Greenland ice sheet melting faster than previously thought. PLEASE RECYCLE!

rose colored glasses? wrote:

To better illustrate what I mean, look at the third graph here:

Image:

http://i42.tinypic.com/5wwef6.jpg

You can see the model extends a very noisy known "forcing function" into a smooth curve with negligible uncertainty for decades, then growing uncertainty. A legitimate model should show an extended structure to that of the prior 100+ years, whether or not it has a generally increasing trend. Unless the natural phenomena that causes the downward fluctuations in past decades no longer exist?

I haven't read the text associated with that figure, but the "wiggles" on the historic left side of the third graph look to be due to unpredictable natural forcings (i.e. volcanic events). It's not clear whether they've accounted for them in the projection as a steady state contribution (obviously not the expected physical reality, but not obviously unreasonable for long term trending) or whether they've simply left them out. Perhaps the text or a reference would clarify. Given a smooth driving function and no discrete natural perturbation events then a smooth output from the model makes sense.

Citizen Runner wrote:It's not clear whether they've accounted for them in the projection as a steady state contribution (obviously not the expected physical reality, but not obviously unreasonable for long term trending) or whether they've simply left them out.

The danger in extending trends from stochastic data based on some "most probable" or "mean" or some other estimate of central tendency, particularly when dealing with data that clearly have a fractal structure and associated power law relationships, is that your estimates of central tendency may be a) wrong and b) meaningless (which I mean as two different things).

If you did some basic statistical analysis of the phenomena that (were inferred to have) caused those prior fluctuations and then did some kind of monte carlo simulation with your model, including these fluctuations in some measure that makes statistical sense, you would see a) significant fluctuation in the best guestimate trends b) huge growth in uncertainty in the model outcome past a few years.

Or so I think, anywy.

Looks like a fun debate. Maybe you guys can come up with a model that estimates the chance of something bad happening if all/most of the fossil fuels on earth are combusted in say 400 years. Could be global warming, global warfare, starvation, ozone depletion etc. I'm not sure but I think that was what the original poster was trying to get at.

rose colored glasses? wrote:

So I'll again plead ignorance on this: "Greenhouse gases going up result in temperatures going up." People say that like it's holy scripture, and yet we've looked at data in this thread showing skyrocketing levels of CO2 over 150 years have NOT actually caused temperatures to skyrocket (although there has been certainly a small increase). You've argued we need to wait for the kettle to boil, so to speak, which may be true. Still, why do you believe this to be true? What's the compelling case?

From the literature I understood that certain gases cause atmospheric warming (greenhouse effect), atmospheric cooling (negative greenhouse effect), and, apparently other gases are neutral, but your question got me to wondering about the mechanism. What I've learned through a bit of looking around is that the energy from the sun is predominantly shorter wavelength (UV and visible light) as a result of its being very hot relative to earth temperatures. The energy radiated from the earth tends to be longer wavelength (infrared) for the opposite reason.

Molecules that are absorptive in the shorter wavelengths, such as the SO2 emitted by volcanos, absorb and re-radiate incoming light energy in random directions such that a portion of the incoming energy is re-radiated before it reaches the earth surface, effectively lowering the energy reaching the surface leading to a cooling effect.

Molecules that are absorptive in the longer wavelengths such as CO2 absorb and re-radiate energy that has been (primarily) emitted by earth's surface, effectively returning some of that energy back to the surface causing a net warming effect at the surface. One piece of evidence supporting the GW theory is that atmospheric temperatures at night will be proportionally higher, which I now understand to be due to this absorption of infrared radiation from the earth surface during that period when the sun is, of course, not a factor.

So, for what it's worth, you've prompted me to understand something in greater detail than previously and can better articulate.

The take away, laying aside the complications and messy interactions of applying this to the real world, is that the "greenhouse effect" distills down to some pretty basic physics involving testable properties of gases.

Thanks for the thoughtful response. I appreciate you have more or less distilled your belief to the following core principle:

Citizen Runner wrote:The take away, laying aside the complications and messy interactions of applying this to the real world, is that the "greenhouse effect" distills down to some pretty basic physics involving testable properties of gases.

I'll need to read a little further to convince myself of this. Testing something at the lab scale is entirely different than testing it at the global scale. That said, I imagine there is extensive literature on the topic and will make efforts to explore some of it.

Can I ask if you know... is solar radiation the only heat source in the climate models?

Hippy!!

BTW, what I'm after here:

rose colored glasses? wrote:Can I ask if you know... is solar radiation the only heat source in the climate models?

... is, how do they include heat from the earth in the models, both heat generated within the earth, and heat absorbed and released by/from the earth (including sea, land and ice) as variable boundary conditions?

I imagine this stuff is in the IPCC report somewhere, but honestly I have to give this thread and related literature very cursory attention for the next few days and get back on track with my own work. :-)

rose colored glasses? wrote:

Thanks for the thoughtful response. I appreciate you have more or less distilled your belief to the following core principle:

Citizen Runner wrote:The take away, laying aside the complications and messy interactions of applying this to the real world, is that the "greenhouse effect" distills down to some pretty basic physics involving testable properties of gases.

I'll need to read a little further to convince myself of this. Testing something at the lab scale is entirely different than testing it at the global scale. That said, I imagine there is extensive literature on the topic and will make efforts to explore some of it.

Can I ask if you know... is solar radiation the only heat source in the climate models?

Are you guys kidding me? You have spent umpteen pages to come to the point of understanding that the basic driver of the whole greenhouse effect is the energy absorbing properties relative to shorter or longer wavelengths of the gas molecules in the atmosphere?!? Are you kidding me?

