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skywatcher at 22:44 PM on 15 July 2011It's the sun
Eric S, why would that apply to me? If you're meaning my post on the thread you link to in #858, my comments were in relation to Tamino's filtering out of 'exogenous factors', in his post How Fast is the Earth Warming?. Since 1998, we have gone from very strong El Nino forcing to a very strong La Nina forcing, and from a solar max to a solar min. Tamino has quantified the adjustments to the timeseries driven by each of these exogenous factors, and for RSS, he estimates solar forcing to have dropped 0.1C of temperature equivalent over the decade for RSS, 0.05C for GISS. Larger forcings (range of up to +0.4/-0.2) are attributable to ENSO, which is right in line with my previous understanding of the forcings. The global-scale solar forcing is perfectly real, but small, and has indeed hindered temperatures over the past decade. It is interesting to note that the 2000s were even hotter than expected on a decadal scale, given the decadal increases from the 1970s, 1980s and 1990s. It's just that relatively speaking the earlier years of the 2000s were hotter and the later years were 'cooler'. -
Eric (skeptic) at 22:44 PM on 15 July 2011It's the sun
KR, do we really need a reference for this? The planet is 72% ocean and weighted more towards low latitudes where the sun is more direct. The highest energy portion of the solar spectrum, about 1 micron and less, are able to penetrate deeper and heat deeper. A lowering of ocean heating due to slightly lower TSI can be easily outweighed by an increase in SST due to the phenomenon like ENSO (warming from less wind, fewer clouds, etc). Thus solar minima are easily outweighed by other factors. -
Paul D at 22:42 PM on 15 July 2011Visions of the Arctic
There's an exhibition called High Arctic at the National Maritime Museum (UK) about the receding Arctic ice: http://www.nmm.ac.uk//visit/exhibitions/on-display/high-arctic/ -
KR at 22:31 PM on 15 July 2011It's the sun
Eric (skeptic) - "Specifically, any change in TSI is applied directly to the oceans, unlike changes in GHGs which mostly melt ice. All other solar changes change the weather which may create temporary warming or cooling." Eric, this is so far off that it's close to being not even wrong. Changes in radiative forcing from TSI or from GHG's have slightly different distributions (particularly in the stratosphere), but all radiative forcings affect the oceans, the ice caps, and the weather. Unless you have a reference or two to support this, I would have to consider your last post or two simply unsupportable. -
michael sweet at 22:28 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
As Icarus pointed out at 6 in this blog, if we use the GISSTEMP record the warming continues unabated. The deniers use HADCRU (which they say is discredited by e-mails) because it does not show all the global warming. I think the lead article should have made a strong point that it is only when you use HADCRU that you find warming slowed. HADCRU is well known to underestimate global warming over the past decade due to lack of Arctic coverage. It is better to use GISS because GISS more accurately reflects what is happening around the globe. Using GISS we find that global warming did not slow during the 00's. Hansen agrees with Kaufman that sulfate aerosols mask a lot of warming. The Faustian bargain will soon come due. When sulfate pollution is controlled the temperature will rise even faster than it currently is rising. -
Eric (skeptic) at 22:22 PM on 15 July 2011It's the sun
skywatcher, my previous post on this thread applies to you as well. The "solar minimum" is not an adequate explanation of why the 2000's were not hotter. Specifically, any change in TSI is applied directly to the oceans, unlike changes in GHGs which mostly melt ice. All other solar changes change the weather which may create temporary warming or cooling. The solar to ocean connection is direct: the sun heats the ocean. A drop in solar TSI due to the "solar minimum" can easily be offset (or "masked") by a relatively small amount of SST warming, the best example being El Nino. Thus, solar mimima do not automatically create atmospheric temperature drops. -
skywatcher at 22:04 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
on cycles, this paper by Vincze and Janosi may be of interest. They discuss the effect of smoothing on identifying the 'AMO', and suggest that the 'O' of AMO should be replaced by a 'V' for Variation. Similar to Tamino's articles about people who find 'cycles' in data where the period of the proposed 'cycle' is large in relation to the total time period under study. Just because you think you find a 'cycle' rather than an apparent variation that is vaguely coincident does not take you any closer to a physical driver of the climate system. As mentioned before (#14 and Dikran above) there is no underlying physical energy transfer mechanism for the PDO, and perhaps the best explanation is an integral result of the events of ENSO. As there is no clear means for PDO to add or remove significant energy from the climate system, why do people hold on to it for an explanation of climate changes? Far more plausible, and with energy flows and physical mechanisms understood in support, are variations in aerosols largely causing the 1960s cooler episode. Given Tamino's analyses (#5), and the data from global analyses such as GISS, and of course the ever-present internal variability of the climate signal, I suspect the 'hiatus', if it even significantly exists, is one already explained by existing climate drivers, the consequence of which will be renewed rapid warming soon. If there really is an aerosol signal, in the last few years of data, then it suggests a scary future, as the other key exogenous factors (esp ENSO, solar) already do a good job of explaining the 2000's.Moderator Response: (Rob P) The PDO is off-topic. Further comments should be made on the relevant thread. -
