Recent Comments

Prev  853  854  855  856  857  858  859  860  861  862  863  864  865  866  867  868  Next

Comments 43001 to 43050:

43001. barry1487 at 02:21 AM on 13 August 2013
       Global warming, Arctic ice loss, and armchair scientists
       

       Geoff,

       http://psc.apl.washington.edu/wordpress/research/projects/arctic-sea-ice-volume-anomaly/

43002. jja at 01:45 AM on 13 August 2013
       Global warming, Arctic ice loss, and armchair scientists
       

       Geoff Hughes
       
       Wipneus PIOMAS

       Volume data with various best-fit curves.

43003. Geoff Hughes at 01:36 AM on 13 August 2013
       Global warming, Arctic ice loss, and armchair scientists
       

       "the volume of ice has decreased approximately 75% over the past 3 decades."

       Can this be true? The link shows the sea ice anamoly and trend, but I do not know how to calculate the percentage change in volume from the information on the graph. I was expecting to see some beginning and ending actual volumes, say, 100 units of ice declining to 25 units over the 30 years. Could you please explain the loss in volume more fully?

43004. Leland Palmer at 15:38 PM on 12 August 2013
       Toward Improved Discussions of Methane & Climate
       

       Here's an interesting paper, on the PETM and the series of smaller Eocene hyperthermal events with accompanying carbon isotope excurstions that followed it, called in this paper the ETM2 and ETM3 events:

       Past extreme warming events linked to massive carbon release from thawing permafrost

       The authors present seemingly convincing correlations between the ETM2 and ETM3 events and orbital variations in insolation. They suggest a negative correlation with CaCO3 content of sediments during a series of orbital variations surrounding and including these events.

       They claim that high latitude melting of permafrost and associated positive feedbacks are the likely cause of these hyperthermal events.

       Unfortunately, other authors claim that the PETM (called ETM1 in this paper) and the other Eocene events have similar C13 and O18 excursion correlations, which demonstrate that the carbon source is similar or identical.

       And, the initial sharp phase of the PETM/ETM1 occurred very rapidly, in less than about 200 years- seeingly too rapidly for any other explanation except methane hydrate release.

       So, if the PETM/ETM1 was a hydrate release event, and the other events have matching C13 and O18 isotope excursions, then ETM2, ETM3 were also likely mainly methane release events, I think.

       So, we are arguably left with a series of orbital climate change driven methane releases.

43005. dwr at 15:15 PM on 12 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       CBDunkerson:  Thanks for the response.

       I see that DMI states that its current 15% sea ice extent estimate "can differ slightly from other sea ice extent estimates".

       Something of an understatement.

43006. Glenn Tamblyn at 14:24 PM on 12 August 2013
       Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
       

       I have sometimnes wondered about an alternative approach to capturing and sequestering CO2, piggy-backing of the fact that we may well need to look at geo-engineering answers down the track.

       The most technically viable geoengineering answer seems to be injecting large volumes of aerosols into the atmosphere to reflect sunlight and cause some cooling. Certainly it is a very far from ideal answer since you still get a lot of other climate impacts, even if aggregate warming were reversed, and it does nothing about ocean acidifcation. But we may need  to go down that road anyway.

       So, since we are possibly going to put 'something' up there any way, why not look at whether we can get that 'something' to do double duty and help with removing CO2 as well as reflecting sunlight. If we lofting large quantities of microscopic particles, the surface area of all that material is enormous - perfect for enhancing rates of chemical reactions.

       What if we simply crushed the very terrestrial rocks that are involved in weathering into fine dust and lofted that into the atmosphere as an aerosol, massively accelerating the natural rate of weathering. Instead of Carbonic acid falling from the sky and weathering happening on the ground, we might instead have see things like calcium bicarbonate falling in the rain.

       Would that sequester carbon? Or would it just mess up the chemistry of the oceans even further?

       Failing that, could some smart chemist come up with another reaction that we could use that would achieve a similar result. Up there wwe have some wonderful resources; CO2, H2O, O2, N2 and energy in the form of sunlight. All the buidling blocks for most of the known chemicals found in Organic Chemistry. Surely someone can think of a chemical pathway that will work.

       The surface area of all those aerosols up there is huge. A sphere with a surface area of 1 m² has a diameter a bit over 1/2 meter. Split that into micro spheres with a diameter of a micron and the total surface area increases by a factor of over 1/2 a million!

       A precious, precious resource.

        And if we can get the chemistry right, a far far more efficient method of trying to draw down CO2 than any of the more mechanical approaches being considered down on the surface.

43007. vrooomie at 12:51 PM on 12 August 2013
       2013 SkS Weekly Digest #32
       

       The cartoon reminds me of the hamster, in Joe Cartoon.....:)

43008. scaddenp at 09:58 AM on 12 August 2013
       Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
       

       Michael, not that it make a lot of difference but 74GW is capacity not generation. From the actual generation, it seems average generation is 22000MW.

43009. michael sweet at 09:34 AM on 12 August 2013
       Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
       

       David,

       It strikes me that it is unrealistic to imagine that 100% of the CO2 that passes the waer jet would be absorbed.  Find some data to support your claim, or withdraw it. The volume of water you want to move seems to me to be much too small to absorb a significant amount of CO2.  You realize that

       The volume transport of the overturning circulation at 24 N has been estimated from hydrographic section data ([4]) as 17 Sv (1 Sv = 10⁶ m³/s), source

       The currents off of Chile also move a tremendous volume of water.  How can you compare the amount of CO2 your scheme would remove to the CO2 those currents absorb?

