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Comments 47801 to 47850:
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Don9000 at 04:13 AM on 7 March 2013Arctic sea ice has recovered
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Dikran Marsupial at 04:13 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
Kevin, there have been other occasions where CO2 has led temperature changes (e.g. uplift of Appalacians leading to increased chemical weathering, reduction of atmospheric CO2 and cooling temperatures), and there is also the fact that if CO2 is released by anthropogenic emissions then obviously any temperature change will lag emissions. Sorry, but you are just engaging in pedantry as far as I can see. Viewing CO2 as a thermostat is misleading as it can also be a forcing, calling it a control knob likewise doesn't tell the whole story as it often acts as a feedback. This pedantry seems to be aimed at avoiding the key point of the story, which is that our anthropogenic emissions are twisting the control knob on the thermostat, and paleoclimate tells us that there is good reason to expect that to have a significant effect.
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Don9000 at 04:10 AM on 7 March 2013Arctic sea ice has recovered
The most recent PIOMAS current ice volume anomaly graphic (31 January 2013) suggests to me that the Arctic Ocean is beginning to behave much more like a seasonally frozen lake or pond than a permanently frozen large expanse of ocean that melts around the edges. Note in particular the annual pattern in the graphed data from the 2010 maximum to the end of January, 2013:
http://psc.apl.washington.edu/wordpress/wp-content/uploads/schweiger/ice_volume/BPIOMASIceVolumeAnomalyCurrentV2.png?%3C?php%20echo%20time%28%29%20?
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Kevin8233 at 04:02 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
Composer99,
First, I should like to draw your attention to the fact that the graph in figure 1(a) goes backwards in time as you go from left to right. So what you are actually seeing is that CO2 and sea levels are dropping very gradually, with brief interludes and irregularities, and then rise very drastically.
Thanks, I am used to seeing this the other way around, and did think it looked odd. But that doesn't counter my points.
Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
Just pointing out that the title of this article can't be accurate. As I pointed out, and everybody agrees, CO2 didn't start or end any of the ice ages. I also pointed out 1 paper for, and yes, someone pointed out one against, temp leading CO2. If temp leads CO2, clearly, CO2 can't be dominate control of temp!
Sorry about the multiple points, but they are all so closely related.
Moderator Response: [RH] Fixed image width. -
Rob Honeycutt at 03:33 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
Kevin... Just to be completely clear here, even if CO2 does lag (noting the most recent research suggesting there is no lag), that doesn't in any way cast doubt on the role of CO2 as a greenhouse gases, nor does it cast doubt on the warming effects of man-made CO2 from burning FF's. It's a complete non-issue with regards to published research.
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grindupBaker at 03:31 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
@1.Kevin "..do they just happen to go up and down together, perhaps each caused by something else..". It's known as hard physics that CO2x2 will force back ~3.5Wm-2 (skeptic Lindzen says 3.4). By simple math that power would raise ocean temp. to full depth by 1 C in 147 years with no other factors. Ocean mixing to depth takes ~1,000 years so it will be less than 147 years for top, say, 1000m. So you ask whether something known to be enough to melt massive ice was simply a coincidence in time with some mysterious other thing never seen (that you cannot suggest yourself) that does precisely the same. I'm sure not. What think you ?
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Dikran Marsupial at 03:27 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
BTW Kevin, if you want to get to the bottom of something, the fastest way to do so is to discuss one issue at a time, or ask one question, or make one point. If you branch off into three or four points in every post it more or less guarantees that many of them won't get answered. Indeed a common tactic in rehtorical debate is to do just this precisely in order to prevent getting to the bottom of the key issue. If someone is genuinely interested in scientific truth, a good indication is generally that they will keep to the point and narrow the discussion to ever more focussed questions that identify the key issues.
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Dikran Marsupial at 03:21 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
Kevin, I don't see any dissconet there with regard to water vapour. The principal difference is that CO2 is a long-lived GHG, whereas water vapour is a greenhouse gas, but its "adjustment time" in the atmosphere is a matter of days, so it only has a lasting effect on the atmosphere if it is amplifying something else that does (e.g. CO2).
"What caused the temp to drop?" largely Milankovic cycles, as has already been pointed out. Orbital cycles are sometimes favourable to initiating a glaciation, sometimes unfavourable.
I would also agree that CO2 in paleoclimate has been mostly a feedback, hence it has been a thermostat, rather than a "control knob", although there have been events where it has initiated warming rather than merely amplifying it (e.g. end of "snowball Earth").
However CO2 as well as being a feedback can also be a forcing (which is what anthropogenic emissions are doing), hence it can also be a "control knob" that we can use to set the thermostat. However in my opinion, going on about knobs or thermostats is missing the point. Paleoclimate shows that CO2 has a substantial effect on climate, hence if we double the atmospheric CO2 concentration (or more) we should expect it to have a substantial effect.
The difference in slope between the start of a glaciation and the end has already been explained by composer99 above.
