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Steven

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #300 on: September 20, 2015, 10:04:56 PM »
In prior posts in this tread I have shown that if the WAIS were to undergo main phase collapse between 2040 and 2100, that it is conceivable that associated methane hydrate decomposition from the armada of icebergs from such a collapse (such as occurred during Meltwater Pulse 1a) might contribute to an associated pulse of natural methane emissions with annual emission rates from 250 to 25 time current annual anthropogenic methane emission rates.

I'm not sure where you get that from.  This article which you posted upthread says the following about Antarctic methane hydrates:

Quote
Wadham and her colleagues calculate there could be anywhere from 70 to 390 billion tons of carbon in hydrates under the East Antarctic ice sheet, and a few tens of billions of tons under West Antarctica.

So even for extreme melt scenarios for the WAIS, the annual rate of methane release from destabilizing/melting hydrates from West Antarctica in the 21st or 22nd century will probably never exceed 1 billion tonnes of methane per year.  For comparison, the current global anthropogenic methane emission rate is about 0.3-0.4 billion tonnes of methane per year (according to wikipedia).
« Last Edit: September 20, 2015, 11:59:05 PM by Steven »

sidd

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #301 on: September 20, 2015, 11:14:40 PM »
Re: Drifthous specific comment on SLR

1)agree that the paper lacks a model for exponential ice sheet collapse. So some discussion of recent models supporting rapid ice sheet collapse might be useful.

2)the recent modelling results for WAIS indicate tcentury scale collapse of Thwaites is not ruled out. Totten is another one with all of Aurora basin behind it.

3)given the possibilities from 2), the onus should be on Hansen's critics to demonstrate that rapid collapse cannot happen given present day icesheet configuration. I doubt this can be done, given recent model results. Perhaps Hansen should make more clear that since the possibility of ice sheet collapse exists, and given the horrific consequences, his paper is a legitimate exploration of the rape of things to come.

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Lennart van der Linde

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #302 on: September 21, 2015, 12:03:00 AM »
sidd,
A 1m SLR by 2100 implies a roughly 20yrs doubling time for ice melt, it seems, so exponential ice sheet loss does seem to be part of current models. But not faster than 20 yrs doubling (yet?) and not (much) past 2100 (yet?). Hansen et al don't explore ice sheet models in this paper, but instead explore the potential effect of exponential ice sheet loss on (mainly) ocean dynamics. Eventually ice sheet models need to be improved, but this paper could be an important step into that direction, I would think. Drijfhout et al do not seem to really appreciate this, for some reason I don't follow.

A-Team

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #303 on: September 21, 2015, 12:10:23 AM »
Quote
scientific consensus is as subject to "group-think" as any other human endeavor.  As ice sheet models will not be sufficiently accurate to even begin to approximate the timing of the start and the rate of acceleration for main phase WAIS collapse; scientific consensus feels very comfortable in calling this black swan scenario a gray swan, thus indicating to society that we do not need to worry about such scenarios  ... erring on the side of least drama is a positive feedback factor for more climate change...Scientists need to learn to take responsibility for their actions

Quote
burden of proof under  precautionary principle should be on Hansen's critics to demonstrate that rapid collapse cannot happen given present day icesheet configuration. I doubt this can be done.

True. Some of the commentary lately from scientists has just been appalling. From the belly of the beast, I would paraphrase Abrupt's remarks as follows:

A viable scientific career today requires a high level of competency in a narrow specialty. Otherwise you can't publish because the narrow specialists out there will nitpick your paper. Thus the soaring number of co-authors per paper.

There are zero provisions in US graduate schools for cross-disciplinary scientific study. Academics are trying to clone themselves in the grad students. A math student taking a physics class is already frowned upon; now picture a budding glaciologist wandering off to a risk analysis, societal studies, ethics or journalism class.

Thus apart from their expertise, many scientists are complete ignoramuses -- even about 'nearby' sciences. That's because all those hours developing the technical proficiency to get papers out the door was time they didn't waste talking to the lab next door, much less taking a risk analysis class, or even reading a newspaper.

Scientists are by nature controversy avoiders. If you don't venture anything novel, you won't be called upon to explain your position. That's good because you haven't given it two second's thought. That would have wasted two seconds better spent on something that advancedyour career. Be a brick in the wall rather than the nail sticking up.

This leads to the acceptability of climate brinksmanship -- the path of least controversy -- say nothing, do nothing, fall back the narrowness of your specialty. Which amounts to see how far we can push it before collapse is really upon us.

=/=/=/

I have an idea under development which consists of a variant we can make on the denier thermometer, only a responsibility thermometer for scientists. Thus Jason Box and more recently Eric Rignot might be up in the blue, just a degree or two below James Hanson. Others like Joughin are at neutral temperatures -- non-committal, not quite persuaded, sticking strictly to established science.

The one I am beginning to have real doubts about is Richard B Alley. He has been putting out rather wishy-washy statements lately downplaying climate change consequences. These are certain to be heard as minimalizing concern and justifying delay. Maybe there is some deeper inside game being played.

We had his absurd pooh-poohing of Jakobshavn last month and now look at the abstract for his AGU2015 address -- with smart phone thinking, we can solve the fuel emission climate issue without really doing anything!

I'm not sure where to place these people playing the scientifically unethical games on the Russian methane scientists. I tend to see this as an academic turf thing (carbon dioxide) rather than delay/deny per se. However from the larger risk management perspective, it is highly irresponsible.

I'll report in a bit on another crazy thing going on with gross inadequacies in volcanic aerosol modeling, which Michael Mann is trying to reassign to missing tree rings! That was totally ruled out long ago -- AE Douglass looked into that particular concern starting in 1894 -- dendrochronology has proven zero error (aka the periodic table isn't missing an element between nitrogen and carbon).

This again is not delay/deny but might be interpreted in a way that fuel disastrous reliance on whacko aerosol geoengineering schemes which is a version of delayism.

I learned over the course of 600 interviews with the press (unrelated equally unwelcome topic) that it is not good enough to get it right scientifically. You have to take the next step and grasp the little that will be heard. Otherwise a very different message than intended may be received.
« Last Edit: September 21, 2015, 12:26:02 AM by A-Team »

Richard Rathbone

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #304 on: September 21, 2015, 12:44:17 PM »
I'm not sure about the Eemian sea level comments of Drijfhout et al, but on the modelling side I think they need to go back to Hansen's paper, read it with a bit more care and attention, say "Ooops", and withdraw them before Hansen puts the boot in. He may or may not have made a cavalier interpretation of Eemian sea level evidence that they know a lot about, but he hasn't made the sort of basic error in his area of expertise that they are ascribing to him.

Lennart van der Linde

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #305 on: September 21, 2015, 08:55:52 PM »
Hansen and Sato elaborate on Hansen et al:
http://csas.ei.columbia.edu/2015/09/21/predictions-implicit-in-ice-melt-paper-and-global-implications/

A fragment:
'Here we give our opinion about the likely speed at which ice sheets will respond to the climate forcing for “business-as-usual” growth of fossil fuel emissions. The resulting rate of increasing climate forcing is far outside the rate Earth has ever experienced. We suspect that glaciologists anticipating very slow response of ice sheets base their opinion in part on the rates of ice sheet change that occurred in response to natural climate forcings, which changed much more slowly than the human-made forcing. The rate of change of greenhouse gases determines Earth’s energy imbalance, and the energy imbalance is the “drive” or “forcing” of ice sheet change...

