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Unforced Variations: May 2015

Filed under: — group @ 11 May 2015

This month’s open thread.

164 Responses to “Unforced Variations: May 2015”

  1. 51
    Killian says:

    47 Chris Machens said, Will a 2015 Arctic sea ice melt season during an El Nino year shatter previous records?

    This possibility occurred to me some time back so I checked EN vs record melts. EL seems to correlate pretty strongly to big melts with a 1-2 year lag. There were EN’s before 98, 05, 07, 10, 12. (I seem to recall one of those might have not had one.)

    I think we’ll will likely see both 2013 and 2014 beaten this summer if export continues out the Fram Strait like it has been this spring, but not a new low because of some thickness built up the last two winters.

    Next year, if the pattern holds, could be a very bad year for ASI.

  2. 52
    Killian says:

    Just double-checked. The chart I found real quickly had El Nino’s in winters ’97-’98, ’04-’05, ’06-’07, ’09-’10. The chart didn’t include ’12, but I’m betting there was one then, too. There was also an El Nino ’02-’03 and either a slight new low or near new low in summer 2003, so at least from 98 to present the effect seems robust.

    This makes sense to me given the flow from the Pacific through the Arctic.

  3. 53
    MA Rodger says:

    Tony Wendle @43.
    You are right in that it was not obvious where Scribbler was pointing you. But then, from my perspective I was saying that with the numbers he was quoting, he had to be (ie obviously) pointing at LOTI.
    Saying that, LOTI has since revised it initial numbers.
    Original .. 2015 76 80 85 75
    As updated 2015 75 80 84 71

  4. 54
    Mike Roddy says:

    Thanks to Susan and Kevin for filling in those details on timber harvesting. I was also not convinced that deforestation was decreasing significantly. This leaves the question of whether IPCC has put enough effort into determining land use carbon impacts with the rigor and detail that are required. My understanding from my last round of research was that IPCC relies on country reports, which are often skewed for internal political reasons. This pattern might be getting worse, especially in North American, which overestimates the sequestration of tree farms. Slowing deforestation is an important mitigation alternative, and better data is urgently needed.
    Sorry to be slow to respond to your prompt responses- busy lately.

  5. 55
    Mike Roddy says:

    Thanks to Kevin and Susan for the data clarifications, especially in noting increased logging in Africa and Russia. I’m not surprised that some areas are increasing logging rather than getting it under control. That leaves the question of why IPCC seems to underestimate logging’s carbon consequences even more in the new IPCC V.

    In my last round of research, I learned that IPCC relied on country reports, including allowing them to choose the methodology. This led me to believe that the US and Canada severely underestimate land use emissions, due to resource industry influence. For example, the US is responsible for roughly 24% of global timber production and consumption. Claiming a 420 MT CO2 burden in this context cannot be correct. Conifer regrowth of clearcuts is slow in northern forests, and the literature shows the emissions effects of industrial logging persist for centuries. Only 15-20% of the carbon is retained in wood products, while the rest goes into the atmosphere. Forest fire emissions are the opposite- 85% of the carbon remains sequestered.

    Some Realclimate principals are IPCC authors and contributors. Have you thought about working to correct these apparent data inaccuracies?

  6. 56
    Robert says:

    @47 (Chris Machens) — 1998 was a strong el nino year, but Arctic sea ice extent did not set a record that year. Prior to 1998, the record appears to be 1995. The next record low was 1999, followed by 2002, 2005, 2007 and 2012 (the current record summer low). The trend in Arctic sea ice extent in 2015 seems to be following closely the trend in 2006 at this point. Source: http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

  7. 57
    Matt McIrvin says:

    An article about the probable unachievability of 2C.

    The author speculates about why scientists don’t want to say this. I think it’s pretty simple: climate has been sold as a binary “tipping point” phenomenon with a threshold at 2C, and if people hear we can’t make 2C, they’ll think we should give up and just emit as much carbon as possible since it’s hopeless and the world is ending anyway. It’s concentration on a single number coming back to bite us.