       Where will all the salt go?

       According to the state of California, the total electricity generation in California is about 74,000 MW.  Since you claim at post 24 that 835 MW is 1/3 of the power used in California I am inclined to think you need to check your math much more carefully.  It is unreasonable to imagine that 1/3 of the power in California is used to pump that single water station.  In general, the amount of water that would need to be pumped is far beyond any reasonable amount that could be pumped.  Where would the gigantic amount of energy come from?

43010. davidnewell at 02:39 AM on 12 August 2013
       Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
       

       Oh yeah, and obviously the technique is imminently scaleable.

43011. davidnewell at 02:37 AM on 12 August 2013
       Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
       

       Michael:

        

       Thank  you for your question.

       PHYSICAL PLANT PROPOSAL　

       Scale of the proposal, by comparison to an existing pumping structure

       　

       1/3 of the electricity used in California, year to year, is employed to power the Edmonston Pumping Station, which lifts fresh water across the Tehachapies, from Northern to Southern California

       Edmonston Pumping Station profile:

       Normal static head: 1,970 ft

       Total flow at design head: 315 ft³/s (9 m³/s) (per unit)

       Motor rating: 80,000 hp (60MW)

       Flow at design head: 315 ft³/s (9 m³/s) (per uniit)

       Total flow at design head: 4410 ft³/s (450,000 m³/h) (Combined)

       Total Motor rating: 1,120,000 hp (835 MW)[2]

       　

       　========================

       Hypothesizing broadly, a 3/4 to 1 gigawatt power plant

       could lift 1/3 the water, or ~1470 cu. feet of water second (150,000cu.M/ Hr.)

       3 times as high, or ~ 6,000 feet.

       This would enable a 2,000 foot "head" of pressure to effect delivery of the ocean water to wherever you may want to run the pipes: in Nevada, whose playas are at approximately 4,000 feet above sea level.

       This comparison is made so that the project can be seen as imminently "doable" if the will to do so is established.

       The envisioned structure would consist of pumps to convey Pacific Ocean water from (probably) the vicinity of Eureka, to lined retention basins located on the Eastern slope of the Sierra Nevada, and thence released and conveyed by piping as circumstances dictate through spray nozzles arranged on the upwind side of the playas to be so utilized. (Sketches are found in the attachment # 1)

       　In my sample, I used the Black Rock Desert Playa as the "example.": it is both relatively close, and better characterized than any of the many other playas which could be employed. (And is a "saline" playa, and thus not changed in this protocol..)

       The spraying of ocean water through adjustable nozzles in fans of approximately 150 foot radius will generate "customizable " droplet sizes to effect varying degrees of CO2 absorption and water evaporation.

       Presuming then a 150 foot radius spray fan, and an average wind speed of 10 MPH, the volume of CO2 which will pass through the plane of the fan half-circle, per year, is ~ 400,000 metric tonnes. This is for one "spray rig", and, ultimately, thousands are envisaged. (See note __)

       ============

        

       It would be desirable to isolate portions of the Playa downwind of the sprayers to retain the water in shallow local ponds. The pH of the impounded waters would be monitored, and deeper levels of the playa soils would be accessed by the use of water jets to"drill down" through the consolidated clays, when necessary. As precipitated carbonates and salts build up in the impoundment, the location of the spray nozzle may be moved to a new area.

       It remains the results of field tests to determine which method of spraying water will be the most satisfactory:

       —The direct spraying of ocean water above the playa surface

       —The vacuum induction of supernatant playa water into the nozzle stream, similar to an "aspirator" mechanism

       or

       — The regeneration of electricity at the spray head location so that supernatant playa water can be pumped through the nozzles.

       In addition, imparting an electrostatic charge to the droplets through electrification of the spray nozzles may be contemplated, to both keep the droplets discrete from one another, and/or modify the residence time of the flight path of the droplets, as described in exhibit 2.

        

       ==============

        

       The 3% NaCl content of the water would be of no significant concern on the already saline playa under discussion.(Of which many others of similar saline character can be found)    The volume of soils in which it would be mixed, over decades, would be be of no concern.  On the other hand, if it is seen as a desireable commodity,  the locus of the spray heads and their localized retention podns can be changed frequently, and the prior spray surface allowed to dry, at which time the NACl can be  scraped up and utilized Other places.  One way, or the other, it's not a problem. 

        

       ===============

        

       Cost estimates, AKA  Wild Guesses:

        

        

       Estimated cost of the proposal implementation:

       Edmonston Pumping Station was referred to earlier as an example of scale. It cost ~$6 billion dollars to build. It flows more water than the proposal, and therefore has larger pipes, but the distance of pumping is shorter than the proposal requires. These facts tend to offset one another.

       Obviously, there are many variables beyond my best guesswork which will modify the actual cost.

       Should the State of California redirect the energy for the Tehachapi pumps to this project, there would be no need for the construction of another power plant.

       Since this seems unlikely, in would not be unrealistic to anticipate another $10 billion in the construction of another power plant.

       It may be noted that if the power plant was co-located with the pumping plant, near the ocean, that the cooling water for the power plant could be part of the water pumped, thus alleviating the environmental problems related to hot-water discharge.

       ==============

        

        

       The scale of the investment needed is (again a guess) about what farmers have put into central pivot irrigation systems over the past 40 years or so.