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Kevin8233 at 03:08 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
Dikran,
Now before we go onto more advanced issues, please can you explicitly state whether you agree with this, and if you don't agree, please explain why not.
Yes and no. Terrible answer, but I'll go on. I agree with the initiation aspect, although I attribute more than just an initiation here, substantial "forcing" as well. I even agree, up to a point, with the feedback mechanism. The main problem I have is this:
The temp leads the CO2, the CO2 generates more heat trapping, the temp goes up...etc. Yes, I understand the Boltzman limitations, however, there is still a disconnect. On another thread here, the feedback loop for watervapor is equal to the temp increase from CO2 - for every temp increase due to CO2, you can expect the same temp increase from watervapor, and maybe some more from the other feedbacks - CO2 climate sensetivity - and since these temps and CO2 concentrations (for the glaciation graphs) are all lower than in the present when this sensetivity relationships were "calculated", they should still all hold up (probably even increase). None of this yet disputes your scenario. Yet.
Why does it end? The CO2 lags the temp. What caused the temp to drop? Another timely astronomical event? It can't be from "diminishing returns" of the CO2 feedback loop, as I stated above, these are all at lower than present values. Since these ice ages all end, and end with regularity (the same regularity that they start with) there must be some other, regular, forcing component to end them.
Since there is another component that starts them, and another that ends them, I will gladly point out that CO2 really can't be the big control knob. Since it really is something else that starts and stops them, it is not too much of a strech to find that this something else also controls or dictates the magnitude of these changes.
Also, on another thread, it is stated that the removal of CO2 from the atmosphere is a worthwhile endeavor because the decline in temp is the same as the incline has been. Looking at the graphs in fig 1a, I would argue that is not accurate. If the rise and fall of the temps and CO2 is from the CO2 feedback loops, then why is the fall so different then the rise? Clearly, there is a different mechanism at play.
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BBD at 03:07 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
I'm surprised nobody has so far mentioned Shakun et al. (2012). This study explores the process by which increased summer insolation at high NH latitudes initates deglaciation and entrains powerful positive feedbacks that ultimately result in full glacial termination. There is an excellent article about S12 at RealClimate by Chris Colose (recently spotted in comments upthread) and also here at SkS.
Very briefly, the process works like this:- By ~19ka, mid/high latitude NH temperature increase causes sufficient melt from NH ice sheets for freshwater flux to inhibit NADW formation and halt AMOC
- NH *cools* as equatorial -> poleward heat transport stops
- With the NH ‘heat sink’ turned off, the SH *warms*, as it must
- Deep water warming in SH causes release of carbon from ocean sediments. This strongly positive feedback globalises and amplifies the warming
- NH melt resumes, fully engaging strongly positive ice albedo feedback
- Deglaciation accelerates until largely complete by ~11.5ka. Holocene interglacial begins
The supposed lag between GAT and Antarctic CO2 disappears. Along with a pseudo-sceptic 'argument'. -
Composer99 at 03:02 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
With regards to your inquiries:
[...] Except for the fact that the glaciation graphs tend to be saw toothed in shape, not sinusoidal.
1. What causes this regularity? With the built in pauses?
2. More importantly, what causes the sharp drop off? Both CO2 and sea level drop rather drastically. Apparently, this is natural, as it repeatedly happens again and again. Why won't it happen again?
First, I should like to draw your attention to the fact that the graph in figure 1(a) goes backwards in time as you go from left to right. So what you are actually seeing is that CO2 and sea levels are dropping very gradually, with brief interludes and irregularities, and then rise very drastically.
With that in mind, the answer to your question #1 is that it takes much longer to form the massive North Hemisphere ice sheets than it does to melt them.
Another factor to consider is that there are several different sets of orbital changes (or wobbles as I have called them upthread) and these have different periodicity, which can accelerate or decelerate climate changes (when these are driven by orbital changes, unlike in the present).
Your question #2 has already been responded to.
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Rob Honeycutt at 03:01 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
LaughinChance @ 30... It's interesting that your link goes to a website called "Global Warming Hoax." And then when you click the link to locate the source of the statement, the link is dead.
Not winning any style points on that one.
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Jeffrey Davis at 02:50 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
What is sinusoidal is the game of whack-a-mole on rebunked talking points.
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DSL at 02:45 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
LaughinChance, note Parrenin et al. (2013). Abstract (my emphasis):
"Understanding the role of atmospheric CO2 during past climate changes requires clear knowledge of how it varies in time relative to temperature. Antarctic ice cores preserve highly resolved records of atmospheric CO2 and Antarctic temperature for the past 800,000 years. Here we propose a revised relative age scale for the concentration of atmospheric CO2 and Antarctic temperature for the last deglacial warming, using data from five Antarctic ice cores. We infer the phasing between CO2 concentration and Antarctic temperature at four times when their trends change abruptly. We find no significant asynchrony between them, indicating that Antarctic temperature did not begin to rise hundreds of years before the concentration of atmospheric CO2, as has been suggested by earlier studies."