Eric the Red at 22:00 PM on 15 July 2011It's Pacific Decadal Oscillation
Barry, I have done some work looking at the linear vs. oscillatory trends. Two cylces have been observed with a period of just under 61 years and an amplitudes of 0.3C. When this is subtracted from the temperature data (CRU), a linear increase of 0.6C / century remains. Should these two trends continue, global temperatures would bottom out again at around 2033 at ~0.1C below current levels, before rising again. The strong La Nina has definitely been an influence as temperatures for 2011 have been below the combined trendline for five of the first six months of 2011. Scaddenp may be correct in that the PDO is just a long term index related to ENSO. -
Eric (skeptic) at 21:55 PM on 15 July 2011It's the sun
In this post /news.php?n=868#58115 Tom Curtis partially attributes cooling since 2008 to an exceptionally low solar minimum. But he effects of a solar minimum are vastly more complex than "cooling". Just two examples, the drop in solar UV (much greater %-age than TSI) creates stratospheric cooling which becomes uneven and creates blocking patterns. Those blocking patterns may induce heat waves or other extreme weather, perhaps generally globally cooling, but not simple. Another factor is high GCR which may produce more low clouds which may also be cooling or perhaps not. The other consideration for Tom is that solar effects, even the simplistic drop in TSI, are subject to the same thermal inertia as AGW (if not more). For example the entirety of lowered TSI could easily be "masked" from appearing in the GAT by a rise in SST (e.g. from El Nino). In that case (I'm not saying that happened recently or not), the solar minimum essentially only causes an OHC drop. -
Dikran Marsupial at 21:52 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
Eric the Red there has not been a large on-going debate as to whether PDO is the cause of the observed warming, except in the blogsphere. You need a physical mechanism that can explain the strenght of the effect, not just a correllation before scientists will take a theory seriously (because corellation is not causation). There is plenty of discussion in the blogs, but that is largely a reflection of the relative quality of science in the journals and in the blogs concerned. "three would be telling" is statistically nonsensical. In the absence of a competing explanation, then three cycles in a dataset would be taken as good evidence for a periodic structure. However in this case there is a competing theory and you would need to revise physics to explain why CO2 and aerosols and solar forcing were not having their expected effect. -
Eric the Red at 21:36 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
Hyperactive Hydrologist, Whether the two warming periods being similar is a coincidence or not has been a subject of a large, on-going debate. The bigger question concerns the intervening cooling period, and the most recent decade. As mentioned previously, one thought is that aerosols arising from two different sources have generated the slowdown in both cases. An alternative has been the PDO cycle. Both are plausible, but may only be part of the answer. If the answer is aerosols, that would argue for a climate sensitivity on the higher side, whereas the PDO would place it on the lower side. Two 60-year cycles could be a coincidence. Three would be telling. -
Eric (skeptic) at 21:23 PM on 15 July 2011It's Pacific Decadal Oscillation
barry, thanks for explaining the distinction between the centenial (mostly secular) and decadal (mostly oscillatory) trends. I believe most of the fluctuation in the secular AGW trend can be explained with natural oscillations. There do not seem to be very strong long term natural trends at the moment. Specifically warming accelerated in the 80's and 90's and decelerated in the 00's. I can also answer my question from January, the La Nina was strong, especially in its effects on the continental US stemming from abnormally cold Pacific temperatures. Those effects still linger, but the La Nina has ended. However it is predicted to return, not good news for drought-stricken Texas and rain-soaked Montana. -
skywatcher at 20:58 PM on 15 July 2011Websites for Watching the Arctic Sea Ice Melt
Arctic ice sea melt looks like being interesting/scary this year. 2011 is currently (14th July) the lowest extent of all years in IJIS, NSIDC, Uni Bremen and DMI graphs for the current date. It's lower even than the record-breaking 2007, even though we're getting through the period where 2007's extent reduced very rapidly. 2011 is currently 265625 sq km below 2007 (IJIS), and over half a million sq km below last year, which itself is the 3rd lowest extent for 14th July. The odds of a new record low extent have just shortened somewhat, but will it be enough to wake people up to what is happening? The canary is struggling for breath... -