        

       "my" proposal dwells with conditions extant in my "local endorheic basin", whose relatively recent collection of huge quantities of cations from the local fresh granite surface seem, to my  eyes, to be a relatively rare occurrence:

        

       however, there may be many other places in the world where it would be easier to provide ocean water to, and spray over alkaline clay-like soils:  but I'm not familiar with them.  It IS unlikely that the huge QUANTITIES of material  are to be found elsewhere:  (as is found in the Great Basin...)  but if the source water is cheaper to obtain, then it's worth considering.

        

       ==================

        

       If it works, it is of course worth the energy, despite the APA's summation of 18 months ago, which is that "Direct Air Capture" is a non-runner. 

       The differences in this are:

       the huge area of sprayed liquid constitutes "the collector", and this offsets the fact that th pH is "moderate", not "highly" alkaline.

        

       The "10 mph average breeze"  consitutes the "air mover"

       The "reactant" doesn't have to be "desorbed" from the collected CO2, at 600 degrees plus, and recycled.

        

       There is no concern about taking "desorbed and liquified" CO2 to some other site and injecting it...

        

       There is a certitude that the mineralization of CO2 will in fact provide "geologic interval" sequestration.

        

       (gratuitous commentary alert..)

       Also, on a personal level, I find this to be an exemplification of the (to me) apparent fact that "what we are for" on this planet, is to "help out" the planet "work", not drive towards individualized  "wealth".  ALL this is, is an elaboration and an "assist" to "how the planet works".

       (end gratuitous comment.)

        

       Please throw me another objection

        

       I appreciate the opportunity to dialogue with people about this premise, who have an understanding of the perilous times we are in.

        

       Sincerely,

        

       David

        

        

43012. John Hartz at 01:00 AM on 12 August 2013
       2013 SkS Weekly News Roundup #32B
       

       Michael: Thanks for bringing the newly released California report, "Indicators of Climate Change in California," to everyone's attention.  I'll highlight it in this week's Weekly Digest. 

43013. michael sweet at 21:30 PM on 11 August 2013
       2013 SkS Weekly News Roundup #32B
       

       The state of California released a report that describes the measured effects of climate change in California.  The linked page has a link to the press release, the report summary and the entire report.  This is an update to a report originally written in 2009.  The report summary includes a list of the effects that had been updated or were new.  I found it interesting to see what the new effects were relative to what was known in  2009 (black carbon and ocean acidification were among the new sections).

43014. chriskoz at 21:24 PM on 11 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       BC@13,

       Thanks for the pointer to the excellent post by Tamino, of which I am aware. Note that Tamino (as well as Hudson 2011 in large part) estimate the forcing from just the sea ice extent data. They model the resulting albedo change between sea ice and open ocean as 0.2 and calculate the resulting extra amount of isolation penetrating water. They asume no changes in other parameters. In particular, the type of ice and the clouds stay the same.

       Riihela et al., (2013) however went beyond that, and have derived the albedo from satelite observations and shown that the type of ice has also changed, quote from the abrstract:
       
       

       ...we present an analysis of observed changes in the mean albedo of the Arctic sea-ice zone using a data set consisting of 28 years of homogenized satellite data⁴. Along with the albedo reduction resulting from the well-known loss of late-summer sea-ice cover^{5, 6}, we show that the mean albedo of the remaining Arctic sea-ice zone is decreasing.

       I don't have access to the full text so I am not sure if my understanding is correct, but I think their sea-ice zone albedo of −0.029±0.011/decade is just the result of change in quality of the remaining ice: i.e. ice becoming darker. Therefore, the resulting climate forcing should be calculated and added on top of Hudson/Tamino forcing. Having reread the former, ignoring the math, I do not feel the extra forcing from Riihela et al., (2013) will increase the perceived .1-.13W/m². In any case, without unknown methane feedbacks, it is not signifficant (yet) compared to the primary CO2 forcing.
       
       I guess "dark snow" project by Jason Box may shed additional light on the decreasing albedo in Arctic. So I'm looking for its results...

43015. jja at 17:12 PM on 11 August 2013
       How much will sea levels rise in the 21st Century?
       

       After crafting a lengthy response and then having it lost due to time out of login status I will summarize.

       @davidnewell I am sorry, the 180 GTco2 was not 2100 it was 2050 here:  figure 38 China LBL 2050 emission

       MA Rogers @30

        

       Thank you for showing me that, I do not exactly grasp the difference between the measured energy imbalance and the RF value, they should be the same in my mind.  What am I missing?

       The value I used was indeed RF values not energy imbalance.  If I use your math and Hansen & Sotos value of .75 (they adjust for the solar minimum) I get a value of (7.5 * .75/.58) * 1.2 which is equal to 11.6 ZJ p.a. this will make a total earth cumulative energy imbalance of 1,000 ZJ by 2100 (86 years) If even a few of the non-linear feedbacks are taken into account and a higher (more realistic) emission scenario is used then the value of energy imbalance by 2100 could easily be 4-6X the current value.  Therefore the total cumulative energy by 2100 will be closer to 3,000 +2,000/-1,000 ZJ .   This will increase if I used the slightly higher values of Balmaseda, Trenberth & Kallen
       
       In addition, if the ECS value is 4.3 then surface warming will be greater and the proportion of heat transferred by convection to land-based ice will increase.

        

       The AF is discussed in Terenzi & Khatiwala here:
       
       

       We believe that the increase in AF can be explained simply by a decrease in the capacity of both the ocean and land-biosphere to absorb anthropogenic carbon, as evinced by decreases in both OF and LF (not shown). This is likely due to saturation effects such as changes in the oceanic Revelle buffer factor (e.g., Keeling, 2005). Indeed, when we linearize the chemistry, which in effect holds the buffer factor fixed, the upward trend disappears (not shown). Thus, even with a fixed emission growth rate, our model, with no carbon-climate feedbacks, predicts future increases in AF because of the nonlinearity of the carbon cycle.