So who ya gonna believe? Al Gore on video? British court responding to a graph? Flying Spaghetti Monster? Science?
Or are you suggesting that CO2 can only be a feedback; when we put it into the atmosphere, it's radiatively inert?
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Dikran Marsupial at 02:39 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
laughinchance - a lot of the change in temperature was caused by CO2 and CO2 changes lag temperature changes by 800+ years. There is no contradiction there, it is just what you would expect if the natural carbon cycle provided positive feedback amplifying the effects of orbital variation.
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DSL at 02:31 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
Yes, they did. Now, what does it mean to you?
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LaughinChance at 02:26 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
Curiously the British Court that defended Al Gore's film found the opposite to be true...
Among the inaccuracies was this:The film suggests that evidence from ice cores proves that rising CO2 causes temperature increases over 650,000 years. The Court found that the film was misleading: over that period the rises in CO2 lagged behind the temperature rises by 800-2000 years.
http://www.globalwarminghoax.com/news.php?extend.29 (among numerous citations!)
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Rob Honeycutt at 02:25 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
BillEverett said... 'I am unhappy with Ally's calling CO2 simply earth's main control knob."
Actually, Dr Alley calls CO2 the "Biggest Control Knob." That would be very different than saying it's the "main" control knob.
I have somewhat of an enhanced version of this analogy. You can maybe think of the whole system as a very complex and sloppy set of gears and pulleys. A forcing is something like solar variation or orbital changes that are actively turning one or more of the gears, and those gears are in turn driving a broad series of other gears and pulleys. Each of those turns at different rates and has a net effect on global temp. CO2 happens to be just one of the cogs in the system that has the largest effect on global temp. Even when a separate forcing is doing the work, that forcing is pushing the "big knob" (CO2) to have the largest effect.
The difference today is, we are directly moving that CO2 knob ourselves. It's still a sloppy system of gears and pulleys, and thus there is some delay in the net effect, as well as uncertainties with what the exact effect will be. But there is no doubt, based on our understanding of how the system works, that we're fiddling with the big knob.
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CBDunkerson at 01:52 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
Kevin, yes in the past CO2 levels have naturally gone up to ~280 ppm, dropped down to ~180 ppm, and repeated over and over again.
You ask, "Why won't it happen again?"
We're at ~400 ppm CO2 and climbing. Completely outside the bounds of that 'natural cycle'. The natural ~100 ppm CO2 drop from that cycle would normally occur over the course of next few tens of thousands of years... we have already increased CO2 by more than that 100 ppm and are still putting enough in to offset the entire decline every fifty years.
So, basically... the phase of the Milankovitch cycle which in the past has caused CO2 levels to drop will 'happen again'. It will just be insignificant in comparison to the rate at which we are increasing CO2 levels.
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Dikran Marsupial at 01:43 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
Kevin, the ice ages are generally understood to be initiated by changes in the Earth's orbit (i.e. Milankovic cycles), which explains the regularity (point 1). Note very carefully that I said "initiated", rather than "caused". This is because the changes in insolation caused by the variation in orbit is not sufficient to cause the observed change in the Earths temperature, so we know that there must be some feedback mechanism that amplifies the effect of the Milankovic cycles.
One of these feedback mechanisms is the carbon cycle. As the world warms up, the oceans release CO2 into the atmosphere, which is a greenhouse gas, which causes a bit more warming, so a bit more CO2 is released and so on. Fortunately there are also negative feedbacks (principally the Stefan-Boltzman law), so this process doesn't continue forever.
Now before we go onto more advanced issues, please can you explicitly state whether you agree with this, and if you don't agree, please explain why not.
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CBDunkerson at 01:32 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
I've been looking at sea level rise maps. At 24 meters Bangladesh and the Netherlands essentially cease to exist... along with various island nations, the U.S. state of Delaware, half of Florida, and most of the major cities on the planet. We'd better hope this study is wrong, actual rise is on the low end of the uncertainty range, or the timescale is in the thousands of years, because even a 'several hundred years' timescale for this kind of sea level rise could be economically devastating.
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Kevin8233 at 01:28 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
shoymore,
There are others, and more recent, but it doesn't much matter.
dr2chase,
all well and good. Except for the fact that the glaciation graphs tend to be saw toothed in shape, not sinusoidal.
1. What causes this regularity? With the built in pauses?
2. More importantly, what causes the sharp drop off? Both CO2 and sea level drop rather drastically. Apparently, this is natural, as it repeatedly happens again and again. Why won't it happen again?
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dr2chase at 01:05 AM on 7 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
I'll have a shot at explainging this to Kevin. The climate has two positive feedback mechanisms of (usually, hopefully) limited range -- albedo, and greenhouse gasses. Shrinking ice sheets increase heat absorption leads to more shrinking ice sheets leads to more heat absorption -- but they cannot shrink past zero. There appears to be a mechanism where increase GHGs (CO2 and CH4) lead to increased warmth leads to increased GHGs -- perhaps because of reduced solubility in the ocean, perhaps because of methane hydrate releases.
