Arguments
How to explain Milankovitch cycles to a hostile Congressman in 30 seconds
Posted on 6 December 2010 by John Cook
Over the last few weeks, I've been publicly put on the spot on two occasions, asked to give very short answers to complex climate questions. On a climate communication panel, Naomi Oreskes asked how I'd answer the CO2 lag question in 30 seconds (and no iPhone app to fall back on). On the Climate Show podcast, Glenn and Gareth asked how I'd answer the global cooling argument in 30 seconds. What's with this 30 second limit?!
Meanwhile, Professor Richard Alley was being grilled by a hostile Republican Congressman who asked him to explain in 15 seconds why climate has changed in the past and how we know humans are causing it now when they didn't back then. I've long been a fan of Richard Alley. Not just because of his rendition of Geoman, possibly the nerdiest song in the history of science. I consider his lecture, The Biggest Control Knob: Carbon Dioxide in Earth's Climate System, must-watch viewing for anyone interested in climate and wishing to understand past climate change at a much deeper and richer level.
But seeing his answer in a Congressional hearing under those conditions, my admiration went up another notch. In 35 seconds, he manages to explain Milankovitch cycles (aka changes in the Earth's orbit) quicker, funnier and with more clarity than I've heard before. Check out the first 60 seconds then continue on for plenty more Alley goodness...
Another video worth watching features Alley and Ben Santer explaining why we know CO2 is causing global warming. They invoke a subject SkS readers will be well familiar with - the stratosphere is cooling while the troposphere is warming.
So next time I'm in a conversation where someone invokes past climate change, I'll be sure to begin by saying "imagine my bald spot is the North Pole". As my parents informed me last weekend, I'm thinning on top so the metaphor should work well.
H/T to Peter Sinclair from Climate Denial Crock of the Week who posted these videos.
- Upton Sinclair
http://theweek.com/article/index/206686/6-global-warming-skeptics-who-changed-their-minds
Climate Crocks has a link on there showing one of them saying his reasoning for changing his mind.
I agree, Rohrabacher is not interested in learning inconvenient truths. Alexandre's quote sums it up.
And yes Alley is brilliant, and to say he is passionate about his work would be a gross understatement. Despite his questionable singing skills, my family (even the toddlers) really enjoyed his video:
I hope that worked.
Bad for ignoring the significance of the HCO.
This entire panel discussion is well worth watching. It's about an hour and 20 mins but the whole thing is great. You can find it here on the C-Span site.
What's with this 30 second limit?!
Rohrabacher offered Alley just 15 seconds, and Alley countered with 30.
15 seconds is probably more in line with Rohrabacher's attention-span, though.
I don't know. From what I viewed Rohrabacher's attention-span was somewhat less than 15 seconds. It seemed that within 5 to 10 seconds of Alley beginning to answer one of Rohrabacher's questions, Rohrahacher begin trying to rebut him.
At least
LordChristopher Monckton this time to testify. That's some progress.How did he ignore the significance of the HCO? Oh, right, he didn't.
We know the North Hemisphere was probably a bit warmer in the HCO, however there is no evidence the entire world was - it falls within the margin of uncertainty, that old double-edged sword. :-)
In any case, projected temperatures - even the more optimist scenarios - will go well above HCO temperatures. The fact temperatures are going near HCO levels at this time, while they should be well under according to natural cycles, supports AGW theory.
If anything, professor Alley's responses were still too wordy (bald spot excepted). When the (very partial) congressmen started his nonsense about Mars experiencing the same climate change as we do, he should have simply said it isn't. When demagogues make statements which they can't prove, you can simply call them on it. This puts the burden of proof on them, and since they *can't* support that position (due to a lack of facts) they'll simply stop using it as an argument.
Simple falsehood should be challenged simply, with the science to back it up if needed. This is why sites such as this one are so useful! :-)
shame he isnt prettier (hmph...and shame it matters) but at least our dana is prettier than theirs...
I have much respect for Alley answering in a good spirited and humorous way while being questioned by such a nutcase regarding such a serious problem. But I'll guess Rohrabacher's right about one thing though: "Wake up America (people like him are your leaders)"!
http://www.c-spanvideo.org/program/ChangePa
Rohrabacher gives Danas from California a bad name.
