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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.
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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!
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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
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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.
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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).
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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.
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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.
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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.
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Lionel A at 21:23 PM on 8 August 2013Fox News found to be a major driving force behind global warming denial
MP3CE
190 years is about right given that Joseph Fourier published articles in 1824 and 1827 as Wiki accknowledges:
Fourier's consideration of the possibility that the Earth's atmosphere might act as an insulator of some kind is widely recognized as the first proposal of what is now known as the greenhouse effect
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carbtheory at 17:25 PM on 8 August 2013It's aerosols
Does a higher atmospheric aerosol ( in the cloud condensation neuclii size range ) content result in a dryer atmoshere? Considering the particle size of dirty emissions between 1940 and 1970 and the cooling during that period, then the concerted effort to clean up emissions post 1970 coinciding with a rise in atmospheric water vapour content, should this correlation be considered as being part of the cause of the post 1970's warming or 1940 - 1970 cooling?
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MP3CE at 15:53 PM on 8 August 2013Fox News found to be a major driving force behind global warming denial
In reality we've known for nearly 190 years that rising CO2 causes global warming, and we know for certain it's well-mixed throughout the atmosphere, as illustrated by measurements from around the world.
Sorry, but I have to disagree with 190 years - I'd rather put 120 years (works of Tyndall and Arhenius), or even less, as these were first hypotesis.
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scaddenp at 14:03 PM on 8 August 2013It's too hard
Well I am not a fan of any kind of subsidy. Forget subsidies renewable whatever, but more importantly stop subsidizing FF. However, seeing as the link is Fox News and headline looks like it meant to be attack on government, I'd say read the actual report instead. The substantial conclusion of that report was that "Finally, many studies have found that the most reliable and efficient way to achieve given climate-change objectives is to use direct tax or regulatory policies that create a market price for CO2 and other greenhouse gas emissions" . Maybe I missed that bit in the Fox take on that? I would strongly agree and I hope after reading the report that Fox readers would urge your president to implement that final recommendation.
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jsmith at 12:42 PM on 8 August 2013It's too hard
I would like to get you guys' opinions on this: It seems it is going to spawn a new meme that goes something like, "NAS says renewable subsidies don't work!"
http://www.foxnews.com/politics/2013/07/18/billions-spent-in-obama-climate-plan-may-be-virtually-useless-study-suggests/#ixzz2ZiIY1MD0
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How much will sea levels rise in the 21st Century?
Agnostic - Hansen says that 5m could happen, not that it would: I consider that statement a cautionary tale about exponential growth, rather than a prediction. Too many people expect (against the math of acceleration) that 3.2mm/year will continue for the 21st century, and Hansen was pointing out with a rather extreme example why that is silly.
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gws at 11:15 AM on 8 August 20132013 SkS Weekly News Roundup #32A
wow, what a collection of articles, quite a week!
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Don9000 at 11:02 AM on 8 August 2013How much will sea levels rise in the 21st Century?
Agnostic @25
Why do you seem to assume anyone at SkepticalScience is "satisfied" with the last IPCC projections? Obviously, as the rate of sea-leve rise is at the upper bounder of those projections no reasonable person would be "satisfied" with them. The scientists surely aren't "satisfied" with those projections, and the IPCC is surely aware it has to work to improve them. Obviously, scientists are trying to understand what is happening, and new understandings have been reported in the scientific literature since the last IPCC report. The next report will incorporate this new understanding.
You say that "more cautious scientists persist, often uncritically, with the IPCC 'consensus'", but surely that is a bit unfair. Is that kind of caution bad and uncritical if it is used because their research needs to be grounded on some kind of widely understood baseline? I don't know which scientists you are referring to, but I suspect most scientists who use the IPCC projections to underlay their own research do so because that is only logical. As an agnostic, you may like to make up your rules as you go along, but it seems to me that most scientists can't indulge in that kind of hubris in pursuing their research. The exception would be the scientists whose research is looking to better project future trends by improving the models. And even they understandably treat the IPCC projections with respect; they are just trying to improve them.