The initial kick that usually leads to change, either cooling or heating, does not need to be large -- if it is large enough to push either feedback mechanism into action, the feedback takes over, and then the change (ahem) snowballs. This is why, in the case of the natural warming out of ice ages, you see the CO2 lagging the change -- the initial kick out of equilibrium is not large, and precedes the first increase in CO2. But that first increase in CO2 leads to more warming -- which precedes the next increase in CO2. And the next increase leads to more warming, etc. This is consistent both with (1) the lag you see written about and (2) claims that CO2 is the cause of most of the warming. You might argue that really this is all about ice caps and albedo, and that would be reasonable, except that we already know that CO2 is a greenhouse gas of no small power (else we would not be here to have this discussion, because the planet would be far colder, even colder than it is during ice ages).
The reason, now, that we see CO2 rises not lagging temperature increases is because the CO2 increase is both artificial and rapid -- the earth (in particular, the oceans) are slow to warm, and we have also outrun any historically observed feedback effects.
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John Hartz at 00:48 AM on 7 March 20132013 SkS Weekly Digest #9
Doug Hutchenson:
You can access a profile of Judith Curry at Source Watch by clicking here.
I presume that Curry is not included in the SkS Misinformers section because updating that section has not been a particlarly high priority activity for members of the SkS volunteer author team. I would also note that neither DeSmog Blog nor Real Climate have posted a profile of Curry.
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Physicist-retired at 00:03 AM on 7 March 2013China Takes a Leading Role in Solving Climate Change
JoeT,
Your links provide some meaningful information, and are much appreciated.
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Composer99 at 23:03 PM on 6 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
BillEverett:
With regards to your point (1), if memory serves (it has been some time since I have watched the video), I do not recall Alley referring to CO2 as a control knob in his speech (although it is referred to as such in the title of the presentation).
He does, I am much more certain, note that the combination of volcanic CO2 emissions and rock weathering of CO2, taken together, regulate the climate in a manner similar to a thermostat (the word 'thermostat' or some synonym is used).
Since the term 'control knob' is used prominently in the title of the presentation, your criticism still stands, as far as I can see.
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BillEverett at 19:49 PM on 6 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
A few points (in addition to seconding or thirding the Tom Curtis motion@19):
1. I am unhappy with Ally's calling CO2 simply earth's main control knob. We encounter lots of control knobs in our everyday lives (or at least we used to in the predominantly analog era): volume control knob, screen brightness control knob, etc. These control knobs work virtually instantaneously. We have had very few control knobs that take significant time to see the effect of turning the knob. The most common examples (perhaps the only examples familiar to most people) is a thermostat: the thermostat for controlling home temperature, the thermostat in the refrigerator, the thermostat for the oven in the kitchen. I wish Ally had originally called CO2 earth's main thermostat.
2. In the older Antarctic ice core data, while CO2 lagged temperature, CH4 was leading by more than CO2 was lagging. With the recent indication that the relative age of the air bubbles and the surrounding ice in the Antarctic core data need adjusting, the CH4 lead would increase as the CO2 lag decreases. As is known, CH4 is converted to CO2 and H2O in the atmosphere on the time scale of a decade. Both CH4 and H2O are greenhouse gases, but their residence times in the atmosphere are relatively short. The residence time of CO2 is on the order of a millenium, which is why it is the main greenhouse gas for long-term climate control.
3. The atmospheric CO2 concentration does not directly control the sea level. Sea level is controlled by the amount of water in the oceans and the temperature of that water (water expands when it warms). When water is stored on land as ice, that water is not running quickly to the sea.. The causal chain is thus: high atmospheric CO2 results in increased temperature, which means warmer oceans and less land ice (more water ran into the sea), and consequently a higher sea level. On the other hand, low atmospheric CO2 results in decreased temperature, which means cooler oceans and more land ice, and consequently a lower sea level.
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shoyemore at 18:39 PM on 6 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
Kevin #12,
The paper you cite was published in 1999.
I suggest it has been superseded by these papers published much more recently:
http://www.nature.com/nature/journal/v484/n7392/full/nature10915.html
http://www.sciencemag.org/content/339/6123/1060.abstract
From the second:
Here we propose a revised relative age scale for the concentration of atmospheric CO2 and Antarctic temperature for the last deglacial warming, using data from five Antarctic ice cores. We infer the phasing between CO2 concentration and Antarctic temperature at four times when their trends change abruptly. We find no significant asynchrony between them, indicating that Antarctic temperature did not begin to rise hundreds of years before the concentration of atmospheric CO2, as has been suggested by earlier studies.
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Doug Hutcheson at 18:35 PM on 6 March 2013China Takes a Leading Role in Solving Climate Change
China is taking climate change seriously
That's good to know. May it long continue.
