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Unforced variations: May 2014

Filed under: — group @ 2 May 2014

This month’s open thread. In order to give everyone a break, no discussion of mitigation options this month – that has been done to death in previous threads. Anything related to climate science is totally fine: Carbon dioxide levels maybe, or TED talks perhaps…


394 Responses to “Unforced variations: May 2014”

  1. 1
    wili says:

    OK, I’ll bite. April was not only the first month above 400 ppm atmospheric CO2 (Mauna Loa), it averaged above 401. In El Nino years, we expect higher levels, since the warmer ocean surface won’t absorb as much CO2.

    So, assuming this El Nino doesn’t fizzle out, how high will we get this year, and how long will we stay above 400? (Can we start a poll or a gentlemen’s and ladies’ wager?)

  2. 2
    John Mashey says:

    Bill Ruddiman’s AGU 2014 Tyndall lecture is finally available online. (H/T Malcolm Hughes).

    I recommend this, and even more get his recent book, Earth Transformed(2013).

    Research by Bill and other scientists has come a long way since Plows, Plagues and Petroleum(2005). I think the Holocene makes much more sense, and the evidence is pretty good that:
    a) For 8,000(5,000) years, human changes to CO2 (CH4) had slowed the normal interglacial cooling, well before the Industrial Revolution started.

    b) For the last 2,000 years, there have been enough people that plagues and wars have been able to cause century-scale CO2 jiggles, where drops have resulted from pandemics and reforestration. The clearest is the unique drop into 1600AD (massive pandemic in Americas), but the smaller drop from pandemics around time of Roman Empire’s decline are also visible.

    Some even quicker (multi-decadal) CH4 jiggles seem human-influenced as well, as per Mitchell, et al(2011):
    “Times of war and plague when large population losses could have reduced anthropogenic emissions are coincident with short periods of decreasing global methane concentrations.”

    Specifically, sometimes invasions of China deliberately destroyed rice paddies and canals.

    SO:
    a) ~1,000
    ~8,000bp to ~2,000bp: millennial effects from adding CO2 and CH4, deforestation.

    b) ~10-100
    2,000bp to start of Industrial Revolution:
    enough humans to cause century scale and even multi-decadal jiggles in CO2/CH4.

    c) ~1-10
    Industrial Revolution onward: by now, CO2/CH4 effects visible on year-to-decade scale.

    Bottom line: This has some implications for attribution of variability on some time-scales, since some of the jiggles appear to have included human contributions, not just natural.”climate changes naturally” is true, but the Earth’s climate has not been entirely natural for ~8,000 years.

  3. 3
    John Mashey says:

    Bottom line: This has some implications for attribution of variability on some time-scales, since some of the jiggles appear to have included human contributions, not just natural.”climate changes naturally” is true, but the Earth’s climate has not been entirely natural for ~8,000 years.

  4. 4
    Russell says:

    The latest alternative climate change theory puts a whole new spin on ‘state of the art. ‘

  5. 5
    Hank Roberts says:

    Probable causes of the abnormal ridge accompanying the 2013-14 California drought: ENSO precursor and anthropogenic warming footprint
    S.-Y. Simon Wang et al.

    DOI: 10.1002/2014GL059748

    The 2013-14 California drought was accompanied by an anomalous high-amplitude ridge system. The anomalous ridge was investigated using reanalysis data and the Community Earth System Model (CESM). It was found that the ridge emerged from continual sources of Rossby wave energy in the western North Pacific starting in late summer, and subsequently intensified into winter. The ridge generated a surge of wave energy downwind and deepened further the trough over the northeast U.S., forming a dipole. The dipole and associated circulation pattern is not linked directly with either ENSO or Pacific Decadal Oscillation; instead it is correlated with a type of ENSO precursor. The connection between the dipole and ENSO precursor has become stronger since the 1970s, and this is attributed to increased GHG loading as simulated by the CESM. Therefore, there is a traceable anthropogenic warming footprint in the enormous intensity of the anomalous ridge during winter 2013-14, the associated drought and its intensity.

