Climate Change

[cheesehead]

Originally Posted by ewmayer

Note that I'm not saying any of the above counterintuitive phenomena are currently occurring or likely to occur in the near future as a result of anthropogenic CO2 emissions, but you asked for "how could", so I gave a few such.

Thank you.

Out-of-order responses:

3) Multiple climate-system equilibria and "tipping point" effects: It's well-documented that massive influxes of fresh water from global warming have on occasion shut down the NADW circulation (a.k.a. "what keeps Europe much warmer than it should be")

But that's exactly what I cited a while ago as an example of what might happen if AGW took us out of the current natural temperature band!

I quoted an article from Atlantic Monthly magazine (IIRC) about how a surge of fresh meltwater from Greenland et al. could shut down the Gulf Stream.

Also, I gave an example of standing on the rim of the Capulin Mountain cinder cone, where falling one way would result in a much longer descent than falling the other way (asymmetrical effects depending on direction of perturbation).

Multiple equilibria and tipping points are not a support for AGW denial unless one shows how they've already affected the climate in such a way as to explain current global warming without anthropogenic CO₂ having an effect.

- a clear example where at small amplitudes (modest warming) things trend the way linear extrapolation predicts, but further forcing leads to nonlinear effects which are wildly different than linear theory predicts.

What I was asking about was the current observed increase in temperatures (I wrote "be having a warming effect") over natural trends.

What nonlinear effect explains current warming observations (not future predictions) without the anthropogenic CO₂ being a cause of warming beyond what would have happened in its absence?

Citing potential future mechanisms by which the warming might reverse is not relevant to my question.

1) Other correlates of anthropogenic CO2 increase have a cooling effect: Smog particles reflecting sunlight back into space, increased warmth leading to increasing cloud cover and having a similar effect, warmer boreal regions turning into active CO2 sinks, etc.

... and they are being taken into account in the calculations. There's still a net warming to be explained -- I ask AGW deniers to show how it's happening without the anthropogenic CO₂ being responsible in proportion to its presence.

2) We've had episodes of massive global warming before: At documented times in the past, earth was significantly warmer and even more CO2-rich than at present (e.g. during the era when Antarctica was warm enough to allow dinosaurs to live there). And yet, rather than suffer the same runaway-greenhouse fate as Venus, Earth always "recovered" from those warm spells and even went in the opposite direction, during the ice ages of the past several million years. How? The IPCC seems strangely silent on this, < snip >

Straw man.

Again, that's skipping what I'm actually asking about (and what the IPCC report was about) -- the observed current warming.

The supposed "strange silence" of the IPCC on irrelevant topics is simply a straw-man distraction.

[ewmayer]

Cheesehead, I suspected you were feeling lonely for a post you could dissect in your usual intensely irritating fashion, but decided to take you at your word and gave a few examples illustrating

"just how could all that increase in CO2 not be having a warming effect (AGW) in addition to whatever natural (nonanthropogenic) cycles are doing?"

I even specifically disclaimed that I was asserting that any of the phenomena I cited was currently at play in any significant manner, and in reply got a hyperventilatory "but that's not an acceptable reason to engage in holocaustAGW denial!!" diatribe from you. Once again you have shown why you are far and away the "most annoying person to debate with on the Forum."

I must chuckle, however, at your repeated claims that "the models account-for/correctly-capture [insert name of complex phenomenon modeled with lots of approximations and fudge factors here]." The list of models which "correctly modeled" every salient aspect of some scientific phenomenon (except for the ones which they didn't) is as long as science is old. Lord Kelvin "correctly modeled" solar thermodynamics (except for nuclear fusion) ... Neutrino physics "correctly modeled" solar neutrino dynamics (except for electron neutrinos spontaneously converting to muon and tau neutrinos during their travels), etc. If you had any idea how many crude approximations are needed just to be able to approximately compute the turbulent dynamics of a cubic meter of air you would not be so quick to treat The Models as holy and infallible, even in the sense of meta-analysis of hundreds of model predictions. "What are the error bars on those error bars?" is not an idle question.

The fact that even high-tech supercomputer-generated weather forecasts are quasi-reliable at most 24-48 hours ahead does not give me massive confidence in "the models" of climate dynamics over decades and centuries. It's a fascinating discipline, but its [alleged] reliability has alas become a political rather than a scientific topic.

Your friend,
-Strohmann

[cheesehead]

Originally Posted by ewmayer

but decided to take you at your word and gave a few examples illustrating

... which is how I interpreted your post. I understood right away that you were trying to be helpful by presenting such examples, not that you were setting them forth as your own arguments.

My thank-you for presenting the items was sincere. That's why I placed it right at the beginning after quoting your disclaimer:

"Note that I'm not saying any of the above counterintuitive phenomena are currently occurring or likely to occur in the near future as a result of anthropogenic CO2 emissions, but you asked for 'how could', so I gave a few such."

I even specifically disclaimed that I was asserting that any of the phenomena I cited was currently at play in any significant manner,

... which I duly noted right away when I read your disclaimer.

and in reply got a hyperventilatory "but that's not an acceptable reason to engage in holocaustAGW denial!!" diatribe from you.