Is the Australian reduction in carbon emissions from the electricity sector and energy demand legitimately able to be sheeted home to the Carbon Tax, or are there other factors in play? (Good news if it is due to the tax.)
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Doug Hutcheson at 18:20 PM on 6 March 20132013 SkS Weekly Digest #9
I was looking for material on Judith Curry, to counter a comment in another forum, but she does not appear on the 'Climate Misinformers' page (unless I have misread). Any reason for her absence from the rouges' gallery?
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Doug Bostrom at 18:00 PM on 6 March 2013China Takes a Leading Role in Solving Climate Change
Further to PluviAL, in the past half-dozen years China has equipped homes with 20GWE+ of domestic solar hot water, the equivalent of 10 of the largest nuclear plants crisply instantiated as facts on the ground. Here in the US we pretty much ignore this ridiculously easy to obtain energy, apparently preferring instead to dream and talk about a resurgence of nuclear power when fraction of the money required to realize our romance with atom splitting could actually solve problems for us immediately. Not to say we shouldn't split atoms, just that we frequently let imaginary perfection be the enemy of factual good enough.
Indeed, China doesn't "just talk about it."
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KR at 16:08 PM on 6 March 2013Reality Drop - using social media to rapidly respond to climate misinformation
As a not unexpected note, WUWT has blocked links from Reality Drop, insofar as they can, using the URL origin.
Apparently WUWT's best response to critiques based on peer-reviewed literature is to stick their fingers in their ears, sing "la la la", and ignore them. That's just sad.
Disengaging from discussion, ignoring other points of view, blocking dissention - I seem to recall complaints from the 'skeptics' on just those items. "Emulating the Enemy", or at least the perception of the enemy, perhaps?
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PluviAL at 15:57 PM on 6 March 2013China Takes a Leading Role in Solving Climate Change
Habilus: I have been to China extensively. In less than 6 years they built the largest High-Speed rail road network in the world. When China sets out to do something they do it, they don't just talk about it. Your comment makes me think the rest of your comments are just as pooly based. That the air is dirty is not a question, so it is a straw man argument on your part. Do you work for the pollution company interests?
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Bob Loblaw at 14:42 PM on 6 March 2013Temp record is unreliable
..and furthermore...
Air temperature measurements were not started with the monitoring of climate in mind. The concept of "climate" probably didn't even exist in those terms until after people started accumulating data. As experience accumulated, methods of measuring temperature improved (and changes need to be accounted for in looking at long-term trends).
Even though historical air temperature records are an incomplete view of historical global conditions, they are useful. Extensive land surface air temperature records go back much further than ocean temperature records. We understand many of the linkages between ocean and land temperatures, and we can account for much of the differences in patterns. AIr temperatures are but one part of the jigsaw puzzle, but they do help.
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scaddenp at 14:13 PM on 6 March 2013Temp record is unreliable
Further to DSL
2- no it is absolutely not a simple average. First "global average temperature" is tough to define (and measure) so what is usually calculated is global average anomaly. Second, all the temperature records use area weighting. However, there is a lot of differences in the detail (and a lot of detail). The advanced section of this article gives you good pointers for more information.
3- Any proxy of use has to have two attributes - a way to tell the time accurately and a way to tell the temperature. The best long term proxy is ice core bubbles. The "lock in" time for a bubble is short and where you have annual snow layers, you have very good clock. Thermometry is also very good compared to most other proxies. Resolution degrades as you go back in time for all proxies. Ice core gets you 600Ka but only for very selected places on earth (greenland and Antarctica). Spelothems are prob next best as far as I know but more problematic for absolute dating and thermometry but wider global coverage. Going back beyond these you lose time resolution badly as you become dependent on radiometric dating resolution. Resolution will depend on the particular technique. In something like benthic forams from marine cores you can good relative time but not absolute time (and a lot of fun interpreting the thermometry).
In short all proxies have issues of one sort or another and paleoclimate studies are best within integrating multiple lines of evidence.Go to http://www.ncdc.noaa.gov/paleo/recons.html for data but read metadata about limitations before leaping to any wild conclusions.
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DSL at 13:41 PM on 6 March 2013Temp record is unreliable
grindupBaker,
1. Public interface. The thermal capacity of the oceans is difficult to explain to the general public, and surface temp is "in your face."
2. Hansen 2010; HadCRU; BEST
3. I'll defer to others.
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Phil L at 13:34 PM on 6 March 2013Reality Drop - using social media to rapidly respond to climate misinformation
brent @ 17, my apolgies for missing the tongue-in-cheek nature of your comment. I agree that Michael Mann's book is a masterpiece, and I'm a big fan of Mark Twain. My use of the term "your ideology" was unwarranted - I mistakenly thought you were dismissing Spurgeon as a citation because of the fact that he was a Baptist preacher, not because of his current obscurity. To me it's a simple question of who said it first, no matter how famous or obscure that person was.