Prediction of sea level rise must be based on physical reasoning incorporating the full range of available information: paleo sea level change in response to paleo forcings, empirical evidence of ice sheet response to modern forcings, knowledge about the status of current energy imbalance, and insights from climate modeling. Paleo evidence indicates that multi-meter sea level rise is possible in a century. Modern observations reveal that parts of the Antarctic ice sheet are ripe for rapid ocean-ice interactions that can destabilize enough ice to raise sea level several meters. Ocean data reveal a substantial planetary energy imbalance, which implies that the subsurface temperature near Antarctic ice shelves will continue to increase. Our climate modeling reveals amplifying feedbacks in the Southern Ocean that spur ice shelf melt and iceberg discharge.

Given all the evidence, a claim that a scenario with 600-900 ppm CO2 forcing within a century would not yield multi-meter sea level rise this century is an extraordinary claim that would require extraordinary proof. Today’s ice sheet models are not capable of providing that proof.'

AbruptSLR

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #306 on: September 22, 2015, 03:41:04 AM »
I think that for AR6 the climate modelers need to learn from the master modeler how to include the influence of earth system states into their projections.  Reading Hansen's and Sato's critique of the AR5 model results for failing to match the observed temperature and salinity of the Southern Ocean by failing to inject ice meltwater, makes me think that the IPCC modelers are more focused on avoiding criticism from doubters than on doing their best to simulate reality.  I only hope that the AR6 modeler learn to better capture the influence of other earth system states like: (a) the instability of marine glaciers; (b) the influence of aerosols on Southern Ocean clouds and winds; and (b) multi-decadal oscillations including PDO, AMO etc.
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sidd

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #307 on: September 22, 2015, 05:09:50 AM »
Hansen and Sato predictions:

"In the near-term, over the next several years, we expect the rate of mass loss from West Antarctica to continue to grow with doubling times of the order of 10 years"

"we expect the doubling time for increasing mass loss by the Greenland ice sheet to be not greater than ~20 years."

there you have it.

AbruptSLR

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #308 on: September 22, 2015, 01:38:25 PM »
In the link provide by Lennart to Hansen & Sato September 21 2015:

http://csas.ei.columbia.edu/2015/09/21/predictions-implicit-in-ice-melt-paper-and-global-implications/

Hansen & Sato point out the correlation between the state of the Antarctic Sea Ice extent and both global warming and the ENSO.  They note that the recent drop in Antarctic Sea Ice extent (see the first & second attached images) may be related to the strengthening El Nino.  In this regards the third image from Fogt et al. (2011) shows how El Nino events and SAM conditions combine to telecommunicate Tropical Pacific Energy to the poles via atmospheric Rossby waves; while the fourth image (also from Fogt et al. (2011)) shows how increasingly possible SAM conditions increase the circumpolar wind velocities that contribute to the advection of warm CDW water to melt Antarctic marine glacial ice. 

In this last regards I provide the linked reference showing that the SAM is becoming more positive (due to AGW), which appears to be leading to a cooling of the main Antarctic continent; however, that telecommunication of energy from the Tropical Pacific is warming Western Antarctica.  Also, I note here that a positive SAM facilitates the telecommunication of Tropical Pacific energy to Western Antarctica, particularly in El Nino years:

Nerilie J. Abram, Robert Mulvaney, Françoise Vimeux Steven J. Phipps, John Turner & Matthew H. England  (2014), "Evolution of the Southern Annular Mode during the past millennium", Nature Climate Change; doi:10.1038/nclimate2235

http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2235.html

Abstract: "The Southern Annular Mode (SAM) is the primary pattern of climate variability in the Southern Hemisphere, influencing latitudinal rainfall distribution and temperatures from the subtropics to Antarctica. The positive summer trend in the SAM over recent decades is widely attributed to stratospheric ozone depletion; however, the brevity of observational records from Antarctica—one of the core zones that defines SAM variability—limits our understanding of long-term SAM behaviour. Here we reconstruct annual mean changes in the SAM since AD 1000 using, for the first time, proxy records that encompass the full mid-latitude to polar domain across the Drake Passage sector. We find that the SAM has undergone a progressive shift towards its positive phase since the fifteenth century, causing cooling of the main Antarctic continent at the same time that the Antarctic Peninsula has warmed. The positive trend in the SAM since ~AD 1940 is reproduced by multimodel climate simulations forced with rising greenhouse gas levels and later ozone depletion, and the long-term average SAM index is now at its highest level for at least the past 1,000 years. Reconstructed SAM trends before the twentieth century are more prominent than those in radiative-forcing climate experiments and may be associated with a teleconnected response to tropical Pacific climate. Our findings imply that predictions of further greenhouse-driven increases in the SAM over the coming century also need to account for the possibility of opposing effects from tropical Pacific climate changes."
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AbruptSLR

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #309 on: September 25, 2015, 09:46:57 PM »
The linked reference (with an open access pdf), provides model resulting indicating that with increased transport of oceanic heat that the Earth will have less thermal energy available to drive violent storms.  As the investigated case is the opposite of the case considered by Hansen et al. (2015); this Kneitzsch et al. (2015) finding supports Hansen et al. (2015) finding that reduced ocean heat transport (due to the collapse of ice sheets) will result in increasingly violent storms in the future.

Knietzsch, M.-A., Schröder, A., Lucarini, V., and Lunkeit, F. (2015), "The impact of oceanic heat transport on the atmospheric circulation", Earth Syst. Dynam., 6, 591-615, doi:10.5194/esd-6-591-2015.


http://www.earth-syst-dynam.net/6/591/2015/esd-6-591-2015.html


Abstract: "A general circulation model of intermediate complexity with an idealized Earth-like aquaplanet setup is used to study the impact of changes in the oceanic heat transport on the global atmospheric circulation. Focus is on the atmospheric mean meridional circulation and global thermodynamic properties.

The atmosphere counterbalances to a large extent the imposed changes in the oceanic heat transport, but, nonetheless, significant modifications to the atmospheric general circulation are found. Increasing the strength of the oceanic heat transport up to 2.5 PW leads to an increase in the global mean near-surface temperature and to a decrease in its equator-to-pole gradient. For stronger transports, the gradient is reduced further, but the global mean remains approximately constant. This is linked to a cooling and a reversal of the temperature gradient in the tropics.

Additionally, a stronger oceanic heat transport leads to a decline in the intensity and a poleward shift of the maxima of both the Hadley and Ferrel cells. Changes in zonal mean diabatic heating and friction impact the properties of the Hadley cell, while the behavior of the Ferrel cell is mostly controlled by friction.

The efficiency of the climate machine, the intensity of the Lorenz energy cycle and the material entropy production of the system decline with increased oceanic heat transport. This suggests that the climate system becomes less efficient and turns into a state of reduced entropy production as the enhanced oceanic transport performs a stronger large-scale mixing between geophysical fluids with different temperatures, thus reducing the available energy in the climate system and bringing it closer to a state of thermal equilibrium."

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A-Team

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #310 on: September 25, 2015, 11:16:39 PM »
Quote
Hansen/Sato: the rate of increasing climate forcing is far outside the rate Earth has ever experienced. natural climate forcings changed much more slowly than the human-made forcing. The rate of change of greenhouse gases determines Earth’s energy imbalance, and the energy imbalance is the “drive” or “forcing” of ice sheet change.
It would almost be worth a separate forum to collect all the situations where the rate of change matters, not just the overall delta between initial and final states. This gets into the topic of hysteresis (history matters) in the earth system which at any given time may be centuries away from equilibrium. We're more familiar with perturbation theory -- the volcano injecting reflective sulfate (or halogen-induced) aerosols and the brief cooling that results.

