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Author Topic: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)  (Read 235199 times)

wdmn

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1000 on: April 29, 2019, 10:33:10 PM »
I'm surprised by the tone of the responses I get when I post a scientific study that contradicts the contention that we're all doomed to perish in a climate catastrophe.  And I'm curious about some of the responses I see on this website when posting positive articles about renewable energy or advocating for cracking down on fossil fuel emissions.

Do you think it doesn't matter?  That there's no point in advocating for change?

Should we just be placing bets on when the first blue ocean event in the Arctic Ocean will occur or the first evidence of widespread MICI in the WAIS?

Ken,

I'm not quite sure of the tone you mention, or whether it was present in my post, but I would point out a few things in response.

1) As I mentioned in my post, the first image I attached was tweeted recently by Greta Thunberg, who is by no means a defeatist.

2) The second series of images in my post was from Glen Peters, who, considering he works to lobby for action on climate change, is not a defeatist.

3) As I concluded in my post, what we are saying is that by not adopting the precautionary principle, we are exposing ourselves to undue risk.

Let me elaborate on the third. Currently you appear to be optimistic that:

a) The market is transitioning fast enough that the incredibly rapid decarbonization of our societies will be possible without passing 2C -- or possibly even 1.5C -- of warming.

b) Countries -- especially petrostates -- have electorates and politicians strong enough to resist the pressures to grow the economy and maintain jobs, and will decide to keep oil and coal in the ground.

I think those of us who are advocating for adhering to the precautionary principle are suggesting that after 30+ years of international meetings, and several international agreements, because global emissions continue to rise -- and are likely under reported, as I provided evidence for in my previous post -- perhaps it is not prudent to trust in a) and b) happening.

If we are not to throw up our hands in despair -- as it appears neither Greta or Glen have -- while still looking at things honestly, then we must throw our resources and efforts behind creating the political climate that will allow for much larger scale, collective efforts to move in a different direction. Before you can plan your path of action, you better know what the risks are. And ignoring the massive risks that exist should we be too late to prevent 2C of warming by relying on a) and b), will lead us to adopt the wrong plan of action.

My previous post makes it quite clear that we need to plan for the large scale removal of CO2 from the atmosphere. As pointed out, this is cannot occur through existing technologies. This suggests that massive, international research and development efforts must be initiated. Whether that is towards nuclear fusion, or something else, I am not fit to decide.

It is also clear that we need to bring an end to deforestation, which most occurs in the tropics, and begin massive reforestation and "re-wilding" efforts. That appears not to be happening, and we appear to be going in the wrong direction. So we had best figure out a way to pull this off, and soon, rather than just trusting in a) and b).

I wouldn't want to speak for anyone else in the thread. That is just how I see things, and that is what I am doing in my life; I believe it's time to dream big and push hard, not just trusting that nature (i.e. the market) will take its corrective course exactly on schedule, and save us from the climate catastrophe. I am advocating for the opposite of passivity, which I believe your optimism risks encouraging.
« Last Edit: April 29, 2019, 10:40:41 PM by wdmn »

sidd

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1001 on: April 29, 2019, 10:49:18 PM »
Re: Weddel-Ross-Amundsen connector

The reference is Vaughan et al. (2011)

doi: 10.1029/2011GC003688

"four candidate seaways across WAIS, none of which connect the Weddell and Ross seas without passing through the Amundsen Sea embayment ice sheet. This establishes the Amundsen Sea embayment ice sheet, not only as the center of current Antarctic ice loss, but one of key importance in understanding deglaciation during recent interglacial periods."

"The methods currently at our disposal do not allow us to constrain, with confidence, which recent interglacial saw the last open West Antarctic seaways. However, given that during the last interglacial (MIS 5e), air temperature in Antarctica was substantially warmer than present for several thousand years [Sime et al., 2009] and at the same time, ice‐loss from Antarctica almost certainly contributed to higher global sea levels [Kopp et al., 2009], it would appear that MIS 5e is a strong candidate."

So, probably open in the Eemian.

sidd

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1002 on: April 29, 2019, 10:51:10 PM »
I'm surprised by the tone of the responses I get when I post a scientific study that contradicts the contention that we're all doomed to perish in a climate catastrophe.  And I'm curious about some of the responses I see on this website when posting positive articles about renewable energy or advocating for cracking down on fossil fuel emissions.

Do you think it doesn't matter?  That there's no point in advocating for change?

Should we just be placing bets on when the first blue ocean event in the Arctic Ocean will occur or the first evidence of widespread MICI in the WAIS?

i'm absolutely sure that despite the fact that we (some of us more than others) shall face serious disruption in their lives, live style, work, transportation, food as well as simple drowning of major ocean side cities, we are not going to be extinct through climate change.

if anything it COULD happen indirectly through human behaviour once the shit hits the fan in serious. considering the possibility that some guys could come up with desperate reactions once their remaing liveable land that is mostly ocean side shall disappear in ocean waters.

IMO the only 99.9% thread (just because 100% does not exist IMO LOL) is that the sea-level will rise by many meters and considering where most people are living and how high their dwelling places lay above sea-level, a human catastrophy in form of social uproar, revolutions an anarchy is inevitable. but still, mankind will survive as long as no-one will press the famous red button and that, i'm afraid is not so certain, as uncertain it is that we are doomed, it's still possible if the kind of the donald will be in charge once time has come.

it will be those who deny who will overreact once denial is rendered impossible by the universal laws of physics.

reallly ugly events always happens to mankind if some of them feel god-like and simply suppress the rules and facts that are universal, have prevailed in throughout history and will prevail at any time in the future as long as the non-infinite future will last.