"People misquote me on the Internet all the time. Please cut that sh1t out" -Albert Einstein
But I realize this discussion has strayed off topic .... Reality Drop looks like a useful tool with potential to complement SkS's carefully researched articles.
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jyyh at 13:32 PM on 6 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
What Tom Curtis said: Seconded. While it's good to debunk denialist articles individually too, the continous stream of crap, illogical presentations and outright lies by the usual suspects may effect also good sites. Luckily, the article refuting Goddard etc. types usually contain their name on the headline so I can skip the article. I mean, I have decided their originals (and comments therein) aren't worth the bandwith, but still someone might still believe then so the debunkings should continue, however frustrating it is. I'd like to call it 'The propaganda-machine of deniers', but I'm still not certain, they might just be assholes having fun at the expense of future generations. (oops, off topic, please delete.)
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grindupBaker at 13:30 PM on 6 March 2013Temp record is unreliable
I have 3 questions (1) Since oceans store same heat per ~20' depth as all air & all land that's relevant (to ~20' depth) why is avg global temp being used rather than ocean heat energy in the graphs publicly discussed ? (2) Is avg global temp a simple avg of all readings, or weighted ? (3) Can I find a proxy historical global temp set (600Ka ? 600Ma ?) to fine time resolution - a millenium ? a century ?). Anybody ?
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Philippe Chantreau at 12:13 PM on 6 March 2013Why SkS withdrew from the Bloggies
Nice Kr :-) Nothing like real data analysis, something that Watts took years to do and when he did he couldn't acknowledge the results. Not surprising since the results invalidated the very initial premise of his site's existence. Nuff said
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KR at 11:54 AM on 6 March 2013Why SkS withdrew from the Bloggies
Doug Bostrom - Less than 1:20 rated as good. Hmm, that seems to indicate a 2-sigma significance result, that "good" is not supported by the evidence for that blog source.
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Riduna at 11:42 AM on 6 March 2013‘Frozen Dirt’ and Methane … ‘We Cannot Go There’
The essay ignores the elephant in the room – methane trapped in clathrate and as gas in surrounding sediments beneath permafrost covering the seabed of the Siberian Continental Shelf. This has been quantified by Shakhova and Semiletov as comprising not less than 1,700 gigatonnes. As a result of seabed permafrost degradation methane has been observed venting to the atmosphere. Because of the shallow depth of water covering the continental shelf, it has no time to oxidize to far less potent CO2.
Continuing loss of sea ice and Arctic Ocean warming, combined with atmospheric warming is likely to result in accelerated loss of seabed permafrost, increasing venting of methane to the atmosphere. This has the potential to reduce sub-seabed pressure, destabilise shallow clathrates, rapidly increasing methane excursions from them to the atmosphere, further amplifying Arctic temperatures and chnaging global climate.
Daniel Bailey rightly observes that “the Kraken does not yet wake... “ But it is already stirring and nothing short of reversing Arctic warming is likely to prevent it (methane) from venting to the atmosphere in such volume as to bring about rapid and permanent climate change before 2100.
Do I hear mutterings about geo-engineering – spraying sulphides at the top of the stratosphere - to prevent this? The clothing industry could produce a whole new range that can withstand acid rain and we could all get on with business as usual.
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Tom Curtis at 11:16 AM on 6 March 2013Carbon Dioxide the Dominant Control on Global Temperature and Sea Level Over the Last 40 Million Years
First, I want to commend Rob Painting on an excellent article. I particularly appreciated the clear statement of the basis for the conclusions, along with the relevant caveats. Could a link to this article be placed at the bottom of the various sea level myth rebutals so that it is not lost in the continuous stream of posts at SkS, and left to languish in obscurity.
In particular, a link would be appropriate on these pages:
How much is sea level rising; and
Why Greenland's ice loss matters.
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Tom Curtis at 11:09 AM on 6 March 2013Why SkS withdrew from the Bloggies
1) Eclectikus makes a variety of claims about Richard Feynman's views on pseudo-science, but does not quote a source for those claims. Google searching, I have found two discussions of pseudoscience by Feynman available on the net. The first, and more substantive, only refers to pseudoscience in the introductory comment which was not part of the actual lecture. In the lecture itself, he only refers to "cargo cult science", a term which is definitely pejorative. Clearly Feynman considers "cargo cult science" and "pseudoscience" to be the same thing.
The distinction between cargo cult science and real science turns out to be a kind of scientific integrity. Feynman describes it as follows:
"... It is interesting, therefore, to bring [the distinction between cargo cult science and real science] out now and speak of it explicitly. It's a kind of scientific integrity, a principle of scientific thought that corresponds to a kind of utter honesty--a kind of leaning over backwards. For example, if you're doing an experiment, you should report everything that you think might make it invalid--not only what you think is right about it: other causes that could possibly explain your results; and things you thought of that you've eliminated by some other experiment, and how they worked--to make sure the other fellow can tell they have been eliminated.