I' also dislike the tone of your final sentence in which you say the SkepticalScience position is one of "virtual endorsement of the IPCC position." SkepticalScience has put up a number of posts about the new science which has been published since the last IPCC report that will inform the next IPCC "position," and most of these posts have drawn attention to the fact that the last IPCC round of projections on future sea-level rise and Arctic ice melt projections are too low. I dare say this is a concern to most of us, as well as many if not most climate scientists, and the IPCC too. That said, like or not, the IPCC is the official international organization that is putting out periodic reports on the state of our understanding of climate change and climate science. It will put out its new reports over the next couple of years, I believe, and we will see what they show.
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Chris8616 at 10:47 AM on 8 August 2013Toward Improved Discussions of Methane & Climate
Does Freshwater Runoff in the Arctic change Ocean Circulation to Unlock Methane Hydrate in the Deep Ocean? (LINK)
Moderator Response:[DB] Condensed link.
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Chris8616 at 09:54 AM on 8 August 20132013 SkS Weekly News Roundup #32A
Does Freshwater Runoff in the Arctic change Ocean Circulation to Unlock Methane Hydrate in the Deep Ocean? Link
Increased Methane emissions from summer Monsoon Link
Methane Hydrate – Ice on Fire Link
Methane in the Arctic Circle Link
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Riduna at 09:52 AM on 8 August 2013How much will sea levels rise in the 21st Century?
Based on paleoclimate evidence, Hansen concludes that global SLR could exceed 5m. by 2100. He says this would occur if polar ice mass loss were to double each decade of the 21st century. Since 2000 polar ice mass loss well in excess of decadal doubling has occurred and is continuing to accelerate, particularly in the Arctic where temperature amplification is over x2 average global surface temperature rise. Hansens analysis is consistent with the present rate of SLR (~3.2mm/yr) rising steadily to ~3 cm/yr by 2050 and continuing to rise to ~ 40 cm/yr by 2100.
More cautious scientists persist, often uncritically, with the IPCC “consensus” that total SLR in the order of 80 cm by 2100 is the likely outcome. This stands in stark contrast with a possible 5 metre global SLR by 2100.
The difference between the two estimates is so great and the implications so devastating were the latter to occur, that the need for reassessment and a more detailed analysis of all factors likely to contribute to SLR is surely justified, particularly for soundly based policy formulation.
Should we be satisfied with the current IPCC prognosis when it appear to be at odds with actual and expected development of factors which contribute to SLR? Is SkS satisfied with its position of virtual endorsement of the IPCC position?
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MA Rodger at 08:40 AM on 8 August 2013How much will sea levels rise in the 21st Century?
jja @23/
My query @19 was specifically aimed at you comment suggesting 5m SLR by 2100 - SLR by 2100 being the topic of the post.
The question you ask concerning temperature rise - the RCP scenarios were derived to allow answers to such questions although not perhaps covering the circumstances you present @23. Obtaining such answers for the RCPs is not a trivial task and so neither is your question.
And I'm not entirely sure why you link to Terenzi& Khatiwala 2009 as it argues against the concept of CO2 feedbacks being apparent within recent observed trends in Af. I would add that these 'observed trends' do result entirely from an assumption they make ("For this experiment, we consider fossil-fuel and industry emissions only, setting emissions due to land use changes to zero.") which I feel is misplaced. Although, saying that, I am holding a watching brief on the present annual increases in atmospheric CO2 which seem to me suddenly higher than previously for an ENSO neutral period (average 2.8ppm pa for the last 6 months).
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Rob Painting at 05:31 AM on 8 August 2013Ocean Acidification: Eating Away at Life in the Southern Ocean
Thanks Bill. Typo fixed.
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DSL at 05:30 AM on 8 August 2013Ocean Acidification: Eating Away at Life in the Southern Ocean
Thanks, Rob. This will help me represent the situation more accurately.
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jja at 05:28 AM on 8 August 2013How much will sea levels rise in the 21st Century?