The Arctic summer encountered much more insolation for thousands of years during the HCO:
If Arctic temperatures weren't much warmer, in spite of much more irradiance, it raises some serious questions about sensitivity.
But either way, the polar bears survived, the Inuit thrived, and Greenland's central ice persisted.
Further, orbital variation is going impose Arctic melting greater than present for nearly all of the next hundred thousand years anyway.
Sorry, try again mate-- everything is not going to be just OK. I would/could elaborate but I imagine I'd only be wasting my time. Maybe others here are more patient than I.
PS: Can we here assume that you then agree with Rohrabacher's beliefs and misguided understanding of the climate science?
Your graphic appears to be a calculated Milankovitch graph a la Hays Imbrie and Shackelton 1976. Interesting that the graph gets prominent play at a denier site (hockeyschtick; they can't even spell shtick correctly). The time scale is in thousands of years. I'm not sure what the relevance of that is for today's situation.
One should also wonder about the CO2 concentrations were at the times when arctic summer insolation was so "much more". Compare that CO2 to today. Perhaps that helps explain why "Arctic temperatures weren't much warmer, in spite of much more irradiance ... the polar bears survived". Perhaps the smaller GHE due to lower CO2 moderated that higher irradiance.
Look at the whole picture: Warming, Arctic melting with comparatively low insolation and high CO2. Maybe its time to start actually watching the climate rather than the shtick.
The effect of insolation on climate is a weak radiative forcing but just enough to cause initial changes which are amplified by greenhouse gas increases that the initial perturbations causes. The important thing that you are missing is that the Holocene Climatic Optimum occurred at different times for different places. This is largely due to the feedback mechanisms and climatic controls of the ice sheets which were still melting away. You have to also consider that sea levels were higher during the Holocene optimum and Dr. Alley suggested by as much as 0.5 m which is not an insignificant amount. Globally temperatures over that period were not much warmer than today (at most 1°C) indicating a high sensitivity from ice as most of the glaciers in the northern hemisphere disappeared at that time and greenland was smaller.
Another important thing that you are missing is the rate of change being different with similar magnitudes, slow changes in temperature give the system more time to reach a new equilibrium state whereas very fast changes (such as the one we are currently causing) can cause chaotic responses.
Further, orbital variation is going impose Arctic melting greater than present for nearly all of the next hundred thousand years anyway.
Add ClimateWatcher to the long list of skeptics who don't understand the concept of dT/dt.
Err, actually, no.
Polar bears only evolved about 150kY ago from brown bears.
Probably due to climate change :D
First, why do you show a graph on that time scale when talking about the HCO? Could you even place the HCO on that graph?
Second, we are talking about global temperatures, not NH ones.
Last, the current warming trend, which will likely exceed HCO temperatures before the end of the century, is *not* due to milankovitch cycles.
Enough with the propaganda already.
Or:
"Your honor, people have died from natural causes for millions of years! Therefore, my client can't possibly have killed the victim!"
That is surprising. However, Curry's defense of Pat Michael's misinforming/deceiving at her blog is surprising. Hang on, then again, maybe it is not entirely surprising given her odd behaviour of late...
The fun is that you can zoom in to periods like the HCO. I hope it's helpful to this type of discussion, and if not, your criticisms here would be helpful to me.
jg
The navigation bar at the top took a few minutes to figure out, but having gotten used to it I quickly came to like it. The rest of the interface is great.
Have you thought about using EPICA data, for a longer record than Vostok?
Also, I noticed that the insolation curves and the orbital geometry curves approach the Y-axis smoothly, then suddenly jump up to meet the other lines.
Come to think of it, how did you decide on scaling factors for the different data sets?
Anyway, for others reading this ... check it out.
jg
Awesome!
This will really help in a debate I am having on a sceptic site right now.
Interesting how the shape of the Methane curve tracks temps more closely than CO2. Quicker response time for Methane and closer temperature dependence probably. And to 100 ky eccentricity cycle seems to be the stronger driver.
As with any piece of software, if it is good we want more more more...
Any chance you could add a feature to allow differences between the NH & SH insolation to be shown.
Thank you for your comments:
Regarding EPICA -- yes. I wanted to work out the bugs and user interface on a smaller data set first.
