Arguments
Recent Comments
Prev 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 Next
Comments 42951 to 43000:
-
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"
-
dwr at 22:09 PM on 10 August 2013Reflections 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.
-
chriskoz at 18:38 PM on 10 August 2013Reflections 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.
-
TonyW at 17:35 PM on 10 August 2013It's methane
Methane levels started to increase again, about 6 or 7 years ago, so this explanation needs updating.
-
scaddenp at 14:06 PM on 10 August 2013CO2 effect is saturated
Sorry looking further up, I see you have answered the question about the distinction in models.
-
scaddenp at 14:04 PM on 10 August 2013CO2 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.
-
Klapper at 13:57 PM on 10 August 20132013 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.
-
StealthAircraftSoftwareModeler at 13:23 PM on 10 August 2013CO2 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.
-
DSL at 13:10 PM on 10 August 2013Fox 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.
-
A Change in the Weather at 12:24 PM on 10 August 2013Fox 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.
-
michael sweet at 12:00 PM on 10 August 2013Understanding 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?
-
Klapper at 11:51 AM on 10 August 20132013 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.
-
Riduna at 09:23 AM on 10 August 2013How 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?
-
deweaver at 08:57 AM on 10 August 2013Ocean 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.
-
CBDunkerson at 08:32 AM on 10 August 2013Reflections 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.
-
shoyemore at 07:47 AM on 10 August 2013Reflections 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
-
DSL at 07:41 AM on 10 August 2013Reflections on a changing Arctic: Less ice means faster warming
Ugh - "significant" > "insignificant"
Doh -
DSL at 07:40 AM on 10 August 2013Reflections 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.
-
mbryson at 07:31 AM on 10 August 2013Reflections 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.
-
Russ R. at 05:42 AM on 10 August 2013Reflections 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.
-
iana at 02:58 AM on 10 August 2013Ocean 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.
-
kkennett09 at 01:04 AM on 10 August 2013There 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.
-
Physicist-retired at 22:48 PM on 9 August 2013Reflections 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.
-
Glenn Tamblyn at 22:15 PM on 9 August 2013Reflections 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.
-
franklefkin at 21:49 PM on 9 August 2013Reflections 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.
-
MA Rodger at 21:28 PM on 9 August 2013How 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). -
Tom Curtis at 21:05 PM on 9 August 2013Nils-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.
-
chriskoz at 20:55 PM on 9 August 2013Reflections 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?
-
grindupBaker at 14:49 PM on 9 August 2013How much will sea levels rise in the 21st Century?
@davidnewell #31 That would be the total carbon emissions of China projected at 2100. 1 ppmv CO2 = 2.13263 Gt carbon (I compute) so that would be 84 ppmv CO2 as China's contribution. I seem to recall China is now neck & neck with USA at ~1.6 Gt carbon p.a., but that's a hazy memory I have.
-
davidnewell at 13:11 PM on 9 August 2013How much will sea levels rise in the 21st Century?
jja, you stated "Current projections hold China to emit 180 GT of carbon by 2100"..
Is that annually,? Do you have a reference??
It ain't gonna happen, but I'd like to see where it came from: that number is both atrocious
and .... totally beyond the capacity of the biosphere to deal with.
.
-
davidnewell at 13:01 PM on 9 August 2013Understanding the long-term carbon-cycle: weathering of rocks - a vitally important carbon-sink
Greetings. A wonderfully informative site.
Currently, I am proposiing that the weathering products of Granite, assembled conveniently in depths of over 8,000 feet thickness in "dry lake playas" located in the "Great Basin" of Nevada, be utilized to sequester CO2 in gigatonne quantities, through the importation of Pacific Ocean water; and through the simple expedient of spraying the water above the playas, whose supernatant water ranges from pH approx. 8.5 to approx. ph 10 .
in fact, i have "patent pending" staus on a patent entitled "Carbon Dioxide Direct Air Capture and Sequestration utilizing Endorheic Basin Alkaline Deposits to effect Mineral Carbonation"
excerpt:
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 __)
==
Tests are being designed to see how much of that 400,000 tonnes of CO2 can be captured.
i GUESS that between 8% and 15% can be 'caught": but this is a guess.
Obviously there is more to it than this, but I would invite consideration, questions, rebuttle, arguments, or any input whatsoever.
We are all in this together.
Thank you.
DavidNewell
-
MA Rodger at 07:33 AM on 9 August 2013How much will sea levels rise in the 21st Century?
jja @29.
