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Comments 104851 to 104900:
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muoncounter at 06:53 AM on 10 November 2010Ice-Free Arctic
#49: "(to do with geomagnetic research, solar winds, " If you want to invoke solar winds, explain recent heating concurrent with weakening of the solar wind. Solar wind output is at its lowest since accurate records began 50 years ago. This finding comes from the seasoned ESA/NASA solar probe Ulysses, which completed nearly three polar orbits of the Sun from 1993 to 2008 Why is it necessary to speculate about these exotic mechanisms? Arctic ice melts in response to warming temperatures. -
muoncounter at 06:41 AM on 10 November 2010Ice-Free Arctic
#35: "What is the effect of cosmic rays? " Not much. Were you referring to something else with "the effect of magnetic flux on high latitude temperatures"? -
scaddenp at 06:25 AM on 10 November 2010CO2 effect is saturated
Norman - I think you are falling for a lot of denialist junk. At best this is amateurs making simplistic analyses about data they dont understand and at worst, the work of clever people practicing on the uninformed (and who dont want to be informed). A first cut filter for the rubbish is the simple question of "is it published?". There are glittering prizes for anyone who can disprove climate theory or come up with an improved theory. If the analysis is sound then why wouldnt you publish? The unscrupulous will say one thing to a naive audience (eg congress) but dont make such claims to their peers. However, this is a good site for finding out what is wrong with the some of wild stuff out there. -
Bob Lacatena at 05:44 AM on 10 November 2010Solving Global Warming - Not Easy, But Not Too Hard
Another wedge that I would identify is human behavior. My specific bone of contention is that in the pre-global-economy world, every office worked from 9-5, and everyone was there at the same times the same days of the week, so that everyone with whom one might need to have contact was simultaneously available. In today's global economy, as likely as not the person you need on that conference call is on the other coast in another time zone, or even another continent and another date (and perhaps in a country with a different work week). There are a number of easy changes here. The first is simply for businesses to stagger their hours more, lowering commuting times and road usage peak volumes. This equates to less congestion, time spent idling, less asphalt and road maintenance, and less human hours wasted listening to talk radio. Similarly, everyone works Monday to Friday, except that a lot of businesses now operate 24-7, so again the old 5 day work week approach is somewhat outdated. I already know people that share cubicles to let the company save money on space (mostly sales reps and managers who are only in the office part time). I frequently choose to work weekends, to take advantage of smaller crowds for leisure time spent during the week (a luxury I have by being self-employed). Beyond this, telecommuting and other options are far more viable than they once were. In general, the point is that we are stuck in a 1950s paradigm that no longer fits and is no longer necessary. All it would take to change is some very cheap tax credits for businesses that comply (based on staggering work hours and days, and the actual use of telecommuting options). -
CBDunkerson at 05:40 AM on 10 November 2010Solving Global Warming - Not Easy, But Not Too Hard
RSVP, the projection is for 2054. Very few people are still going to be driving the same car in 2054 that they are today... even without fuel economy standard changes. Thus, the need to buy new cars is a pre-existing condition rather than something introduced by improving the fuel economy of those new cars. -
Albatross at 05:18 AM on 10 November 2010Keep those PJs on: a La Niña cannot erase decades of warming
Sphaerica, Thanks. I'm no expert on this either, but if I were using the RSS data (which, as you know, is much more reliable) I'd use their TMT data. The RSS page has a nice figure showing how the weighting works for different channels,I am not aware of such a figure for UAH. For UAH, one could regress the AMSU ch 5 or ch 6 against the near-surface surface data. But Spencer had something up on his page a while ago about problems they are experiencing with splicing/comparing the near-surface layer data because of orbital changes. I could be remembering incorrectly, but I recall that the conversion factor in the past has been calculated between the SAT record and mid-tropospheric temperatures (i.e., using independent data)...but Drs. Schmidt, Santer or Sherwood would likely be the go to persons on this. -