Ken Feldman

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1003 on: April 30, 2019, 12:51:48 AM »
The link references demonstrate that surface melt water on Antarctic ice shelves does not necessarily lead to hydrofracturing and collapse of the ice shelf.  Furthermore, ice-sheet models do not currently include the effects of surface melt water and will need to be improved.

https://www.nature.com/articles/544306a

Quote
Kingslake et al. use historical satellite imagery and aerial photography to show that about 700 large-scale lake and stream systems have persisted for decades on Antarctica's ice shelves (and on some of the glaciers that feed them), often transporting water by as much as 120 kilometres. For example, the authors find that meltwater lakes and streams have existed on the Roi Baudouin Ice Shelf since 1947. A handful of previous studies5,10 have documented surface lakes and streams on individual ice shelves over a span of a few years. But the authors' work is the first to extensively map meltwater features and drainage systems on all of Antarctica's ice shelves, over multiple decades.

Streams and rivers, like lakes, act as surface loads on ice shelves, but they also play a crucial part in the movement and distribution of meltwater. As discussed by Kingslake and colleagues, a stream can form when a lake overflows, allowing meltwater to be transported to lower elevations, and perhaps into another lake. Alternatively, Bell et al. show that a large river (or river network) can enable a substantial proportion of an ice shelf's total meltwater volume to be exported to the ocean — often by a large waterfall at the ice edge, as observed on the Nansen Ice Shelf by the authors. This process of meltwater export therefore mitigates the risk that meltwater-induced ponding will lead to ice-shelf break-up.

Surface meltwater on the Nansen Ice Shelf was first detected in 1909 by Ernest Shackleton and his Nimrod team, who repeatedly had to cross, and navigate around, lakes and streams on their way to the magnetic South Pole11. Now, Bell and colleagues use satellite imagery to show that six of the eight summer melt seasons between 2006 and 2015 were warm enough to allow the formation of a large-scale river network and ice-edge waterfall, facilitating surface-meltwater export to the ocean. Once the waterfall formed, it persisted for 5–25 days, and for longest when air temperatures were highest.

https://www.nature.com/articles/nature22048

Quote

Antarctic ice shelf potentially stabilized by export of meltwater in surface river
Robin E. Bell, Winnie Chu, Jonathan Kingslake, Indrani Das, Marco Tedesco, Kirsty J. Tinto, Christopher J. Zappa, Massimo Frezzotti, Alexandra Boghosian & Won Sang Lee

Nature volume 544, pages 344–348 (20 April 2017) | Download Citation

Abstract

Meltwater stored in ponds1 and crevasses can weaken and fracture ice shelves, triggering their rapid disintegration2. This ice-shelf collapse results in an increased flux of ice from adjacent glaciers3 and ice streams, thereby raising sea level globally4. However, surface rivers forming on ice shelves could potentially export stored meltwater and prevent its destructive effects. Here we present evidence for persistent active drainage networks—interconnected streams, ponds and rivers—on the Nansen Ice Shelf in Antarctica that export a large fraction of the ice shelf’s meltwater into the ocean. We find that active drainage has exported water off the ice surface through waterfalls and dolines for more than a century. The surface river terminates in a 130-metre-wide waterfall that can export the entire annual surface melt over the course of seven days. During warmer melt seasons, these drainage networks adapt to changing environmental conditions by remaining active for longer and exporting more water. Similar networks are present on the ice shelf in front of Petermann Glacier, Greenland, but other systems, such as on the Larsen C and Amery Ice Shelves, retain surface water at present. The underlying reasons for export versus retention remain unclear. Nonetheless our results suggest that, in a future warming climate, surface rivers could export melt off the large ice shelves surrounding Antarctica—contrary to present Antarctic ice-sheet models1, which assume that meltwater is stored on the ice surface where it triggers ice-shelf disintegration.

https://www.nature.com/articles/nature22049

Quote

Widespread movement of meltwater onto and across Antarctic ice shelves
Jonathan Kingslake, Jeremy C. Ely, Indrani Das & Robin E. Bell

Nature volume 544, pages 349–352 (20 April 2017) | Download Citation
A Corrigendum to this article was published on 08 November 2017

This article has been updated

Abstract

Surface meltwater drains across ice sheets, forming melt ponds that can trigger ice-shelf collapse1,2, acceleration of grounded ice flow and increased sea-level rise3,4,5. Numerical models of the Antarctic Ice Sheet that incorporate meltwater’s impact on ice shelves, but ignore the movement of water across the ice surface, predict a metre of global sea-level rise this century5 in response to atmospheric warming6. To understand the impact of water moving across the ice surface a broad quantification of surface meltwater and its drainage is needed. Yet, despite extensive research in Greenland7,8,9,10 and observations of individual drainage systems in Antarctica10,11,12,13,14,15,16,17, we have little understanding of Antarctic-wide surface hydrology or how it will evolve. Here we show widespread drainage of meltwater across the surface of the ice sheet through surface streams and ponds (hereafter ‘surface drainage’) as far south as 85° S and as high as 1,300 metres above sea level. Our findings are based on satellite imagery from 1973 onwards and aerial photography from 1947 onwards. Surface drainage has persisted for decades, transporting water up to 120 kilometres from grounded ice onto and across ice shelves, feeding vast melt ponds up to 80 kilometres long. Large-scale surface drainage could deliver water to areas of ice shelves vulnerable to collapse, as melt rates increase this century. While Antarctic surface melt ponds are relatively well documented on some ice shelves, we have discovered that ponds often form part of widespread, large-scale surface drainage systems. In a warming climate, enhanced surface drainage could accelerate future ice-mass loss from Antarctic, potentially via positive feedbacks between the extent of exposed rock, melting and thinning of the ice sheet.