I gave up on my arithmetic decades ago. However I use the following conversion between global energy imbalance in ZJ pa & W/m^2:- 1 ZJ pa = 0.062 W/m^2. So with one exception, I am in accordance with your calculation in the second paragraph @29.
I do take exeption to your value for the TOA imbalance. It looks like you have used the figure (or more correctly 'a figure' as it is not well defined) for the "present" net anthropogenic forcing, that is the change in such forcing since pre-industrial times. As that forcing has now resulted in significant warming (thus increasing outgoing radiation), the remaining imbalance is a smaller value. That value is given by Hansen & Sato as 0.58 W/m^2 for 2005-10 (although this is another figure that is not well defined) which would thus equal 9 ZJ pa. (The annual change in OHC would comprise the majority of this figure and can be used to add a certain robustness to the value. Adding 10% to the 0-2000m figure to account for warming below 2000m and a further 10% for surface/atmospheric warming, and so using Levitus (graphed here) over the last half decade, that yields 7.5 * 1.2 = 9ZJ pa. That's spooky!)
From the bottom paragraph of the PIOMAS page, the energy required to melt 1 cu km of ice can be obtained and so to melt 360 cu km & produce 1mm SLR requires 0.109 ZJ. THus energy to melt ice for 50mm SLR = 5.5 ZJ significantly more than half the global imbalance derived above.I'm afraid that the numbers you present within the following paragraphs @29 are not at all to my liking. The 80%AF by 2100 which you appear to take from fig 5 of Terenzi& Khatiwala 2009 is entirely bizarre. I don't even recognise the AF data prior to 2005 in that graph and given the other 2100 values derived within the paper, explanation is surely required for such a high value. And within the paper, the derivation of the 80% remains undiscussed outside section 4.2 which tends to rather deflate its usefulness.
The "TOA" numbers (again) look like forcing not imbalance. ECS (4.3 and 2.3 are both currently valid estimates) is not required for the calculation of future global imbalance. Imbalance is a matter of how much of the forcing is equalised by increasing temperatures, not per se the actual temperature required to achieve equalisation. Factoring in fast feedbacks (reduced arctic albedo) extend the life of the imbalance rather than increase the imbalance. Slow feedbacks which would include CO2 emissions from melting permafrost and hydrate methane ("Slow feedbacks?" some might ask.) are less easily accounted for but being themselves subject to speculation perhaps take this far enough off to make such lengthy discussion off topic.Heaping worst case upon worst case does have its limits. If anthropogenic forcings are increased high enough, we will surely reach a point where 5m SLR pa is possible. But I would suggest that with such a level of forcing/imbalance, SLR would not be a primary bringer of doom.
The one caviat here is the mass launching of ice bergs (your final factor) which do not need to melt to create SLR, but that 'speculation' should revolve around potential sources of such a launching.
-
deweaver at 07:21 AM on 9 August 2013Ocean Acidification: Eating Away at Life in the Southern Ocean
Rob,
From OA not OK: "The concentration of calcium in seawater doesn't change much with depth or location. This is because it has only one main source (the weathering of carbonate rocks) and, because weathering is slow, the ocean is well mixed in terms of the time scale for supply of calcium by weathering. But, as we have said, the relative concentration of carbonate species and the concentration of total carbonate species does change with depth. This is true even without a human influence".
However you say: "Significant global-scale alterations (in Ca) depend on the rate at which calcium is expelled by volcanic activity and, therefore, vary substantially only at million-year time scales (Montañez [2002], Stanley [2006])".
A quick analysis indicates that weathering is probably the main factor and volcanic activity, especially sulfur and CO2 emissions make the OA problem worse. Nothing like a little H2SO4 to decrease the alkalinity of the seawater.
You are correct, a true description of the problem is boring, but if you don't want to operate at the level of a “true believer” such as religious fundamentalist (with invincible ignorance), we have to utilize the boring and make it interesting. The scaling of pipes and fizzing of soda in the mouth are my, clearly limited and inadequate, attempts to tie a boring subject to the common observable world and make it interesting.
-
Rob Painting at 06:12 AM on 9 August 2013Ocean Acidification: Eating Away at Life in the Southern Ocean
John Bruno - even within the scientific literature the term 'keystone species' has taken on a broader definition than described by earlier work. It can include prey species, such as the Antarctic pteropod, under this broader definition. I don't doubt for a minute that ecologists/biologists still commonly use term in the way described by zoologist Robert T Paine. Picking nits here I reckon.