I suppose by 'energy imbalance' they're talking about imbalance over energy needed for stable (equable) climate but that per se does not provide specifics on how problems with imbalance will scale (other than getting monotonically worse), nor in which situations the differences between fast ramp and slow ramp are significant. In far-from-equilibrium thermodynamics, the oddest things can happen with just a nudge. Alternatively the situation can be so buffered from change that fast vs slow have hardly distinguishable sensitivities.

Mundane rate example: we had a prodigous monsoon rain event here at the house, a half inch of rain in 10 minutes on already wet alluvium, about 5% of the annual total in 1/6*24*365 of the time. That had a very dramatic effect on sediment loading of even the smallest of dry washes that would never have occurred had it been spread out over its proportionate part of the water year -- those would have summed to zero.

There are counterparts to this all over climate science; in Greenland, rain events and melt seasons overwhelming subglacial drainages giving effects where the overall outcome is a lot more than the sum of slowed parts. Another might be the rate of stratospheric methane loading overwhelming hydroxyl radical production. This topic is distinct from but easily conflated with extreme one-off events. The latter is not so much about a shorter time scale than sampling from a different distribution when more energy is in the system (eg water vapor).
« Last Edit: September 26, 2015, 03:42:27 AM by A-Team »

AbruptSLR

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #311 on: September 26, 2015, 07:02:47 AM »
Quote
Hansen/Sato: the rate of increasing climate forcing is far outside the rate Earth has ever experienced. natural climate forcings changed much more slowly than the human-made forcing. The rate of change of greenhouse gases determines Earth’s energy imbalance, and the energy imbalance is the “drive” or “forcing” of ice sheet change.


I suppose by 'energy imbalance' they're talking about imbalance over energy needed for stable (equable) climate but that per se does not provide specifics on how problems with imbalance will scale (other than getting monotonically worse), nor in which situations the differences between fast ramp and slow ramp are significant. In far-from-equilibrium thermodynamics, the oddest things can happen with just a nudge. Alternatively the situation can be so buffered from change that fast vs slow have hardly distinguishable sensitivities.


In the following linked article James Hansen, Makiko Sato, Pushker Kharecha and Karina von Schuckmann (January 2012) explain the concept of Earth's energy imbalance and its implications (including: (a) that previously slow ramp positive feedbacks can become fast ramp positive feedbacks when the planetary energy imbalance is high, and (b) that aerosol forcing can have a major impact on Earth's energy imbalance [see the two attached images]):

http://www.giss.nasa.gov/research/briefs/hansen_16/

Extract: "Earth's energy imbalance is the difference between the amount of solar energy absorbed by Earth and the amount of energy the planet radiates to space as heat. If the imbalance is positive, more energy coming in than going out, we can expect Earth to become warmer in the future — but cooler if the imbalance is negative. Earth's energy imbalance is thus the single most crucial measure of the status of Earth's climate and it defines expectations for future climate change.
Energy imbalance arises because of changes of the climate forcings acting on the planet in combination with the planet's thermal inertia. For example, if the Sun becomes brighter, that is a positive forcing that will cause warming. If Earth were like Mercury, a body composed of low conductivity material and without oceans, its surface temperature would rise quickly to a level at which the planet was again radiating as much heat energy to space as the absorbed solar energy.
Earth's temperature does not adjust as fast as Mercury's due to the ocean's thermal inertia, which is substantial because the ocean is mixed to considerable depths by winds and convection. Thus it requires centuries for Earth's surface temperature to respond fully to a climate forcing.
Climate forcings are imposed perturbations to Earth's energy balance. Natural forcings include change of the Sun's brightness and volcanic eruptions that deposit aerosols in the stratosphere, thus cooling Earth by reflecting sunlight back to space. Principal human-made climate forcings are greenhouse gases (mainly CO2), which cause warming by trapping Earth's heat radiation, and human-made aerosols, which, like volcanic aerosols, reflect sunlight and have a cooling effect.

The measured planetary energy imbalance provides an immediate accurate assessment of how much atmospheric CO2 would need to be reduced to restore Earth's energy balance, which is the basic requirement for stabilizing climate."

Caption for the second attached image: "Figure 4. Expected Earth energy imbalance for three choices of aerosol climate forcing. Measured imbalance, close to 0.6 W/m2, implies that aerosol forcing is close to -1.6 W/m2"
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AbruptSLR

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #312 on: September 26, 2015, 03:55:28 PM »
As Hansen et al have been working on the Hansen et al. (2015) draft paper for eight years, we should all realize that it took that long not because Hansen is slow, but because he and his associates were putting-up the "good fight" against uncertainty mongers during the faux hiatus period.  As discussed in the following Hansen et al. (2011) reference (with an open access pdf) the Earth's energy imbalance (planetary energy imbalance) concept is used to reduce confusion about:
(a) Short-term fluctuations of energy imbalance associated with such factors as heat uptake by the oceans and negative aerosol forcing (which doubters were downplaying) and
 (b) Changes in radiative forcing functions from the land, sea ice, ice sheets, etc. associated with the currently very high rate of change of energy imbalance that is changing the rates of response of many positive feedback mechanisms.
None of this is new, and mainstream climate scientists are all familiar with Hansen et al's various arguments over the decades.  What is new is that the faux hiatus is now at an end, and it is more difficult for doubters to belittle Hansen et al's well-reasoned arguments.
The first image introduces the concept of Energy Imbalance and Climate Forcing.  The second image relates Climate Response and Global Mean Surface Temperature.  The third image introduces the concept that Climate Response can occur at different rates (slow, intermediate & fast).  The fourth image presents key on-oceanic contributors to climate forcing.  My next post will provide four more figures from Hansen et al. (2011).

Hansen, J., Sato, M., Kharecha, P., and von Schuckmann, K. (2011), "Earth's energy imbalance and implications", Atmos. Chem. Phys., 11, 13421-13449, doi:10.5194/acp-11-13421-2011.

http://www.atmos-chem-phys.net/11/13421/2011/acp-11-13421-2011.html

http://www.atmos-chem-phys.net/11/13421/2011/acp-11-13421-2011.pdf

Abstract: "Improving observations of ocean heat content show that Earth is absorbing more energy from the Sun than it is radiating to space as heat, even during the recent solar minimum. The inferred planetary energy imbalance, 0.58 ± 0.15 W m−2 during the 6-yr period 2005–2010, confirms the dominant role of the human-made greenhouse effect in driving global climate change. Observed surface temperature change and ocean heat gain together constrain the net climate forcing and ocean mixing rates. We conclude that most climate models mix heat too efficiently into the deep ocean and as a result underestimate the negative forcing by human-made aerosols. Aerosol climate forcing today is inferred to be −1.6 ± 0.3 W m−2, implying substantial aerosol indirect climate forcing via cloud changes. Continued failure to quantify the specific origins of this large forcing is untenable, as knowledge of changing aerosol effects is needed to understand future climate change. We conclude that recent slowdown of ocean heat uptake was caused by a delayed rebound effect from Mount Pinatubo aerosols and a deep prolonged solar minimum. Observed sea level rise during the Argo float era is readily accounted for by ice melt and ocean thermal expansion, but the ascendency of ice melt leads us to anticipate acceleration of the rate of sea level rise this decade."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #313 on: September 26, 2015, 04:17:39 PM »
This post is a continuation of my last reply to provide more of Hansen et al (2011) images illustrating key implications of the old Earth's energy imbalance concept, that many have chosen to ignore, or belittle, during the faux hiatus period (I note that Hansen and his various associates have produced numerous other papers before and after 2011, that elaborate on their insights; and I am sure that there will be more papers after the Hansen et al. (2015) draft paper, providing still more insights on other positive feedback mechanisms including: deep atmospheric convection & ECS, methane emissions from hydrates & permafrost degradation, tropical & boreal forest degradation, ocean acidification & plankton degradation, changes in water cycles, wildfires, insect assaults on vegetation, and other feedbacks that were previously considered to be slow response and that will shortly be recognized as fast response Earth Systems).