       Yes, with a more rapid loss of arctic sea ice, the increase in boreal emissions and the potential for collapse of natural carbon sinks will incrase the AF even greater, couple this with a more realistic emissions scenario and 5 or even 21 M of SLR by 2100 will be barely noticed by a loose group of remnant humanity living hand to mouth for basic survival. 

43016. Riduna at 17:01 PM on 11 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       Faster Warming Means Less Ice

43017. Tom Curtis at 07:10 AM on 11 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       rockytom @15, whatever his other vices, Spencer cannot have lied simply by saying that Antarctic sea ice was increasing while Arctic sea ice was declining:

       

       (Tamino)

       Tamino had this to say in his most recent comment on Antarctic sea ice (of which I am aware):

       "Both [Antarctic sea ice area and extent]  have shown increase over time which is statistically significant. The smoothed values for extent have increased by about 0.57 million km^2, area by about 0.51 million km^2. The reason for its increase is uncertain, but two possibilities which have been suggested are: 1, increased precipitation (snowfall) due to warming near the tropics; 2, intensification of the “polar vortex” perhaps due to changes in stratospheric ozone concentration.

       Despite the fact that the southern ice pack is larger overall than the northern, its increases are much smaller than the decreases noted for the northern hemisphere, 1.96 million km^2 in extent and 1.92 million km^2 of area. This puts the lie to claims (oft repeated) that southern gain even “almost” balances northern loss — the northern extent loss is 3.4 times as great as the southern extent gain while northern area loss is 3.8 times as great as southern area gain. When one is nearly 4 times as big as another, they are certainly not “balanced” and anyone who claims so is either a fool or an outright liar."

       (Original emphasis)

       I don't have much to add to that except to note that the extended satellite record from 1973 shows a declining trend in Antarctic sea ice due to an initial sharp decline from 1973 to 1978 (PDF).  Further, while Manabe et al (1991) predicted a thickening of Antarctic sea ice, and some more recent models (3 of 12 assessed by Stroeve et al (2007) also show a declining trend - the models are not consistent enough on this point to say that either increasing or decreasing Antarctic sea ice in the short term are prediction of climate science.  Sea ice dynamics are not captured well in climate models either in the Arctic (where the decline is massively under predicted) nor the Antarctic (where the predictions are inconsistent between models).

43018. william5331 at 06:10 AM on 11 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       If the sea releases heat into the atmosphere, this cools, not warms, the ocean.  It also releases more water vapour into the atmosphere which can cause low pressure weater systems with accompanying clouds.  This increases Albedo.  This is clearly seen this year (2013) and while it will only delay the ultimate melt, it is interesting to see Gaia fighting back.

43019. CBDunkerson at 04:09 AM on 11 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       dwr, the DMI page states that it uses 15% sea ice extent. There is also a red note at the bottom which says they recently changed their methodology to adjust for coastal zones. A link in that red text goes to the version prior to the adjustment... which seems more in line with the other sources.

       http://ocean.dmi.dk/arctic/icecover.uk.php

       Thus, the higher ice extent DMI is showing compared to the other sources is apparently due to the fact that they are now measuring the ice extent over a larger total area.

43020. rockytom at 03:28 AM on 11 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       I recently watched Roy Spencer lie to congress ( a U. S. Senate committee) by stating that although sea ice was declining in the Arctic, it was increasing in the Antarctic and concluding that other testimony to the same committee on Arctic sea ice was only part of the story.  It was Spencer who told only part of the story as he did not mention that the polar ice in the Antarctic is land based while that in the Arctic is sea ice (adjacent to Greenland which is land ice) and that all areas are losing ice as the planet warms.  There is solid evidence that ice shelves tied to land ice in Antarctica are losing ice by being undercut by warming seas, therefure speeding Antarctic glaciers movement to the sea.  Spencer's testimony was astoundingly simplistic, but not unexpected from such an "expert."  

43021. keitho at 01:44 AM on 11 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       Thank you for posting this fascinating article. The effects of reduced albedo, even at very high latitudes and hence low angle of incidence of the sun's rays , are obviously very important.

        

       The other effect of reduced sea ice must be the reduction in insulation of the Arctic ocean water. Presumably open sea water must be able to release heat to the cold atmosphere, without the inhibiting effect of a blanket of ice covering it, more readily. Does anyone have any thoughts on this?

43022. StealthAircraftSoftwareModeler at 22:36 PM on 10 August 2013
       CO2 effect is saturated
       

       Moderator [DB] post to my comment @266: I cover several things in my post, but they covered the three items in Tom Curtis’ post at @263. He was not called out for “being all over the map.”

       He claims in 263:1 that I do not seem to understand what models are, and I show that I build software models for a living. I may not know a lot about LBL models, but I know a lot about software, physics based models, testing models, and so on.

       Then Tom Curtis covers lots of excellent data in 263:2 and the Dessler 2008 paper. This shows that LBL models are accurate in computing reduced IR flux for CO2. This is directly related to whether not CO2 is fully saturated, is it not? I was questioning this because I was concerned about the accuracy of models because Myhre 1998 use models to arrive at the 5.35 coeffcient in the generally accepted CO2 forcing function (ΔF = 5.35*ln(C/C0) W/m2). TC showed support that models (including MODTRAN) are pretty accurate. I believe that now, for the most part.