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1004 on: April 30, 2019, 02:49:03 AM »
The linked reference indicates that the Northwest portion of the Ross Ice Shelf has basal ice melt rates that are about ten times higher than previously assumed by consensus climate science.  While this may not be an immediate threat to WAIS stability, it certainly contributes to partially destabilize the RIS:

Craig L. Stewart et al. (2019), "Basal melting of Ross Ice Shelf from solar heat absorption in an ice-front polynya", Nature Geoscience, DOI: https://doi.org/10.1038/s41561-019-0356-0

https://www.nature.com/articles/s41561-019-0356-0

Abstract: "Ice–ocean interactions at the bases of Antarctic ice shelves are rarely observed, yet have a profound influence on ice sheet evolution and stability. Ice sheet models are highly sensitive to assumed ice shelf basal melt rates; however, there are few direct observations of basal melting or the oceanographic processes that drive it, and consequently our understanding of these interactions remains limited. Here we use in situ observations from the Ross Ice Shelf to examine the oceanographic processes that drive basal ablation of the world’s largest ice shelf. We show that basal melt rates beneath a thin and structurally important part of the shelf are an order of magnitude higher than the shelf-wide average. This melting is strongly influenced by a seasonal inflow of solar-heated surface water from the adjacent Ross Sea Polynya that downwells into the ice shelf cavity, nearly tripling basal melt rates during summer. Melting driven by this frequently overlooked process is expected to increase with predicted surface warming. We infer that solar heat absorbed in ice-front polynyas can make an important contribution to the present-day mass balance of ice shelves, and potentially impact their future stability."

Edit: I note that it is the Northwest corner of the RIS which currently buttresses the Byrd Glacier.
« Last Edit: April 30, 2019, 05:07:08 PM by AbruptSLR »
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wdmn

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1005 on: April 30, 2019, 06:54:45 AM »
@Ken Feldman,

I note that you have chosen not to reply to the arguments made in my last two posts, and am wondering as to why.

Sleepy

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1006 on: April 30, 2019, 07:28:12 AM »
Why argue with someone who denies conclusions by a AR6 author? Let him derail some other thread.
Omnia mirari, etiam tritissima.
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Science is a jealous mistress and takes little account of a man's feelings.

kiwichick16

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1007 on: April 30, 2019, 09:59:49 AM »
@  Sleepy.......+1

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1008 on: April 30, 2019, 06:03:02 PM »
The linked commentary warns that abrupt permafrost thawing could double the GHG emissions from consensus climate science estimates from the permafrost this century:

Turetsky et al. (2019), "Permafrost collapse is accelerating carbon release", Nature 569, 32-34, doi: 10.1038/d41586-019-01313-4

https://www.nature.com/articles/d41586-019-01313-

Extract: "Current models of greenhouse-gas release and climate assume that permafrost thaws gradually from the surface downwards. Deeper layers of organic matter are exposed over decades or even centuries, and some models are beginning to track these slow changes.

But models are ignoring an even more troubling problem. Frozen soil doesn’t just lock up carbon — it physically holds the landscape together. Across the Arctic and Boreal regions, permafrost is collapsing suddenly as pockets of ice within it melt. Instead of a few centimetres of soil thawing each year, several metres of soil can become destabilized within days or weeks. The land can sink and be inundated by swelling lakes and wetlands.

We estimate that abrupt permafrost thawing in lowland lakes and wetlands, together with that in upland hills, could release between 60 billion and 100 billion tonnes of carbon by 2300. This is in addition to the 200 billion tonnes of carbon expected to be released in other regions that will thaw gradually. Although abrupt permafrost thawing will occur in less than 20% of frozen land, it increases permafrost carbon release projections by about 50%. Gradual thawing affects the surface of frozen ground and slowly penetrates downwards. Sudden collapse releases more carbon per square metre because it disrupts stockpiles deep in frozen layers.

Furthermore, because abrupt thawing releases more methane than gradual thawing does, the climate impacts of the two processes will be similar. So, together, the impacts of thawing permafrost on Earth’s climate could be twice that expected from current models."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1009 on: April 30, 2019, 07:23:59 PM »
The linked reference indicates that: "Our results imply decreased future ocean carbon storage due to gyre expansion and two opposing feedbacks to expanding oxygen-deficient zones, the net effects of which on ocean carbon storage require future research."

Frank J. Pavia, Robert F. Anderson, Phoebe J. Lam, B. B. Cael, Sebastian M. Vivancos, Martin Q. Fleisher, Yanbin Lu, Pu Zhang, Hai Cheng, and R. Lawrence Edwards (April 29, 2019), "Shallow particulate organic carbon regeneration in the South Pacific Ocean", PNAS, https://doi.org/10.1073/pnas.1901863116

https://www.pnas.org/content/early/2019/04/25/1901863116

Significance
Plankton in the sunlit surface ocean photosynthesize, fixing dissolved CO2 into particulate organic carbon (POC). This POC sinks and is respired, releasing CO2 into subsurface waters that are sequestered from the atmosphere. The depth scale over which this regeneration happens strongly affects atmospheric CO2, but estimates to date have been sparse and challenging to interpret. We use a new geochemical method to determine POC regeneration depth scales at unprecedented resolution in the South Pacific Ocean, finding shallow regeneration in both oxygen-deficient zone and oligotrophic gyre settings. Our results imply decreased future ocean carbon storage due to gyre expansion and two opposing feedbacks to expanding oxygen-deficient zones, the net effects of which on ocean carbon storage require future research.