Dikran Marsupial at 20:34 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
Hyperactive Hydrologist If it did, it would only be masking the warming due to the additional CO2 emissions, and when the aerosol emissions end, they are quickly removed from the atmosphere (unlike the CO2) and the enhanced greenhouse effect would rapidly reassert itself again in a big way. Of course we all want the standard of living in the third world to improve with time (at least I would hope we all want that); however in order to achieve that without making our global environmental problems even worse, we need to reduce our emissions in the first world. However that is a topic for a different thread. -
Hyperactive Hydrologist at 20:33 PM on 15 July 2011Climate Change Impacts on California Water Resources
I did a project on the Colorado basin recently. Major issues are due to demand. Some of my conclusions. • The initial apportionment of water under the Colorado River Compact was based on data collected over a short period, at a time of relatively high flow. Current water balance suggests that the sum of the entitlements is higher than current flows. • No consideration was taken for environmental needs within the Compact as a result discharge to the Gulf of California is close to zero. • Pollution is a major problem, partly due to very low river flow, with high salinity of river water especially in the southern reaches. Desalination plants at the Mexican border reduce the salinity of the river water before it enters Mexico. • There is no organisation which has overall control over the basin. • Agricultural use of water has grown rapidly over the last century and accounts for 80% of the water used. • Many of the crops grown in the basin are exported to other regions or countries for example exporting hay and rice to Japan. • Huge subsidies on water prices are allowing farmers to grow crops which would otherwise not be economically viable. • Rapid population growth has increased water demand substantially. The population grew by 10-35% between 2000 and 2010 in the 7 states within the Colorado basin. This growth is expected to continue. • Population growth is, in part, indirectly driven by cheap water prices. • Residential water usage is amongst the highest in the United States, however, water prices are some of the lowest. • Much of the Infrastructure in Colorado basin is funded partly by the federal government. The United States collectively is paying for infrastructure • Open water evaporation from reservoirs is a major problem, with losses estimated to be approximately 2MAFY. • Climate Change will increase temperatures in the Colorado basin by 2-4°C. Reduced run off will decrease flows in the Colorado River by 10-30%. By tackling some of the issues with demand and getting rid of subsidies on water prices many of the issues could be dealt with relatively easily. For instance increasing block tarrifs need to be employed. Also the actual cost of water needs to be evaluated including the payments for existing infrastructure. -
Hyperactive Hydrologist at 20:16 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
Broken link? Indian Coal Rush -
Hyperactive Hydrologist at 20:15 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
Dikran - thanks for your response. Could we see a the trend in global temperatures continuing if India decides to start building coal power stations at an increasing rate? 1.2billion people in India, we can't expect them to go without electricity forever. -
Rob Painting at 19:12 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
Barry - "The point of your post is that the globe has not warmed as we had expected, and we've come up with a new analysis to answer that. We've changed our narrative and we need to be careful in expressing it properly." Barry, you seem to imply some sort of flip-flop by SkS. That's not the case, there's a significant difference between "skeptic" claims of global cooling (wrong) and slower rate of warming (right). I don't expect the future rate of warming will be steady, nor did I expect the past decade to be, so there's no narrative to change. Heck, even the ocean heat content data and sea level rise, show a slowdown during this period. However, when you step back and look at the long-term trend, global warming just keeps on trucking. Like the teeth of a mangled hand saw blade, the future will see global warming in fits and starts. Indeed if the past equator-to-pole, and surface-to-deep-ocean, temperature gradients are any indication of the future, then we should expect periods where there is very little surface warming - when the deep ocean heats up. But also intervals where there is abrupt warming. The abrupt warming intervals are what concerns me. -
Dikran Marsupial at 18:51 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
Hyperactive Hydrologist IIRC the most recent IPCC WG1 report attributes most of the warming in the first half of the 20th century to solar forcing. The similarity in the rates is probably just a coincidence; the warming we see is a result of changes in multiple forcings, both positive and negative, so there are many ways to get the same trend. -