MA Rodger @19
If arctic sea ice dissappears by 2030 on June 1st and there is a 4.3 (or so) temp response to 2XCO2 and we continue with BAU emissions so that continued warming increases natural emissions of GHG from boreal forests and peat as well as producing a step-change increases in methane emissions from boreal terresterial and sub-sea permafrost AND this happens under a regime of constant declines in Natural carbon sink capacities so that the AF goes from 42% to 80% by 2100,( LINK )
In this scenario, what do you suppose is the Global average temperature above pre-industrial levels?
Moderator Response:[RH] Shortened link.
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Bill Bishop at 05:11 AM on 8 August 2013Ocean Acidification: Eating Away at Life in the Southern Ocean
Thanks for this post on an important topic, Rob!
A typo jumped out at me - "hyrononiums" should be "hydronium".
If you're not part of the solution, you're part of the precipitate!
~Bill Bishop
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MA Rodger at 05:00 AM on 8 August 2013How much will sea levels rise in the 21st Century?
grindupBaker @21.
(OHC is straying off the topic of SLR somewhat, mind.) The 13ZJ p.a. from ORAS4 isn't the current rate which is more like ~8 ZJ p.a. and so not far off the ~6 ZJ p.a. of Levitus 0-2000m. And why not use ORAS4 in preference to Levitus? ORSA4 is too new? It's not a direct measurement system? It stops at 2010? You will have to ask a proper user.
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grindupBaker at 02:17 AM on 8 August 2013How much will sea levels rise in the 21st Century?
@MA Rodger #19 The ORAS4 OHC anomaly graph that I've seen shows an increase of 13.7 ZJ p.a. from 2000-2010. Why is this not being used as the current warming rather than the ~5 ZJ p.a. that "everybody" seems to be using ? Also, that graph shows a 50 ZJ cooling for Mt Pinatubo over 1 year in 1992. I think the OHC warming descriptions past & future need to be split into two quantities (with and without volcanoes) for two purposes because cooling from volcanoes is a statistical probability so needs factoring in for some deliberations, but S.B. factored out when comparing OHC anomaly with the radiative imbalance that mostly causes it.
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Leland Palmer at 02:01 AM on 8 August 2013Toward Improved Discussions of Methane & Climate
Whoops, make that C13 depleted carbon (C12 enriched), in the last paragraph above.
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Leland Palmer at 01:54 AM on 8 August 2013Toward Improved Discussions of Methane & Climate
Here's a quote from Hansen's paper linked to above, which claims that a low level runaway greenhouse, making most of the planet uninhabitable, is probable if we burn all of the fossil fuels:
The potential carbon source for hyperthermal warming that received most initial attention was methane hydrates on continental shelves, which could be destabilized by sea floor warming (Dickens et al., 1995). Alternative sourcesinclude release of carbon from Antarctic permafrost and peat (DeConto et al., 2012). Regardless of the carbon source(s), it has been shown that the hyperthermals were astronomically paced, spurred by coincident maxima in Earth's orbit eccentricity and spin axis tilt (Lourens et al., 2005), which increased high latitude insolation and warming. The PETM was followed by successively weaker astronomically-paced hyperthermals, suggesting that the carbon source(s) partially recharged in the interim (Lunt et al., 2011). A high
temporal resolution sediment core from the New Jersey continental shelf (Sluijs et al., 2007) reveals that PETM warming in at least that region began about 3000 years prior to a massive release of isotopically light carbon. This lag and climate simulations (Lunt et al., 2010a) that produce large warming at intermediate ocean depths in response to initial surface warming are consistent with the concept of a methane hydrate role in hyperthermal events.Hansen limits himself here to discussing the PETM, a hyperthermal event from about 50 million years ago, and the decreasing series of hyperthermal events that followed it. As Dickens points out, this behaviour is consistent with the hydrates behaving like an electronic capacitor, charging and then discharging in a decreasing series as the deposits become more and more depleted.
But there have in fact been a series of such mass extinction events associated with carbon isotope signatures perfectly matching an influx of several trillion tons of C13 enriched methane from the methane hydrates into the atmosphere. Canditate events for the methane catastrophe hypothesis include the End Permian, the End Triassic, and the PETM.