Joel Huberman - See the Royal Society Report (2005) hyper-linked in the blog post. Experience tells me that including equations is a major turn-off for readers. The Royal Society Report is a very easy read for those wanting to delve into this a bit deeper.
Deweaver - If I wrote as you have suggested I would simply bore readers to tears. The OA not OK series (button near top left of page) deals with this topic in more detail, and is written by experts on ocean chemistry. Readers wanting a bit more depth can simply read through the enitre series.
Rockytom - the brackets denote that the shells are made of chalk, not that all calcium carbonate is chalk. Will look at tweaking that.
-
scaddenp at 05:58 AM on 9 August 2013Ocean Acidification: Eating Away at Life in the Southern Ocean
deweaver - see the very large series on "OA is Not OK" (button on top left under the thermometer) or here for the first article in the series. It certainly deals with the physical chemistry aspects.
-
Leland Palmer at 05:52 AM on 9 August 2013Toward Improved Discussions of Methane & Climate
Even if there are a series of past mass extinctions associated with carbon isotope excursions suggestive of massive methane release from the hydrates, there is still the question of rate- how rapidly did these events occur?
Here's a paper from a location in China, which has a particularly high resolution stratigraphic record of the PETM.
Their calculated duration of the first large probable methane release during the PETM?
Less than 210 years:
The δ13C record from the Nanyang Basin thus represents the highest resolution PETM record available to date, thus facilitating detailed investigations into the PETM event. In the Nanyang record, the PETM was triggered within a 2 cm interval, indicating that its onset occurred in less than 210 years. This favors the hypothesis that the PETM was caused by a massive release of methane hydrate (δ13C =–60‰) from the continental slope. Other hypotheses for carbon release, such as decomposition of rich organic sediments, burning of peat land and tectonic processes, would have led to a slow carbon release rather than a rapid emission.
The authors go on to discuss various explanations for the initial carbon isotope spike triggering the PETM, including global warming, but conclude that a catastrophic event such as a massive earthquake and submarine landslide must have been responsible for the initial massive release. Magmatic intrusion from flood basalt eruptions might also qualify as a catastrophic event. They do discuss the subsequent further slow decline in C13 ratios, and say that that slower decline may be due to subsequent methane release from the hydrates stimulated by positive feedback.
But, there were a subsequent series of hyperthermal events, after the PETM, as discussed by Hansen. Those events apparently associate with orbital changes and so with orbital driven global warming.
Were those subsequent hyperthermal events also due to catastrophic events? This does not seem very likely, to me- that a series of catastrophic events timed to orbital cycles would occur.
This subsequent decreasing series of smaller hyperthermal events appears to be tied to orbital changes in insolation, and so to global warming.
So why did orbital variations in insolation trigger this declining series of probable methane hydrate releases?
Perhaps there was a shallow region of permafrost bound hydrates near one of the poles, capable of being triggered by global warming... perhaps like our own East Siberian Arctic Shelf (ESAS).
-
jg2013 at 05:32 AM on 9 August 2013There is no consensus
My wife's good friend teaches 6th grade in San Diego, California. A few days ago she told me she covers "global warming" in her class but emphasizes there's no scientific consensus and explained to me her understanding of the issue, which basically mimics the fox news disinfo. She's otherwise a liberal-minded person.
She's actually teaching the disinfo to her 6th grade classes and has been for years.
I rebutted her misconceptions but she had read a lot of bad info on the subject and wasn't receptive to my points over dinner. She let me install the Skeptical Science app on her iPhone, though.
My point in posting here is that I'm alarmed that school teachers are spreading misconceptions in the guise of preaching "both sides of the issue because every issue has two sides," as if both sides are correct or unprovable or convincing. Some global climate change group needs talk to teachers in the san diego public school system.
-
jja at 04:43 AM on 9 August 2013How much will sea levels rise in the 21st Century?
MA Rodger @24
my comments @23 was a restatement of 16 and in response to you @19 when you said, "To melt enough ice to achieve 50mm SLR p.a. would require roughly 5 ZJ p.a. which is not far from the entire energy imbalance today at the TOA"question: (are you sure your math is right here?) There are approximately 2,712,096,000 seconds between now and 2100 and the TOA is about 1.7W/m^2 at the tropopause (5.14E14m^2) which yields about 2.35 X 10^24 joules of total extra energy between now and 2100 at current TOA) or 2,350 Zj at todays imbalance.
in my scenario above I was showing that even without carbon feedbacks, the expected AF was going to go to .8 which means that additional increases in emissions will contribute significantly more to the atmospheric burden than the same incremental emissions in past years. Even without the feedbacks that I had mentioned in 23.