Hyperactive Hydrologist at 18:46 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
Apologies if this is off topic: From just eyeballing figure 1 the increase in temperature between 1910 and 1940 seems to be similar to current rate of warming. Is this just due to the early on set of global warming from emission during the industrial revolution? Or is there some natural forcing during that period as well? -
Rob Painting at 18:45 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
Cynicus - " This question keeps nagging in the back of my head and I would like to have this clear: "Why wasn't the hottest decade hotter?", you imply: without Eastern Asian aerosol emissions it would have been even warmer?" I don't imply, I state at much. That's a consequence of the statistical modelling of radiative forcing used by Kaufmann (2011). The two climate modelling studies cited in the post show that Asian reflective aerosol emissions are more potent than either European or North American emissions - historically the worst polluters. Dr James Hansen also seems to be of the opinion that the sun-shield provided by sulfates is much stronger than commonly suggested in scientific circles. If he and Kaufmann are right, and only time and further research will tell, then there's a lot of warming in the pipeline. -
ranyl at 18:08 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
"Or, is the Kaufmann aerosol paper trying to explain a slowdown in warming that doesn't even exist?" This is true but considering things carefully compared to all others barometers of excessive energy in the system the actual rise in air temperature has been modest at least. As well as the direct reflection of SO2 there are also the very large brown clouds over Asia which heat the atmosphere and trap energy in the system but shade the surface bringing in another artificial cooling of surface temperatures. China is about to cut its SO2 emissions as the air is getting hard to breath there now. http://business.globaltimes.cn/china-economy/2011-03/632936.html What is the climate sensitivity to GHG again?????! Also it has recently been shown that due to the effects of nitrogen ferttilisation, despite being a biodiversity diaster has been cooling the planet due to ozone interactions and enhancement of the apparent CO2 fertilization effect (excess nitrogen in the eco-system has fertilized the forests making the land CO2 sink seem greater than it actual is).http://www.nine-esf.org/ENA Now all these cooling influences are short term and the cuases for need to cease for health reasons alone, so that means that warming if GHG theory is correct is about to truly start to get going. This is concerning considering how much it is going already. Add in the La Nina prevelance in the 2000's and the solar low and well that 2010 was the hottest year on record seems beyond understanding unless the CS is a lot higher than thought, or in line with paleoclimatic suggestion. 400ppm peak anyone!!!??? That gives a carbon budget of 4 years to prepare for what is likely to be the most rapid change in the earth's climate so far. -
villabolo at 17:47 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
Robert Gates @ #20: "If you listen to the AGW skeptics, they are preparing for a Little Ice Age to begin any day now and to last for decades." What I've seen at WUWT and Steve Goddard's sites is that they, and their posters, are predicting everything and anything. I challenged Goddard to give his prediction for the state of the Arctic ice cap in 2020. His answer was that the Arctic ice cap would grow, shrink or stay the same. I taunted him on the predictive power of 'skeptic' science. Their Orwellian view amounts to "The earth is cooling, it's cooling! Isn't it good that it's (naturally) warming (we'll get to pet the dinosaurs)." Since they have set the 'goal posts' everywhere, they cannot go wrong. In any case, we have a thermal lag of 1F(?) within 30 years and a highly reduced Arctic ice cap. What's the calculated rise in temps for an ice free Arctic, 5-6F? That, in turn, creates a feedback loop for Siberian Methane production due to increased melt and methanogen metabolism. As for aerosols, China might be giving us a large chunk of it but, if we were to have a global depression, all nations' aerosols would be lowered. I don't think that GW will be leveled by the 'three sisters'. -
MarkR at 17:41 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
I was surprised by the publication of this article, but in a way it sort of makes sense - it appears warming was less than it would otherwise have been without China's aerosols. 800 million Hiroshima's worth of heat entered the upper oceans since 1998, trillions of tons of ice have melted and a few hundred million Hiros have gone into the deep ocean. So we were definitely not in radiative balance either. We still warmed, just not by as much. The thing with aerosols is that you have to keep increasing them to keep pace with CO2. Seems unlikely that China will, but perhaps other industrialising countries will help prop up our sunshade. -
cynicus at 17:36 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