Bob Lacatena at 04:59 AM on 10 November 2010Keep those PJs on: a La Niña cannot erase decades of warming
I regressed AMSU LT data versus AMSU near surface data, by using the "Show data as text" link at http://discover.itsc.uah.edu/amsutemps/execute.csh?amsutemps. Perhaps the difference lies in what the AMSU near surface data actually represents. I'm not well informed on that particular detail. -
RSVP at 04:57 AM on 10 November 2010Solving Global Warming - Not Easy, But Not Too Hard
CBDunkerson #46 "So the end result is no change in the cost to you." Except that you had to buy a new vehicle every how many years? -
Albatross at 04:50 AM on 10 November 2010Keep those PJs on: a La Niña cannot erase decades of warming
Sphaerica @36, Excellent observations. The unusually high AMSU channel 5 temps., given the circumstances, are for obvious reasons proving to be somewhat of a headache for "skeptics". As for the conversion factor, that is not my field of expertise. But Dr. Gavin Schmidt might be able to help you out. Were you regressing the Channel 5 data against the surface GISTEMP data, or all surface data (i.e., including over the oceans)? Please let us know if Dr. Schmidt gets back to you. -
Bob Lacatena at 04:33 AM on 10 November 2010Keep those PJs on: a La Niña cannot erase decades of warming
I've been following the UAH temperatures regularly, and I think it is quite telling that despite the La Nina, except for a short period in October, those temps are hovering around (just below or above) the record temperatures. In fact, they recently spiked over the record again, after first collapsing into what in my own mind I call a "bundle point" (Apr 21 and Nov 21 seem to regularly see temperatures converge, before diverging again, no doubt due to interesting factors that I won't speculate on here). On those temperatures, a question... as Ned pointed out, the UAH temps appear to be an outlier at +0.14C per decade, but I believe that value is for tropospheric, not surface, temperatures, so to compare them is apples to oranges. I also believe that I've read that the conversion factor is roughly 1.2, so +0.14C/decade troposphere equates to a surface change of +0.168C (pretty close to NASA GISS at +0.166C). Which gets to my question. I believe I've read that the conversion factor is 1.2, but when I run my own regression on the data from AMSU (which only runs from 2002 to the present), depending on the smoothing period, then I get a factor anywhere from 1.53 to 1.56, with a pretty good R2 of anywhere from .95 to .96. That would turn the UAH +0.14C into +0.217C surface anomaly, making it an extreme outlier on the high end. The question: What is the appropriate conversion factor, and if it is 1.2, where did it come from? And does the higher conversion factor that I'm finding in the last decade point to another change in the system, where a warmer world sees a higher discrepancy between the surface and the troposphere? -
CBDunkerson at 04:21 AM on 10 November 2010Solving Global Warming - Not Easy, But Not Too Hard
quokka #41: "Increasing energy prices (in this case petrol) will certainly curtail consumption but will have adverse economic consequences." Why? If it used to cost you $800 per year to buy 260 gallons of gasoline needed to commute to and from work each day why would there be adverse economic consequences if in the future it cost you $800 per year to buy 130 gallons of gasoline to commute to and from work each day? Yes, the price of a gallon of gasoline has doubled... but the amount of gasoline you use has been cut in half. So the end result is no change in the cost to you. Less fuel consumption, no impact on the consumer, and a significant revenue stream which can be devoted to cleaning up the problems caused by the fuel. That's a powerful way to utilize efficiency improvements. -
RSVP at 04:13 AM on 10 November 2010Solving Global Warming - Not Easy, But Not Too Hard
KR "the Sahara, or large chunks of Northern Africa" Where all the natural gas is?? -
RSVP at 04:12 AM on 10 November 2010Solving Global Warming - Not Easy, But Not Too Hard
quokka 41 "The conclusion - energy must have very low emissions AND reasonable price to keep the humans happy." I remember a TV documentary years ago about how Eskimos burnt whale blubber in a tiny jar sufficient to keep the igloo nice and warm. The energy was just right so that it igloo didnt melt. They looked happy, and achieved this without computers. -
Solving Global Warming - Not Easy, But Not Too Hard
RSVP - Not a lot of viable cropland in the Mohave Desert, the Sahara, or large chunks of Northern Africa. Plenty of places to put solar collectors without interfering with cropland. -