The first image summarizes key contributors to planetary energy imbalance.  The second image compares observed and calculated imbalance with different (slow, intermediate & fast) climate responses.  The third image shows key contributors to SLR in 2005 to 2010 as background to understand why during the faux hiatus that AR4 ignored ice sheet SLR contributions, and why AR5 increased the AR4 SLR projections by about 50% to begin to consider some ice sheet contribution while still ignoring the risk of rapid WAIS contribution; which is a key to the warnings of Hansen et al. (2015).  The fourth image clarifies accounting of the "missing energy" issue touted by doubters during the faux hiatus and the measured changes in energy imbalance.

Again, all of these points are old; however, now with a possible Godzilla El Nino developing, and a positive PDO underway; it is far more difficult for doubters to characterize the grey swan of future high energy imbalance (driving violent storms etc) as a black swan.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #314 on: September 27, 2015, 05:38:22 AM »
The linked article by Carbon Brief reviews the linked reference by Srokosz & Bryden (2015) about the physical findings of the RAPID project from 2004 to 2014 that is monitoring the AMOC, and has found that the AMOC is slowing-down (see the attached plot) as Hansen et al. 2015 notes.  The scientists are not sure how much of the slowdown is due to ice melting from the GIS and how much from natural oscillations:

http://www.carbonbrief.org/blog/2015/06/the-atlantic-conveyor-belt-and-climate-10-years-of-the-rapid-project/


Srokosz, M.A. and Bryden, H.L. (2015) Observing the Atlantic Meridional Overturning Circulation yields a decade of inevitable surprises, Science, doi:10.1126/science.1255575

https://www.sciencemag.org/content/348/6241/1255575.short?related-urls=yes&legid=sci;348/6241/1255575

Structured Abstract: "BACKGROUND
 
A 2002 report, Abrupt Climate Change: Inevitable Surprises, highlighted the North Atlantic circulation as possibly subject to abrupt change in a warming climate. Likewise, the 2001 Intergovernmental Panel on Climate Change (IPCC) report suggested that the Atlantic Meridional Overturning Circulation (AMOC) could weaken over the 21st century. As this circulation carries heat northward, giving the United Kingdom and northwest Europe a temperate climate, this generated renewed efforts to make observations of the AMOC. In particular, it led to the deployment of an observing system across the Atlantic at 26.5°N in spring 2004, which last year achieved a decade of measurements.


ADVANCES
 
In addition to the baseline decade of 26.5°N observations, there have been other ongoing measurements that capture components of the AMOC, some of which are not continuous or of much shorter duration. Together these observations are leading to a more complete picture of the AMOC. The 26.5°N AMOC observations have produced a number of surprises on time scales from subannual to multiannual. First, the range of AMOC variability found in the first year, 4 to 35 Sv (Sverdrup, a million cubic meters per second, the standard unit for ocean circulation), was larger than the 15 to 23 Sv found previously from five ship-based observations over 50 years. A similarly large range to that at 26.5°N has subsequently been observed at 34.5°S. Second, the amplitude of the seasonal cycle, with a minimum in the spring and a maximum in the autumn, was much larger (~6.7 Sv) than anticipated, and the driving mechanism of wind stress in the eastern Atlantic was unexpected as well. Third, the 30% decline in the AMOC during 2009–2010 was totally unexpected and exceeded the range of interannual variability found in climate models used for the IPCC assessments. This event was also captured by Argo and altimetry observations of the upper limb of the AMOC at 41°N. This dip was accompanied by significant changes in the heat content of the ocean, with potential impacts on weather that are the subject of active research. Finally, over the period of the 26.5°N observations, the AMOC has been declining at a rate of about 0.5 Sv per year, 10 times as fast as predicted by climate models. Whether this is a trend that is a decline due to global warming or part of the so-called Atlantic Multidecadal Oscillation/Variability, inferred from sea surface temperature measurement, is also a subject of active research. There is no doubt that continuously observing the AMOC over a decade has considerably altered our view of the role of ocean variability in climate.


OUTLOOK
 
The 26.5°N AMOC observations are stimulating the development of further AMOC observing systems both to the north, in the North Atlantic subpolar gyre, and to the south, in the South Atlantic. The aim is to obtain a holistic picture of the AMOC from south to north. Given the surprises and insights into the Atlantic circulation that observations have produced to date, it is not too much to expect that with the new observations there will be future “inevitable surprises."
« Last Edit: September 27, 2015, 03:45:06 PM by AbruptSLR »
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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #315 on: September 27, 2015, 05:22:16 PM »
As it may not be clear to some readers: the SLR, and increase in violent storms, projected by Hansen et al (2015) work synergistically together to increase the risk of both coastal, and inland, of flood inundation, for reasons including:

(a) Increasingly frequent violent storm both increase storm surge and increase precipitation, related flooding; and for cities located at the mouth of rivers (think most large cities like NYC, London, etc) these factors can combine (adjusted for phase relations) synergistically.  Furthermore, strong low-pressure storms (like hurricanes and typhoons) can temporarily increase local sea level by reducing the local downward atmospheric pressure.

(b) The increase in sea level (including ice sheet contributions) not only increase the base water elevation, but it also: (1) increases local erosion which then increases storm surge inundation; and (2) increases both astronomical tides and storm surge (compared to current projections) as the increase water depth reduces the influence of bottom friction that would otherwise suppress the tides and storm surge elevations.

(c) As global warming (and associated planetary energy imbalance, which experiences a pulse increase as the ice sheets collapse) increases the duration of hurricane/typhoon seasons; the risk of associated storm surge inundation increasingly overlap with the risk of river stage flood events (which also increase as global warming activates hydrological cycles including high precipitation events); which increases the risk of flood events for cities near rivers  in hurricane/typhoon areas (like: New Orleans, Tokyo, New York, etc).
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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #316 on: September 28, 2015, 06:01:36 PM »
It should also be noted that the observed slowdown in the AMOC, which may be a precursor to even more slowing in the future will lead to an 8inch to 14inch sea level rise on the east coast of the United States since the gulf stream current draws water away from the shoreline.
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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #317 on: September 28, 2015, 07:12:46 PM »
To my mind, by definition a Black Swan is unexpected by science, while a Grey Swan describes a right-tailed PDF/low probability event (e.g. with a return period like 1 in 10,000 years). In this regards, the main phase collapse of the WAIS, before 2100, was considered a Black Swan in AR4, and a Grey Swan in AR5's footnotes (but was not considered in AR5's summary SLR values).  However, Hansen and Sato (2015) say that they believe that the most probably scenario for a WAIS collapse this century results in a 10-year doubling time for its SLR contributions (through 2100); which should make this a White Swan event, that should be considered by all climate change modelers and policy makers.