  6. 6
    wili says:

    Gavin is quoted extensively in a recent post at ClimateCentral on a new study about terrestrial sources of Arctic methane: “Arctic Methane Emissions ‘Certain to Trigger Warming’”
    http://www.climatecentral.org/news/arctic-methane-emissions-certain-to-trigger-warming-17374

    Here’s the link to the abstract of the actual study:
    http://onlinelibrary.wiley.com/doi/10.1111/gcb.12580/abstract

    “A synthesis of methane emissions from 71 northern, temperate, and subtropical wetlands” Merritt R. Turetsky and 16 others (!). In Global Climate Change Biology.
    Perhaps Gavin could write up a lead post on this interesting study for discussion here?? ‘-)

  7. 7
    robert says:

    Outstanding TED talk, Gavin. You’ve made an important and compelling point, very succinctly: The models have skill.

    One point: “Each additional order of magnitude in space means 10,000 more calculations…” ? I would’ve thought 1,000 more calculations (10^3)…

    [Response: Timestep also needs to decrease – so that’s 4 dimensions, not three. – gavin]

  8. 8
    Mal Adapted says:

    John Mashey: “Earth’s climate has not been entirely natural for ~8,000 years.”

    Strong support for naming the Anthropocene Epoch.

  9. 9
    sidd says:

    We see Zachariae breakup faster than Nioghalvfjerdsfjorden. The reason may be a submarine trough leading under the former, allowing warmer Atlantic Intermediate water to reach the ice base. Zachariae also has a deeper caviity under it that extends over a larger area.

    Read all about it

    http://membrane.com/sidd/greenland-2013/Zachtrough/

    sidd

  10. 10
    Shelama says:

    I’m hoping that either RealClimate or Tamino will do a post on Lovejoys’s
    “Scaling fluctuation analysis and statistical hypothesis testing of anthropogenic warming”

    Is such a thing in the works or possible?

  11. 11
    Chris Dudley says:

    I’m wondering how far BAU can go in terms of emissions. Do we have the resources to do three doublings all on our own? Four doublings? Five?

    I’m not talking about feedbacks, but just fossil carbon pools that could be resources with the right kinds of incentives. For example, in addition to tar sands in Canada, there is oil shale in Utah. Thin coal seams might be gasifies in situ as well. All of those things return energy. Currently, some cement plants are using their carbon dioxide to grow algae to make biofuels. Would we ever do calcination just to get carbon dioxide to make fuels? Would such a thing end up being carbon neutral owing to the quicklime attracting carbon dioxide from the atmosphere? We might expect abundant sources of hydrogen under some generation schemes. Would that be used to upgrade deep fossil carbon deposits such as oil source rock or tight-gas shale? Is there potentially five or ten times more oil and gas to be had than we have thus far considered?

    Just how monstrously large could that camel be whose Keystone XL nose is sniffing around the edges of the tent?

  12. 12
    Pete Dunkelberg says:

    Breaking! The IPCC is confusing people.
    http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2194.html

  13. 13
  14. 14
    wili says:

    CD@#11: The first bar graph at this site is more inclusive (and it has a shorter url!):
    http://burycoal.com/blog/why-bury-coal/

    There is a heck of a lot of proven reserves of coal in the ground, and if methane hydrates can be effectively extracted, that would represent an enormous additional source. Even if you figure that we have to quadruple emissions to double atmospheric levels, many doublings seem possible.

  15. 15
    Susan Anderson says:

    Useful TED talk, and glad to find the transcript here:
    https://www.ted.com/talks/gavin_schmidt_the_emergent_patterns_of_climate_change/transcript#t-69887

    for fairly deaf nonagenarian who might be interested in the note about reductionism. And even I could understand it! Great job.