Tom Dayton at 04:06 AM on 10 November 2010CO2 effect is saturated
Thanks CB! I didn't think to look in the "temperature" section for that graph. I skimmed there, and skimmed the result of clicking the "i" for more info, and though I found no listing of the wavelengths covered by "total OLR," I take that to mean you are correct that it covers a wide range. -
RSVP at 04:05 AM on 10 November 2010Solving Global Warming - Not Easy, But Not Too Hard
How is it not so that a plot of land designed for collecting solar power, isnt one plot less for growing food? (with exception of mushrooms perhaps) The same could be said about displacing land for forests. -
Tom Dayton at 03:59 AM on 10 November 2010CO2 effect is saturated
Norman, without knowing more about the image you linked to, it is difficult to respond. But I'm going to guess that your graph presents an average across a really wide range of longwave radiation. In contrast, Figure 1 at the top of this Skeptical Science page (the Intermediate tabbed pane) is presented to illustrate the reduction of outgoing radiation in the very particular wave numbers that are specific to greenhouse gases. Your graph does not contradict that. Energy trapped (delayed in escaping, really) by greenhouse gases raises the temperature of the atmosphere/land/water, which causes an increase in that system's attempted emission of radiation to space. Radiation outside of the greenhouse gases' absorption wavelengths will merrily escape to space, so total longwave radiation escaping will increase. The problem is that the escaping total cannot increase fast enough to prevent the temperature from increasing, because the increase in the escaping radiation is a response to the increasing temperature. -
quokka at 03:57 AM on 10 November 2010Solving Global Warming - Not Easy, But Not Too Hard
#39 CBDunkerson Important point that has far reaching implications, and shows why the climate problem is so difficult. Increasing energy prices (in this case petrol) will certainly curtail consumption but will have adverse economic consequences. That may be perfectly acceptable up to a certain point, but extended further could lead to major economic crisis. In that context, environmental concerns including climate go to the bottom of the list of priorities. It it possible to conceive of a future caught between energy poverty due to peak whatever and environmental collapse, in permanent economic crisis that is very difficult to break out of. The conclusion - energy must have very low emissions AND reasonable price to keep the humans happy. -
dana1981 at 03:52 AM on 10 November 2010Solving Global Warming - Not Easy, But Not Too Hard
CBDunkerson - thanks, that's what I was driving at about Ville's unrealistic assumption. As Ann has pointed out, we're not operating in a vacuum where all else is held constant other than these wedges. There will no doubt be some sort of mechanism to put a price on carbon emissions eventually, which can be adjusted as necessary to address Jevons paradox. I just didn't want to come out and say it because I don't want the discussion to devolve into shouting about a carbon tax. -
CBDunkerson at 03:52 AM on 10 November 2010CO2 effect is saturated
Tom, I believe this is the graph and related text in question. However, it says nothing about wavelength. The suggestion seems to be that increasing CO2 should reduce ALL wavelengths of OLR... which doesn't seem an accurate statement of greenhouse gas behavior to me. In short, a straw man... the graph shows that total long wave radiation is not decreasing, but the claim that it should be has no basis in AGW theory. -
Tom Dayton at 03:40 AM on 10 November 2010CO2 effect is saturated
Norman, where exactly is that image on climate4you.com? The image itself does not give enough information about exactly what the graph represents (e.g., what wavelengths). -
JMurphy at 03:30 AM on 10 November 2010Ice-Free Arctic
Arkadiusz Semczyszak wrote : "The conclusions suggest themselves ..." Not to me, at least. Your first link doesn't mention anything to do with the quote you referred to from Camburn (to do with geomagnetic research, solar winds, sun cycles or jet streams). Your second link does refer to sunspots but doesn't mention jet streams or anything to do with climate on earth. And the main graph at that link (just like every other sunspot graph I've seen) doesn't seem to correlate to any temperature reconstructions going back that far, that I'm aware of, especially over the last 50 years or so. Please 'suggest' those conclusions. -
Norman at 03:22 AM on 10 November 2010CO2 effect is saturated
Still won't connect. I will try another graph from Climate4you that shows the same thing, cycles but no downward direction for the outgoing longwave radiation. Outgoing longwave radiation cycles but does not trend down. -