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rudreaming at 00:51 AM on 8 August 2013How much will sea levels rise in the 21st Century?
jja @ 16
Use of the RCP 4.5 scenario as the basis for this SLR projection is indeed questionable. Emissions data indicate we are continuing right along the “business as usual” pathway towards some 900 ppm CO2 plus several hundred additional ppm in CO2 equivalents from other GHGs, by 2100. I have yet to see any significant indications that we will deviate much from this path. Any discussion of projected SLR should surely use the “business as usual” scenario as the basic starting point.
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Leland Palmer at 00:10 AM on 8 August 2013Toward Improved Discussions of Methane & Climate
Here is a link to Hansen's paper, the one that says that a low level runaway heating scenario is possible, if we burn all of the fossil fuels:
Climate Sensitivity, Sea Level, and Atmospheric CO2
There's a good summary of Hansen's perception of the methane hydrate problem included in that paper.
I don't think his model includes atmospheric chemisty effects as postulated by Isaksen's modeling. These atmospheric chemistry effects including increased stratospheric water vapor, increased tropospheric ozone, and increased methane lifetime due to the exhaustion of the hydroxyl radical oxidation mechanism would likely make the low level runaway worse than Hansen's modeling suggests, I think.
What would result?
A more severe low level runaway, or something even worse?
A mostly uninhabitable planet, or an entirely uninhabitable planet?
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ridethetalk at 23:37 PM on 7 August 2013Where SkS-Material gets used - Coursera's Climate Literacy Course
I too have just finished this course and, as a few people here have also mentioned, I didn't learn a whole lot though did consolidate a lot of what I previously knew. For that alone, it was worth the time investment. I signed up for the signature track - not sure yet whether this was worth it or not as I fell ill and missed the deadline for two of the weekly tests. Blitzed most of the other tests, assignments and final exam so may get a "Distinguished" Statement of Accomplishment (whatever that means) anyway.
One thing of interest that I was previously unaware of was British Columbia's US$30 carbon tax - if only we had something as progressive here (but Big Kev is moving us to an ETS linked to the EU price and the Mad Monk wants to screw it completely!) - I hope that isn't too political.
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TonyW at 20:08 PM on 7 August 2013Toward Improved Discussions of Methane & Climate
Apparently, Shakhova and Semiletov have a paper to be published soon, in Nature. They seem very concerned about abrupt methane releases, so I'm sure that the paper will present more discussion points.
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MA Rodger at 19:20 PM on 7 August 2013How much will sea levels rise in the 21st Century?
jja @16.
I don't know if your 5m SLR by 2100 was a "throw-away" but I it is rather too high. While such a figure does appear in the lieterature, from Jim Hansen no less, do note that within Hansen & Sato 2011, the 5m rise is argued from the admitted position of it being "an improbable outlier." And the proposed non-linear solution from Hansen & Sato just makes matters worse as it requires an impossible 300mm SLR p.a. for the end of the century.
To achieve 5m SLR by 2100, indeed to achieve rates of SLR much above 20mm p.a. does require some explanation as to how the ice and the heat get together. 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. Sure the imbalance could get bigger in future decades but to expect more than 10-20% of it to get to the poles to melt ice? That does require explaining.
There is one mechanism that readily springs to mind. Ice bergs would work. They don't even need to melt to cause SLR, and bobbing round the tropics would get them to the heat as well as increasing the TOA imbalance so making more 'heat' available. But such ice berg speculation does require an answer to the question as to the source of these ice bergs because 5m of ice berg-induced SLR requires almost 2 million cu km of ice berg. That's a lot of ice.
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Riduna at 10:09 AM on 7 August 2013How much will sea levels rise in the 21st Century?
Thank you jja @ 16 - that explains everthing!
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Riduna at 10:05 AM on 7 August 2013How much will sea levels rise in the 21st Century?
William @ 15 ... "That sea level rise is for every degree that the sea warms".
Really? Then why is this not stated in the article?
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jja at 09:32 AM on 7 August 2013How much will sea levels rise in the 21st Century?