  16. 16
  17. 17
    Random says:

    So I hope it’s totally fine that I keep on nagging about the model-data comparisons. I wonder what has happened to them. Have they been abandoned? Or is an overhaul in the works to incorporate Kosaka & Xie? Anyway – I miss them.

  18. 18
  19. 19
    Ryan R. (u14086078) says:

    Hello,

    As an undergraduate student (majoring, not in climate science, but in biological sciences), the debate concerning the causation (and its implication) of rising carbon dioxide levels has always interested me.

    Upon viewing the graph (in the ‘Carbon Dioxide Levels Climb…’ article) plotting the atmospheric CO2 concentration against time, one thought that occurred to me was the controversial notion that global warming, due to atmospheric insulation, is merely the outcome of a naturally occurring cycle, rather than solely mankind’s fault. The fact that we have reached the greatest peak in CO2 concentration in the atmosphere strongly points at a largely unnatural cause in our day and age.

    A question, from a mind unlearned in green technology and climate science: is there no chemical or technological means to reverse the increase in concentration of atmospheric CO2? Limiting the increase is one thing – reversing it is another. Yet, I understand there are almost insurmountable problems with this thinking.

    Yet, with whatever technological means the future makes available, perhaps such a line of thinking is not totally absurd.

    The problem I personally foresee with such a course of action, I suppose, is that any chemical reaction converting CO2 en masse would ultimately produce products that would be no better than CO2 itself. (For example: enormous financial costs aside, hydrogenating CO2 to formic acid (H2CO2) would be unreasonable and unfeasible, let alone destructive.)

  20. 20
    Stan K says:

    I come up against denialists in nontechnical forums, recently one with a Ph.D. in meteorology against my masters in optical engineering. He may be a paid gunman as I know such propaganda and misinformation organizations exist. Does any such organization exist for the people who recognize the problem and want to take action? Wars cannot be won unless all the small skirmishes are statistically won and sometimes whole battles can be lost or won based on one small skirmish. There are websites of various levels of technical competence that I can go to. But I think what is needed is an army of people of various levels of technical competence trained for argument and the enemy’s psychological techniques. When one of the fighters needs help, he could call in an “air strike” from those with more expertise, like most posters here. Just a thought. This IS a war.

  21. 21
    Hank Roberts says:

    “Ryan R” — have you tried the Start Here button at the top of the page?
    Care to post a link to your college’s biology department page? Some courses there will help on biogeochemical cycling and rates of ecological change.

    “Stan K” — one guy’s opinion: “nontechnical forums” are loaded with third hand copypasting. Test it — copy text from the assertion into a web search box. Do it again days later; see how much it’s spread. Most of that stuff is being rebunked. It’s been debunked; find it in the Skepticalscience lists.

    A copypaster, even those that aren’t automated bots, is there to distract you. Chasing third hand rebunking of old claims tires you out and annoys the audience. New thinking won’t appear in “nontechnical forums” — test what you read, search for its reuse, before being suckered into replying.

  22. 22

    #20-1–

    And perhaps too obvious–don’t be intimidated by claimed credentials. Some of these cats are not above lying about that, too.

  23. 23
    Killian says:

    2 John Mashey says Bill Ruddiman’s AGU 2014 Tyndall lecture is finally available online. (H/T Malcolm Hughes).

    I recommend this, and even more get his recent book, Earth Transformed(2013).

    Research by Bill and other scientists has come a long way since Plows, Plagues and Petroleum(2005). I think the Holocene makes much more sense, and the evidence is pretty good that:
    a) For 8,000(5,000) years, human changes to CO2 (CH4) had slowed the normal interglacial cooling, well before the Industrial Revolution started.

    b) For the last 2,000 years, there have been enough people that plagues and wars have been able to cause century-scale CO2 jiggles, where drops have resulted from pandemics and reforestration. The clearest is the unique drop into 1600AD (massive pandemic in Americas), but the smaller drop from pandemics around time of Roman Empire’s decline are also visible.