       In 263:3 he jumped on Lindzen with valid comments, so I with drew my usage of his comment about the effects of CO2.

       Then my longest part is a lot of data about MODTRAN and the reduction of IR flux. MODTRAN has been shown to be accurate by Tom Curtis in 263:2 and Dessler 2008, so I am using its data. My ultimate point is that both Myhre and MODTRAN cannot be correct. The entire topic is about whether no CO2 is fully saturated. This is all about the CO2 forcing function (ΔF = 5.35*ln(C/C0) W/m2) from Myrhe 1998 and the coefficient of 5.35. I run MODTRAN and I get 4.58 in clear skies. In cloudy skies I get a value of 3.61. Most of the planet is cloudy, so the 3.61 value, if MODTRAN is correct, is probably more accurate. These values from MODTRAN disagree with Myrhe 1998. I am not claiming incorrectness on anyone’s part – only showing that they are inconsistent. You guys cannot claim that CO2 is not fully saturated and it has a large effect because of the 5.35 coefficient, then claim that MODTRAN is accurate.

       Does this help clear up my point? And does it show that I am actually on topic?

43023. BC at 22:25 PM on 10 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       Chriskoz at 1. There was a post by Tamino 6 October analysing the forcing due to Arctic albedo changes

       http://www.skepticalscience.com/arctic-antarctic-sea-ice-insolation.html

       Here's an extract from the article -

       In fact Hudson states that

       "Results show that the globally and annually averaged radiative forcing caused by the observed loss of sea ice in the Arctic between 1979 and 2007 is approximately 0.1 W m-2"

43024. dwr at 22:09 PM on 10 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       I've been pondering over the sea ice extent data recently.  In particular I'm struck by the disparity between DMI's extent and that of JAXA, NSIDC, ROOS... in fact, *all* of the others.

       As of 9th August, DMI indicates cover of 8.5 m/km^2; the others are around the 6.5 m/km^2.

       I know that DMI use 30%, whereas most of the others use 15%; but then I'd have thought this would have made DMI extent smaller rather than larger than the others?  Surely there are more cells with 15% ice than 30% ice? 

       And even accounting for the percentage difference, surely 2 m/km^2 is too large an extent difference to be explained by different counting methods?

       Can anyone offer an explanation or tell me where I'm going wrong?

       Thanks.

43025. chriskoz at 18:38 PM on 10 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       Russ@5,

       I don't know what your "different picture of global ice" means because mod has snipped you (no doubt rightly so) but I agree the picture of antarctic ice is quite different. That's why this article about Arctic does not consider Antarctic, not because, as if, according to you, "the Earth had only one pole".

       Other commenters already hinted the differences. I'd like to add, that the different response of antarctic ice is consistent with the global warming we are experiencing. Notably, the recent studies have linked the increased antarctic winter iceshelves with the decreased salinity of surface waters due to the melt of antarctic icesheet. So, that phenomenon should not be seen as a "sceptic"-proclaimed "recovery" but as another bad news, that we are loosing the antarctic icesheet - at increasing speed.

43026. TonyW at 17:35 PM on 10 August 2013
       It's methane
       

       Methane levels started to increase again, about 6 or 7 years ago, so this explanation needs updating.

43027. scaddenp at 14:06 PM on 10 August 2013
       CO2 effect is saturated
       

       Sorry looking further up, I see you have answered the question about the distinction in models.

43028. scaddenp at 14:04 PM on 10 August 2013
       CO2 effect is saturated
       

       Please can we make sure that you are not confusing models in the sense of GCM (which would have a complexity considerably larger than say  CFD models for airplane simulation) and LBL models which would be at least an order of magnitude simpler, mathematically and computationally. I cant see why you think the accuracy of 5.35 is so important - how much difference does it make whether it is 5.1 or 5.8? To my mind, this part of the equation pales to insignificance compared to uncertainities in feedback. 

       It also puzzling how you can read and Dessler (read the more recent papers) and yet make a statements about effect of cloud uncertainties. The best we have would put the net effect of clouds about approximately zero. If you have a substantial criticism then perhaps follow up here or here. Note that clouds are both positive and negative. 

       It would also be interesting to know what your alternative hypothesis is. If the obviously change in net forcings is not cause of observed climate, what do you propose instead and what is your case for this making physical sense.

43029. Klapper at 13:57 PM on 10 August 2013
       2013 SkS Weekly News Roundup #32A
       
       @Klapper #3:
       
       
       
       "Moderator Response:

       [DB] Assertions lacking evidence get disregarded quickly."

       Using data downloaded today from the NOAA/NCDC (ftp://ftp.ncdc.noaa.gov/pub/data/anomalies/monthly.land_ocean.90S.90N.df_1901-2000mean.dat) show the following annual averages by global temperature anomaly rank for the calender year:

        

       Rank	Year	Global SAT anomaly
       1	2010	.658
       2	2005	.651
       3	1998	.633
       4	2003	.623
       5	2002	.612
       6	2006	.597
       7	2009	.595
       8	2007	.589
       9	2004	.578
       10	2012	.575

       As you can see the assertion that the rank range is 8 to 9 is incorrect. The RSS global TLT anomaly is 11th.

43030. StealthAircraftSoftwareModeler at 13:23 PM on 10 August 2013
       CO2 effect is saturated
       

       Tom Curtis @263:

       It has been a little while for me. Sorry for responding slowly and appearing to drag out a topic, but I read what you guys send, I do some research, and I think about things a bit. I’m trying not to jump to conclusions and I am really trying to dig into things to get a better understanding.