It should be noted that there are a few basic assumptions involved in the RCP4.5 assumption:
1. (Saviour Technology) CO2 carbon capture from coal plants will be implemented and emissions will be held steady state after 2035 with reduced emissions even during population growth after 2035. Current projections hold China to emit 180 GT of carbon by 2100.
2. Arctic sea ice loss rates will (magically) slow and then stop before summer seas become ice free in the arctic until after 2065 (projections around 2085) allowing for much less global albedo change and keeping summer arctic temperatures closer to the 20-year average.
3. Magically slower Arctic sea ice loss rates allow for a much slower arctic permafrost melt and associated natural emissions feedbacks.
4. Thermohaline current continues at only a very slightly decreased intensity, allowing for continued significant natural CO2 sink in the North Sea.
5. Boreal forests and boreal peat do not significantly contribute to natural emissions.
6. Greenland and Western Antarctic ice loss rates do not rise significantly due to natural feedbacks and the lack of saviour technology (CCS) to halt emissions.
7. Amazon forest carbon sequestration continues at current rates.
8. Climate forcing is consistent with a 2XCO2 sensitivity of 2.3 and not 4.3 'C per doubling of CO2 (Arctic Summmer sea ice free by 2030 scenario).
9. Natural methane sources do not increase significantly due to magically slow arctic sea ice loss.
as long as those assumptions hold true then we can stay within the RCP 4.5 scenario as well as expect only 1Metre of Sea level rise by 2100. Otherwise, the scenario is closer to 6-8C of average warming by 2100 with closer to 5Metres of sea level rise.
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william5331 at 06:17 AM on 7 August 2013How much will sea levels rise in the 21st Century?
(12) That sea level rise is for every degree that the sea warms. The 0.8 degree warming we have seen so far is in the atmosphere. Because of it's inertia, the huge sensible heat of water and the huge volume involved, it will take quite a while to see a degree warming in the sea.
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Andy Skuce at 04:42 AM on 7 August 2013Update on BC’s Effective and Popular Carbon Tax
More on the BC Carbon Tax
Mark Jaccard and another article discussing how carbon tax revenues should be spent.
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dr2chase at 01:22 AM on 7 August 2013How much will sea levels rise in the 21st Century?
@Agnostic - "Given this statement should we now be observing global mean sea level ~1.6 metres above the pre-industrial?"
AINE, but no, not yet. "Next few centuries" is a somewhat vague term, and the bulk of our CO2 excess and temperature increase are both relatively recent (another vague term). For example, from two charts that Google found for me, in 1900 our world total yearly emissions were about 2Gt CO2-equivalent, 4Gt in 1930, 8Gt in 1960, and 16Gt in 1975 (this is eyeball addition of developing and developed). 25Gt in 2000, and 32Gt in 2010. So, roughly, doubling every 30 years, but with a special bonus kick from 1960-1975.
Charts:
Developed and developing CO2e
World wide CO2Also worth noting is that the thermal mass of the oceans is incomprehensibly large. After a discussion on Slashdot I went and did the math carefully -- if the ice caps could all be dumped into the ocean and melted (but not raised to room temperature) it would cool them by only 2 degrees C. And I really do mean "incomprehensible" -- my gut gives no guidance for those quantities, I really do need to just follow the math. I think that is one thing that helps climate-skepticism to persist -- my gut, and probably most other people's, simply says "no way, that can't be right." But simple physics and arithmetic says it is.
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Tom Curtis at 00:08 AM on 7 August 2013John Christy on High Temperature Records in the US
KR @5 (and others), Christy labels his graph as a graph of standing records as at Dec 31, 2012. Thus any record formed earlier in the period, but superceded, will not appear on the graph. That is, it is a graph of standing records, not of running records. The main article discusses the difference quite clearly. Importantly, for standing records, given no trend in the data, the probability of a record is the same in each year, no matter how close to the beginning or end of the record.
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Tom Curtis at 00:03 AM on 7 August 2013John Christy on High Temperature Records in the US
Christy has short changed us on relevevant information for this graph.
To begin with, he does not tell us how many stations were operational in each year.