Abstract
Particulate organic carbon (POC) produced in the surface ocean sinks through the water column and is respired at depth, acting as a primary vector sequestering carbon in the abyssal ocean. Atmospheric carbon dioxide levels are sensitive to the length (depth) scale over which respiration converts POC back to inorganic carbon, because shallower waters exchange with the atmosphere more rapidly than deeper ones. However, estimates of this carbon regeneration length scale and its spatiotemporal variability are limited, hindering the ability to characterize its sensitivity to environmental conditions. Here, we present a zonal section of POC fluxes at high vertical and spatial resolution from the GEOTRACES GP16 transect in the eastern tropical South Pacific, based on normalization to the radiogenic thorium isotope 230Th. We find shallower carbon regeneration length scales than previous estimates for the oligotrophic South Pacific gyre, indicating less efficient carbon transfer to the deep ocean. Carbon regeneration is strongly inhibited within suboxic waters near the Peru coast. Canonical Martin curve power laws inadequately capture POC flux profiles at suboxic stations. We instead fit these profiles using an exponential function with flux preserved at depth, finding shallow regeneration but high POC sequestration below 1,000 m. Both regeneration length scales and POC flux at depth closely track the depths at which oxygen concentrations approach zero. Our findings imply that climate warming will result in reduced ocean carbon storage due to expanding oligotrophic gyres, but opposing effects on ocean carbon storage from expanding suboxic waters will require modeling and future work to disentangle.

See also:

Title: "Earth's Oceans May Lose a Key Part of Their Ability to Capture Carbon"

https://www.inverse.com/article/55357-warming-oceans-aren-t-as-good-at-capturing-carbon

“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

Ken Feldman

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1010 on: April 30, 2019, 08:03:40 PM »
Ken,

While I appreciate your perspective, it seems to be out of step with reality.

The first image below was recently tweeted by Greta Thunberg showing that pathways required to limit warming to 1.5C (see below). All realistic pathways rely on negative emissions, which will either require massive reforestation (which means limiting and reversing urban sprawl and other development), or carbon capture technology powered by non-emitting energy sources we currently do not have.

The second set of three images comes from Glen Peters, Research Director at the Centre for International Climate Research. It shows the required emissions reductions for 2C, or to meet the Paris agreement. It shows what is required by the rest of the world if India, China, the Euro zone and the US achieve emissions reductions consistent with Paris.

Caption: a) Global warming under 2 °C with a 75% probability, with negligible development of engineered sinks and land use change (LUC); (b) global warming under 2 °C with a 66% probability and negligible development in engineered sinks and LUC; and (c) global warming under 2 °C with a 75% probability, and with scalable development in engineered sinks and LUC.)

Please note three things, which Glen Peters also recognizes: 1) As far as we know, passing 2C of warming will make it very difficult to avoid catastrophic climate change; 2) The image assumes 2017 as a turnaround date. This did not happen (nor is it expected to happen this year), making the required reductions even more significant; 3) It is likely that the emissions pathways laid out are optimistic, since they rely on IPCC projections which have been proven to understate the risks; and it has recently been confirmed that emissions from the tar sands are up to 64% higher than reported (see https://www.cbc.ca/news/technology/oilsands-carbon-emissions-study-1.5106809?__vfz=medium%3Dsharebar). If this is the case in Canada we can expect that emissions are also higher than reported elsewhere in the world, meaning that we have already emitted more (and potentially much more) than assumed by these pathways.

Last month a "massive analysis" came out stating all of the above in a different way:

"The massive analysis shows that meeting the 2C target is exceptionally difficult in all but the most optimistic climate scenarios. One pathway is to immediately and aggressively pursue carbon-neutral energy production by 2030 and hope that the atmosphere's sensitivity to carbon emissions is relatively low, according to the study. If climate sensitivity is not low, the window to a tolerable future narrows and in some scenarios, may already be closed.

... If the climate sensitivity is greater than 3 Kelvin (median of assumed distribution), the pathway to a tolerable future is likely already closed."

Subsequent to this massive analysis, the preliminary results from the new generation of climate models -- which will inform the next IPCC report -- began to be released.

"Early results suggest ECS values from some of the new CMIP6 climate models are higher than previous estimates, with early numbers being reported between 2.8C and 5.8C. This compares with the previous coupled model intercomparison project (CMIP5), which reported values between 2.1C to 4.7C. The IPCC’s fifth assessment report (AR5) assessed ECS to be “likely” in the range 1.5C to 4.5C and “very unlikely” greater than 6C. (These terms are defined using the IPCC methodology.)"

https://www.carbonbrief.org/guest-post-why-results-from-the-next-generation-of-climate-models-matter

The median given by AR5 was 3C (or 3K). The difference with the new models is represented graphically below in the third image.

As we are now seeing the new models are giving a value of ECS ranging from 2.8C to 5.8C, with a median of 4.3C.

So what is to be gained by assuming the lower risk scenarios, when, should you be wrong -- as I would suggest the overwhelming amount of evidence now indicates -- we expose ourselves to a tremendous amount of risk?