Details that could throw doubt on your interpretation must be given, if you know them. You must do the best you can--if you know anything at all wrong, or possibly wrong--to explain it. If you make a theory, for example, and advertise it, or put it out, then you must also put down all the facts that disagree with it, as well as those that agree with it. There is also a more subtle problem. When you have put a lot of ideas together to make an elaborate theory, you want to make sure, when explaining what it fits, that those things it fits are not just the things that gave you the idea for the theory; but that the finished theory makes something else come out right, in addition.
In summary, the idea is to give all of the information to help others to judge the value of your contribution; not just the information that leads to judgement in one particular direction or another."
(Quoted from here.)
Let's be very direct about this. A cherry picker does not "... give all of the information to help others to judge the value of your contribution". Somebody who does not calculate the predictions of their theory does not "... give all of the information to help others to judge the value of your contribution". Somebody whose account of the science contradicts itself does not "... give all of the information to help others to judge the value of your contribution".
Therefore, by Feynman's definition there is no doubt that the Coleman article is "cargo cult science", ie, pseudoscience.
Eclecticus can disagree with that assessment if he likes, but he cannot honestly do so while quoting Feynman as his authority. If he disagrees, he owes us his own definition of "pseudoscience", and he needs to justify it with rational argument - something he appears unprepared to do.
It should be noted that one person falling below this ideal does not make a discipline pseudoscience. Science is a self correcting communal activity. Individual scientists are human, and like most humans tend to protect favoured theories from criticism to some extent. But the scientific community as a whole, particularly the scientist's peers in the discipline will not be so slack. In this respect, climate science is clearly scientific; whereas the AGW "skeptical" movement is astonishingly reticent in criticizing even the most absurd ideas, provided they would make taking action against global warming, if true. The political effect of those theories clearly outways, in their minds, any commitment to scientific integrity. That, and perhaps, a fear that if they are too open in exposing the fallacies of their fellow travellors, their fellow travellors might return the favour.
2) It was well said by some ancient sage, and recorded in the Tanakh that,
That was said while books where still written by hand on parchment. You can imagine that sage's distress if confronted with the internet.
The point is that, even if we confine ourselves to scientific papers (for example), there is far more material produced than any one person could hope to read, let alone analyse and understand. To cope with modern flood of information, we need spam filters.
As noted, this applies even in science. That is the purpose of peer review, which is supposed to weed out papers that are obviously poorly supported or simply wrong. Peer review does not pretend, and cannot hope, to eliminate all errors from scientific papers. But it does aim to ensure that any errors that make it through to publication are either subtle, ie, not easy to find, or interesting, ie, to show that they are errors you need to learn something new.
A good science blog should also be a spam filter. It should weed out the pseudoscience, and the misleadingly presented. It should present only posts which are reasonable summaries of the science, which are interesting, and encourage people to learn critical thinking rather than gullibility.
By this standard Skeptical Science is a good science blog.
By this standard, WUWT is the antithesis of a good science blog. It does not weed out the bad articles, such as that by Coleman. It certainly does not encourage critical thinking, but instead teaches gullibility. The same can be said of all four remaining short listed nominees for the best science award at the blogees.
Regardless of what definition Eclectikus contrives to maintain his belief that WUWT is a good science blog, the fact remains that as a spam filter to filter out bad science and bad reasoning, WUWT fails abysmally. Indeed, it works more to filter out good science and good reasoning rather than the reverse.
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Doug Bostrom at 10:44 AM on 6 March 2013Why SkS withdrew from the Bloggies
Eclectikus: 93.- doug_bostrom, some of them only support a reading diagonal, maybe, but "WUWT" is not specifically a divulgative blog like this, and this has to be in the reader's mind.
Twenty articles and not a single one you're prepared to unreservedly endorse as "good?" Having nothing more specific to work with I take it thereby that when you say "I've also read good articles at WUWT" you mean some proportion fewer than 1:20 are "good" by your own estimation.
Perhaps if I'd provided a larger sample (50?) we'd learn something more about the "good versus something else" ratio. As it stands, some proportion less than 1/20th useful is not an impressive record. But that's not necessarily the end of the story; it's still possible that you could identify which of the sample consisting of the last twenty climate science related articles at WUWT strike you as good.
Unfortunately even if 1:10 articles or even 1:5 articles at WUWT prove to be worthwhile we're still seeing confirmation of John Cook's original point of his blog post.
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Leto at 10:43 AM on 6 March 2013Why SkS withdrew from the Bloggies
Eclectikus@106. The definition did not seem to come up in that video - unless I missed it. But it doesn't matter where the definition came from - the way you have applied the definition is invalid, even if the definition had some merit in another context, with the appropriate caveats in place.
It would be reasonable to characterise as "pseudoscience" a discipline that was unable to explain any empirical data or produce any empircal predicitons. On the other hand, it would be ludicrous to characterise a discipline as pseudoscience simply because it failed to explain all empirical data, or had a few unknowns, like physiology and climatology.
