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Comments 43051 to 43100:

  1. How 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.

  2. How 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.

    .

  3. Understanding 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

  4. How 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.

  5. Ocean 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.

  6. Ocean 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.  

     

     

  7. Ocean 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.

  8. Leland Palmer at 05:52 AM on 9 August 2013
    Toward 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.

    High-resolution carbon isotope record for the Paleocene-Eocene thermal maximum from the Nanyang Basin, Central China

    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).

  9. There 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.

  10. How 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.

  11. Fox 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.   

  12. Ocean 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

  13. Ocean 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. 

  14. 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. 

  15. Joel_Huberman at 01:49 AM on 9 August 2013
    Ocean 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!

  16. citizenschallenge at 01:38 AM on 9 August 2013
    Fox 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

  17. Skeptical 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.

  18. Ocean 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).

  19. Fox 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.

  20. How 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.

  21. Fox News found to be a major driving force behind global warming denial

    Non-liberal, I meant. 

  22. Fox 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.  

  23. Fox 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

  24. It'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?

  25. Fox 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.

     

  26. It'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.

  27. It'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

  28. 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. 

  29. 2013 SkS Weekly News Roundup #32A

    wow, what a collection of articles, quite a week!

  30. How 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.

  31. Toward 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.

  32. 2013 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

  33. How 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?

  34. How 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).

  35. Ocean Acidification: Eating Away at Life in the Southern Ocean

    Thanks Bill. Typo fixed. 

  36. Ocean Acidification: Eating Away at Life in the Southern Ocean

    Thanks, Rob.  This will help me represent the situation more accurately.

  37. How 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.

  38. Ocean 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

  39. How 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.

  40. How 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.

  41. Leland Palmer at 02:01 AM on 8 August 2013
    Toward Improved Discussions of Methane & Climate

    Whoops, make that C13 depleted carbon (C12 enriched), in the last paragraph above.

  42. Leland Palmer at 01:54 AM on 8 August 2013
    Toward 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.

  43. How 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.

  44. Leland Palmer at 00:10 AM on 8 August 2013
    Toward 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?

  45. Where 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.

  46. Toward 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.

  47. How 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.

  48. How much will sea levels rise in the 21st Century?

    Thank you jja @ 16 - that explains everthing!

  49. How 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?

  50. How 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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