    Some even quicker (multi-decadal) CH4 jiggles seem human-influenced as well, as per Mitchell, et al(2011)…

    Bottom line: This has some implications for attribution of variability on some time-scales

    And you just laid out exactly why consumption must fall so far in most societies/nations, and why getting below 300ppm is vital. Even an extremely low-carbon 7 billion is likely to keep CO2 rising over time without serious efforts to avoid that.

    On the plus side, I long ago realized how easily we could avoid glacial periods by judicious land use changes and FFs over long time periods. We should be able to literally never see another glacial.

  24. 24
    DIOGENES says:

    METHANE

    Today’s CP discusses a very interesting recent article on Methane emissions. One takeaway: “The permafrost carbon feedback is one of the important and likely consequences of climate change, and it is certain to trigger additional warming … Instead of reducing emissions, we currently are on track with the most dire scenario considered by the IPCC.”

    http://thinkprogress.org/climate/2014/05/02/3433592/methane-wetlands-permafrost/

    Today’s CP methane study also references a 2011 methane study focused on thawing permafrost. Equally interesting in this latter study are the comments; they constitute one of the most interesting comment threads I have seen on any climate advocacy blog. Highly recommended.

    http://thinkprogress.org/romm/2011/02/17/207552/nsidc-thawing-permafrost-will-turn-from-carbon-sink-to-source-in-mid-2020s-releasing-100-billion-tons-of-carbon-by-2100/

  25. 25
    SecularAnimist says:

    Ryan R wrote: “A question, from a mind unlearned in green technology and climate science: is there no chemical or technological means to reverse the increase in concentration of atmospheric CO2?”

    This gets into mitigation, discussions of which our hosts have asked we eschew on this month’s UV thread.

    But the answer is yes — the already dangerous anthropogenic excess of atmospheric CO2 can be drawn down and sequestered in soils and biomass by organic agriculture and reforestation. See the item linked below (previously posted on the April UV thread):

    Reversing Climate Change Achievable by Farming Organically
    Rodale Institute
    April 23, 2014

  26. 26
    Chris Dudley says:

    wili (#14),

    That is a good start. A chart a little farther down is taken from “Storms of my Grandchildren” and has the notation “Emitted CO2 (ppm)” so the immediate uptake into the biosphere and oceans is not accounted for. So, taking about 350 GtC to-date (2006) and about 110 ppm above preindustrial (280 ppm) at that time I get about 900 GtC to get to the first doubling. I get about 2900 GtC in reserves shown in the chart so that comes to about 2.7 doublings available all on our own, without carbon dioxide feedbacks such as permafrost rot. Now the methane hydrate in that chart is a one shot thing. And, depending on processing the oil shale may be as well. Tar sands leave a residue but that can be burned so we are probably getting all the carbon there too. So, in terms of fossil reduced carbon, we’re really looking at source rock for existing oil and gas fields (including tight gas shale) now gas reserves have probably jumped quite a bit since those charts were made. Lets say they doubled. Then we might have about 800 GtC to multiply by some factor for buried carbon we could access through in situ upgrading with hydrogenation fracking. If that factor is 5 then that is an additional 4000 GtC so 6900 all together. That comes to 3.9 doublings. If the factor is 10 (probably appropriate for Marcellus type source rock), then that is 8000 additional GtC so 10,900 GtC all together. That comes to 4.6 doublings.

    With a fast feedback climate sensitivity of 3 C per doubling that comes to 8 C of warming for the bar chart as presented, 11.7 C of warming if we can rend 5 times more carbon from already exploited source rock or 13.8 C of warming if it is ten times more. Hansen’s book indicates that the sensitivity increases at these very high forcings so including slow feedbacks that may be 28 C of warming as a minimum. That is not enough to make the oceans boil, but it does make a lot of the Earth’s surface uninhabitable by mammals.