CBDunkerson at 01:48 AM on 10 November 2010Solving Global Warming - Not Easy, But Not Too Hard
Relating Jevons paradox back to the wedges and issues raised by The Ville and Ann would go something like this; Wedge 1 proposes doubling fuel efficiency from 30 mpg to 60 mpg (bother me not with metric conversions). Of course, if you did that gasoline might still cost $2 per gallon (or whatever)... but that gallon is going to allow you to drive twice as far. Thus, if you drive the same amount you did before you are going to spend half as much on gasoline. When gas prices shot up a few years ago people drove less. Ditto during the current recession. Thus, it seems clear that if gasoline prices were cut in half people would drive more. Indeed, Jevons paradox suggests that they would drive more than twice as much as they did before... mainly due to more people driving more often. For instance, people who previously took mass transit might drive because it was now actually cheaper. In any case, it is clear that doubling gasoline efficiency will not halve gasoline consumption and thus wedge 1 would fail... UNLESS gasoline prices were increased to keep the cost of driving high enough that people would not drive more. The same logic applies to wedges 3 & 4 and any other efficiency improvements. Increased efficiency inherently leads to lower cost and higher usage... unless costs are artificially inflated. -
Arkadiusz Semczyszak at 01:36 AM on 10 November 2010Ice-Free Arctic
Camburn says that: “ Geomagnetic research is showing that solar winds and the sun's cycles play an extremely important role in the placement of the jet streams.” I think he's right. If compared to the work on the optimum of the middle Holocene: “We do not know whether the Arctic Ocean was completely devoid of ice, but the areas north of Greenland, it was more open water than today ... " - says geologist and researcher Astrid Lysa ...” (NGU). “Changes that took place 6000-7000 years ago were controlled by other climatic forces than those which seem to dominate today ... " ... and this paper: “Evidence of 6 000-Year Periodicity in Reconstructed Sunspot Numbers”, M. A. Xapsos and E. A. Burke, 2009, Solar Physics, Volume 257, Number 2, 363-369: “We have examined these data using Hurst analysis, a moving average filter, and Fourier analysis. All of the procedures indicate the presence of a long term (≈6 000 year) cycle not previously reported.” The conclusions suggest themselves ... -
Ricki at 01:21 AM on 10 November 2010Skeptical Science moving into solutions
The most fundamental policy response is a price on carbon (and other gases). This is the best way to drive the economic change needed. We also need to agressively construct renewable energy (and not build any new coal power stations). -
CBDunkerson at 01:14 AM on 10 November 2010Solving Global Warming - Not Easy, But Not Too Hard
What The Ville is describing in #34 is commonly known as Jevons paradox... which, as it happens, was first formulated in relation to coal usage. Basically, economist William Stanley Jevons showed that when efficiency improved it led to an increase in usage so great that the total fuel consumption went UP. His specific example was the use of coal after James Watt vastly improved the efficiency of coal powered steam engines. They went from being an expensive niche product to cheap and widespread use... with corresponding greater total coal consumption. The same effect has been seen repeatedly with efficiency improvements since then... to the point that it is often considered a given in economic theory that efficiency improvements will lead to increased consumption. That said, there is a proven method of preventing the Jevons effect. Specifically, if fuel costs are somehow held steady (e.g. by enacting a carbon tax) then the increased efficiency does NOT lead to lower costs and usage does not increase. -
JMurphy at 01:02 AM on 10 November 2010Solving Global Warming - Not Easy, But Not Too Hard
You're right, Grim_Reaper - thanks. It was due to putting a '2' at the beginning of the link, rather than the " from the same key. It should have been http://web.mit.edu/newsoffice/2010/solar-storage-1026.html. -
kinvore at 00:45 AM on 10 November 2010How you can support Skeptical Science
Thank you so much for your wonderful site! It is informative, accessible, and a great source of information (which in turn makes it the ultimate weapon against disinformation). -
Grim_Reaper at 00:43 AM on 10 November 2010Solving Global Warming - Not Easy, But Not Too Hard
JMurphy @ #32: The link doesn't seem to work. Here's an alternative. The molecule that's caused interest is called fulvalene diruthenium. -