  8. 58
    Icarus62 says:

    I’d just like to thank Mike for his inline response to my comment in the April thread. That does indeed clarify matters – I had missed the point about it referring to Northern Hemisphere temperature (which is rising faster than global mean temperature), and that we have already seen over 1°C of NH warming since the pre-industrial. The explanation is much appreciated.

  9. 59
  10. 60
    wili says:

    “An article about the probable unachievability of 2C.

    The author speculates about why scientists don’t want to say this. I think it’s pretty simple: climate has been sold as a binary “tipping point” phenomenon with a threshold at 2C, and if people hear we can’t make 2C, they’ll think we should give up and just emit as much carbon as possible since it’s hopeless and the world is ending anyway. It’s concentration on a single number coming back to bite us.”

    It’s really beyond belief that we have done so little to curb our ff habits. It’s as if some one had a habit of lying on a particularly comfy couch, but far above it were dangling darts and daggers of various sizes. The lounger has been warned that the threads holding these soon-to-be missiles are about to break, but he is just too lazy and stupid to get off his tuckus. Finally some thread start to break and is told that even if he starts to move now, some of the darts are going to hit him. And this is seen as a reason to not get up because it’s too late anyway!

    I’m sure there are better analogies, but the whole picture is just utterly and terrifyingly stupid and tragic.

  11. 61

    Re tipping points

    In 2013, a study noted that there is an ongoing debate if Arctic sea ice has already passed a “tipping point”, or if it is likely in the future. They pointed out, “Several recent studies argue that the loss of summer sea ice does not involve an irreversible bifurcation, because it is highly reversible in models”. The study identified in 2007 abrupt transition in seasonal variability which persisted since then, and made a distinction between bifurcation and non-bifurcation `tipping point’. http://arxiv.org/abs/1204.5445

    Tipping points are not necessarily irreversible. However, they might push the system into a situation when other teleconnections become more apparent (sub system trigger), and ice sheet mass balance lose, or permafrost melt come with irreversible changes, at least on a timescales relevant for humans.

  12. 62
    Hank Roberts says:

    > climate has been sold as a … threshold at 2C

    Who’d buy nonsense like that?

    2C is a best guess from the paleo record about rates of changes that didn’t wipe out most of life on Earth in the past.

    Doesn’t mean going right up to the edge of that is either safe or catastrophic. Because there’s no edge there. Increasing uncertainty, rather. No civilization we know about survived rapid environmental changes.

  13. 63
  14. 64
    Hank Roberts says:

    This may be useful for informing us about shifting baselines:
    http://grail.cs.washington.edu/projects/timelapse/

  15. 65
    Mike Roddy says:

    There is another problem with the 2C limit. It assumes that the world will put the brakes on fossil fuel burning and deforestation enough to reach a certain threshold and stay there. Meanwhile, additional carbon dioxide stays in the atmosphere for centuries, and effects such as reduced carbon sinks and methane escapes will continue. That’s why scientists need to talk more about the upper curve, and expected pathways. The simplification of a target temperature creates a distortion.

  16. 66
    Hank Roberts says:

    http://pubs.acs.org/doi/abs/10.1021/acscentsci.5b00148

    Microbial Control of Sea Spray Aerosol Composition: A Tale of Two Blooms

    DOI: 10.1021/acscentsci.5b00148
    Publication Date (Web): May 18, 2015

    It will be a long time, I guess, before climate models can cope with changing plankton populations as they correlate with wind and wave changes — which apparently directly affect cloud formation.

  17. 67
    Chuck Hughes says:

    Somebody posted a link to this article earlier “The Awful Truth About Climate Change That Nobody Wants to Admit”, so I thought I would hopefully get some objective opinions about this…

    http://www.vox.com/2015/5/15/8612113/truth-climate-change

    First off, I noticed that Joe Romm didn’t think much of the op-ed and proceeded to pretty much take it apart piece by piece:

    http://thinkprogress.org/climate/2015/05/18/3644824/really-awful-truth-about-climate-change/

    I have a lot of respect for Joe Romm and his opinions but I don’t think he did a really good job of explaining why the original VOX piece was “incorrect” other than Joe seemed to think it was accepting defeat. My understanding is that there is NO human mechanism for removing CO2 from the atmosphere at this time other than to stop burning ff and reforest and let nature do the work.