       1) I think I have a pretty good idea of what models are, why they are built, how they are used, and what many of their weakness are: I have a physics degree and computer science degree and have been software building models for 30 years for aircraft, threats, radars, missiles, various aircraft sensor and weapons, and earth components such as terrain and weather (not climate, but weather as it impacts these systems). I test my models for aircraft with other models, measurement data in labs and anechoic chambers (http://www.tdk.co.jp/tfl_e/chamber/chamber01/5.html), tests from poll models (http://www.thehowlandcompany.com/radar_stealth/Bluefire_Helendale.htm) and actual flight tests. I know from first hand experience that testing is critical and that models and lab tests do not always match very well to what happens in the real world.

       My question @261 was more related to verification and validation of the various LBL models as they relate to the atmosphere. My concern was for the accuracy of the 5.35 coefficient in the CO2 forcing equation. If this value was derived from models without any real world measurements to back it up, then I would be highly suspicious of it.

       I would not dispute Newtonian mechanics for orbital prediction since that is easy physics. The climate, however, is very complex and making accurate predictions is hard. Think more along the lines of trying to predict where a gold ball will land after being hit with a golf club. Let’s say we need 1% or 2% accuracy too. That is wicked hard even if you know the exact initial conditions of the ball when it leaves the club face. You will have to run a complex and iterative numerical-methods simulation that considers many things: winds, ball drag (which is a function of many things), spin on the ball, lift induced by rotating body, and so on -- hard stuff to be accurate. Think about why we have GPS and laser guided bombs (which I know a lot about) – we do not use dumb unguided bombs because they are very inaccurate -- we can model the physics with extreme precision but still cannot hit anything with a dumb bomb. There simply is too much uncertainty in the environment, even on a very small scale. Therefore, we install guidance and targeting systems to compensate for errors and drift as it develops during the bomb delivery. (I also think the iterative growth in errors within GCM is a huge problem, but I’ll get into that over on the models topic).

       2) I dug into Dessler et al 2008 in JOGR, and that was an impressive study and test. That helps me gain confidence that the models are at least in the ball park in terms of accuracy with respect to the real world. Excellent charts, data, and a great study on Dessler’s part.

       3) I was wondering if the Lindzen reference was the same guy at MIT. I wasn’t sure and I wasn’t claiming or supporting it at all. It was just a data point in a list of points about the effects of CO2 and how they varied a lot. Granted, Lindzen was an extreme outlier and I withdraw his data point from my previous point @261.

       I spent a bit of time playing with MODTRAN running numbers on the reduced IR flux from CO2 and cloud effects. Since the chart you reference above shows that MODTRAN matches fairly close to IRIS Satellite data, I think my analysis below should be accurate.

       I found that for no clouds and CO2 at 294.3 ppm the IR flux is 288.97 W/m2. At 800 ppm CO the IR flux is 284.39 W/m2. The ratio of 800 to 294.3 is approximately e, so the natural log of this is very close to1. Using this I compute that coefficient for the CO2 forcing function is 4.58. This is 15% less than Myhre 1998, and his value of 5.35 is 15% less than the previous IPCC value of 6.3. I am sure that Myhre is a good scientist, but it seems that MODTRAN has been shown to be accurate, yet its output disagrees with Myhre. I find the wide range of values from MODTRAN, Myhre, and IPCC over the last decade not very reassuring in that scientists have a solid grip on these values. I know and fully accept that it is a very noisy world, so I fully expect that this value is hard to determine.

       Furthermore, when I run similar numbers using clouds in MODTRAN, I get an IR flux of 261.78 W/m2 for 294.3 ppm CO2, and 258.11 W/m2 at 800 ppm CO2. This yields a CO2 forcing function coefficient of 3.61, which is 21% less than MODTRAN with no clouds, and a full 33% less than Myhre. So while CO2 is not technically fully saturated, its effect is small relative to clouds. The reduced IR flux just from clouds alone is 27 W/m2 when compared to clear sly. Since 60% to 70% of the earth is covered with clouds, it seems logically correct to me that clouds are a major player in IR flux. If doubling CO2 reduces IR flux by 3.7 W/m2, but clouds reduce it by 27 W/m2, then clouds are over 7 times stronger than CO2. A small change in cloud coverage could easily overwhelm the effect of CO2, making the issue of whether or not CO2 is fully saturated really a moot point. Is this not correct?

       Given the magnitude of the effect of clouds, how has climate science determined that most of the global warming since 1950 is most likely due to CO2? That seems like an impossible thing to determine. In 1950 CO2 was about 310 ppm and today it is 400 ppm. Even using Myhre’s CO2 forcing coefficient of 5.35, CO2 has only blocked 1.36 W/m2 in the clear sky portion of the atmosphere. Where there are clouds the effect is even less. Isolating CO2 when so many other moving parts of the earth’s energy balance are also changing seems impossible, especially given we do not have very good data on clouds since before satellites (about 1970). How can the IPCC claim that it is very confident that CO2 has caused most of the recent warming?

       KR @265. The devil is always in the details. The horse is never dead. There is nothing that is *true*. Science can only falsify things and cannot prove something to be true. Some scientific theories are accepted as true only because they have withstood the test of time and have not been shown to be false. I seriously doubt that climate science is any where near achieving this status.

       Moderator Response:

       [DB] You are all over the map here, with much of your comment off-topic for this thread.  Please direct comments towards models to one of the model thread.  Your question about attributions is discussed on a number of threads, summarized here.