This seems to me the underlying message of ASLR's posts.

wdmm,

I replied above by posting the IPCC 2018 report, which clearly indicates the remaining emissions allowable to meet the 1.5 C limit and 2.0 limit.  Yes, it will take a massive effort, but now that renewable cost less than fossil fuels and electric cars are nearing cost parity with gas powered vehicles, it's foreseeable that we'll be on track for the emissions cuts needed.  And a world running on carbon-free electricity and carbon neutral transportation by 2050 is not out of the question.

Again, here's a link to the IPCC 2018 study:

https://www.ipcc.ch/2018/10/08/summary-for-policymakers-of-ipcc-special-report-on-global-warming-of-1-5c-approved-by-governments/

I've also posted the study showing that if all fossil fuel infrastructure were replaced at the end of its useful life by renewables or carbon-free sources, we'd meet the emissions budgets.  I've posted extensively in the policy and solutions threads on the progress we're making in deploying renewables, battery storage, direct capture of carbon and battery electric vehicles.

As to the CIMP 6 models, keep in mind that it's early yet.  The first results may not hold up.  And many climate scientists are skeptical about the stories that have come out.

https://www.sciencemag.org/news/2019/04/new-climate-models-predict-warming-surge

Quote
In earlier models, doubling atmospheric carbon dioxide (CO2) over preindustrial levels led models to predict somewhere between 2°C and 4.5°C of warming once the planet came into balance. But in at least eight of the next-generation models, produced by leading centers in the United States, the United Kingdom, Canada, and France, that “equilibrium climate sensitivity” has come in at 5°C or warmer. Modelers are struggling to identify which of their refinements explain this heightened sensitivity before the next assessment from the United Nations’s Intergovernmental Panel on Climate Change (IPCC). But the trend “is definitely real. There’s no question,” says Reto Knutti, a climate scientist at ETH Zurich in Switzerland. “Is that realistic or not? At this point, we don’t know.”

Quote
Many scientists are skeptical, pointing out that past climate changes recorded in ice cores and elsewhere don’t support the high climate sensitivity—nor does the pace of modern warming. The results so far are “not sufficient to convince me,” says Kate Marvel, a climate scientist at NASA’s Goddard Institute for Space Studies in New York City. In the effort to account for atmospheric components that are too small to directly simulate, like clouds, the new models could easily have strayed from reality, she says. “That’s always going to be a bumpy road.”

Quote
In assessing how fast climate may change, the next IPCC report probably won’t lean as heavily on models as past reports did, says Thorsten Mauritsen, a climate scientist at Stockholm University and an IPCC author. It will look to other evidence as well, in particular a large study in preparation that will use ancient climates and observations of recent climate change to constrain sensitivity. IPCC is also not likely to give projections from all the models equal weight, Fyfe adds, instead weighing results by each model’s credibility.

I'll concede that article does conclude that the world may be warming faster than humans can cope with.

I think we're on the same page (along with activists like Greta Thunberg) about the need to reduce emissions and draw greenhouse gases out of the atmosphere into permanent sinks.  Given that it may be too late, as many of the other posters in this thread claim, are we out of touch with reality?

Mozi

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1011 on: April 30, 2019, 08:05:43 PM »
Perhaps it would be better to take your debate to a different thread.

Ken Feldman

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1012 on: April 30, 2019, 10:05:44 PM »
As some has noted earlier in this thread, RCP2.6 is no longer attainable.
https://news.agu.org/press-release/new-studies-highlight-challenge-of-meeting-paris-agreement-climate-goals/
A short quote and snipping out the top image from the second study with Peters.
Quote
Stone, with the National Institute of Water and Atmospheric Research, said Peters’ study shows no one country can slip up in the goal to meet climate goals.

“It is hard to argue against their conclusion that we need to start seriously considering options such as the deployment of solar geoengineering, with all of the risks that entails, if the world is serious about achieving the Paris Agreement goals,” he said.

Here's a good article explaining why you can't make statements like "RCP 2.6 is no longer attainable"

https://www.theatlantic.com/science/archive/2019/01/rcp-85-the-climate-change-disaster-scenario/579700/

Quote
There are a few reasons it’s hard to say which RCP comes closest to our reality. First, most of the RCPs tell roughly the same story about global emissions until about 2025 or 2030. Second, the RCPs describe emissions across the entire sweep of the 21st century—and the century mostly hasn’t happened yet. Trying to pick the most likely RCP in 2018 is a bit like trying to predict the precise depth of late-night snowfall at 4:32 a.m.

The RCP 8.5 scenario may also become less likely in years to come, even if major polluters like the United States, China, and India never pass muscular climate policy. RCP 8.5 says that the global coal industry will eventually become seven times bigger than it is today. “It’s tough to claim that … that is a business-as-usual world,” Hausfather says. “It’s certainly a possible world, but we also live in a world today where solar is increasingly cheaper than coal.”

Here it is in graphical form (pink dots are observations through 2018, updated 3/6/2019), from a website maintained at Columbia University, Dr. James Hansen's employer.