    I guess theoretically it’s possible for humans to create something that might do this in the future but the technology doesn’t currently exist. Therefore we’re stuck at 400ppm and rising. I’ve said this before on here that we have a problem with human nature. Any solutions we come up with depend heavily on humans changing their behavior and it’s just not in the cards.

    So VOX vs. Joe Romm…. which opinion is closer to reality? Anyone care to weigh in?

    Thanks

  18. 68
    Hank Roberts says:

    If you can’t do anything else about climate change, you can always grow dirt.
    http://www.eurekalert.org/pub_releases/2015-05/ysof-dsc051915.php

  19. 69
    MA Rodger says:

    The NOAA NCDC global anomaly is posted for April at +0.74°C, the 4th warmest April on record and down on last year’s. This ranking matches the revised values for GISTEMPS which is now showing the =3rd warmest April and also down a bit on last year. So the rolling 12-month average for both is dithering a bit although still very much scorchio.

  20. 70

    CH 67,

    Google “biochar.”

  21. 71
    Matthew R Marler says:

    I have added to my climate sensitivity calculation, and I make it clearer that I am only calculating the response of the surface temperature:

    Omitted from the foregoing is a potential increase in the DWLWIR from a warmer atmosphere (the feedback from the feedback). One approach is to compute the ratio of the energy radiated from the atmosphere to the surface ( 319 W/m^2) to the total energy transferred from the surface ( 24 + 88 + 398 = 510 W/m^2), and assume that ratio (0.63) applies recursively to each increase in energy transfer from the Earth surface. Doing that, the effect of a 4 W/m^2 increase in DWLWIR is equivalent to 4(1/0.37) ~ 4(2.7) ~ 11 W/m^2, so the surface sensitivity is 0.9C per doubling of CO2 concentration, but with substantial uncertainty. If the radiant energy absorbed directly from the sun by the atmosphere (75 W/m^2) is added to the denominator to get 585 W/m^2, the ratio is 0.55, and the surface sensitivity is approximately 0.7C.

    That addresses what I called “the feedback from the feedback”.

  22. 72
    Killian says:

    56 Robert said, @47 (Chris Machens) — 1998 was a strong el nino year, but Arctic sea ice extent did not set a record that year.

    It’s exactly as I said. El Nino, in this case fall/winter/spring 97-98, and low follows in 1 – 2 years, in this case 1990. But you’re right, I misstated 98 as extent low.

  23. 73
    Killian says:

    Brain farting today. Sorry! No new low after 98 El Nino. There were lower extents the next two years, but not by much, and a steady decline trend till we hit the 2005 whopper.

  24. 74
    Lawrence Coleman says:

    Just been trying to explore a hunch of mine. My hunch is that as the earths angle of rotation changes due to so much weight of ice is being lifted off the arctic, this imbalance will cause additional stresses on continental and oceanic tectonic plates resulting in more major seismic events happening per given time frame. Taking the problem backwards doesn’t yield much understanding – thus earthquakes themselves lead to the earths axis being tilted (with respect to other earthly landmarks) as only the angular velocity vector changes not the rotation on axis as seen from space. If the earth was in a vacuum and unaffected by gravitational forces another-words having no near celestial neighbours then the angle of it’s axis would not be effected, however because the sun and neighbouring massive planets exert significant gravitational forces and the earth bulges at the equator I feel that this would create a wobble in space much like a balancing weight falling off your car’s tyre and it is this wobble that could cause further movement in the earth crust thus triggering more earthquakes and volcanic eruptions.
    Am I off the mark here or is there some credence in what I said?
    Thanks!

  25. 75
    Lawrence Coleman says:

    Another thing I’ve been thinking about, is the stresses on Antarctic ice shelves especially where they meet land ice by rising sea levels. There is much talk about the disintegration of the Larson C ice shelf or the east Antarctic peninsula in particular in coming decades by warm circum-polar currents and warming of the atmosphere but could the rising sea level pushing up from below cause a catastrophic fracturing of the ‘hinge’ between the ice shelf and the land ice?