So, are you saying that climate science is pseudoscience in the same way that physiology is pseudoscience?
And, while we are on the topic, how would denialist climate theory stack up against the requirement that it must have explanatory and predictive power to be considered science? What empircal data is better explained by a denialist than by consensus climate science? Even cherry-picked snatches of noise do not get explained by any of these guys, just pointed out - with the statistical sophistication of an astrologist. The latest effort at WUWT includes drawing a fat yellow horizontal line over an uplsoping trend of ocean-heat content and calling it a pause in global warming, a challenge to AGW. How is that not pseudoscience, by any definiton?
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Composer99 at 10:33 AM on 6 March 2013China Takes a Leading Role in Solving Climate Change
Habilus:
I am fairly certain this is the third time today I have noted that someone has misunderstood the ad hominem fallacy. Tom Curtis & I were both rather pert with you, that is true. However, we also addressed the substance of your claim (insofar as there was any to begin with). We would have committed the fallacy only if our responses had solely been our concluding remarks.
(Interestingly, I came across this essay while looking for a concise definition to use above which argues that there is no ad hominem fallacy.)
I still don't see where the problem with Australia losing out on carbon ETS (to be accurate) revenue is, insofar as it results from Australian individuals, families, and businesses reducing their carbon usage more aggressively than the government projected. And as Tom Curtis notes, the Australian government diverts the ETS revenue into payments to Australians to offset cost increases from the scheme. So if the ETS generates less revenue than generated, I suppose that less money would be paid out - but this would balance out as reduced carbon usage by Austalian individuals, families and businesses means they are not affected as much by costs passed downstream by emitters.
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scaddenp at 10:13 AM on 6 March 2013Why SkS withdrew from the Bloggies
Hmm, Weart is great account of the historical background. SoD "insigificant trace gas" series is great introduction to basic physics, but for overview of science, it's hard to beat the IPCC WG1 report.
There is no talk of "closing blogs" - how could you? But if you are interested in scientific truth as opposed to ideology-driven anti-science why would bother to read sites that misinform? (and I would hasten to add that Spenser and Curry arent in the sewer with WUWT). The usual reason is to seek confirmation of what you hope is true. A science education is about training the mind on how not to fool yourself.
Discussion on models belongs in the "Models are unreliable" thread. However, there are some caveats to observe when thinking about GCM models. While purposes overlap, there are two reasons for creating computer models. We could be realising well-established conceptual models for a useful purpose (eg tomorrows weather or plotting a probe to Hyperion). Or we could be testing our conceptual models by checking computation against observation. GCMs are used for both but differences in intent change what is actually done. In both cases, comparisions or predictions have to be made against uncertainties inherent in both the computations from the models and in the measurements of the real world. This leads to very different levels of robustness about predictions. In evaluating models, it often better to think of model skill (performance of model predictions compared to null hypothesis). Current GCMs have no skill at decadal level prediction for instance. They have considerable skill in many other areas.
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Philippe Chantreau at 09:45 AM on 6 March 2013Why SkS withdrew from the Bloggies
I will stop comparing climate science with Quantum theory if you stop making meaningless arguments about the "age" of an area of science.
Your "endemic problem" is BS. Fake skeptics' theories are mutually exclusive ("i.e. it's the sun" and "climate sensitivity is low") and have no grounding in reality. They're made up according to the need of the moment. Nothing follows in the litterature that is worth considering. In an effort of your own rethoric, youonly cite various wordings of what is the same thing, without showing that the thing was any different. I'm unimpressed. As for the "snowfalls are a thing of the past", I have never seen any such statement from a source that is worth reading. Considering the enormity of it, please provide a source.
Watts' problem is not one of communication, it's one of incompetence:
http://wattsupwiththat.com/2009/06/09/co2-condensation-in-antarctica-at-113f/
Not only did they give this much serious consideration, but the peanut gallery in the comment thread keeps on ridiculing the people trying to inject some sense in the discussion, the kind who could understand the phase diagram. That's a legitimate source to you? Really?
I still go read these posts when I need a good laugh. In subsequent ones they do little high school experiments and eventually conclude "it seemed like a good idea at the time."
Now please explain to me how these buffoons add quality to any kind of debate about science. Goddard was described by Smokey as writing "informative posts."
Eventually Watts had to distance himself from Goddard's incompetence in an effort to keep up appearances. That's too bad, it was more entertaining when he was on. board...
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Bob Loblaw at 09:32 AM on 6 March 2013Why SkS withdrew from the Bloggies
Eclectikus:
You've bought into Judith Currie's "uncertainty monster", and unfortunately you don't have the knowledge to recognize it for what it is (which is not much). The sources you are using are seriously overblowing the significance of the uncertainties.
You've been asking about sources summarizing climate science. I suggest you try reading Spencer Weart's The Discovery of Global Warming.
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