9:26 PM GMT on February 16, 2008
I have an actual question for Ricky (which BTW I'd have more of were it not for all the trash that gets posted here by the usual suspects).

What do you think of this new paper? It seems like a potential big deal.

"CO2 forcing induces semi-direct effects with consequences for climate feedback interpretations"

"Climate forcing and feedbacks are diagnosed from seven slab-ocean GCMs for 2 × CO2 using a regression method. Results are compared to those using conventional methodologies to derive a semi-direct forcing due to tropospheric adjustment, analogous to the semi-direct effect of absorbing aerosols. All models show a cloud semi-direct effect, indicating a rapid cloud response to CO2; cloud typically decreases, enhancing the warming. Similarly there is evidence of semi-direct effects from water-vapour, lapse-rate, ice and snow. Previous estimates of climate feedbacks are unlikely to have taken these semi-direct effects into account and so misinterpret processes as feedbacks that depend only on the forcing, but not the global surface temperature. We show that the actual cloud feedback is smaller than what previous methods suggest and that a significant part of the cloud response and the large spread between previous model estimates of cloud feedback is due to the semi-direct forcing."
104. SteveBloom
9:20 PM GMT on February 16, 2008
jer, the problem isn't me but our host. In effect, posting that kind of garbage (which isn't even refutable since it's just an essay) implies that you think Ricky is incompetent or a liar.

BTW, those areas of interest listed in Humlum's CV aren't all that impressive. A look at his pubs makes it clear that he doesn't venture much outside certain narrow aspects of glaciology/paleoglaciology. Regarding the subject matter of the text you posted, it's even more clear that Humlum lacks any relevant expertise.

Also, it's not apparent to me reading his essay why his kind of modeling would be exempt. Perhaps you can enlighten us on that point.
103. LowerCal
12:17 PM PST on February 16, 2008
#99) Buster, perhaps you are limiting your concept of "heat energy" to the speed of motion of molecules/atoms. Molecules/atoms can shed some of their "heat energy" as infrared radiation. When that happens they slow down. That is how the "heat energy" is lost without the loss of molecules/atoms.
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102. LowerCal
11:50 AM PST on February 16, 2008
#99) Buster, no elements or molecules, none needed, just infrared radiation.
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101. sebastianjer
1:51 PM EST on February 16, 2008
Nice Try Steve.

I'm sure if anyone wants to check out Ole Humlum they will see that his credentials are at lest as impressive as yours :). Here is a part of his CV you may have missed

Comparison and integration of different climate proxy series.

Scientific applications of numerical modeling in geomorphology; e.g. modeling of active layer and permafrost thermal characteristics.

Mapping Arctic and Antarctic surface temperature changes and geomorphic effects during the observational period.

Mapping, monitoring and modeling natural cold-climate geomorphic processes and -hazards.
Member Since: August 26, 2005 Posts: 1030 Comments: 11197
100. SteveBloom
5:09 PM GMT on February 16, 2008
Re #96: Interesting, jer. You could change a few words around and make this into an attack on all of science (since most of it has to deal with a degree of uncertainty). I must say the tone sounds a little bitter.

Also, having a quick look at his publication record, this is mighty bold talk for a glaciologist who doesn't appear to use models in his own work.
98. quasigeostropic
3:04 AM EST on February 16, 2008
JER, that is why they will NEVER prove man-made GW....because models are biased.
Member Since: November 20, 2007 Posts: 21 Comments: 192
97. LowerCal
10:17 PM PST on February 15, 2008
Sully, I was thinking rushed also. In a hurry, a low budget or an inexperienced producer ... I couldn't say.

JER, I'm off to bed to too. I'll read your comment tomorrow.
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96. sebastianjer
12:28 AM EST on February 16, 2008
Computer models and the real world

Global climate is in a continuous dynamic state of flux, representing an analogue system, where everything is happening simultaneously. In contrast to this, computer models are digital, attempting to solve a problem by repetitive calculations (iterations), before moving on to solving the next problem, etc. This represents a drawback for computer-based modelling of climate.