The total record is 128 years long, but the records are only >80 years in length. That means that for some years, at least, not all stations used recorded data in that year. Straightforwardly, in each year, for each day, there can only be as many records as there are stations collecting data on those days. So, assume all records are 81 years long. In that case, the probability of a new record on any given day for each station is 1 in 81 (and a quarter that for February 29th); and the expected number of records given no trend is just the number of stations recording on that day times the probability of a record on that day. If you have twice as many stations recording on one day as on another, you would expect twice as many records on the former day compared to the later.
As it happens, we know the records are at least 81 years long, so therefore no record starts later than 1931, and no record ends earlier than 1975. Thus during the period 1931-1975, there are 974 records for each day (ignoring missing data). In contrast, prior to 1931 and after 1975 there may be fewer records, potentially much fewer records. To make a meaningful comparison across the years we need to know the number of stations active in each year; or better yet, Christy should have normalized the plot by the number of stations active in each year.
Secondly, Christy does not tell us the duration of operation of each station.
The probability of a record for each date on any give day is 1/(station record duration in years). Thus, if one station is in operation for the full 128 years, it only has a probability of 1/128 of a record on any given day, or only 63% of the probability of a daily record . Therefore in periods in which the majority of records are of greater length, the probability of an new daily record is deflated compared to periods in which they are of shorter length.
Thirdly, Christy does not tell us whether he is using adjusted or unadjusted data.
In the early part of the record, Stevenson screens were haphazardly deployed. A multitude of other factors also effect the record. The consequence is that if Christy is using the unadjusted data, he is inflating the early record due to contaminating factors.
Fourthly, Christy does not tell us the geographical distribution of the stations.
The stations of the USHCN are more thickly concentrated in the north east of the Contigous United States (CONUS) then elsewhere, and less thickly concentrated in the south west, particularly the wouth west excluding California. The result is that, with two years of equal mean warmth over the CONUS, with one being hotter in the north east and the other in the south west, the former will show more record high temperatures.
Finally, Christy does not tell us which version of the USHCN he is using.
Without that data, it will be difficult to reproduce his graph, and ensure that the 974 stations include all stations with greater than 80 years of duration.
Klaus Flemløse: Very good remarks. The John Christy statistics must be verified. I have added a remark in this respect to the blog. Do you have a better formulation than mine. ?
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John Christy on High Temperature Records in the US
Indeed, Christy is presenting rather deceptive un-normalized data. The longer the record for any particular station, the fewer records will be seen, with a probability of 1/n where 'n' is the number of observations - and that is the reason why the record highs he presents seem to indicate no rise in temperatures.
A far more useful statistic is the ratio of highs to lows, as discussed in Meehl 2009 (see a SkS article on the paper here); the ratio cancels out the number of observations, normalizing for the length of observation, and leaves behind trends in record observations.
[Source]
Once again, this demonstrates how selecting an accurate yet out of context subset of data (cherry-picking) can present misinterpretations of reality.
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Alexandre at 22:44 PM on 6 August 2013John Christy on High Temperature Records in the US
Of course: number of records is very different from a temperature time series, but it sounds a lot like the same to the layman.
Early in the record you'll probably have a lot of record breaking. I'm sure no Olympics had as many Olympic records as Athens 1896...
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Jos Gibbons at 22:37 PM on 6 August 2013John Christy on High Temperature Records in the US
It’d be good to see a bar chart similar to Christie’s in which each of his bars’ height is divided by the number of years up to and including the year that bar occurs in, so the years can be fairly compared, and one would presumably see an obvious warming trend even by eye. Could anyone here post either such an image or tabulated data that could be used to build one?
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Buddy at 22:21 PM on 6 August 2013John Christy on High Temperature Records in the US
Isn't a more "accurate" measure of "land surface" climate change, the use of the RATIO of "new daily record highs" to "new daily record lows"? With the passing of time, the probability of new record highs AND new record lows.....drops. But in a warming climate, the RATIO will be > 1.0 over the longer term (decades and centurys).