Ken Feldman

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1013 on: April 30, 2019, 10:30:12 PM »
The linked reference indicates that changes in the Arctic plant community could result in the Artic being a net sink for carbon under the RCP 4.5 projection.

https://www.pnas.org/content/115/15/3882.short

Quote

Dependence of the evolution of carbon dynamics in the northern permafrost region on the trajectory of climate change

A. David McGuire, David M. Lawrence, Charles Koven, Joy S. Clein, Eleanor Burke, Guangsheng Chen, Elchin Jafarov, Andrew H. MacDougall, Sergey Marchenko, Dmitry Nicolsky, Shushi Peng, Annette Rinke, Philippe Ciais, Isabelle Gouttevin, Daniel J. Hayes, Duoying Ji, Gerhard Krinner, John C. Moore, Vladimir Romanovsky, Christina Schädel, Kevin Schaefer, Edward A. G. Schuur, and Qianlai Zhuang

PNAS April 10, 2018 115 (15) 3882-3887; first published March 26, 2018 https://doi.org/10.1073/pnas.1719903115
Significance

We applied regional and global-scale biogeochemical models that coupled thaw depth with soil carbon exposure to evaluate the dependence of the evolution of future carbon storage in the northern permafrost region on the trajectory of climate change. Our analysis indicates that the northern permafrost region could act as a net sink for carbon under more aggressive climate change mitigation pathways. Under less aggressive pathways, the region would likely act as a source of soil carbon to the atmosphere, but substantial net losses would not occur until after 2100. These results suggest that effective mitigation efforts during the remainder of this century could attenuate the negative consequences of the permafrost carbon–climate feedback.


Abstract

We conducted a model-based assessment of changes in permafrost area and carbon storage for simulations driven by RCP4.5 and RCP8.5 projections between 2010 and 2299 for the northern permafrost region. All models simulating carbon represented soil with depth, a critical structural feature needed to represent the permafrost carbon–climate feedback, but that is not a universal feature of all climate models. Between 2010 and 2299, simulations indicated losses of permafrost between 3 and 5 million km2 for the RCP4.5 climate and between 6 and 16 million km2 for the RCP8.5 climate. For the RCP4.5 projection, cumulative change in soil carbon varied between 66-Pg C (1015-g carbon) loss to 70-Pg C gain. For the RCP8.5 projection, losses in soil carbon varied between 74 and 652 Pg C (mean loss, 341 Pg C). For the RCP4.5 projection, gains in vegetation carbon were largely responsible for the overall projected net gains in ecosystem carbon by 2299 (8- to 244-Pg C gains). In contrast, for the RCP8.5 projection, gains in vegetation carbon were not great enough to compensate for the losses of carbon projected by four of the five models; changes in ecosystem carbon ranged from a 641-Pg C loss to a 167-Pg C gain (mean, 208-Pg C loss). The models indicate that substantial net losses of ecosystem carbon would not occur until after 2100. This assessment suggests that effective mitigation efforts during the remainder of this century could attenuate the negative consequences of the permafrost carbon–climate feedback.

The last sentence of the abstract is worth repeating.

Quote
This assessment suggests that effective mitigation efforts during the remainder of this century could attenuate the negative consequences of the permafrost carbon–climate feedback.


wdmn

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1014 on: April 30, 2019, 10:35:44 PM »
Perhaps it would be better to take your debate to a different thread.

It's okay. I don't need to respond. I will allow readers to decide whether Ken's reply to my first post was a strong one, or whether it was begging the question.


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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1015 on: May 01, 2019, 06:49:05 AM »
Re: CMIP6 coming in hot

Early days yet and all that, but one thing to keep in mind is that ECS is not derived, as I naively imagined, for letting the model run to equilibrium. Rather, i am informed by a modeller that an approximation is used

doi: 10.1029/2003GL018747

open access, read all about it, extrapolates the results to zero TOA flux. I can think of several ways this can go wrong with slowish climate feedbacks, no doubt there are others.

And then there's the clouds. And the aerosols. And ...

But most important, the real climate never finds the most likely trajectory, just a likely one. And if you dont correctly model the continually evolving landscape that guides all trajectories, you can wind up quite far away from what actually happens.

So, perhaps best to look at nearer future, things like TCR. I see that TCR is also coming in hotter in the models i have looked at, but not quite so much.

sidd

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1016 on: May 01, 2019, 09:36:56 AM »
One doesn't need models to understand what's behind us. Adding to last years record emissions, this planet passed safe(?) levels forty years ago. Maybe the EPA realized that when writing the 1983 report? What the IPCC really says (considering the RoW) is that the US (and it's western ilks) must be at net zero emissions ~2030.

Adding to my comment here:
https://forum.arctic-sea-ice.net/index.php/topic,2205.msg196975.html#msg196975
Others have argued for SRM as well, recycling an old comment from last year with Kevin Lister:
Kevin Lister, research fellow at Climate Institute, Washington D.C. argues for the need to lower the global average temperature to +0,5°C above pre.industrial. And the use of SRM.



https://unfccc.int/sites/default/files/resource/97_Talanoa%20Submission_climate%20institute.pdf

<snipping out the quote, those who are interested will read it anyway>
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1017 on: May 01, 2019, 03:48:38 PM »


Edit: I note that it is the Northwest corner of the RIS which currently buttresses the Byrd Glacier.

If I remember correctly a radar study of the shelf found 'rucking' mid shelf making it appear that when it 'grounded' ,last time, the forces from behind were so powerful as to drive these 'rucks'

As such I worry that there is a 'breaking point' (literally) in the shelf where back pressure leads to the contact with the ocean floor below being lost and so massive ,sudden , 'float off' of Ross followed by its rapid break up and melt.