Paul D at 00:34 AM on 10 November 2010Solving Global Warming - Not Easy, But Not Too Hard
"Miles??? Per gallon??? What happened to metrics?" Indeed. We have mixed metrics here. Suggest that the following are used as standard: gCO2 equiv/kwh - electricity gCO2/km - transport gCO2/passenger km - individual passengers -
Paul D at 00:23 AM on 10 November 2010Solving Global Warming - Not Easy, But Not Too Hard
Dana: "Ville - assuming that coal power prices will drop is unrealistic." That obviously wasn't the point I made. A 20% reduction in emissions, roughly equates to 20% reduction in fuel used per kwh, which equates as a 20% cut in electricity prices, which equates to less efficient gadgets and people not worrying about leaving lights on. So for a short time, you have emission reductions, until cheaper energy prices result in emissions increasing again. -
Alexandre at 00:18 AM on 10 November 2010Skeptical Science moving into solutions
Mike #8 Economic modelling is a great and difficult subject. It would be really nice if they manage to get some guest posts here. -
Daniel Bailey at 00:18 AM on 10 November 2010Ice-Free Arctic
Hey, there's been an Artful Dodger sighting! Welcome! The Yooper -
RSVP at 00:04 AM on 10 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
CBDunkerson #63 "Look, you said that the only way that Mars could have had liquid water in the past was if the Sun had been hotter then. I have shown that this is incorrect" I agree (for a change ;) ), please check the following for more plausible explanations... http://en.wikipedia.org/wiki/Comet_Hale-Bopp "Hale-Bopp's orbital position was calculated as 7.2 astronomical units (AU) from the Sun, placing it between Jupiter and Saturn and by far the greatest distance from Earth at which a comet had been discovered by amateurs.[10][11] Most comets at this distance are extremely faint, and show no discernible activity, but Hale-Bopp already had an observable coma.[5]" Now, for any of this to have significance in the discussion, you have to assume that the coma is caused by melted water, (which is not necessarily the case as there are other more volitile components), however, comets generally get noticed before they pass within Earth's orbit, and they do contain a lot water. Aside from what has been brought up in all these earlier comparisons iwith Mars, the rotation and tilt of planets might be easier to assume having altered over time and having affect on climate, than the Sun's brightness. On the link about Hale Bopp, it says, "Comet Hale-Bopp's activity and outgassing were not spread uniformly over its nucleus, but instead came from several specific jets. Observations of the material streaming away from these jets[42] allowed astronomers to measure the rotation period of the comet, which was found to be about 11 hours 46 minutes.[43]" Then you data on the rotation and tilt of Mars itself... http://www.universetoday.com/14889/mars-rotation/ "For all of its differences, here’s one situation where Mars is very similar to Earth. Mars’ rotation is 24 hours, 39 minutes, and 35 seconds. In other words, Mars only rotates 39 minutes more slowly than Earth." http://www.universetoday.com/14894/mars-tilt/ "Astronomers know that the current tilt of Mars’ axis is just a fluke. Unlike Earth, the planet‘s tilt has changed dramatically over long periods of time. In fact, astronomers think that the wobble in the tilt might help explain why vast underground reservoirs of water ice have been found at mid-latitudes, and not just around the planet’s poles. It’s possible that in the distant past, Mars was tilted at a much more extreme angle, and the ice caps were able to grow across the planet. When the tilt was less extreme, the ice remained, and was covered by a layer of dust." If I have to make a point (based on all of the above), it would be that even if the mean temperature of the Earth were supposely 33 degrees colder without CO2 in the atmposphere, there would still likely be portions of the Earth with temperatures high enough to melt water. -
CBDunkerson at 23:12 PM on 9 November 2010Ice-Free Arctic
Heh... obviously I meant 'leveling off BEFORE hitting zero'. The standard hypothesis, as articulated by Riccardo in the article, is that ice loss is being driven primarily by air temperature rise from global warming and ice-albedo feedback. As the amount of ice declines the change in albedo from any further decline becomes smaller and thus there would be 'diminishing returns' and a long period of slowly declining sea ice. Obviously the volume trend, as inferred by PIOMAS, tells a different story unless it suddenly changes course radically some time in the next few years OR the PIOMAS results are off. I don't think the latter is likely based on verifications against other data sources (as I mentioned previously and Artful Dodger has just explained in more detail). However, with Cryosat-2 now online and the current volume trend only a few years from hitting zero I think we'll have a clear answer some time relatively soon. -