    So, it would seem that the advent of low cost and functionally unlimited renewable energy which could give us a cheap source of hydrogen for novel exploitation of buried fossil carbon, may grant us enormous new destructive powers. It further seems unlikely that CCS could handle such a glut, we’d run out of places to bury the carbon dioxide. (Sorry for the mitigation reference in this thread.) It may give us almost two more doublings of carbon dioxide concentration. Perhaps the nose of that very large camel should be kept out of the tent.

  27. 27
    Fred Magyar says:

    Stan K,
    ‘Never wrestle with pigs. You both get dirty and the pig likes it.’ George Bernard Shaw

  28. 28
  29. 29
    Colin Johnstone says:

    @ robert (post 7)

    “One point: “Each additional order of magnitude in space means 10,000 more calculations…” ? I would’ve thought 1,000 more calculations (10^3)”

    Just to be a bit more clear, the size of the timestep is limited by the amount of time it takes information to travel across one element of your grid (see CFL condition). If you increase the resolution by a factor of 10 in each direction, then you decrease the size of each element in the your grid by a factor of ten, which means that information takes a factor of ten times less amount of time to travel across an element in your grid, and so your timestep goes down by a factor of ten. You then need to do ten times as many calculations to evolve your system for the same amount of time. Additionally, your grid is a thousand times a large, so this corresponds to ten thousand times as many calcualtions.

    @ gavin

    Great talk! I do not understand what you meant when you said “it’s the whole, or it’s nothing”. It sounded like you were saying that either every physical process must be taken into account, or we could learn nothing from climate models. This is clearly not true, and I am sure you didn’t mean that, so I am interested to know what you did mean.

  30. 30
    Thomas says:

    Colin:
    CFL limit applies to explicit methods, implicit methods can use large time steps, but at the often large cost of solving systems of equations.
    I don’t think the horizontal and vertical dimensions are equivalent either, they could be increased by different factors. If horizontal variation is covered by spectral methods, then things will scale differently as well.

  31. 31
    DIOGENES says:

    HEALTH ASPECTS OF CLIMATE CHANGE

    I inadvertently stumbled across this article while searching for something else. Addresses health aspects of climate change.

    Am J Respir Crit Care Med. 2014 Mar 1;189(5):512-9. doi: 10.1164/rccm.201310-1924PP.
    Climate change. A global threat to cardiopulmonary health.
    Rice MB1, Thurston GD, Balmes JR, Pinkerton KE.

    Recent changes in the global climate system have resulted in excess mortality and morbidity, particularly among susceptible individuals with preexisting cardiopulmonary disease. These weather patterns are projected to continue and intensify as a result of rising CO2 levels, according to the most recent projections by climate scientists. In this Pulmonary Perspective, motivated by the American Thoracic Society Committees on Environmental Health Policy and International Health, we review the global human health consequences of projected changes in climate for which there is a high level of confidence and scientific evidence of health effects, with a focus on cardiopulmonary health. We discuss how many of the climate-related health effects will disproportionally affect people from economically disadvantaged parts of the world, who contribute relatively little to CO2 emissions. Last, we discuss the financial implications of climate change solutions from a public health perspective and argue for a harmonized approach to clean air and climate change policies.

  32. 32
    Chris Dudley says:

    Hank (#16),

    I’m not quite sure what you are getting at. If the accessible fossil carbon pool is much larger than usually assumed, then carbon feedbacks may not be all that significant in terms of warming. In the factor of ten scenario in #26, probably most of the soil carbon would be oxidized, but at only 2000 GtC that only results in 0.24 more doublings and 0.72 C additional warming when placed on top of a huge anthropogenic warming.

    Gavin may be able to say if the upturn in response in the right hand sector of fig. 30 of “Storms of my Grandchildren” is owing to not recognizing the limit on biosphere carbon available for feedbacks or not since he ran some of the models.