The jump you observe at the origin is a programming challenge that I need to remove; but right now it is helpful when I add a new graph and fail to scale it correctly (it tells me which direction off the screen it is).
Regarding scaling factors, I estimated scaling to match similar graphs I've seen, but this is an inadequate answer. I welcome suggestions.
Glenn, please elaborate on what you mean by showing differences between NH and SH insolation. I currently allow a comparison between, e.g., Northern Summer to Southern Summer, are you asking for Northern Summer to Southern Winter or some calculation between datapoints?
thanks again,
jg
You have to remember Rohrabacher is not the audience when Alley is speaking to him. He is merely the antagonist in the forum. What is important is that people hear Alley teach the antagonist the error in his thinking. Therefore, it's not Alley's job to convert Rohrabacher, it's his job to teach the broader audience by politely responding to Rohrabacher's misinterpretations.
I try to use exactly this thinking when I engage climate change deniers on various forums. I try to be polite. (I really do try!) I try not to make it a personal goal to convert the person I'm talking to. But I try, to the best of my abilities, use that denier as a way to teach the broader reading audience what I've learned about the science of climate change. Science that I have primarily learned here at SkS.
A simply amazing communicator at the top of his game.
The Yooper
+1 We scientists have to be able to parry the rhetorical tactics that troglodytes like Rohrbacher use. That means *short, declarative* statement first -- that's right/wrong, that's true/false -- FOLLOWED BY the explanation. Alley too often doesn't do this. He went right to the explanation, often obliquely.
Santer starts his rebuttal with:
"Dr. Michaels' analysis is wrong; it's just completely incorrect."
THAT is how it should be done.
While I know that correlation doesnt equal correlation, the match of the milankovitch cycles to ice-age cycle is so striking that surely you arent suggesting that these arent the dominant forcing? The fine details of the mechanism are another story.
1.The 100,000 year problem
2. The 400,000 year problem
3. The stage 5 problem.
4. The transition problem.
And these are only a few of the problems.
Helpful tip: then you may want to re-think your approach a bit. Visitors who pose questions framed with thought, and with cited sources, get a lot more interaction and positive attention.
Or you could keep on posting unsupported assertions.
Being a glass-half-full person, I opt for positive dialogue myself. I feel I get much better and informative conversations that way (and therefore learn more).
Your Call.
[ - Edit:
OK, I see you added some bits. If you would delineate your position relative to the consensus on each, and also let on where you base your differing opinion (what source do you have for that), you'll find a more helpful and fulfilling interaction.
End Edit - ]
The Yooper
Again, are you seriously looking at the milankovitch cycle and glaciation and saying you think milankovitch theory is wrong?
Also, what relevance do you think any of milankovitch forcings have to climate in human terms? How much effect do you get from 0.25W/m2 change in one part of globe over one hundred years from orbital variation compared to 3.7W/m2 over whole globe in same time period?
Do you have an open link to Crowley?
Thank you Yooper.
The Milankovitch theory does have problems. Do I think it is wrong?
From my research, and this was yes....dated....I came away with thinking it was not wrong nor correct.
I have not read the Crowley paper and would be most interested in reading it.
The level of proof a few years ago was quit thin.
In ref to the 3.7W/m2....I am not comfortable with that number. I know it is cited in IPCC, but it is also reflective of what the sensativity is. And that is still a wide open question.
3.7W/m2 (well lets say 3.5-4W/m2) - no sensitivity involved in this number at all. These are sum of direct forcings from anthropogenic emissions. Read that section of the IPCC carefully. Number matches pretty much the measurement from Evan 2006.
There are two parts to acceptance of milankovitch theory.
1/ there is the observation that ice-age matches the milankovich forcings at 65N to an extraordinary degree. If milankovitch forcings are not involved, then there is a major problem explaining the observations.
2/There is the explanation (models) explaining how an orbital forcing with a very small global forcing value can produce large-scale global climate change.
I would say 1/ is incontrovertible and that the broad features of 2/ are well established. There are however numerous detail aspects of 2/ that remain active research areas. I would also say that none of the problems in the details are relevant to the question of climate over next 100 years. The feedbacks are very slow and in the case of the all-important GHG feedbacks, completely overwhelmed by human emissions.