Tony Noerpel at 23:11 PM on 9 November 2010Skeptical Science moving into solutions
Mike thanks for that link. I agree with the general sentiment to keep the discussion about the problem space separate in some way from the solution space. Also there are several dimensions to the solution space. The first is simply the technology, itself, from caulking to fusion. The second is the economic discussion, what we can afford to do and what we cannot afford not to do. The third is the social problem - how to convince society to implement the technology and that they cannot afford not to do it. The third may be the most difficult. -
Pete Dunkelberg at 22:54 PM on 9 November 2010Ice-Free Arctic
CBDunkerson #43 ... we should know in the next few years whether this 'fast decline' scenario or the 'leveling off' prediction is correct. Unless you believe in negative ice, leveling off is a sure bet. :) -
adelady at 22:51 PM on 9 November 2010Antarctica is gaining ice
Did you look at the graphs showing increasing loss of land ice? Or not. -
CBDunkerson at 20:24 PM on 9 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
On the 'Sun may have not been dim in the past' link... in addition to the moderator's point about the article actually exploring mechanisms for the OPPOSITE argument (that the Sun WAS dim) it should be noted that the article was written in 1987. The whole 'the sun may not have been much dimmer in the past' idea which the article describes as "highly speculative" back then would now, with the benefit of 23 years of additional research, fall into the category of 'implausible fiction'. -
Artful Dodger at 20:17 PM on 9 November 2010Ice-Free Arctic
Despite some of the comments above, PIOMAS has already undergone extensive Model Validation. Long before CryoSat-2, NASA's ICESAT mission provided 5 years of sea ice thickness data (2003-07). Researchers also used data from US Submarine cruises, and moored Buoy Arrays to have 3 independent sources of data. More details on the model, assimilation procedures and validation results can be found here. -
CBDunkerson at 20:09 PM on 9 November 2010Ice-Free Arctic
Pete Dunkelberg #41: "Note that heat transport into the Barents Sea has an influence out of proportion to its fraction of the Arctic heat budget." Aha... precisely the theory I was going on back in comment #10. There is clearly something major missing from the Arctic sea ice prediction models and this seems like a strong candidate to me. It also suggests a very different 'end game' for the Arctic sea ice than current models... because if a large portion of the ice loss is being driven by influx of warmer water there should be no 'slowing down' of the decline. Indeed, it should just keep accelerating as less ice = stronger currents = more warm water imported. Given that there was only 4000 km^3 of ice left this past September (average for the month) and it has been dropping about 1000 km^3 per year for the past decade we should know in the next few years whether this 'fast decline' scenario or the 'leveling off' prediction is correct. -
esjope at 19:50 PM on 9 November 2010Solving Global Warming - Not Easy, But Not Too Hard
Marcus @ #29: Our company produces biodiesel and bio-oil from waste fat and oil. It is easy when you have a good point source of raw material. But collecting small amounts from here and there ruins both the economy and energy balance of the fuel production. Fast food industry is already (at least in Europe) producing fuel from their waste oil. Collecting the oils from households is not an option at the moment. Producing fuel from waste has a very good energy balance and is definitely a part of the solution. -
JMurphy at 19:38 PM on 9 November 2010Solving Global Warming - Not Easy, But Not Too Hard
Something coming out of MIT recently gives a pointer as to how solar energy can (and, no doubt, will) be stored more efficiently and effectively : Catching the sun’s heat - Storing thermal energy in chemical form has the potential to make it indefinitely storable and transportable. "This is the thermo-chemical approach, in which solar energy is captured in the configuration of certain molecules which can then release the energy on demand to produce usable heat. And unlike conventional solar-thermal systems, which require very effective insulation and even then gradually let the heat leak away, the heat-storing chemicals can remain stable for years." -