  33. 33
    Colin Johnstone says:

    Thomas, you are right of course. Gavin didn’t state clearly exactly what type of numerical scheme he was talking about, so maybe my assumption was wrong. I guess it was just a quick statement about how computation time increases with resolution, and not to be taken too seriously.

  34. 34
    Buck Smith says:

    Ground truth is forcing due to CO2 plus feedbacks is less than the forcing which repeatedly drives the earth into ice ages from periods of warmer temperatures and high CO2

    [Response: Sure. But how is that comforting or relevant in any way? Those were huge changes too. – gavin]

  35. 35
    Thomas says:

    Colin, To be fair, I think Gavin is quite familiar with the algorithms and the scaling laws of them. What is tougher to determine is how things will scale with modern highly parallel computing, where both memory and computational capability are distributed. Off-chip communications tends to become more important than floating point operations. And off-chip data access can be affected by the combination of better data partitioning and larger on-chip data caches.

    [Response: Chip design/multiple cores etc. are a big reason why computing power is increasing – it’s not just about the speed of single processors. The increases in scale I discussed are not as simple as the heuristic I discussed but that is a pretty code rule of thumb. Other issues are that at higher resolution we are moving to different grids (Cartesian –> Cubed sphere or icosahedral) but we are also adding more tracers (chemistry/aerosols) that have changed the balance between column physics and advection in how long it takes to run a model. The other heuristic that is worth mentioning is that real clock time for climate models has been static for decades (at around 3-5 years per day). – gavin]

  36. 36
    gavin says:

    [Response: On another topic, another triumph for scientific prediction: no contrarian blogs mentioned the Nenana ice classic this year.]

  37. 37
    Killian says:

    34 Buck Smith says Ground truth is forcing due to CO2 plus feedbacks is less than the forcing which repeatedly drives the earth into ice ages from periods of warmer temperatures and high CO2

    [Response: Sure. But how is that comforting or relevant in any way? Those were huge changes too. – gavin]

    Don’t see how this can be true except at some threshold of CO2 + feedbacks, so I assume you meant present levels?

  38. 38
    Tony says:

    Colin,

    I took Gavin’s phrase, “it’s the whole, or it’s nothing”, in the context of what he was saying, that it’s impossible to learn anything much from looking at one small piece of the system (either in locality or factors) since there are so many other areas and factors that impact that small piece. This is true no matter how large the piece is.

  39. 39
    mgardner says:

    #31 Diogenes

    Along those lines:

    http://www.nytimes.com/reuters/2014/05/05/world/asia/05reuters-india-migrants.html?hp

    “India deployed troops in Assam on Saturday after more than 30 Muslims were gunned down in three days of what police said were attacks by Bodo tribal militants, who resent the presence of settlers they claim are illegal immigrants from Bangladesh.

    Modi has repeatedly called for tighter border controls and last week said illegal immigrants from Bangladesh living in the state of West Bengal should have their “bags packed” in case he came to power.”

    No scientific study, no dry academic language. Just a picture of the convolution of the climate system with the human ecosystem– imagine what it will be like after a few decades of rising sea level?

    So Diogenes– what’s that global cooperative mitigation/adaptation plan of yours again?

  40. 40
    Hank Roberts says:

    > If the accessible fossil carbon pool is much larger

    The increasing ease of access to fossil carbon _is_ largely a feedback.
    Most of the increasingly accessible fossil carbon was under Arctic ice or permanently frozen — until we messed things up. Now it’s becoming more easily accessible. Our own actions are part of the feedback from burning carbon.

  41. 41
  42. 42
    Salamano says:

    @36. Gavin…

    Couldn’t the same be said that “RC didn’t mention the DC Cherry Blossom Bloom Date” … “this year”..?