For a shelf the size of France this is a real concern!
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1018 on: May 01, 2019, 04:28:00 PM »
The attached image is from the 4th National Climate Assessment estimates of RSLR for the USA coastlines in 2090 under RCP 8.5 (which I believe errs on the side of least drama, ESLD), which the EPA warns about in their new report “Guidance about Planning for Natural Disaster Debris."  Nevertheless, EPA Administrator Andrew Wheeler (of the Trump Administration) is stating 'that global warming won't hit hard for another 50 to 75 years.'  It seems that the Trump Administration is trying to score political points with its base by belittling climate change action, while covering its ass by issuing consensus science climate change reports.

Title: "EPA can’t deny its own warnings on climate change (Editorial)"

https://www.masslive.com/opinion/2019/04/epa-cant-deny-its-own-warnings-on-climate-change-editorial.html

Extract: "Now the EPA is cautioning local governments to prepare for climate-induced crises. A report last week comes despite references by EPA Administrator Andrew Wheeler that global warming won’t hit hard for another 50 to 75 years."
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1019 on: May 01, 2019, 04:30:47 PM »


Edit: I note that it is the Northwest corner of the RIS which currently buttresses the Byrd Glacier.

If I remember correctly a radar study of the shelf found 'rucking' mid shelf making it appear that when it 'grounded' ,last time, the forces from behind were so powerful as to drive these 'rucks'

As such I worry that there is a 'breaking point' (literally) in the shelf where back pressure leads to the contact with the ocean floor below being lost and so massive ,sudden , 'float off' of Ross followed by its rapid break up and melt.

For a shelf the size of France this is a real concern!

+1
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1020 on: May 01, 2019, 04:43:49 PM »
...
So, perhaps best to look at nearer future, things like TCR. I see that TCR is also coming in hotter in the models i have looked at, but not quite so much.

sidd

As a reminder, the attached image was posted in Reply #755:

Image Caption: "Figure 27. Time evolution of annual global mean air surface temperature anomalies for the idealized CO₂ forcing simulations abrupt-4xCO2 (red), 1pctCO2 (blue) and the control simulation (piControl; green). Solid lines are fits obtained with a two-layer energy balance model (discussed in sub-section 6.3). Also depicted are estimates of ECS and TCR."
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1021 on: May 01, 2019, 05:47:50 PM »
The Drawdown organization ranked disposal of old refrigerant materials (CFCs, HCFCs and HFCs) as the #1 ranked priority for limiting GMSTA increase by 2050.  The National Geographic Society is majority owned by 21st Century Fox; thus it is not surprising that the linked article by the National Geographic, cites this as '... an incredibly important solution."  As the risk of leakage of old refrigerant materials into the atmosphere is not considered in the SSP baseline scenarios, this matter actually represents a climate risk (of 17 years worth of US CO2 emissions equivalent if it is not dealt with) rather than a solution:

Title: "One overlooked way to fight climate change? Dispose of old CFCs."

https://www.nationalgeographic.com/environment/2019/04/disposing-old-cfcs-refrigerants-reduces-climate-change-greenhouse-gases-cheaply/

Extract: "Last year, a coalition of scientists and policy experts at the nonprofit Drawdown ranked the top one hundred climate change solutions by level of impact. No one guessed that refrigerant management, which includes CFCs and two other classes of chemicals known as HCFCs and HFCs, would top the list. But it did.

The Drawdown study estimated that properly disposing of old refrigerants, rather than letting them leak into the air, would be equivalent to preventing nearly 90 gigatons of carbon dioxide from reaching the atmosphere. That’s more than 17 years of U.S. CO2 emissions.

“It’s an incredibly important solution,” said Chad Frishmann, Drawdown’s Research Director.

But in order to achieve consensus, negotiators of the Montreal Protocol had to be forward-looking. The nations of the world agreed to ban future production of ozone-depleting chemicals but quantities of ozone-depleting gases that already existed, materials that have come to be known as “banks,” were left out of the agreement. The banks weren’t insignificant either. In 1988, the year before the protocol went into effect, the size of the CFC bank was slightly more than that year’s global emissions of CO2."

See also:

Extract: "Materials - Refrigerant Management

https://www.drawdown.org/solutions/materials/refrigerant-management

Extract: "In October 2016, officials from more than 170 countries met in Kigali, Rwanda, to negotiate a deal to address this problem. Through an amendment to the Montreal Protocol, the world will phase out HFCs—starting with high-income countries in 2019, then some low-income countries in 2024 and others in 2028. Substitutes are already on the market, including natural refrigerants such as propane and ammonium.

Scientists estimate the Kigali accord will reduce global warming by nearly one degree Fahrenheit. Still, the bank of HFCs will grow substantially before all countries halt their use. Because 90 percent of refrigerant emissions happen at end of life, effective disposal of those currently in circulation is essential. After being carefully removed and stored, refrigerants can be purified for reuse or transformed into other chemicals that do not cause warming."