       Assuming scientists do not know what they are doing because it disagrees with your preconceptions is simply arguing from your personal ignorance.  Much of what you claim is unknown is actually fairly well-understood by science.

       It would be helpful to adopt a more streamlined approach to both your comment construction, the threads on which you place them and operate with less of a presumption that the science must be wrong.

43031. DSL at 13:10 PM on 10 August 2013
       Fox News found to be a major driving force behind global warming denial
       

       Change, the best recent piece I've seen on that observation is from Michael Fumento, a Reaganite, and it includes commentary on AGW. 

43032. A Change in the Weather at 12:24 PM on 10 August 2013
       Fox News found to be a major driving force behind global warming denial
       

       I don't think "conservative" is the most accurate descriptor for Fox News. Limits, moderation, and restraint are conservative ideas. Respect for the truth is a conservative idea. The scientific method is the epitome of a conservative idea. Fox exhibits these rarely. More often, they loudly express radical, reactionary, antisocial ideas that deny science and disrespect the truth.

43033. michael sweet at 12:00 PM on 10 August 2013
       Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
       

       David,

       How much energy will it take to pump that much water from the Pacific up to the Great Basin?  Where will that energy come from?  Is that really the best use of that much energy? What will you do with the left over salt?

43034. Klapper at 11:51 AM on 10 August 2013
       2013 SkS Weekly News Roundup #32A
       

       From the 2012 NOAA climate report:

       "Four major independent datasets show 2012 was among the 10 warmest years on record, ranking either 8th or 9th, depending upon the dataset used."

       That's not quite true according to my most recent analysis of RSS, UAH, GISS, NCDC and HADCRUT4 datasets. The range is from 9th to 11th (not 8th to 9th).

       Moderator Response:

       [DB] Assertions lacking evidence get disregarded quickly.

43035. Riduna at 09:23 AM on 10 August 2013
       How much will sea levels rise in the 21st Century?
       

       MA Rodger – Thank you for your comment @ 28 in which you note that … “The paleoclimate evidence does show very convincingly that small increases in global temperature will result in very large SLR”.

       It does indeed – but that very large SLR is likely to come from rapid loss of land based ice so it would seem that heat does get to polar ice causing mass loss, or the ice sheets are much more responsive to polar amplified temperature than hitherto thought  is this a wrong assumption?

43036. deweaver at 08:57 AM on 10 August 2013
       Ocean Acidification: Eating Away at Life in the Southern Ocean
       

       Iana,

       
       Considering that the discharges of Calcium from the rivers of the world are from weathering, where do you have any data showing volcanic emissions are a dominant source of Calcium for the oceans.   The acid gas emissions from volcanic sources are real. 

        

       http://pubs.usgs.gov/circ/circ1133/chemsetting.html  Notice the hardness (as CaCO3) is a fair fraction of seawater (50%) and often near saturation, whereas the concentrations of soluble salts (NaCl) is a small fraction of seawater. 

43037. CBDunkerson at 08:32 AM on 10 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       Russ wrote: "A more comprehensive view would consider global sea ice area..."

       Ok. The third graph you posted shows global sea ice area... and a clearly declining trend.

       Comprehensive view considered. Now back to the specifics of what is going on in the Arctic.

43038. shoyemore at 07:47 AM on 10 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       Russ R.,

       mbryson is right. Nothing wrong with a discussion of Antarctic Sea Ice, but once you get to the nitty-gritties, the Arctic is mainly ocean, Antarctica is mainly land ice.

       Though I hope you are not arguing that there is some "compensatory" mechanism ensuring that Arctic + Antarctic Sea Ice is roughly constant. That is about the same as the "Jesus is just moving the ice from the Northern to the Southern Hemisphere" argument I have heard some deniers make.

       Even a cursory look at your bottom chart shows that on a global scale, sea ice is declining, as is land ice and summer snowpack in the "cryosphere" generally.

       This site has some good threads on Antarctic ice. The topic of this thread is the effect on albedo of Arctic ice decline, and the Arctic is indeed warming faster than anywhere on the planet.

       www.skepticalscience.com/antarctica-gaining-ice-intermediate.htm

43039. DSL at 07:41 AM on 10 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       Ugh - "significant" > "insignificant"

       
       Doh

43040. DSL at 07:40 AM on 10 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       Russ, if you want to be taken seriously as someone who's interested in scientific progress, avoid doing what you have done.  You accuse others of ignoring data, but you fail to point out why the data are meaningful.  The same logic is used with "GMST trend is statistically significant over the last 15 years!"  So what?  No one talks about Antarctic sea ice.  Why should they?  I'm not saying it can't be relevant; I'm asking you to tell me why it is.

43041. mbryson at 07:31 AM on 10 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       Russ:  Conditions in the arctic and antarctic are very different, so combining the data doesn't clarify what's going on, it obscures it.  Antarctic sea ice is strictly a winter phenomenon, so its greater extent (apparently due to a strengthened antarctic gyre and possibly fresher surface water from increased melting of land ice) has no significant effect on albedo.  Meanwhile, warmer, saltier subsurface water is undermining large glaciers.  

       In the arctic, on the other hand, the increased melt/ decreased area happens during summer and makes a big difference to albedo (even when ice extent remains high, meltwater on the surface reduces albedo).  The trend there is running well ahead of models, and trying to make it 'go away' by combining it with antarctic sea ice measures is a fool's errand. 

43042. Russ R. at 05:42 AM on 10 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       Notably absent from this analysis and discussion is any mention whatsoever of Antarctic sea ice. One might easily get the impression that our planet has only one pole.