    I guess conceivably contrarians and mainliners will be jumping to one or the other of these depending on when it suits what they want to call attention to. Or, do you conceive of a time where the Nenana Ice Classic will show a very late start date and it NOT be labeled natural variability? [Or, the Cherry Blossoms blooming way early and it NOT be labeled climate change..?]

    [Response: There isn’t a symmetry here. There are dozens of posts here that discuss the necessity of placing events in context as opposed to using them in and of themselves to ‘prove’ something. If we had only had posts on cherry blossoms in years when they were early, you might have a point, but I don’t recall any such posts. By contrast, WUWT had ~half a dozen(?) posts on Benana last year. Context is all and cherry picking of single events is mostly misleading when ever it is done. – gavin]

  43. 43
    Radge Havers says:

    @~39
    Just a request. Let’s not open the floor to further chaotic and degenerative verbal gyrations on The One True Holy of Holies…

  44. 44
    DP says:

    Previously we mentioned sulphate aerosol pollution and wondered what would happen if China got serious about air pollution control. According to a recent news item they are now planning to do so. Consequences for the Earth’s climate?

  45. 45
  46. 46
    Hank Roberts says:

    > if China got serious about air pollution control.

    You can find some answers to your question using
    ‘oogle: china sulfate “climate model”

  47. 47
    Chris Dudley says:

    Hank (#41),

    Nope. I’m thinking of something different. Worse living through chemistry: use renewable energy to split water, then pump the hydrogen into petroleum source rock to sop up the type IV kerogen which has too low a hydrogen content to form liquids or gas otherwise. Then bring the resultant hydrocarbons up to use as fuel. That would give access to carbon that we would not bother with if we did not have a source of low cost energy to throw at it. Low cost renewable energy almost makes it inevitable that immature source rock like the the Green River Formation will be heat processed to get oil. But as renewable energy becomes even cheaper, even more irresponsible schemes may be put in place. This sort of thing has already been proposed for coal-to-liquid and biomassto-liquid. http://www.pnas.org/content/104/12/4828.full What is novel here is to use the heat and pressure at the depths of oil source rock to run the reaction. I guess you might call it a hybrid renewable hydrogen-geothermal-fossil carbon way to make things much much worse than we’ve yet imagined at a profit.

    If you want to call it a feedback, it would be a Buckminster Fuller feedback where our time spent with fossil fuels has given us the technological wherewithal to move to renewables in a world shaking manner. Misapplication of those new powers could have much more deadly consequences than what got us here so far.

    The whole concept that peak oil would help with the m-word is mistaken. We haven’t even begun to produce oil from fossil carbon unless we control emissions by choice and leave those profitable but deadly schemes alone. Tar sands, oil shale, and now in situ hydrogenation must be stopped.

  48. 48
    sidd says:

    Prof. Schmidt writes:
    “at higher resolution we are moving to different grids (Cartesian –> Cubed sphere or icosahedral”

    I see adaptive grids in ice sheet models these days, and some ocean or atmosphere models using them. Are the approaches still predominantly Eulerian in nature, or have there been serious efforts in the Lagrangian direction ? I do see some comoving approaches in some icesheet work.

    sidd

  49. 49
    Thomas says:

    Gavin. Adding more local physics improves the ratio of local work to communications. Note also that each generation of chip increases the vector (SSE) performance, so that potential ops per clock per core is going up dramatically, even as clock rates stagnate. Ensuring that the most intensive parts of your code vectorize should be given a high priority.

  50. 50
    Dan H. says:

    Kevin,
    Another interesting natural observation of the recent warming. The average peak date over the past decade is April 2, ranging from an earliest of March 20 (2012) to the latest on April 10 (2014). During the 1960s, the average date was April 7, ranging from March 29 to April 15. So, the increase has been 5 days over the past 50 years. However, if we go back further, the average peak date during the 1920s was April 3, with an earliest date of March 19 (1921 & 1927) and a latest of April 13 (1924), similar to recent years. The Washington Post predictions of much earlier peak dates may be premature.


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