@4 Riccardo, Thanks. I think I understand better now. I had the impression that this article (and Kaufmann) was about decadal trends but instead it is primarily about a few years (i.e. <10 years variability)? Rob Painting: This question keeps nagging in the back of my head and I would like to have this clear: "Why wasn't the hottest decade hotter?", you imply: without Eastern Asian aerosol emissions it would have been even warmer? -
Tom Curtis at 17:14 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
Sorry, forgot to mention La Nina in my point (6) above. -
Tom Curtis at 17:12 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
Barry @19, I don't know about "our" narrative, but my narrative has been: 1) You don't measure trends just by measuring maxima; 2) You don't measure global temperatures by excluding the poles from the globe; 3) You don't determine long term trends by looking at less than a decades data; 4) Taking 1-3 into account, there has been ongoing global warming in the period 2001-1010 at a rate similar to the preceding two decades; 5) There may have been a slight reduction in the rate of warming in the last three years due primarily to an unusually for the 2000's cold year in 2008, although an unusually warm year for any other decade of the instrumental record; 6) That slight reduction in the rate of warming was probably due to increased aerosols from China, and to an exceptionally (second lowest in 100 years) low solar minimum. I see nothing in this paper to change that narrative. On the contrary, all I can see is a plausible explanation of some noise in the trend, which tends to confirm (6). Further, I notice that a significant defect of the paper is that it does not use a temperature index including polar values, and does not relate the explanation to the very unusual Arctic warmth. -
Tom Curtis at 17:00 PM on 15 July 20112nd law of thermodynamics contradicts greenhouse theory
alistair @1075: You noted that the radiative equilibrium is achieved at 5 km altitude. This is, of course, a feature of our current atmosphere because it contains gases that emit and absorb in the IR portion of the spectrum, ie, in the wavelengths of peak emissions for a black body at 255 degrees K. In the non-greenhouse case, the case with no IR absorbing or emitting gases, radiative equilibrium necessarily is achieved at the surface. That is because, with no IR radiating gases, all radiation to space from Earth must come from the surface. As all radiation comes from the surface with no green house gases, it necessarily follows that the altitude of radiative equilibrium is at the surface. It follows that the surface temperature will be the temperature that results in radiative equilibrium, ie, 255 degrees K. With no GHG, and ignoring the effect of ozone, the average temperature at 5 km will be 206 degrees K (255 - 5 * the dry adiabatic lapse rate). Heat would cease being carried from the surface by convection once the atmosphere establishes a thermal profile equal to the dry adiabatic lapse rate. Most importantly, if heat did not stop being carried away by convection, you would be invoking a violation of the first and/or second law of thermodynamics. Specifically, the heat being carried away would not be then radiated to space because there would be no IR radiating gases in the atmosphere. Therefore it would accumulate until equilibrium of heat exchange with the surface was achieved, something accomplished when the dry adiabatic lapse rate describes the heat profile of the atmosphere. Heating beyond this point would require net heat to flow from the colder to the hotter body (2nd law violation), or else the heat in the atmosphere to be dissipated without flowing back to the surface. As we have established the heat is not radiated to space because of there being no IR radiating gases, the second case requires non-conservation of energy. -
alistair at 16:24 PM on 15 July 20112nd law of thermodynamics contradicts greenhouse theory
Your claim that the greenhouse warming at the Earth's surface is 33K is plain wrong. This is because for an opaque [to IR] atmosphere, the -18°C equilibrium with space is in the upper atmosphere, about 5 km up. The surface temperature is then set by the rise in temperature from the lapse rate, c. 6.5K/km. So, the Earth's surface temperature is c. 33K higher than the upper atmosphere's radiative equilibrium 'temperature'**. If you take out the GHGs, the IR radiation from the Earth's surface is then not absorbed in the atmosphere, so it cools. However, your claim that the earth's surface would fall to -18°C is plain wrong because you still have the lapse rate, a consequence of gravitational potential energy. Because only a small proportion of heat is directly radiated from the Earth's surface, most is convected away and because the IR emissivity of N2/O2 is very low, that heat remains as sensible heat. The real GHG warming of the earth's surface is a bit less than 10K. If you still believe it's 33K then you have to go back to your basic education. **To calculate that you have to do a Hottel analysis. [-snipped-] -
R. Gates at 15:41 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