With the feedbacks that I am mentioning in 23 the TOA will be closer to 5 W/m^2 by 2100 and may be as high as 7.5. This is without a potentially catastrophic arctic methane release. In addition, the arctic albedo change will produce a direct heating of the greenland ice sheet. Finally, using the correct ECS value of 4.3 not 2.3 we will find an atmospheric warming effect that will produce average global temperatures of closer to 8 C by 2100. This is, still, without arctic catastrophic methane release.In this enviornment we can easily see 5M of sea level rise, or even 21 meters if ice shelf collapse occurs.
-
heb0 at 04:28 AM on 9 August 2013Fox News found to be a major driving force behind global warming denial
I suggest that, if Volponoca wants to engage in worthwhile covnersation related to the topic at hand, he obtain more of a focused approach and less of one that resembles a drive-by attempt to inflame discussion.
Moderator Response:[JH] Your observation is spot on. All of Volponoca's posts have been deleted because they violated three activites prohibited by the SKS Comments Policy, i.e., trolling, sloganeering, and excessive repetition.
-
rockytom at 04:02 AM on 9 August 2013Ocean Acidification: Eating Away at Life in the Southern Ocean
Rob,
In the second bullet of your post you say "...make their shells of calcium carbonate (chalk)..."
Most readers of SKS are sophisticated enough to know that all calcium carbonate is not chalk, but some may not be. Therefore, the use of chalk in the second bullet may be misleading. Also, it could be made clear that pteropods are small gastropods (being really nitpicking).
Otherwise, thanks for an informative post. I need to brush up on my kinetics and non-equilibrium chemistry.
Tom
-
deweaver at 03:38 AM on 9 August 2013Ocean Acidification: Eating Away at Life in the Southern Ocean
A very unclear article. A real discussion of carbonate chemistry in relationship to CO2 fugacity, alkalinity, pH, and Ca activity is required.
As anyone knows that lives in a hard water area, there is no “energy barrier” beyond nucleation issues (a kinetic issue) to the precipitation of CaCO3 from supersaturated water (your pipes, especially hot water lines end up getting plugged by scale – CaCO3).
No explicit discussion of the carbon pumping issue on upwelling waters, where the bloom on the surface creates a carbon biomass flow down to the deeper waters that get mineralized to CO2, which shifts the pH and carbonate/bicarbonate ratio which then upwells bringing non-supersaturated water to the surface with pH in the 7.6 range or lower. If you just aerated this upwelling water, with ambient air, until the pH increases to 8.1, you would be supersaturated again, assuming you didn’t nucleate the solution and precipitate the CaCO3. This is hard to do (lots of aeration) because of the slow kinetics of the CO2 hydration reaction to carbonic acid and why you have carbonic anhydrase in your lungs and saliva – you can’t get CO2 out of your lungs fast enough without this enzyme (as a side note, without this enzyme, soda pop wouldn’t fizz in you mouth and would be “flat” – seawater has slow kinetics with no free enzyme)
It is these upwellings that have caused the problems in the shellfish hatcheries in Oregon/Washington/BC Canada in the last several years. Of course they tried adding NaOH or NaCO3 to the water to get the pH up and get the water supersaturated, but it didn’t work because adding concentrated base to the seawater created local area during mixing (a mixing kinetic issue) where the supersaturation was extreme and small nuclei of CaCO3 were created and the existance of these nuclei prevented formation of kinetically unstable supersaturation. They got the pH and alkalinity correct, but not the supersaturation.
The problem is real, but the discussion is light weight. Most of the local impacts we will see in the next several decades are driven primarily by natural processes creating excessive local CO2 partial pressures in the water. The local partial pressures are in the 1000 ppm range to get near zero supersaturation (depending upon local water chemistry details).
When this low pH water upwells, CO2 is transported into the atmosphere until the pH increases to the 8.1 range. This pH shift is caused by the loss of CO2 to the atmosphere and to incorporation into biomass by photosynthesis. Once photosynthesis removed enough CO2 to shove the pH above 8.1, the ocean surface starts adsorbing CO2 from the atmosphere and the biomass being created transports carbon back to the deeper water. The oxidation of that biomass creates a low oxygen level in the deep water (dead zones) and increases the CO2 partial pressure (fugacity) while decreasing the pH and carbonate activity.