Bern at 18:34 PM on 9 November 2010Solving Global Warming - Not Easy, But Not Too Hard
Phila @ #28: It already *has* happened - if you consider the lack of regulation of the finance sector and the resulting economic chaos of the last few years... Marcus @ #29: Wikipedia suggests that in the US, at least, waste vegetable oil could substitute for as much as 1% of fossil oil consumption. Only a very small part, but still, 1% of however many $billions is a lot of potential value. (~20million barrels per day, at ~$80/bbl, = $1.6billion per day, so 1% of that would be $16m per day, or $5.8billion per year worth of oil) -
Norman at 16:30 PM on 9 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
Also not to forget this one. Sun may have not been dim in the past.Moderator Response: I don't understand your point. The article you linked to says that the notion that the Sun was not dim in the past "remains highly speculative." The article focuses instead on describing several mechanisms that could have made the Sun dim. -
Pete Dunkelberg at 16:26 PM on 9 November 2010Ice-Free Arctic
Oops. The title of Irina Mahlstein's dissertation is Ocean heat transport as a cause for model uncertainty in projected Arctic warming. -
Norman at 16:25 PM on 9 November 2010Climate change from 40 million years ago shows climate sensitivity to CO2
#62 Tom Dayton Thanks for linking the slide show. Some of the slides remained blank. Here is a graph for you that shows little relationship between CO2 and temp over the eons. Not much of a match between CO2 and Temp. Faint Young Sun and Paradox. During the faint Sun, the CO2 levels were low.Moderator Response: Regarding your first link, a simple correlation between only CO2 and temperature over the entire history of the Earth of course will not be straightforward, because CO2 was not the only forcing of climate during that entire period, and also acted as a feedback. But recently CO2 has been the dominant forcing; see "There’s no correlation between CO2 and temperature," and for background see "CO2 is not the only driver of climate," where you should be sure to click the Intermediate tab. Regarding your second two links, I don't understand your point. -
Pete Dunkelberg at 16:19 PM on 9 November 2010Ice-Free Arctic
After reading Neven, google up this dissertation Ocean heat transport as a cause for model uncertainty in projected Arctic warming [large pdf] and especially Chapter 2, Ocean heat transport as a cause for model uncertainty in projected Arctic warming. Note that heat transport into the Barents Sea has an influence out of proportion to its fraction of the Arctic heat budget. Further study of this heat transport looks to be a key to reducing the uncertainty of Arctic sea ice projections. -
Norman at 16:11 PM on 9 November 2010CO2 effect is saturated
Climate4you has graphs that may conflict with this statement. "So we have multiple lines of empirical evidence for an enhanced CO2 greenhouse effect. Satellite measurements confirm that less longwave radiation is escaping to space. Surface measurements detect increased longwave radiation returning back to Earth at wavelengths matching increased CO2 warming. And of course the result of this energy imbalance is the accumulation of heat over the last 40 years." Graph which indicates that longwave radiation is not following CO2 increase. Explanation given to the above graph: "For the equatorial region, the diagram above suggests a certain chain of events, indicating the existence of a mechanism regulating the surface temperature: Periods of surface warming appears initially to be associated with decreasing outgoing longwave radiation (OLR). After some surface warming, OLR then stops decreasing and instead begins to increase, and after a while, surface air temperature then begins to decrease, etc. This chain of events is clearly illustrated by, e.g., the time period around the 1998 El Niño event (diagram above). Part of the explanation of the above succession of events might be that tropical surface warming leads to enhanced atmospheric convectional transport of heat to high levels of the atmosphere above the Equator, resulting in enhanced longwave radiation at the top of the atmosphere. This, in turn, eventually leads to surface cooling, which results in reduced atmospheric convection, etc. Also the potential connection to variations in tropical sea surface temperatures and the tropical cloud cover is interesting, and should be considered in a more detailed analysis." This graph shows poor correlation of CO2 to Longwave raditation. This graph questions the conclusions of the Skeptical Science.Moderator Response: Your first link is broken.
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