       A more comprehensive view would consider global sea ice area, not just the northern hemisphere.  And that perspective would show a somewhat different picture:

       

       (-snip-)

       (-snip-)

       Moderator Response:

       [DB] The topic of this thread is The Arctic, not the Antarctic.  As others have helpfully noted for you, take your attempted discussion of things Antarctic to one of the more appropriate thread.

       Further, please familiarize yourself with this site's Comments Policy before posting any further comments.  Please also ensure that all future comments comply with the Comments Policy.  Subsequent off-topic comments similar to this will be simply deleted.

       Off-topic snipped.

43043. iana at 02:58 AM on 10 August 2013
       Ocean Acidification: Eating Away at Life in the Southern Ocean
       

       "A quick analysis indicates that weathering is probably the main factor and volcanic activity, especially sulfur and CO2 emissions make the OA problem worse."

       Complete and utter rubbish. Peer reviewed or I call BS.

43044. kkennett09 at 01:04 AM on 10 August 2013
       There is no consensus
       

       Jg2013

       I am glad you brought up this point.  As a public school teacher I can attest to the notion that the disinformation swirling around global warming and climate change is happening at my high school in Michigan.  A science teacher at my school shows his students “The Great Global Warming Swindle” and not for the purposes of demonstrating the use of propaganda.  Although I do not teach in the science curriculum, I do teach U.S. Government and Politics and I am privy to the forces unleashed upon teachers regarding these issues.  The “teach the controversy” phenomenon, pushed by the Heartland Institute, et al, is alive and well and is straight out of the tobacco industry playbook to “deny the science” and manufacture doubt”.  I am sure you are aware of the book Merchants of Doubt by Naomi Oreskes which does a nice job of explaining the tobacco industry's playbook which is currently in use by the fossil fuel industry.

43045. Physicist-retired at 22:48 PM on 9 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       Trends in Arctic sea ice loss are easier to spot when considering volume (as opposed to area or extent).  See, for example, this:

       http://iwantsomeproof.com/extimg/siv_annual_polar_graph.png

       More here:

       https://sites.google.com/site/pettitclimategraphs/

       And I agree, Glenn - watching daily events/data coming from the Arctic this year has been nothing short of stunning.

43046. Glenn Tamblyn at 22:15 PM on 9 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       franklefki

       Agree with what you say with one proviso. Year to year variability can swamp the trend briefly. But the long term trend, using a several year average for example, is clear cut.

       This year in the Arctic is stunning. Stunningly strange. Huge cracking events through Feb-April, Significantly colder and cloudier this year. Several cyclones that have (are as I speak) smashing the thin ice up. The possibility of an ice free Pole this year, maybe an ice free Eastern Hemisphere. But much reduced ice loss in the Beaufort & Chukchi seas. Smoke from forest fires in Russia moving out over the arctic. Jet Stream doing weird stuff. Record highs in parts of northern Canada and Greenland. Then freezing the next day.  The Kara sea taking forever to melt out. And ice transport out through the Fram Strait almost shut down.

       Hold onto your hats.

43047. franklefkin at 21:49 PM on 9 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       Given everything that is stated in the article, it seems unlikely that a recovery is possible.

        

       There is more CO2 in the atmosphere - so there is more TOA forcing,

       There was less ice last year - so there should be less this year

        

       This positive feedback loop is tantamount to a runaway heating loop - bounded only by the fact that once the ice is gone - its gone.  Of all the postulated theories, this one seems the most likely to be tested the earliest.  It seems likely that there will be some kind of a rebound (at least for this year) in the quantity of artic ice.  The next few years will be very telling.

43048. MA Rodger at 21:28 PM on 9 August 2013
       How much will sea levels rise in the 21st Century?
       

       davidnewell @31 & grindupBaker @32.
       The CDIAC estimates for China's 2011 CO2 emissions is 2.48 GtC. Such a rate of emissions would total 217 GtC over the period 2014-2100 although its impact on atmospheric levels would have to be reduced by the Af (which wasn't employed @32). CDIAC put China not neck-and-neck with USA but head-and-shoulders ahead (US 2011 estimate is 1.47 GtC), although these two remain the big beasts with a big gap down to the next biggest - India 3rd (0.62 GtC) & Russia 4th (0.46 GtC).

43049. Tom Curtis at 21:05 PM on 9 August 2013
       Nils-Axel Mörner is Wrong About Sea Level Rise
       

       Tamino now has a post analyzing Morner's use of the Fremantle data mentioned in point 5 of my post @51 above.

43050. chriskoz at 20:55 PM on 9 August 2013
       Reflections on a changing Arctic: Less ice means faster warming
       

       Given albedo change numbers, the obvious next step is to integrate the function delta energy absorbed over the arctic during summer months (may thru september) and average the energy over the whole year and the global surface. It would be interesting to compare the resulting forcing with the existing imbalance of 0.6W/m2 and the delta forcing the human increase of 2ppm/y brings.

       Has anyone done that? Which delta forcing would be higher? It would be interesting to predict arctic albedo delta forcing until 2100. Of course not on IPCC estimates (which we know are completely wrong in arctic with respect to any parameter) but e.g. on Maslowski's estimates which are right on track. I guess IPCC did not even take arctic albedo changes into their scenarios in AR5.

       So, with delta albedo established at about -10% since satelite records, can anyone come with ballpark forcing figure I am asking?

Prev  853  854  855  856  857  858  859  860  861  862  863  864  865  866  867  868  Next