  26. 76
    David B. Benson says:

    Chuck Hughes @ 67 — There are means, all of which require energy, to split CO2 into C and O2,
    CO2 –> C + O2
    other than natural photosynthesis. To see the scale of the problem just growing trees, Irrigated afforestation of the Sahara and Australian Outback to end global warming
    http://www.springerlink.com/content/55436u2122u77525/

  27. 77
    Thomas O'Reilly says:

    #67 I’d go with VOX myself: “The obvious truth about global warming is this: barring miracles, humanity is in for some awful shit.”

    Doesn’t look good at all. However I cannot imagine projecting global energy use and mix today from way back in 1980. Yet this is what people try to do from 2015 to 2050. A lot can happen in 35 years on planet earth, in any direction.

    Staying under 2C seems impossible to me and given current status quo energy use projections that will likely break circa 2035.

    Still the only “number” worth anything is the CO2e PPM figures eg currently CO2 @ 400ppm needs to come back down to under 300ppm asap. The rest is “maths” isn’t it?

    By the time CO2 hits 450ppm ~2035 it will be way too late to do much at all about anything, but find a way to “survive”. Except for those like me already in a box by then.

  28. 78
    patrick says:

    #57 & @67 >Anyone care to weigh in?

    The author himself, David Roberts, does, with a follow-up:

    http://www.vox.com/2015/5/19/8624229/the-news-on-climate-is-awful-so-now-what

    “Still, 2°C or no 2°C, the task ahead remains the same: to get to zero carbon, or as close as possible, as soon as possible; to prepare for a hotter, more volatile future; to protect the most vulnerable, who did the least to cause the problem; and, along the way, to tell the truth about how we’re doing.”

  29. 79

    #67–Chuck, my take is that the two pieces hardly disagree on the most basic reality. As Roberts says (and Romm quotes):

    Geden makes the same mistake when he writes, “the climate policy mantra — that time is running out for 2°C but we can still make it if we act now — is a scientific nonsense.” No. It may be a nonsense, but it’s not a scientific nonsense. No branch of science, certainly not climatology, can tell us what the humans of 2050 are capable of. We are all, on that score, making educated guesses, and a knowledge of history, politics, and economics will be just as important to that judgment as any knowledge of the physical sciences.

    IOW, Roberts isn’t saying that 2C can’t be done, he’s saying that it won’t be done. And the difference from Romm’s take?

    …that doesn’t mean 2C is easy to do or that we will do it — just that if we ever got off of our asses the way the Greatest Generation did, it would require us to invest only a smidgen of our wealth to make the transition, and we’d be paid back again and again in productivity gains and health gains and energy security gains. And of course there’s that whole not destroying a livable climate thing.

    In essence, they are both saying that the main obstacle to an adequate response to the climate crisis is human psychology, and particularly its social and political aspects.

    What Romm disputes, it seems to me, is whose fault it is. He is saying, loud and clear, that the scientific community has been giving good information all along, and not pandering to politicians’ need for good news, as Roberts asserts.

    But whose fault a mess may be is always a secondary issue–and quite often a counterproductive distraction.

  30. 80
  31. 81
    Rick Brown says:

    Re: 67, 69, Vox (David Roberts) v. Romm, also see Robert’s follow-up piece: http://www.vox.com/2015/5/19/8624229/the-news-on-climate-is-awful-so-now-what

  32. 82
  33. 83
    Mal Adapted says:

    Thomas O’Reilly:

    Staying under 2C seems impossible to me and given current status quo energy use projections that will likely break circa 2035.

    Where do you get 2035? From AR5 fig. 12.5, even under RCP8.5 the GMST anomaly won’t hit 2 degrees C until 2050. If you’re challenging that figure, you’ll need to support your argument.

  34. 84
    llewelly says:

    Thomas O’Reilly:

    I’d go with VOX myself: “The obvious truth about global warming is this: barring miracles, humanity is in for some awful shit.”

    I think Romm makes some very good points about the many ways in which Roberts was wrong about the history of what climate scientists have been saying, and when the 2 C target became a settled issue.