This study certainly offers a plausible scenario for the slowing of the rise in global temperatures. An important measurement will be the average temperatures of the decade from 2010-2019. There could be a real mixed bag here. Fro example: How much will the sulfate aerosol emission from China have slowed in the decade? What if we enter into a Dalton or Maunder type minimum with the sun? What if we have a series of La Nina years continuing through the decade? Given this potential "triple whammy" of cooling forces, if somehow 2010-2019 is even hotter as a decade than 2000-2009, this will certainly be quite telling, or even if temperature simply level for the period. If you listen to the AGW skeptics, they are preparing for a Little Ice Age to begin any day now and to last for decades. I think they'll be disappointed, but, considering what it means for continued warming, you almost wish they would be right. -
Ari Jokimäki at 15:39 PM on 15 July 2011Thinning on top and bulging at the waist: symptoms of an ailing planet
About two months ago, a paper by Roy & Peltier was published. Their results are very well in line with this new study: "Recent trends in the two primary anomalies in the rotational state of the planet are analyzed in detail, namely those associated with the speed and direction of polar wander and with the non-tidal acceleration of the rate of axial rotation (via the measurement of the changing oblateness of the Earth's shape). It is demonstrated that a significant change in the secular trends in both of these independent parameters became evident subsequent to approximately 1992." -
barry1487 at 15:31 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
It is interesting, but that was not my point. I don't think what we explore here should be constrained by the skeptic narrative, but the main thrust of this blog is rebutting skeptical views.Explaining climate change science & rebutting global warming misinformation
(Headline on the home page here) All I'm suggesting is a small change to accommodate skeptical readers, and which in any case would be consistent with the science. The point of your post is that the globe has not warmed as we had expected, and we've come up with a new analysis to answer that. We've changed our narrative and we need to be careful in expressing it properly. -
guinganbresil at 15:01 PM on 15 July 2011Trenberth on Tracking Earth’s energy: A key to climate variability and change
Ken Lambert #31:"The CERES satellite data quoted in the Aug09 paper for 2000-05 were adjusted to an estimated imbalance of 0.9W/sq.m from an absolute value of about +6.4W/sq.m. The latest data shown in Fig 3 above shows an Rt value varying around the 1.0W/sq.m. How is this data 'adjusted' from the absolute value?"
It looks to me like the CERES product "EBAF" provides only clear-sky fluxes for all regions... Figure 3 should not be interpreted to represent actual net radiation - It doesn't include the effects of clouds... -
Rob Honeycutt at 15:01 PM on 15 July 2011Monckton at odds with the very scientists he cites
Camburn @ 12... No, I think Dr Abraham has stated this correctly. There are regions that show warming during the Medieval times, but that warming occurred in different regions and at different times. And some places, like the Tibetan Plateau saw no MWP period at all. You might double check the Vostok ice core for a MWP. I don't see it there. Byrd core? Nope. Not there either. Miller 2010 states that the planet has been on a slow cooling trend globally over the past 6000 years force by a changing tilt in the planet's axis. We have likely warmed the planet to about equal with the Holocene Optimum, which is a reversal of the natural trend. What is unprecedented is that we have reversed this natural global cooling trend over the course of about 1% of the time span of the Holocene. -
scaddenp at 14:46 PM on 15 July 2011Monckton at odds with the very scientists he cites
Hmm, worth noting the AR4 comments on HCO. I'd say there was evidence it was warmer then. I don't know the global picture well, but certainly local evidence of higher sea level in NZ and Australia earlier and also evidence of glacial retreat further back in HCO than now. Timing of the HCO particularly hemispherically may be more problematic, but the sealevel proxy is worth noting.Response:[DB] Thanks for weighing in. I was referring to Hansen & Sato 2011, which contend current temperatures have equalled those of the HCO. From P. 19:
"Augmentation of peak Holocene temperature by even 1°C would be sufficient to trigger powerful amplifying polar feedbacks, leading to a planet at least as warm as in the Eemian and Holsteinian periods, making ice sheet disintegration and large sea level rise inevitable.
Empirical evidence supporting these assertions abounds. Global temperature increased 0.5°C in the past three decades (Hansen et al., 2010) to a level comparable to the prior Holocene maximum, or a few tenths of a degree higher."
The biggest issue by far with Camburn's Tale is the implied because-it-was-warm-before-therefore-this-current-warming-is-nothing-to-be-worried-about. Of course, that approach only makes sense if one knows little about climate science other than what one has been spoon-fed on denialist blogs. The underlying physical processes responsible for the previous warmings brought up as a diversionary tactic (the MWP, the RWP and the HCO) are pretty well understood to be different than that faced by mankind today (anthropogenically-sourced CO2).