For Hansen & Sato (2015) see:
http://csas.ei.columbia.edu/2015/09/21/predictions-implicit-in-ice-melt-paper-and-global-implications/


However, I suspect that many readers do not realize the extent to which the developed world functions in a curated, artificial, socio-economic environment; built on substantial factors of safety; that they are trading for a future existence of high-uncertainty, in exchange for living a BAU existence for a just a few more decades.  I imagine that many readers believe that because reticent scientists demand 95% confidence before these scientists include various radiative forcing and feedback mechanisms into their climate models, that this somehow maintains a high level of certainty and confidence, when nothing could be further from the truth.  The truth is that policy makers are hoping to exchange our current substantial factors of safety for modern societal functionality, for responses to climate change that may only remain "resilient" for three to four more decades, and thereafter will exhibit progressive collapse (particularly if the WAIS does collapse and accelerates the planetary energy imbalance, and contributes to abrupt SLR this century).
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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #318 on: September 29, 2015, 09:08:23 PM »
The linked article discusses a pay-walled report entitled: "A Strategic Vision for NSF Investments in Antarctic and Southern Ocean Research (2015)" that prioritizes science in Antarctica:

http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=21741


Extract: "Melting Ice Sheets, Genomic Studies, and Deep-Space Observations Are Top Priorities for Next Decade of Antarctic and Southern Ocean Research
 
WASHINGTON -- An initiative to better understand how melting ice sheets will contribute to sea-level rise, efforts to decode the genomes of organisms to understand evolutionary adaptations, and a next-generation cosmic microwave background experiment to address fundamental questions about the origin of the universe are the top research goals for Antarctic and Southern Ocean science recommended in a new report from the National Academies of Sciences, Engineering, and Medicine.
 
The report, which offers a strategic vision to guide the U.S. Antarctic Program at the National Science Foundation over the next 10 years, also recommends that NSF continue to support a core program of investigator-driven research across a broad range of disciplines and strengthen logistic and infrastructure support for the priority research areas.
 
“The discoveries emerging from the Antarctic and the Southern Ocean advance our understanding of how our planet works and how our universe formed,” said Robin Bell, professor of geology and geophysics at the Lamont-Doherty Earth Observatory of Columbia University in New York and co-chair of the committee that conducted the study.  “Continued Antarctic and Southern Ocean research will produce new insights that will be critical as society adapts to the global consequences of change in these remote regions.”
Informed by extensive input from the scientific community, the committee selected the three large-scale research goals based on the criteria of compelling science, potential for societal impact, time sensitivity, readiness and feasibility, and key areas for U.S. and NSF leadership.  Additional criteria included partnership opportunities, impacts on NSF program balance, and the potential to help bridge disciplinary divides.
 
The report proposes a major new effort called the Changing Antarctic Ice Sheets Initiative to investigate how much and how fast melting ice sheets will contribute to sea-level rise.  The initiative’s components include a multidisciplinary campaign to study the complex interactions among ice, ocean, atmosphere, and climate in key zones of the West Antarctic Ice Sheet, and a new generation of ice core and marine sediment core studies to better understand past episodes of rapid ice sheet collapse."
A second strategic research priority is to understand from a genetic standpoint how life adapts to the extreme Antarctic environment.  For more than 30 million years, isolated Antarctic ecosystems have evolved to adapt to freezing conditions and dramatic environmental changes, and now must adapt to contemporary pressures such as climate change, ocean acidification, invasive species, and commercial fishing.  Sequencing the genomes and transcriptomes of critical populations, ranging from microbes to marine mammals, would reveal the magnitude of their genetic diversity and capacity to adapt to change. 
 
In addition to being a vast natural laboratory, Antarctica has a dry, stable atmosphere that offers an ideal setting for astrophysical observations.  The report recommends a next-generation experimental program to observe cosmic microwave background radiation, the “fossil light” from the early universe.  This would include an installation of a new set of telescopes at the South Pole, as part of a larger global array, which will allow highly sensitive measurements that could detect signatures of gravitational waves.  Such observations might provide evidence that could confirm the theory of cosmic inflation and the quantum nature of gravity, as well as address other enduring questions about the nature of the universe.
 
“Although remote, the changes occurring in the Southern Ocean and Antarctica can directly influence the United States,” said committee co-chair Robert Weller, senior scientist at Woods Hole Oceanographic Institution in Massachusetts.  “But these are challenging areas to do research, so there is a pressing need to prioritize the allocation of resources in order to assure reliable, safe support for critical observations and research campaigns.”
 
The report recommends the following as key needs for supporting and implementing the priority research goals and other areas of Antarctic and Southern Ocean science:   
•         Expanded access to remote field sites, including a deep field camp and logistics hub, over-snow traverse capabilities, and improved all-weather access to research stations and field locations by air;
•         Design and acquisition of a new heavy icebreaker ship and an ice-capable polar research vessel;
•         Support for sustained observations through strategic augmentation and coordination of existing observational networks;
•         Improved communications and information technology for data transmission; and
•         Efforts to facilitate more open and coordinated data collection, sharing, and integration.
 
The report notes that the priority research initiatives all require some degree of collaboration among NSF divisions, with other U.S. agencies, and with other nations.  In addition, NSF can play an important role in developing Antarctic-themed educational resources for K-12, undergraduate and graduate programs, and informal education institutions."


http://www.nap.edu/catalog/21741/a-strategic-vision-for-nsf-investments-in-antarctic-and-southern-ocean-research

Committee on the Development of a Strategic Vision for the U.S. Antarctic Program; Polar Research Board; Division on Earth and Life Studies; National Academies of Sciences, Engineering, and Medicine

A Strategic Vision for NSF Investments in Antarctic and Southern Ocean Research (2015)
Description
Antarctic and Southern Ocean scientific research has produced a wide array of important and exciting scientific advances. Spanning oceanography to tectonics, microbiology to astrophysics, the extreme Antarctic environment provides unique opportunities to expand our knowledge about how our planet works and even the very origins of the universe. Research on the Southern Ocean and the Antarctic ice sheets is becoming increasingly urgent not only for understanding the future of the region but also its interconnections with and impacts on many other parts of the globe.
Prepublication: 978-0-309-37784-3
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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #319 on: October 02, 2015, 11:14:54 PM »
The following reference about the influence of the recent increased Agulhas leakage on tropical Atlantic warming has relevance to my Reply #202 and the response of the AMOC:

Joke F. Lübbecke, Jonathan V. Durgadoo, and Arne Biastoch (2015), "Contribution of increased Agulhas leakage to tropical Atlantic warming", Journal of Climate, doi: http://dx.doi.org/10.1175/JCLI-D-15-0258.1


http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-15-0258.1


Abstract: "The upper tropical Atlantic Ocean has markedly warmed since the 1960s. It has been shown that this warming was not due to local heat fluxes, and that the trade winds that drive the coastal and equatorial upwelling have intensified rather than weakened. Remote forcing might thus have played an important role. Here model experiments are used to investigate the contribution from an increased inflow of warm Indian Ocean water through Agulhas leakage. A high-resolution hindcast experiment with interannually varying forcing for the time period 1948 to 2007, in which Agulhas leakage increases by about 45% from the 1960s to the early 2000s, reproduces the observed warming trend. To tease out the role of Agulhas leakage, a sensitivity experiment designed to only increase Agulhas leakage is used. Compared to a control simulation it shows a pronounced warming in the upper tropical Atlantic Ocean. A Lagrangian trajectory analysis confirms that a significant portion of Agulhas leakage water reaches the upper 300m of the tropical Atlantic Ocean within two decades, and that the tropical Atlantic warming in the sensitivity experiment is mainly due to water of Agulhas origin. Therefore, it is suggested that the increased trade winds since the 1960s favor upwelling of warmer subsurface waters, which in parts originate from the Agulhas, leading to higher SSTs in the tropics."
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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #320 on: October 03, 2015, 03:48:00 AM »
Per the linked article volcanoes can collapse so rapidly that (in the right location) they can produce megatsumamis. While Bill McGuire has estimated that such extreme events might only happen once in every 10,000 years, he has also estimate that should sea level rise abruptly (as proposed by Hansen et al (2015)) then the frequency of such megatsunami events would increase due both to the influence of the higher sea level on the stability of volcanoes but also due to the influence of changing precipitation patterns, which can also weaken volcanic slopes:


http://www.cbsnews.com/news/is-ancient-800-ft-megatsunami-wave-a-sign-of-things-to-come/

Extract: "Tsunami expert Bill McGuire, a professor emeritus at University College London who was not involved in the research, said the study "provides robust evidence of megatsunami formation [and] confirms that when volcanoes collapse, they can do so extremely rapidly."