    Romm is also right to point out that in several places Roberts made the mistake of interpreting what reporters wrote, or what the headlines said, as what the scientists said.

    It is almost as if Roberts thought about it like this: politicians are doing very little, so therefor, climate scientists and advisers must not be communicating the gravity of the situation. Romm is pointing out that does not follow.

    And I think Romm is also right to point out that physics, technology, and economics all imply the cost of limiting to global warming to less than 2 C is probably only a tiny fraction of global GDP, even if it is large in absolute terms.

    The belief that 2 C is no longer achievable is really all about political pessimism. And that is the core of Roberts’ argument, actually. Unfortunately I think that pessimism is entirely justified; so far the politicians have done very little compared to what needs to be done, and they have only done that much after enormous efforts from climate scientists and activists. China seems to be changing course, but I don’t see any other large emitter changing course in the next 10 years.

    However, even if political pessimism is ignored, I do agree humanity is in for some awful shit. I think even 2 C of global warming easily meets the definition of “awful shit”. In fact, even 1 C may meet the definition; by some estimates, the Eemian was only 1 C warmer, but probably had sea levels about 5 meters higher. Romm did call the Hansen and Sato paper that compared the Eemian with today a “must read”, so at the very least he thinks that is a plausible risk. I do not know if Romm thinks we are committed to a future as bad as that implied by the comparison, however.

    But it is still the case that large reductions in emissions are achievable, are far less expensive than the costs resulting from our current course, and that they can save many lives. And that will remain true even if politicians continue to dawdle for another 10 or even 20 years.

  35. 85
    Greg Simpson says:

    My understanding is that there is NO human mechanism for removing CO2 from the atmosphere at this time other than to stop burning ff and reforest and let nature do the work.

    There are ways, and not just the capture of burned biomass carbon. For instance, you can let crushed serpentine absorb carbon dioxide. But it’s slow, can’t be done near people (asbestos is a serpentine), and it is best done with non-carbon energy to run. Who’s going to bother?

  36. 86
    Hank Roberts says:

    > mechanism for removing CO2
    Letting the oceans recover — as happened during WWII. See above.
    Big effect.

  37. 87
    Thomas says:

    There are lots of methods that could be used at least at the laboratory to remove CO2. As Greg points out, that don’t all require the reduction of CO2 to carbon. There are methods to enhance carbonate creation. There is also biomass with sequestration, which would be carbon negative energy. The real issue with CO2 drawdown is scale, we’ve been emitted multiple cubic kilometers of CO2 per year, and those sorts of volumes of anything imply a huge effort would be needed.

    Lawrence, the tugs on the earth cause what is called precession, with a period of roughly 23,000 years. It may be the difference between the
    rotation vector of the solid earth, and the liquid iron core, which drives the generation of the planets magnetic field. There of course will ge changes in the combination of rotational forces, and the changing gravity field. But I think these rates of change aren’t so large when compared to the accumulation of stresses from the motions of the plates themselves. So the triggering of earthquakes is probably not going to be a global phenomena. However local changes, for instance the local unweighting as ice sheets melt could be locally very significant.

  38. 88

    Well, there’s Klaus Lackner’s approach. He’s been working on air capture of CO2 for quite some time–it was prominently featured in “Fixing Climate,” which I wrote about back in 2009. At that time, his ‘artificial tree’ technology was being developed by a startup called Global Resource Technologies. They looked as if they might make some headway when they got a big hit of development capital, changing their name in the process to Kilimanjaro Energy. But after that, the company went silent, barring a tilt at the Virgin Earth Challenge:

    http://www.virginearth.com/finalists/kilimanjaro-energy/

    Now it seems that Lackner has moved on, and is working on a slightly different technology. He thinks that Kilimanjaro’s proposed price point of $100/ton is plausible, but that $50/ton might be possible. The problem of sequestering the carbon remains an issue, of course–Lackner envisions geological sequestration, but that remains troubling for some. Anyway, here’s the first story on any of this that I’ve seen in a while:

    http://www.earthisland.org/journal/index.php/elist/eListRead/passive_carbon_capture_can_clean_up_our_air_but_the_technology_lacks_/

  39. 89
    MA Rodger says:

    Mal Adapted @83.
    This discussion of a “circa 2015” date for reaching +2ºC appears very similar to words exchanged at the end of last months Unforced Variations that reached resoution here.