This issue is all about non-equilibrium thermodyamics applied to carbonate chemistry. You need a full understand of your freshmen physical chemistry and some understanding of kinetics and non-equilibrium chemistry. -
Fox News found to be a major driving force behind global warming denial
These media outlets are not only"Presenting contrarian scientists as "objective" experts", but are in addition presenting pure lobbyists as experts, such as Marc Morano, Pat Michaels, and the like - people who accept money to make statements supporting their clients interests, rather than along reality or evidence.
-
Joel_Huberman at 01:49 AM on 9 August 2013Ocean Acidification: Eating Away at Life in the Southern Ocean
Thanks for a very interesting article, Rob. One thing confuses me. It's not clear to me how the concentration of carbonate ions in ocean waters can decrease as the concentration of CO2 in the air increases. I think my confusion might be cleared up if you were to provide chemical equations showing the relevant species (CO2, H+, HCO3-, CO3--, etc.) and then use those equations to explain how CO3-- could decrease even as CO2 and H+ increase. Thanks!
-
citizenschallenge at 01:38 AM on 9 August 2013Fox News found to be a major driving force behind global warming denial
Thanks for posting this and thanks for your generous REPOSTING policy
"Fox News: A driving force behind global warming denial"
http://whatsupwiththatwatts.blogspot.com/2013/08/fox-news-driving-force-behind-global.html
-
Antignor at 01:09 AM on 9 August 2013Skeptical Science Firefox Add-on: Send and receive climate info while you browse
Just installed the FireFox add-on, but I have the same problem as Alexandre: I can't log in. When I click the Log In button nothing happens.
-
John Bruno at 23:49 PM on 8 August 2013Ocean Acidification: Eating Away at Life in the Southern Ocean
Minor correction: Pteropods are not keystone species: they are an abundant and important prey item. A keystone species is defined as a species that has a large and disproportionate affect on community structure relative to its biomass. Keystones are nearly always high level carnivores as a result and their impact is via top down control of competitive dominants rather than bottom up resource provision. See Power et al 1996 Bioscience (Sept issue).
-
CBDunkerson at 23:47 PM on 8 August 2013Fox News found to be a major driving force behind global warming denial
MP3CE & Lionel A, Fourier discovered that the Earth was warmer than could be explained by the amount of sunlight it received and suggested that 'something' in the atmosphere might act as an insulator, but he never determined that this was actually the case.
Tyndall demonstrated that the atmosphere was indeed responsible for the 'extra heat' and that the gases involved included water vapor, methane, and carbon dioxide... in 1859. Also, Tyndall's finding that CO2 and the other greenhouse gases absorbed infrared radiation was an observation... not a hypothesis. That is, he actually measured the amount of infrared absorption rather than just hypothesizing that it might happen. Thus, the 'correct' figure for knowledge that 'CO2 causes warming' would probably be 154 years.
-
MA Rodger at 22:14 PM on 8 August 2013How much will sea levels rise in the 21st Century?
Agnostic @25.
You are wrong to say "Based on paleoclimate evidence, Hansen concludes that global SLR could exceed 5m. by 2100."Hansen & Sato 2011 (and apoligies that my link @19 was to Hansen et al 2011 and not as intended to Hansen & Sato 2011,) refers in turn to Hansen 2007 where it is plain that the doubling period assumed (ie 10 years) was purely a "quantitative example" and not evidentially based, saying "Of course I cannot prove that my choice of a ten-year doubling time for nonlinear response is accurate, but I am confident that it provides a far better estimate than a linear response for the ice sheet component of sea level rise under BAU forcing."
In Hansen & Sato 2011, the GRACE data from Greenland & Antractica is used to support a short doubling period for ice cap melting although with the rider that "These data records are too short to provide a reliable evaluation of the doubling time." This probably remains the case even though we can today add 3 years-worth of data to the data available to Hansen & Sato 2011. (See here for Greenland - usually 2 clicks to download your attachment) Non-linearity is now more apparent but to conclude that the doubling is every decade and will continue so up to 2100 remains a step too far (if not two steps).
The paleoclimate evidence does show very convincingly that small increases in global temperature will result in very large SLR. The paleoclimate evidence does not show the rate of SLR we should expect. My own reasons for dismissing a 5m SLR by 2100 are laid out @19. -
Terranova at 21:31 PM on 8 August 2013Fox News found to be a major driving force behind global warming denial
Non-liberal, I meant.
-
Terranova at 21:30 PM on 8 August 2013Fox News found to be a major driving force behind global warming denial
Non-conservative? That's a new one! Guess that makes me anon-libetal.
Prev 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 Next