"Our point is that flank collapses can happen extremely fast and catastrophically, and therefore are capable of triggering giant tsunamis," said Ramalho.

Though some scientists question whether a volcano of this size really would collapse, the new study is the latest evidence to support concerns about the threats posed by volcanic flanks. Several have collapsed over the past several hundred years, including eight smaller ones in Alaska and Japan.

A handful of previous other studies have proposed much larger prehistoric collapses and resulting megatsunamis, in the Hawaiian islands, at Italy's Mt. Etna, and the Indian Ocean's Reunion Island. But critics have said these examples are too few and the evidence too thin.

Based on his own work, McGuire said that such megatsunamis probably come only once every 10,000 years."
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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #321 on: October 03, 2015, 10:05:43 AM »
Although I have posted this information in other threads, I thought that I would note that per the linked reference (see attached images) rapid ice melting is already moving the location of the Earth's rotational axis, and if/when the WAIS collapse occurs (possibly this century), we can expect a rather dramatic shift in the Earth's poles (also note that the Earth's magnetic pole is shifting rapidly in the opposite direction as the rotational pole).

Chen, J. L., C. R. Wilson, J. C. Ries, and B. D. Tapley (2013), Rapid ice melting drives Earth's pole to the east, Geophys. Res. Lett., 40, 2625–2630, doi:10.1002/grl.50552

http://onlinelibrary.wiley.com/doi/10.1002/grl.50552/abstract;jsessionid=DC0A43068ECB437A2C94A16B705A82BE.f02t03

Best,
ASLR
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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #322 on: October 04, 2015, 02:53:37 AM »
The linked reference presents both analysis and field observations of a major calving event at Greenland’s Helheim Glacier.  The research identified the physical mechanisms operating during calving events, which result in "… glacial earthquakes, globally detectable seismic events whose proper interpretation will allow remote sensing of calving processes occurring at increasing numbers of outlet glaciers in Greenland and Antarctica."  This include remote monitoring of calving for key outlet glaciers like Jakobshavn, PIG and Thwaites; which it Hansen et al. (2015) is correct, will become very important stating immediately (note that Posts #152 & 153 in the linked thread in Antarctic folder provides satellite image evidence that the residual Thwaites Ice Tongue appears to currently be destabilizing: http://forum.arctic-sea-ice.net/index.php/topic,72.150.html#lastPost )


T. Murray, M. Nettles, N. Selmes, L. M. Cathles, J. C. Burton, T. D. James, S. Edwards, I. Martin, T. O’Farrell, R. Aspey, I. Rutt and T. Baugé (17 July 2015, Published Online June 25 2015), " Reverse glacier motion during iceberg calving and the cause of glacial earthquakes", Science; Vol. 349, no. 6245, pp. 305-308, DOI: 10.1126/science.aab0460


http://www.sciencemag.org/content/349/6245/305.abstract?sid=76ef658e-614c-409d-848f-b8e53f184c97


Abstract: "Nearly half of Greenland’s mass loss occurs through iceberg calving, but the physical mechanisms operating during calving are poorly known and in situ observations are sparse. We show that calving at Greenland’s Helheim Glacier causes a minutes-long reversal of the glacier’s horizontal flow and a downward deflection of its terminus. The reverse motion results from the horizontal force caused by iceberg capsize and acceleration away from the glacier front. The downward motion results from a hydrodynamic pressure drop behind the capsizing berg, which also causes an upward force on the solid Earth. These forces are the source of glacial earthquakes, globally detectable seismic events whose proper interpretation will allow remote sensing of calving processes occurring at increasing numbers of outlet glaciers in Greenland and Antarctica."

See also:
http://www.latimes.com/science/sciencenow/la-sci-sn-glacier-earthquake-iceberg-greenland-ice-20150625-story.html
http://www.npr.org/sections/thetwo-way/2015/06/25/417457888/study-reveals-what-happens-during-a-glacial-earthquake
http://phys.org/news/2015-08-glacial-earthquakes-sea-level.html

Extract: "It is only recently that scientists learned of the existence of glacial earthquakes–measurable seismic rumblings produced as massive chunks fall off the fronts of advancing glaciers into the ocean. In Greenland, these quakes have grown sevenfold over the last two decades and they are advancing northward, suggesting that ice loss is increasing as climate warms. But exactly what drives the quakes has been poorly understood. Now, a new study elucidating the quakes' mechanics may give scientists a way to measure ice loss remotely, and thus refine predictions of future sea-level rise. The study appears this week in the early online edition of the leading journal Science.
It shows that as the glacier front falls off into the water, or calves, there is a kickback. The rest of the glacier moves rapidly downward and backward–something like a skateboard that slips out from under a rider's feet and goes backward as the rider falls forward. This is what produces the quake, say the researchers. The force of that kickback can be so great, it can reverse the glacier's flow for a few minutes, from the equivalent of about 95 feet per day forward to about 130 feet per day backward. Earlier studies have shown that glaciers often speed up after calving, but did not show the more immediate backward motion that apparently produces the quakes.

"This gives us a far better explanation for the source of the earthquakes than we had before," said Meredith Nettles, a seismologist at Columbia University's Lamont-Doherty Earth Observatory and a coauthor of the study. "It will move us a long way towards being able to use remotely detectable seismic signals to estimate mass loss from a major class of events in both Greenland and Antarctica.""
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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #323 on: October 05, 2015, 08:10:24 PM »
The linked research present measurement from the GRACE satellite that confirm the RAPID findings that the AMOC is currently slowing down faster than expected due to natural fluctuations, which supports Hansen et al. (2015)'s position on this matter:

Felix W. Landerer, David N. Wiese, Katrin Bentel, Carmen Boening andMichael M. Watkins (2015), "North Atlantic meridional overturning circulation variations from GRACE ocean bottom pressure anomalies", Geophysical Research Letters, DOI: 10.1002/2015GL065730



http://onlinelibrary.wiley.com/doi/10.1002/2015GL065730/abstract


Abstract: "Concerns about North-Atlantic Meridional Overturning Circulation (AMOC) changes imply the need for a continuous, large-scale observation capability to detect changes on interannual to decadal time scales. Here, we present the first measurements of lower North-Atlantic-Deep-Water (LNADW) transport changes using only time-variable gravity observations from Gravity Recovery and Climate Experiment (GRACE) satellites from 2003 until now. Improved monthly gravity field retrievals allow the detection of North Atlantic interannual bottom pressure anomalies and LNADW transport estimates that are in good agreement with those from the ocean RAPID-MOCHA array. Concurrent with the observed AMOC transport anomalies from late-2009 through early-2010, GRACE measured ocean bottom pressures changes in the 3000–5000 m deep western North Atlantic on the order of 20 mm-H2O (200 Pa), implying a southward volume transport anomaly in that layer of approximately −5.5 Sv. Our results highlight the efficacy of space-gravimetry for observing AMOC variations to evaluate latitudinal coherency and long-term variability."
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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #324 on: October 07, 2015, 07:44:41 PM »

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #325 on: October 08, 2015, 07:36:24 PM »
The linked article reviews paleo-data w.r.t the bipolar see-saw mechanism associate past abrupt climate change events.  The paper states: "Our Antarctic high resolution data also suggest possible teleconnections between changes in low latitude atmospheric circulation and Antarctic without any Greenland temperature fingerprint."  This last statement highlights the risk that a modern increase in ENSO intensity (due to anthropogenic forcing) could trigger Antarctic ice mass loss independently of what Greenland's Ice Sheet does:

A. Landais, V. Masson-Delmotte, B. Stenni, E. Selmo, D.M. Roche, J. Jouzel, F. Lambert, M. Guillevic, L. Bazin, O. Arzel, B. Vinther, V. Gkinis and T. Popp  (15 April 2015) "A review of the bipolar see–saw from synchronized and high resolution ice core water stable isotope records from Greenland and East Antarctica", Quaternary Science Reviews, Volume 114, Pages 18–32, doi:10.1016/j.quascirev.2015.01.031


http://www.sciencedirect.com/science/article/pii/S0277379115000554

Abstract: "Numerous ice core records are now available that cover the Last Glacial cycle both in Greenland and in Antarctica. Recent developments in coherent ice core chronologies now enable us to depict with a precision of a few centuries the relationship between climate records in Greenland and Antarctica over the millennial scale variability of the Last Glacial period. Stacks of Greenland and Antarctic water isotopic records nicely illustrate a seesaw pattern with the abrupt warming in Greenland being concomitant with the beginning of the cooling in Antarctica at the Antarctic Isotopic Maximum (AIM). In addition, from the precise estimate of chronological error bars and additional high resolution measurements performed on the EDC and TALDICE ice cores, we show that the seesaw pattern does not explain the regional variability in Antarctic records with clear two step structures occurring during the warming phase of AIM 8 and 12. Our Antarctic high resolution data also suggest possible teleconnections between changes in low latitude atmospheric circulation and Antarctic without any Greenland temperature fingerprint."
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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #326 on: October 13, 2015, 08:18:11 AM »

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #327 on: October 13, 2015, 07:07:58 PM »
And still more responses by Hansen et al, to Dale Berner, amongst others:
http://www.atmos-chem-phys-discuss.net/15/20059/2015/acpd-15-20059-2015-discussion.html

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #328 on: October 13, 2015, 10:05:36 PM »
Do read the short paper 'Predictions Implicit in “Ice Melt” Paper and Global Implications' by Hansen and Sato and posted 12th October 2015.

http://www.columbia.edu/~jeh1/mailings/2015/20151012_IceMeltPredictions.pdf

This paper arises out of the discussion of the title parer to this thread. It is excellent and relevent to many of the discussion threads here. 

For example it places the detailed observations of Greenland glacier calving by Espen and others, and of Thwaites and Pine Island glaciers by AbruptSLR and others in their longer term context. It shows how such observations are important as "canaries in the coal mine".

Other highlights are predictive discussion of changes in ocean temperature, especially in the North Atlantic and implications for AMOC (atlantic meridional overturning circulation), and of winter extent of Antarctic ice shelves.

Policy implications concerning global CO2 levels are also summarised brilliantly.

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #329 on: October 14, 2015, 12:42:32 AM »
And still more responses by Hansen et al, to Dale Berner, amongst others:
http://www.atmos-chem-phys-discuss.net/15/20059/2015/acpd-15-20059-2015-discussion.html

It looks like citizen science is making some small contributions to the climate risk fight; and Neven should be complemented for running such a fine Forum.
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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #330 on: October 14, 2015, 07:50:46 PM »

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #331 on: October 15, 2015, 10:09:48 AM »
Yes, their comments about model biases, global energy imbalances, and therefore about estimated climate sensitivity in several of their responses are important.

Basically, models have smoothed out the oceanic response to the energy imbalance of CO2 forcing, and this makes model climate sensitivities appear lower than they really are. 


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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #332 on: October 17, 2015, 10:57:40 PM »
Quote
Review status
This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). A final paper in ACP is not foreseen.
https://archive.is/JudhH#selection-615.0-619.138

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #333 on: October 17, 2015, 11:05:28 PM »
And look at the response Williams et al got:
http://www.atmos-chem-phys-discuss.net/15/C7958/2015/acpd-15-C7958-2015-supplement.pdf

Yes

Quote
Extreme events are much more likely to occur after 2100 – therefore we recommend to avoid terminology such as “dangerous”. Hmm, yes, I guess that we should not be concerned about anything that happens 85 years from now – the dickens with those characters. The Dutch can migrate to Switzerland, after all.

didn't look good. Stoat reckons
Quote
is the reply of someone who has given up.


Richard Rathbone

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #334 on: October 18, 2015, 02:20:56 PM »
And look at the response Williams et al got:
http://www.atmos-chem-phys-discuss.net/15/C7958/2015/acpd-15-C7958-2015-supplement.pdf

They were making comments that showed they hadn't read the paper, I expected them to get short shrift, though perhaps not quite as bluntly put.

crandles

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #335 on: October 18, 2015, 04:27:39 PM »
They were making comments that showed they hadn't read the paper, I expected them to get short shrift, though perhaps not quite as bluntly put.

That is quite a different view to Stoats view that

the make-or-break one is Drijfhout et al.

Quote
The title of the paper is more suggestive than is justified by the scientific evidence. The conclusions cannot be regarded as being robust, as they are insufficiently supported by both modeling results and observations

Quote
which is fatal
{presumably to the paper having a chance of being published}

Lennart van der Linde

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #336 on: October 19, 2015, 09:26:25 AM »
For some reason the peer review process has been stopped and the discussion is closed:
http://www.atmos-chem-phys-discuss.net/15/20059/2015/acpd-15-20059-2015-discussion.html

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #337 on: October 19, 2015, 11:51:53 AM »
For some reason the peer review process has been stopped and the discussion is closed:
http://www.atmos-chem-phys-discuss.net/15/20059/2015/acpd-15-20059-2015-discussion.html

As I posted earlier
Quote
Review status
This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). A final paper in ACP is not foreseen.

IOW it did not get through peer review.


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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #338 on: October 19, 2015, 02:51:20 PM »
And look at the response Williams et al got:
http://www.atmos-chem-phys-discuss.net/15/C7958/2015/acpd-15-C7958-2015-supplement.pdf

Yes

Quote
Extreme events are much more likely to occur after 2100 – therefore we recommend to avoid terminology such as “dangerous”. Hmm, yes, I guess that we should not be concerned about anything that happens 85 years from now – the dickens with those characters. The Dutch can migrate to Switzerland, after all.

didn't look good. Stoat reckons
Quote
is the reply of someone who has given up.
Given up - yes: Given up on explaining things to people who can't (or refuse to) look beyond their sausage plate's horizon (as we say in Barvaria). This "recommendation" is beyond science. It is psychopatho-logics. Thus it warrants exactly the response they got.

Lennart van der Linde

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #339 on: October 19, 2015, 03:09:59 PM »
As I posted earlier
Quote
Review status
This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). A final paper in ACP is not foreseen.

IOW it did not get through peer review.

Yes, missed your earlier post...

Lennart van der Linde

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #340 on: October 19, 2015, 03:11:38 PM »
Given up - yes: Given up on explaining things to people who can't (or refuse to) look beyond their sausage plate's horizon (as we say in Barvaria). This "recommendation" is beyond science. It is psychopatho-logics. Thus it warrants exactly the response they got.

Yes. Let's hope Hansen will give his explanation of what happend soon.

crandles

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #341 on: October 19, 2015, 03:14:31 PM »

As I posted earlier
Quote
Review status
This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). A final paper in ACP is not foreseen.

IOW it did not get through peer review.

Hmm maybe not. That is now saying
Quote
Review status
This discussion paper is under review for the journal Atmospheric Chemistry and Physics (ACP).