Hence my refering to Camburn "prosecuting a narrative".
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Camburn at 14:21 PM on 15 July 2011Monckton at odds with the very scientists he cites
DB: I have to get to sleep. Time permitting, tomorrow I will post links for the RWP.Response:[DB] Then post them here: Ljungqvist broke the hockey stick
The RWP is off-topic on this thread.
Sleep well.
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TJ Brookes at 14:15 PM on 15 July 2011Great Barrier Reef Part 3: Acidification, Warming, and Past Coral Survival
Maybe somebody needs to drop this report on Julia Gillard and Tony Abbotts desks and ask is this what you are aiming for..... I am in constant outrage at the lack of leadership... -
Camburn at 14:05 PM on 15 July 2011Monckton at odds with the very scientists he cites
Ok....I thought this was common knowledge: Warmer in China during the Holocene Optimum China warmer during Holocene Optimum Alley 2000 Greenland Ice core data confirms warmth. North Greenland beaches ice free during the Holocene Optimum. Greenland North Beach ice free during holocene optimum Data from Antarctica showing the early Holocene Optimum in the ice cores: Antarctic Ice cores showing Holocene historical temperaturesResponse:[DB] It is common knowledge:
- The Alley core data dates to no more recently than 1905. Recent temperatures at the drill site are unprecedented.
- The Vostok core data (and the other Antarctica core data) use 1950 as present.
- The China Holocene paper looks to verify the existence of the Holocene optimum via pollen data, nothing more.
You are throwing "stuff" at walls in the hope that some may stick (you grasp at straws). Regardless, this amorphous discussion serves no purpose on this thread. If you wish to prosecute this narrative further, do it here:
Grasp away there.
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scaddenp at 14:04 PM on 15 July 2011It's Pacific Decadal Oscillation
Fair enough about index - the "SO" about ENSO was an index and there is the MEI for expressing ENSO strength. However, ENSO is now reasonably well understood as a coupled ocean/atmosphere phenomena where the physical system can be expressed if not predicted very well. PDO remains just an index. It's an indicator of what is happening the oceans, it is not yet linked to any causitive physical system. And that index may be no more than another expression of the ENSO physical system. The interest with temperatures is not to link them to any index, but to link them to underlying physical system. This would happen if it was discovered there was an underlying ocean phenomena beyond ENSO. -
Camburn at 13:25 PM on 15 July 2011Monckton at odds with the very scientists he cites
"Other studies reinforce the view that when considered either by hemisphere or globally, the temperatures we are experiencing now are truly unprecedented". Mr. Abraham: I would suggest that you change the wording of this sentence. We all know that the Holocene Optimum had temperatures warmer than present temperatures. And indications from sea level proxy data, pollin data proxy etc strongly indicate that the Roman Warm Period was warmer than present temperatures. As far as the MWP, areas had substained temperatures as warm or warmer than present temperatures.Response:[DB] "We all know that the Holocene Optimum had temperatures warmer than present temperatures."
Umm, nope. Got a source for that? Anyway, that's off-topic.
"the Roman Warm Period was warmer than present temperatures"
Again wrong. And off-topic again.
"As far as the MWP, areas had substained temperatures as warm or warmer than present temperatures."
Still wrong. And still no cites, so now you're just trolling.
Look, if you're not going to even try to adhere to the standards expected of one adding comments on a climate science blog forum (Rule #1, always back up assertions with links to reputable sources), then don't expect your comments to survive moderation.
Be advised.
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Rob Painting at 13:03 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
Barry -"it looks like we've finally admitted what the skeptics have been saying, and have leapt upon the first reason to explain it that we can. We've dropped one argument in favour of another that contradicts the first." Barry, "skeptics" have been predicting global cooling for decades now, but the Earth keeps on warming - pretty much like we expect it to. Rather than constrain ourselves to "skeptic" narratives isn't it useful or at least interesting to examine why there is short-term variability? -
barry1487 at 12:56 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
I've posted in the PDO thread. I think we're missing something there. -
Bob Lacatena at 12:51 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
From the OP:As East Asia begins to install smokestack scrubbers to reduce sulphate pollution...