Oh?

I thought I was careful to avoid the second person when stating my counters to each of the items, so as not to seem to be directing my counterarguments at you, but instead to be directing my responses to a hypothetical third party raising those arguments. (I remember, when proofreading, catching a couple of "you"s I'd automatically used without thinking, then rewording those sentences.) Where did I fail?

"Diatribe?"

Webster's (http://www.merriam-webster.com/dictionary/diatribe) says the non-archaic definitions are:

2 : a bitter and abusive speech or writing
3 : ironic or satirical criticism

What was bitter, abusive, ironic or satirical (or, for that matter, hyperventilatory) about my posting?

I regret that my posting appeared so negatively directed toward you. Can you help me understand where I went wrong with it?

I can see that it might have helped if I had explicitly pointed out that my counterarguments were to be interpreted as being directed toward a hypothetical third party AGW-denier raising the three examples you presented. But I recall thinking that you were no longer as much of an objector to AGW as you seemed to be two years ago. It didn't occur to me that you might think I was casting you in the role of AGW-denier even though I (a) avoided second-person and (b) acknowledged your disclaimer -- am I mistaken about your current orientation in regard to AGW-objecting?

[__HRB__]

Originally Posted by ewmayer

The fact that even high-tech supercomputer-generated weather forecasts are quasi-reliable at most 24-48 hours ahead does not give me massive confidence in "the models" of climate dynamics over decades and centuries. It's a fascinating discipline, but its [alleged] reliability has alas become a political rather than a scientific topic.

If one must use non-linear models, then accurate prediction isn't a good measure of reliability. I believe any reasonable policy would have to be designed to a) switch attractors and b) reduce the lyapunov exponent of the result. That way, one cannot find optimal policies, but one might at least be able to identify dominated ones, i.e. where there is no trade-off between model variance and model bias.

So, two questions are: is a) possible and how do we validate b)?

BTW, one reason why this is so strongly politicized, is that any environmental change benefits the more adaptable humans, and if adaptability follows a skewed distribution, then the possibility exists for politicians to bargain with the difference between the mean and the median. With this in mind, it isn't surprising that AGW is predominantly championed by socialists, who see it as an excellent opportunity to impose policies on people with a larger responsibility for human productivity, i.e. the evil worker-exploiting (= job-creating) capitalists.

[cheesehead]

Originally Posted by ewmayer

I must chuckle, however, at your repeated claims < snip >

... and I will respond to your misunderstandings about those claims after we straighten out the other matter.

[cheesehead]

Has a team now determined that Milankovitch cycles are indeed sufficient to have triggered past ice ages? Solved the 100,000-year problem, the 400,000-year problem, the stage 5 problem, the unsplit peak problem and the transition problem? (http://en.wikipedia.org/wiki/Milankovitch_cycles)

That seems to be what this Oregon State University press release is saying about "a publication to be released Friday in the journal Science".

"Long debate ended over cause, demise of ice ages – may also help predict future"

http://oregonstate.edu/ua/ncs/archiv...predict-future

CORVALLIS, Ore. – A team of researchers says it has largely put to rest a long debate on the underlying mechanism that has caused periodic ice ages on Earth for the past 2.5 million years – they are ultimately linked to slight shifts in solar radiation caused by predictable changes in Earth’s rotation and axis.

In a publication to be released Friday in the journal Science, researchers from Oregon State University and other institutions conclude that the known wobbles in Earth’s rotation caused global ice levels to reach their peak about 26,000 years ago, stabilize for 7,000 years and then begin melting 19,000 years ago, eventually bringing to an end the last ice age.

The melting was first caused by more solar radiation, not changes in carbon dioxide levels or ocean temperatures, as some scientists have suggested in recent years.

“Solar radiation was the trigger that started the ice melting, that’s now pretty certain,” said Peter Clark, a professor of geosciences at OSU. “There were also changes in atmospheric carbon dioxide levels and ocean circulation, but those happened later and amplified a process that had already begun.”

The findings are important, the scientists said, because they will give researchers a more precise understanding of how ice sheets melt in response to radiative forcing mechanisms. And even though the changes that occurred 19,000 years ago were due to increased solar radiation, that amount of heating can be translated into what is expected from current increases in greenhouse gas levels, and help scientists more accurately project how Earth’s existing ice sheets will react in the future.

“We now know with much more certainty how ancient ice sheets responded to solar radiation, and that will be very useful in better understanding what the future holds,” Clark said. “It’s good to get this pinned down.”

. . .

Sometime around now, scientists say, the Earth should be changing from a long interglacial period that has lasted the past 10,000 years and shifting back towards conditions that will ultimately lead to another ice age – unless some other forces stop or slow it. But these are processes that literally move with glacial slowness, and due to greenhouse gas emissions the Earth has already warmed as much in about the past 200 years as it ordinarily might in several thousand years, Clark said.