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #343 on: October 19, 2015, 08:21:27 PM »
Yes, some bracing responses to Thorne's comments.   Well done to the lead author Hansen for being so combative, and so bringing out clearly the differences of opinion.

This discussion paper and the open review process are a great illustration of the debating that is present in publishing scientific papers.  Many people who are not close to academic research seem to think published papers are always wholly definitive. In practice, discussion and conclusions are often contingent to some extent, and the reader needs to bring their judgement when reading them.


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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #344 on: October 21, 2015, 01:56:03 AM »
I am up at the journal site and not seeing anything about " A final paper in ACP is not foreseen" which is their standard language for article rejection.
http://www.atmos-chem-phys-discuss.net/15/20059/2015/acpd-15-20059-2015-discussion.html

It said two minutes ago "This discussion paper is under review for the journal Atmospheric Chemistry and Physics (ACP)." Confusingly, the date on the page is 15 July 15 even though the last comment is the editors, dated 18 Sept 15.

"Status: closed (peer review stopped)" simply means that the journal has kept to the mid-September schedule it announced months ago. I believe that designated reviewers get one comment and authors get to respond, no further back and forth of reviewers responding to authors; designated editor makes the final decision.

I wonder who JudH is. Odd that someone would bother to archive this at a 3rd party site. Odd too if they replaced the 'under review' remark with 'final not foreseen'. Why not just link to the journal page instead? Possibly there is an editor or publisher above the designated article editor.

Is JudH trying to document an override of a previously announced decision, or forging the event? How would JudH know in advance that there was going to be a change, that it would be worth archiving?

https://archive.is/JudhH
« Last Edit: October 21, 2015, 09:09:04 AM by A-Team »

Lennart van der Linde

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #345 on: October 21, 2015, 07:06:20 AM »
Also see:
http://scienceblogs.com/stoat/2015/10/19/joan-crawford-has-risen-from-the-grave/

"Rumour has it that ACP’s online system switches to “Final publication not foreseen” when a certain amount of time has elapsed without the authors replying to all open-discussion comments and the editor making a decision."

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #346 on: October 21, 2015, 10:00:25 AM »
The page is still saying "Review status.This discussion paper is under review for the journal Atmospheric Chemistry and Physics (ACP)." The mysterious date above this has changed to 23 Jul 2015 from July 15th date yesterday.

Note that a paper, once accepted for the discussion journal, stays online permanently regardless of whether it is accepted for the main journal. In some cases, a discussion journal article continues to be cited in subsequent years in other papers by other authors in other journals, even though it never passed peer review into the main journal.

In other cases, the authors keep re-submitting revised versions to other journals of descending rank until the article is eventually published (after a new round of review), usually with a somewhat different title and abstract.

In still other cases, the initial article is terribly flawed but nonetheless gets through peer review on the first go-round. I've given examples of all three in other forums.

This article was never destined to move the policy needle -- which is hardly science-aware, much less science-driven in the US -- under any of these scenarios.

Hansen has submitted 40 replies to comments on the following dates, burdensome. The last of these was just 6 days ago. Everything is moving on schedule; the authors have not yet submitted a revised article for the co-editor's consideration that I can see. The only oddity is the JudH archive which could either be a journal algorithm glitch or a prank.

04 Aug 15   1
06 Oct 15   1
09 Oct 15   3
12 Oct 15   6
13 Oct 15   28
15 Oct 15   1

Here is the review process. http://www.atmospheric-chemistry-and-physics.net/peer_review/interactive_review_process.html
Quote
Open discussion (8 weeks)

Upon online publication the paper is open for public review and discussion, during which interactive comments can be published by designated referees (anonymous or named) and all interested members of the scientific community (named). Normally, every discussion paper receives at least two referee comments. Authors are asked to take part in the discussion by posting author comments as response to referee comments and short comments of the scientific community. For more information see interactive public discussion.
Final response

After the open discussion the authors are expected to publish a response to all comments (within 4 weeks, can be extended upon request). The co-editor can also publish additional comments or recommendations. Normally, however, formal editorial recommendations and decisions shall be made only after the authors have had an opportunity to respond to all comments, or if they request editorial advice before responding.
Submission of revised manuscript

Submission of a revised manuscript is expected only if the authors have satisfactorily addressed all comments, and if the revised manuscript meets the high quality standards of ACP (review criteria). In case of doubt, the authors shall consult the co-editor on whether she/he recommends preparation and submission of a revised manuscript or not. Normally the revised manuscript should be submitted no later than 4 to 8 weeks after the end of the open discussion. If more time is required for manuscript revision, the authors can request an extension.

Peer-review completion

In view of the access peer review and interactive public discussion, the co-editor either directly accepts/rejects the revised manuscript for publication in ACP or consults referees in the same way as during the completion of a traditional peer-review process. If necessary, additional revisions may be requested during peer-review completion until a final decision about acceptance/rejection for ACP is reached.
« Last Edit: October 21, 2015, 10:15:55 AM by A-Team »

crandles

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #347 on: October 21, 2015, 01:30:25 PM »
I copied https://archive.is/JudhH link from Stoat's http://scienceblogs.com/stoat/2015/10/17/hansen-et-al-rip/ post

I would guess that was done in case discussion papers that fail peer review are moved to a different location causing link on blog to fail rather than suggesting he expected apparent decision to be reversed.

Lennart van der Linde

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #348 on: October 21, 2015, 07:45:13 PM »
Hansen has submitted 40 replies to comments on the following dates, burdensome. The last of these was just 6 days ago. Everything is moving on schedule; the authors have not yet submitted a revised article for the co-editor's consideration that I can see. The only oddity is the JudH archive which could either be a journal algorithm glitch or a prank.

04 Aug 15   1
06 Oct 15   1
09 Oct 15   3
12 Oct 15   6
13 Oct 15   28
15 Oct 15   1

Don't forget his first response to the referees on Oct 19th.

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Re: Hansen et al paper: 3+ meters SLR by 2100
« Reply #349 on: October 22, 2015, 12:36:16 AM »
Quote
guess that was done in case discussion papers that fail peer review are moved to a different location causing link on blog to fail
Article are given permanent methodical links across the whole Copernicus portfolio of journals, the last 4 years minimally. None are moved to new urls, many reasons not to. That would be bad design because in theory the 'foreseeing of no final publication' could be appealed and revisited, necessitating multiple relocations subject to human error.

If they were moved, easy enough to find instantly by full title search at google. An unaffiliated archival service is not an official record; it could be hacked, edited, spoofed, mitm'ed etc. Just like with PayPal, it's better to type in journal url letters yourself.

Remember, the 'discussion journal' is a journal in its own right: not every submission is approved by the editor for the discussion journal. This differentiates it from a mere storage area.

Quite a few submissions need to be brought up to snuff in terms of typos, graphics and grammer before wasting precious reviewer time; others are just double-publishing attempts, plagiarized content, or crank rubbish that the editor disposes of. There is no public record of unaccepted submissions because cranks and phonies would then link to these like they had been published, damaging the brand. I don't know of any way to filter for all articles for which 'final publication is not foreseen'.

Quite a good system.

I enjoy reading rejected articles, finding value in some parts, and sometimes wondering (like the poor authors?) what the heck from so wrong with them that they weren't fixable even accommodating all the reviewers' suggestions. Payback for past slight? Turf protection by a reviewer? The full story is not really disclosed.

Quote
Gravitational and magnetic measurements collected over Jakobshavn Isbræ suggest that the ice/bed interface in the main trunk of the glacier consists of a sediment wedge of up to 2400 m thick that reaches more than 54 km inland of the grounding line (Block and Bell, 2011)