Good god, gentlemen, this is common knowledge of anyone with even the most cursory exposure to the whole AGW phenomena.

Holey Kablooey Batman wrote:...this is common knowledge of anyone with even the most cursory exposure to the whole AGW phenomena.

rose colored glasses? wrote:

Thanks for the thoughtful response. I appreciate you have more or less distilled your belief to the following core principle: Citizen Runner wrote:The take away, laying aside the complications and messy interactions of applying this to the real world, is that the "greenhouse effect" distills down to some pretty basic physics involving testable properties of gases.

I would say my belief is based on my understanding of the ensemble of information. That basic physical properties of materials support the notion of a greenhouse effect is one factor, but I'm not discounting that there are other factors in play, my understanding of all these factors is not "expert", and that the "experts" knowledge of all the factors is and will always be imperfect.

rose colored glasses? wrote:

Can I ask if you know... is solar radiation the only heat source in the climate models?

I've never looked into this. That said, the only primary energy sources in play that I can think of would be solar radiation and nuclear decay in the earth's core. I don't know how significant the latter is or if there is any reason to suspect that it is varying on the time scale of interest. My best guess would be that it doesn't matter to an analysis looking at deviations from a presumed steady state, but I don't know what the modelers do with it. The models do represent stored heat in the oceans, land, and atmosphere at various levels of detail, but those are not primary sources.

rose colored glasses? wrote:

Holey Kablooey Batman wrote:...this is common knowledge of anyone with even the most cursory exposure to the whole AGW phenomena.

A common sign of a common mind is apparent willingness to be spoonfed "common knowledge" without probing it with a little enthusiasm.

A common sign of an uneducated mind is a lack of understanding of some very basic physics.

Holey Kablooey Batman wrote:A common sign of an uneducated mind is a lack of understanding of some very basic physics.

I've been reading your posts with much interest, you seem to be the brightest poster I've encountered on this subject despite your admitted ignorance.

I would like to point out a few things that I haven't seen mentioned yet:

- it's becoming more apparent that clouds play a profound part in controlling the global thermostat. It's my understanding that many of the computer models do not account for clouds, and all those that do factor in a positive feedback for clouds. Mounting evidence seems to indicate that clouds have a negative feedback.

- it's also my understanding that none of the models factor in the affect oceanic temperature oscillations, like El Nino and La Nina, have on the climate. These are extremely powerful forces that AGW promoters ignore.

- The global surface temperature record is grossly inaccurate. Spatially it is very incomplete, for example nobody was recording temperatures at the poles, in central Africa, or in the middle of any ocean in 1880. Also, an audit done by a private group on US temperature stations found 70% of the stations to have siting errors that can cause possible temperature recording errors of 2 degrees C or more. There's no reason to expect other surface stations in other countries to be any more accurate.

http://www.surfacestations.org/

So you know where I'm coming from, I used to believe humans were the main cause of climate change until I started looking into myself. Once I did I couldn't find a coherent argument for how humans could drive such a complicated process simply by adding more CO2 to the air. That would be believable if CO2 was the only variable, but it's just 1 of who knows how many variables (hundreds?). And humans have no influence on almost all the other variables. Also, the fact that the current warming predates the rise in CO2 doesn't help the AGW argument.

I'd be interested in seeing more of your questions and conclusions as you delve deeper in to the subject. Thanks for posting.

Blowing.Rock Master wrote:

Also, the fact that the current warming predates the rise in CO2 doesn't help the AGW argument.

I'm curious how you can support this statement as it would indeed be a very strong counter argument. Everything I've seen shows CO2 levels beginning to rise starting around the mid-1800s and a significant warming much later.

As for the climate models, I'll just point to this FAQ (it's short) from the IPCC report acknowledging some of the shortcomings in the climate modeling state of the art, more or less as you've described. I do this just to note that identifying deficiencies in the process does not in itself contradict the product.

The problem with all of this is that the world is cooling, and has been for a decade.

http://climaterealists.com/index.php?id=9316

Wow, looks like this didn't die. I've got some catching up to do once I catch up with my real work.

This again?

Come on, please

Super Conservatively Watched wrote:

This again?

Come on, please

Don't worry. It has only taken 11 pages to get to the point of realizing that the theory of AGW is driven by the energy absorbing properties of CO2.

Real progress.

Citizen Runner wrote:

Blowing.Rock Master wrote:

Also, the fact that the current warming predates the rise in CO2 doesn't help the AGW argument.

I'm curious how you can support this statement as it would indeed be a very strong counter argument. Everything I've seen shows CO2 levels beginning to rise starting around the mid-1800s and a significant warming much later.

As for the climate models, I'll just point to this FAQ (it's short) from the IPCC report acknowledging some of the shortcomings in the climate modeling state of the art, more or less as you've described. I do this just to note that identifying deficiencies in the process does not in itself contradict the product.

http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-8-1.html

Here's a chart of 10 different temperature reconstructions going back at least 1,000 years. Only 1 reconstruction shows temperature starting to rise after 1800. The other 9 show the rise starting between 1600 and 1800.

Here's a graph showing that CO2 didn't start rising above the background norm until the mid 1800s, conveniently about the time that the oft published surface temperature record begins. That's 50 to 250 years after temperatures started to rise.

I am curious about your statement that a deficient process can produce a valid product. Seems to me that if required inputs are either missing or have the wrong sign, then the only way the product is valid is through sheer luck. Are the model builders really that lucky?