  40. 90
    Peter Wright says:

    Would anyone like to have a go at calculating a ballpark figure for how much co2 is effectively displaced by fitting a south facing roof with white roof sheets. This must counter agw to some degree as any such roof will reduce planitary albedo. Just like to know if its significant when considering ones personal impact. Thank you.

  41. 91
    Tony Weddle says:

    Mal Adapted,

    Maybe not quite 2035 but perhaps you didn’t read this article in SciAm, by Mike Mann?

    I believe Hansen has also suggested dates around then, though I can’t find references at this time.

    IPCC ruminations are necessarily quite conservative.

  42. 92
    Hank Roberts says:

    For Peter Wright: some numbers and calculators can be found
    https://www.google.com/search?q=cool+white+roof+co2+warming

    Current cautions, e.g.: http://www.gaf.com/warranties_technical_documents/low_slope_technical_advisory_bulletins/english/roof_color_impact_on_condensation_in_roof_systems_tab_c_2013_20.pdf

    From experience, this condensation issue matters even in temperate areas where the official cool roof sites will tell you not to worry about it.

    As to CO2/warming, it’s not simple: http://www.csmonitor.com/Environment/2014/0213/Cool-roofs-in-warming-cities-They-may-come-at-a-cost-study-finds

  43. 93
    Chuck Hughes says:

    “The shift required to achieve 2°C would have to be enormous — utterly without historical precedent — and it would have to get underway soon. Hoping for a fundamental shift in human consciousness and politics in the next 10 to 15 years amounts to hoping for a miracle. That’s what hoping for 2°C means — banking on a miracle.” ~ David Roberts

    I think that’s the gist of the situation. It’s not “scientifically impossible” to stay below 2C but in terms of human behavior, “Highly unlikely.”

    Once the Arctic becomes completely ice free, I would expect a whole slew of feedback’s to kick in which would push temperatures even further. I don’t know how potential feedback’s are factored into the Climate Models. Nobody seems to really know how much time we have either. I guess it’s not possible to know that. Sequestering CO2 at anywhere near the levels we’re emitting it seem to be far in the future. That’s the crux of the situation. Humans don’t do anything at that level. If the Oceans are a carbon sink and plants are a carbon sink and it’s still not getting the job done, how is “Biochar” going to make up the difference? I don’t get that. All of the proposed solutions for sequestering CO2 by humans appear to me to be “pie in the sky” theories. I’m sure most of them work but being able to implement such a task at a level anywhere equal to what the oceans and plants are already doing is a bit of a stretch I think. But what do I know?

    Thank you for all the great responses. I’m not trying to be disagreeable, just voicing my opinion.

  44. 94
    freemike says:

    Forbes has a new denier piece claiming Arctic ice has receded at all from 1979 levels. It looks like they are talking about area not volume. I’m an amateur so if someone could give me the lowdown on this misinformation I’d appreciate it.

    http://www.forbes.com/sites/jamestaylor/2015/05/19/updated-nasa-data-polar-ice-not-receding-after-all/

    [Response:Anything you read in Forbes is probably just made up — at least when it comes to science. (Maybe their financial advice is good, but somehow their freedom to make things up would make me a skeptic about that.) Rather than read misinformation and ask us to un-mis-inform you, you might just read the perspective of people that know something — e.g. start here: https://nsidc.org. NB: I did take a look at the “article”, and as far as I can tell he’s confusing global extent (Arctic + Antarctica_ with Arctic sea ice (Antarctic sea ice indeed has increased). Averaging the two is like averaging Iraq with New Zealand and concluding there is world peace.–eric

  45. 95
    Steve Fish says:

    Re- Comment by Peter Wright — 21 May 2015 @ 12:14 PM, ~#90

    For the US, rooftop plus black asphalt pavement area is around 100 thousand square miles which is about 2.6% of land area (3.8 million square miles). I would guess that suitable roof area (south facing, not in shade and so on) might be around 0.5% of the land area. Paint it white and it would increase (not decrease) albedo and you would have to maintain it and keep it clean. I suspect that the CO2 cost of doing this would be pretty high.