Does anyone have any idea what the time frame will be on this? My nightmare scenario would be ten or fifteen years of masked global warming, followed by a sudden, nightmarish takeoff that stuns the skeptics and the public and the politicians... but by then it's much, much too late. -
barry1487 at 12:34 PM on 15 July 2011It's Pacific Decadal Oscillation
Revisiting this topic after discussion in a recent thread: I think it's clear that the PDO has a negligible impact on centennial trends (if at all), but the skeptical focus is on decadal trends, and the argument is that the global temperature trend of the last 30 years or so is partly a result of the upswing (to about 1998). A question i've had in mind is about the difference between ENSO and PDO, where the former is linked to short-term fluctuations in the global temperature record, but the PDO is not. the language most often used is something like 'PDO shifts heat around within the system, but doesn't influence global temps.' I do not understand why one ocean/atmosphere system with fluctuating temperature indices should impact global temps (ENSO) and another shouldn't. In the other thread, I asked about this and was directed here with the comment, "PDO is basically an index whereas ENSO is a physical system." PDO and ENSOS are both expressed as indices - temperature indices. I don't see how one is a 'physical system' and one isn't. Nor does it matter what causes PDO or ENSO for the purposes of my enquiry. If PDO has a decadal influence on global temps, then it can be said that the thirty year global temp trend to 1998 may partly be a result of the PDO warm phase. Solar variability and cosmic rays show no trend for this period, but if PDO can be linked to decadal fluctuations in global temps, then the notion that natural factors have had a negligible effect on the trend for this period is undermined. Consequently, the trend rate for the last 30-40 years is only partly to do with CO2. I think skepticism has largely moved on from claiming the PDO is responsible for global warming on centennial scales, but I don't think we yet have a satisfactory response to argument about PDO effect on shorter time-scales. -
Andy Skuce at 12:09 PM on 15 July 2011Thinning on top and bulging at the waist: symptoms of an ailing planet
Yvan Dutil You are correct that change day length is rather less of a tidy story than the changes in oblateness measured by SLR and GRACE. Day length is affected not only by mass distribution changes in the atmosphere, oceans, cryosphere and lithosphere but also by changes in angular momentum in the Earth's outer, liquid core. Dynamical effects in the outer core produce measurable changes in day length with a cycle of 65-80 years. You may find this article to be of interest. -
Eric (skeptic) at 12:03 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
barry, thanks for the correction http://cses.washington.edu/cig/pnwc/compensopdo.shtml I don't want to discuss that further here, it was only supposed to be an example. -
scaddenp at 12:00 PM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
The proper thread would be Its the PDO. PDO is basically an index whereas ENSO is a physical system. There is some evidence that PDO may be long-lived integrator of the ENSO cycle. See the linked article. -
Andy Skuce at 11:49 AM on 15 July 2011Thinning on top and bulging at the waist: symptoms of an ailing planet
WSteven: Yes, thanks, you are right, centrifugal force is a fictional force, like the Coriolis force, but I figured that the people who already knew why the equator bulged wouldn't be confused by the term and those who didn't know wouldn't have heard of centripetal forces. There's often a trade-off between precision and clarity when it comes to terminology. -
barry1487 at 11:42 AM on 15 July 2011Why Wasn't The Hottest Decade Hotter?
That begs another a question I have in my mind from previous comments at this blog and others. I've read in various places that the PDO moves heat around, and doesn't by itself contribute to fluctuations in global temperature. This is different from ENSO, where it is explained that this ocean atmosphere system does have that influence. I've never understood why these systems should be distinct in this fashion. If PDO does provide multi-decadal influence on global temperature (as ENSO does on shorter time scales), then there's meat to the argument that the PDO is signal is apparent in the instrumental record, and that the high warming rate of the last 30 years may partly stem from that. This doesn't affect the centennial trend much, but it would have an impact on the last 30 years or so, which trend has been argued to be a result almost entirely of CO2, natural factors (solar, cosmic rays) showing little trend. Dunno if this is the right thread for discussing that... -
Rob Honeycutt at 11:40 AM on 15 July 2011Monckton at odds with the very scientists he cites
AT @6... When filtering out all the duplicate references there are 297 papers listed as part of the CO2science MWP project. I've just started collecting and reading the papers. What's immediately and clearly evident is the 1) the MWP is heterogeneous both spacially and temporally, and 2) there are far fewer southern hemisphere proxies. When you start digging in you start realizing what a large and complex project it must be to put together a global proxy record for the past 2000 years.
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