While the laws of physics may be beyond discussion, it is not always equally clear or predictable which concept or process will predominate over which when a huge number of competing processes are acting simultaneously as is the case for climate. The description of the individual concepts in a model may well be correctly defined in the mathematical formulations, but the dominance or subservience of one process to others is defined by the modeller, not by the model itself. The modeller decides that issue in the way the program code is written.

In the end, the computer model therefore simply mirrors the intellectual choices of the modeller and only puts numbers to them. If those choices are based on flawed reasoning or insufficient observational evidence, it is naive to believe that the model will somehow remove this fundamental problem through sheer number crunching power. That would be to attribute qualities of judgment to models which they simply do not have. In essence, a mathematical model does not relieve the intellectual burden of determining which variable or process is dominant over which. The modellers have to make a decision on this when writing the code and this choice then becomes an integral part of the model.

Most relationships between parameters in a complex of natural processes are nonlinear relationships. As one variable changes, another may change exponentially. What is even more complicating is the fact that a number of such parameters may change simultaneously as a certain process unfolds. In addition, a relationship that may be believed to be linear when studied in isolation, may turn up being nonlinear in the context of simultaneous changes in other parameters. It is therefore entirely likely that it forever will be impossible to predict the future development of nature by way of numerical models (Pilkey and Pilkey-Jarvis 2007).

Anyhow, computer models of climate can never be superior to the knowledge based understanding derived from experiments and classic field observations. Models may prove powerful instruments in improving our understanding of complicated laws and process associations. But until the empirical knowledge coded into them is perfect and comprehensive, they still have to be considered as predictive tools with many limitations.

The world’s perhaps most cited climatologist, Reid Bryson, stated as early as in 1933 that a model is "nothing more than a formal statement of how the modeller believes that the part of the world of his concern actually works". Global climate models are often defended by stating that they are based on well established laws of physics. There is, however, much more to the models than just the laws of physics. Otherwise they would all produce the same output for the future climate, which they do not. Climate models are, in effect, nothing more than mathematical ways for experts to express their opinions about how the real world operates.


Any discussion on this would be welcome, butI'll check tomorrow since I need to hit the sack

Member Since: August 26, 2005 Posts: 1030 Comments: 11197
95. sullivanweather
12:14 AM EST on February 16, 2008
I thought that they could've done a much better job.

It seemed to me that the program was rushed through production to make the airwaves as quickly as possible. The examples they used in many cases were poor.
Member Since: March 8, 2007 Posts: 273 Comments: 12612
94. LowerCal
9:08 PM PST on February 15, 2008
I vaguely (lol) remember that part. I thought it had something to do with the haziness of the sky.

Anyway, it was another "I decided to look into it for myself" effort by a lay person. Not up to usual NatGeo level and definitely short of NOVA quality.
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93. sullivanweather
11:56 PM EST on February 15, 2008
I thought that they used horrible examples to how the climate has changed.

The example I used above I thought topped the cake. Looking at stars and trying to determine the weather from them is simply nonsense. I really don't know how that would convince anyone that the climate is changing.
Member Since: March 8, 2007 Posts: 273 Comments: 12612
92. LowerCal
8:51 PM PST on February 15, 2008
Sully, I saw it the first time it aired. I thought it was kind of vague. (Of course no one yet knows exactly what each degree would mean.) It also seemed kind of disjointed.

I've seen more informative and compelling documentaries on related subjects.
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91. sebastianjer
11:28 PM EST on February 15, 2008
Was anyone else in here able to catch six degrees?

Did not see it yet Sully, I have National Geographic Channel on demand on cable so can watch it any time. I'm waiting until I'm in the right mood, which may be never, lol

Member Since: August 26, 2005 Posts: 1030 Comments: 11197
90. sullivanweather
11:13 PM EST on February 15, 2008
Was anyone else in here able to catch six degrees? If so, what was your opinion of the program?

Ricky, what say you? I'm sure you were able to catch it...
Member Since: March 8, 2007 Posts: 273 Comments: 12612
89. sullivanweather
8:48 PM EST on February 15, 2008

Just didn't want to see you get fustrated when buster completely ignores your response

Member Since: March 8, 2007 Posts: 273 Comments: 12612

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Dr. Ricky Rood's Climate Change Blog

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I'm a professor at U Michigan and lead a course on climate change problem solving. These articles often come from and contribute to the course.

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