    Steve

  46. 96
    Thomas says:

    Peter at 90. I remember seeing a figure of ten square meters offsets the
    global forcing of a ton of CO2. So you might have an impact similar to a few tons. I think the average American per capita emmision is over ten tons however, so you’f have to do something like a hundred meters squared per year.

  47. 97
    Thomas O'Reilly says:

    #83 see Earth Will Cross the Climate Danger Threshold by 2036
    The rate of global temperature rise mayhave hit a plateau, but a climate crisis still looms in the near future By Michael E. Mann | Mar 18, 2014
    http://www.scientificamerican.com/article/earth-will-cross-the-climate-danger-threshold-by-2036/

  48. 98
    Thomas O'Reilly says:

    #83 “If you’re challenging that figure, you’ll need to support your argument.”

    try
    http://www.realclimate.org/index.php/archives/2013/10/sea-level-in-the-5th-ipcc-report/
    and http://www.realclimate.org/index.php/archives/2013/09/the-new-ipcc-climate-report/

    “That the IPCC often needs to correct itself “upward” is an illustration of the fact that it tends to produce very cautious and conservative statements, due to its consensus structure – the IPCC statements form a kind of lowest common denominator on which many researchers can agree. The New York Times has given some examples for the IPCC “bending over backward to be scientifically conservative”. Despite or perhaps even because of this conservatism, IPCC reports are extremely valuable – as long as one is aware of it.” stefan @ 27 September 2013

    or Doctor James Hansen “+2 degrees is a prescription for disaster” end quote
    Two degrees of global warming is not ‘safe’: Hansen Tuesday 5 May 2015
    http://www.abc.net.au/radionational/programs/breakfast/two-degrees-of-global-warming-is-not-safe/6444698

    http://www.columbia.edu/~jeh1/mailings/

  49. 99
    Thomas O'Reilly says:

    #78 etc
    “And in general, I agree. I have written in the past about how the integrated assessment models (IAMs) used to create these scenarios contain such a wide array of contestable assumptions, about developments in so far in the future, that it is ludicrous to interpret their results as anything but thought exercises.”

    “Hoping for a fundamental shift in human consciousness and politics in the next 10 to 15 years amounts to hoping for a miracle. That’s what hoping for 2°C means — banking on a miracle.”

    …. why?

    “Look around. There is no such grand mobilization in the offing. Progress on carbon reduction remains fitful and scattered. It is difficult to envision a sudden unanimity around carbon reduction sufficient to see global emissions peak in the next five to 10 years and decline rapidly every year thereafter. And so the likely outcome at this point is exceeding 2°C.”

    eg Current IEA et al projections have FF energy use & therefore global GHGs increasing annually up to 2040 at this point. David Roberts seems immanently rational to me.

    It’s “possible” to stay below +2C, if “we” wanted to do more than “talk”.
    But it’s also “possible” to alleviate world hunger and disease causing childhood deaths and War within 5 years too if “we” really wanted to = a miracle and/or a global revolution in thinking and temperament. Which isn’t going to happen.

  50. 100
    Thomas O'Reilly says:

    Science 22 May 2015: Dynamic thinning of glaciers on the Southern Antarctic Peninsula; B. Wouters

    Growing evidence has demonstrated the importance of ice shelf buttressing on the inland grounded ice, especially if it is resting on bedrock below sea level. Much of the Southern Antarctic Peninsula satisfies this condition and also possesses a bed slope that deepens inland. Such ice sheet geometry is potentially unstable. We use satellite altimetry and gravity observations to show that a major portion of the region has, since 2009, destabilized. Ice mass loss of the marine-terminating glaciers has rapidly accelerated from close to balance in the 2000s to a sustained rate of –56 ± 8 gigatons per year, constituting a major fraction of Antarctica’s contribution to rising sea level. The widespread, simultaneous nature of the acceleration, in the absence of a persistent atmospheric forcing, points to an oceanic driving mechanism.
    http://www.sciencemag.org/content/348/6237/899