“One of the biggest concerns right now is how the Greenland and Antarctic ice sheets will respond to global warming and contribute to sea level rise,” Clark said. “This study will help us better understand that process, and improve the validity of our models.”

. . .

If this had been some reporter's summary, I would wonder whether the article was over-claiming what the actual findings were. But it's a media release from Oregon State U. itself, so ...

[cheesehead]

A passage in the Wikipedia article linked above (http://en.wikipedia.org/wiki/Milankovitch_cycles) has me wondering about the frequent derision voiced by AGW-deniers along the lines that:

(My paraphrase) Only a couple of decades ago, scientists were predicting global cooling -- that the climate was heading for another Ice Age. Now they say we're headed for global warming! Obviously they can't make up their minds and we can't trust these predictions.

The Wikipedia article mentions:

An often-cited 1980 study by Imbrie and Imbrie determined that, "Ignoring anthropogenic and other possible sources of variation acting at frequencies higher than one cycle per 19,000 years, this model predicts that the long-term cooling trend which began some 6,000 years ago will continue for the next 23,000 years."

Is that 1980 study (or some misunderstanding or misquotation thereof) what is being referred-to by folks making that can't-trust-em argument -- in some cases, at least?

(I don't know.)

[cheesehead]

For graph-watchers:

NASA's Goddard Institute for Space Studies surface temperature analysis

http://data.giss.nasa.gov/gistemp/graphs/

In particular:

Global Land-Ocean Temperature Index

http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.lrg.gif

[cheesehead]

Originally Posted by ewmayer

Once again you have shown why you are far and away the "most annoying person to debate with on the Forum."

... because I use fewer rhetorical distortions than you do.

Sorry about that, Ernst. You'll just have to live with it until you complete your rhetorical-distortion-addiction-recovery program (RDARP).

If you had any idea how many crude approximations are needed just to be able to approximately compute the turbulent dynamics of a cubic meter of air you would not be so quick to treat The Models as holy and infallible, even in the sense of meta-analysis of hundreds of model predictions.

If you were to treat my words as written instead of your straw-man versions, you'd not be so quick to chuckle at your own sprightly self-humor. I suppose you have to find your jollies where you can, but your RDARP can teach you about alternate sources of amusement that don't require distortions of reality.

The fact that even high-tech supercomputer-generated weather forecasts are quasi-reliable at most 24-48 hours ahead does not give me massive confidence in "the models" of climate dynamics over decades and centuries.

For which of the following prediction tasks is the historical record of how often I've fastened my seatbelt when I drive likely to be a more accurate indicator?

a) my chances of being late for my doctor appointment in Waukesha 45 minutes from now, or

b) my chances of ever dying in an auto accident

For which of those two prediction tasks is the total precipitation along my driving route, for the hour immediately preceding my departure for that appointment, likely to be a more accurate indicator?

[retina]

http://dir.salon.com/story/comics/to...omo/index.html

[cheesehead]

An AGW-denier argument involving climate model discrepancies bites the dust while audience dines on pizza.

https://scienceandtechnology.jpl.nas...ls/?NewsID=536

(my underlining)

KECK INSTITUTE FOR SPACE STUDIES (KISS) LECTURE SERIES

The MSU Debate, Climate Auditing, and the Freedom of Information Act
Thursday, September 3, 2009
Pizza and soda lunch (sponsored by KISS) at Noon (Cahill Building Patio, Caltech)
Lecture at 1pm (Hameetman Auditorium in the Cahill Building, Caltech)

Dr. Ben Santer
Program for Climate Model Diagnosis and Intercomparison
Lawrence Livermore National Lab

Since the late 1960s, scientists have performed experiments in which computer models of the climate system are run with human-caused increases in atmospheric concentrations of greenhouse gases (GHGs). These experiments consistently showed that increases in atmospheric concentrations of GHGs should lead to pronounced warming, both at the Earth's surface and in the troposphere. The models also predicted that in the tropics, the warming of the troposphere should be larger than the warming of the surface.

Observed estimates of surface temperature changes are in good agreement with computer model results, confirming the predicted surface warming. Until several years ago, however, most available estimates of tropospheric temperature changes obtained from weather balloons and from satellite-based Microwave Sounding Units (MSUs) implied that the tropical troposphere had actually cooled slightly over the last 20 to 30 years - in sharp contrast to the computer model predictions. For nearly a decade, this apparent disconnect between models and reality has been used by some scientists and politicians to argue that human-caused changes in greenhouse gases have no effect on climate.

Recent work by a consortium of scientists from 12 different institutions has largely resolved this long-standing conundrum. Research published by this group indicates that there is no fundamental discrepancy between modeled and observed tropical temperature trends when one accounts for:
1) the currently large uncertainties in observations;
2) the statistical uncertainties in estimating trends from "noisy" observational time series.

These results refute a highly-publicized claim that model and observed tropical temperature trends "disagree to a statistically significant extent". This claim was based on the application of a flawed statistical test and the use of older observational datasets.

The talk will summarize some of the history of the "great MSU debate," and will also cover recent reaction to the resolution of this debate.