The graphs linked below, show three time frames of the ratio of New Daily Record Highs....to New Daily Record Lows. The first link shows the ratio on a DECADAL time frame, and the second graph shows the ratio on a YEARLY time frame....and the third link shows the ratio on a MONTHLY time frame (for the previous 13 months).
DECADAL: http://climatechangegraphs.blogspot.com/2012/08/ratio-of-new-record-high-temps-to-new_30.html#!/2012/08/ratio-of-new-record-high-temps-to-new_30.html
YEARLY: http://climatechangegraphs.blogspot.com/2012/08/ratio-of-new-daily-record-high-temps-to.html#!/2012/08/ratio-of-new-daily-record-high-temps-to.html
MONTHLY (last 13 months): http://climatechangegraphs.blogspot.com/2012/08/ratio-of-new-record-high-temps-to-new.html
Not surprisingly.....there is "variability", and the shorter the time frame, the more the variability. However, on an annual basis or a decadal basis.....the upward trend is clear.
Klaus Flemløse: I have linked to this graphs in the last part of the blog post !
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bouke at 17:59 PM on 6 August 2013John Christy on High Temperature Records in the US
What do you mean by "The expected number of records for the current year is calculated by definition"?
KFL:I will change the this to "is calculated by 1/n"
What is a "balance year"?
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Andy Skuce at 11:48 AM on 6 August 2013Toward Improved Discussions of Methane & Climate
None of the references in the Guardian article point to observations of shallow gas hydrates on the ESAS. There are shallow gas hydrates (around 60 metres depth) reported in Yamal, some 2000 km away, but those are (according to the author) relict hydrates thought to have been formed when that area was overlaid by an icesheet (or a marine transgression) and have been preserved in a metastable form after disappearence of the icesheet (or regression of the sea). As far as I know, nobody has proposed those kinds of events in this part of eastern Siberia. On the contrary, the local sea level on the ESAS has risen since the last glacial maximum, submerging the permafrost that formed when the shelf was exposed land.
All of the references cited show that hydrates form below 200 metres depth in areas of permafrost. The Shakhova et al 2010 paper does not present any geophysical or sampling evidence for hydrates above 200m on the ESAS. Permafrost, yes, gas leaks yes, but not shallow hydrates.
There's little doubt that a warming climate will provide huge carbon cycle feedbacks in the Arctic, from both carbon dioxide and methane. MacDougall, Avis and Weaver have showed that, by the end of the century, feedbacks from thawing land permafrost will increase temperatures by 0.25 to 1.0 degree Celsius from carbon dioxide emissions alone. That's 174 billion tonnes of carbon emissions over the next several decades in their median case. For me, that's more worrying than conjectural methane eruptions from the ESAS. Having said that, I will be following the future research results there with interest and anxiety.
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johnroberthunter at 10:37 AM on 6 August 2013How much will sea levels rise in the 21st Century?
Two points:
(1)
"A draft version of the next report from the IPCC (AR5), due for publication in 2014, was recently leaked. Although the information is subject to change, the draft report says sea levels are likely to rise by between 29 and 82 centimeters by the end of the century, (compared to 18-59 centimeters in the 2007 report)."
- this is comparing apples with oranges. There are at least three differences in the ways in which each of these projections were derived: (a) the "18-59 centimetres" quoted for the 2007 report does not include an adjustment of 0-0.17 m for "scaled-up ice sheet discharge" which accounts for dynamic land-ice processes not otherwise simulated by the glaciological models, (b) the periods are different (roughly 1990-2095 for the 2007 projections and 1995-2090 for the AR5) and the "emission scenarios" are different (as indicated in the article; the highest "scenarios" being A1FI for the 2007 projections and RCP8.5 for the AR5). All these differences need to be taken into account before a meaningful comparison can be made.(2) The "in the pipeline" effect is predominantly due to the fact that a substantial proportion of the greenhouse gases that we emit stay in the atmosphere for a very long time (millennia). So it's as if we've turned up the heating to our house and left it on "high" - the house (and the Earth) takes a long time to come into equilibrium with this enhanced level of heating (e.g. the oceans have to warm and land-ice melts).
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