Edit: I note that any potential 'solution' to our climate change situation is not a solution unless it is actually implemented.  Consensus climate science has been identifying potential 'solutions' since at least the 1980's and yet since that time we have continuously followed a BAU pathway.
« Last Edit: May 01, 2019, 06:16:05 PM by AbruptSLR »
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1022 on: May 01, 2019, 09:19:07 PM »
The GRACE satellite was an amazing tool from April 2002 until June 2017 & I look forward to seeing even better results from GRACE-FO:

Byron D. Tapley, et al. (2019), "Contributions of GRACE to understanding climate change", Nature Climate Change, volume 9, pages358–369, DOI: https://doi.org/10.1038/s41558-019-0456-2

https://www.nature.com/articles/s41558-019-0456-2

Abstract: "Time-resolved satellite gravimetry has revolutionized understanding of mass transport in the Earth system. Since 2002, the Gravity Recovery and Climate Experiment (GRACE) has enabled monitoring of the terrestrial water cycle, ice sheet and glacier mass balance, sea level change and ocean bottom pressure variations, as well as understanding responses to changes in the global climate system. Initially a pioneering experiment of geodesy, the time-variable observations have matured into reliable mass transport products, allowing assessment and forecast of a number of important climate trends, and improvements in service applications such as the United States Drought Monitor. With the successful launch of the GRACE Follow-On mission, a multi-decadal record of mass variability in the Earth system is within reach."

See also:

Title: "GRACE mission data contributes to our understanding of climate change"

https://news.utexas.edu/2019/04/29/grace-mission-data-contributes-to-our-understanding-of-climate-change/
&
https://phys.org/news/2019-04-grace-mission-contributes-climate.html

•   Extract: "GRACE enabled a measure of the quantity of heat added to the ocean and the location for said heat that remains stored in the ocean. GRACE has provided detailed observations, confirming that the majority of the warming occurs in the upper 2,000 meters of the oceans.
•   GRACE has observed that of the 37 largest land-based aquifers, 13 have undergone critical mass loss. This loss, due to both a climate-related effect and an anthropogenic (human-induced) effect, documents the reduced availability of clean, fresh water supplies for human consumption.
•   The information gathered from GRACE provides vital data for the federal agency United States Drought Monitor and has shed light on the causes of drought and aquifer depletion in places worldwide, from India to California"
Image caption: "Global representation of trends and variability in ice and water mass recovered by GRACE over 15 years. The top figure, which shows trend maps over Antarctica, Greenland and part of the Arctic, represent changes in ice mass. The middle trend map mainly represents changes in the terrestrial water storage. The bottom figure shows variability in ocean bottom pressure. In the last figure, the color scales represent variability, with the highest variability shown in red. Credit: Cockrell School of Engineering, The University of Texas at Austin"

See also:

Title: "GRACE-FO"

https://gracefo.jpl.nasa.gov/

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Sleepy

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1023 on: May 02, 2019, 07:35:01 AM »
Last year, a coalition of scientists and policy experts at the nonprofit Drawdown ranked the top one hundred climate change solutions by level of impact. No one guessed that refrigerant management, which includes CFCs and two other classes of chemicals known as HCFCs and HFCs, would top the list. But it did.
Heh, refrigerants was once my way into all of this, it started in the early 90s when talking to a really good hvac engineer. Heat pumps was my No1 hobby for many years and I don't need assistance to take care of those I use myself. My oldest in (24/7/365) use, is now 14 years old and even though it is "leak free" it has leaked (manufacturing and installation) and will leak during/after de-installation. All domestic heat pumps will leak at some point in time.
Most during operation thanks to crappy installations...

Everyone in that business knows that CFC is still around and why it shouldn't be used, everyone.
The newer blends is a result of the refrigerant oligopoly defending patented blends.
There has been alternative refrigerants for as long as there has been heat pumps.

Still, CFC is the only real success story we have to date, levels are dropping in the atmosphere.


Edit; instead of just vomiting over these companies I will try to add some more substance. Had breakfast and then checked the main AGGI site but it still wasn't updated with numbers for 2018 so I took a graph for R32 (HFC-32), "the new blue" from the refrigerant industry. It's not new, but comes with the same nasty property like non patended refrigerants like ethane(R170), propane (R290) and propylene (R1270), namely fire hazards.
R32 is also toxic and produces hydrogen fluoride while burning. R32 has been used for a long time in blends like the popular R410a, a blend of R32 and R125.
R125 is useless as a refrigerant, it's used to lower the fire hazards of R32.

Using AR4 numbers:
R410a has a GWP of 2088, R32(675), R125(3500).
R170(6), R290(3) and R1270(2)

Aha, someone says, R410a/R32 must surely be more efficent than the hydrocarbons!?
No. Adding a modeled COP comparison with R410a as baseline, as the second image.

I've used propylene myself in a R410a heat pump, for cooling it's great but for heating it only works really well down to ~0°C, to be able to use it effectively in sub zero temps you need to add ethane to increase the pressure in/of the blend. My problem some years back was that ethane was incredibly expensive, so I shelved further tests. But it will work just fine. In a domestic heat pump there's normally ~1kg of R410a or slightly less.
The fire hazards involved with hydrocarbons are easily fixed with sensors and fans but/and I guess people have a lot more flammable stuff in their homes without thinking about it at all.

The last twist here is that when you use hydrocarbons you lower the charge of refrigerant to roughly ~0,5kg (also visible in the second image). Lastly adding a P/T-comparison made almost seven years ago, when playing with these things. A 80/20 blend would do just fine as a drop in replacement for R410a. You don't even have to change the oil...

Edit2: Forgot the real twist but it's visible if you read carefully and look at the second image. When replacing R410a with a proper HC blend, you will have a better COP on your existing machine.

Hmm, sorry for this lengthy rant of memories...
« Last Edit: May 02, 2019, 02:06:14 PM by Sleepy »
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1024 on: May 02, 2019, 05:32:49 PM »
For those who doubt that the Earth's geomagnetic field can reverse at a very rapid rate, consider that during the Laschamp event (or Laschamps event for purists) the magnetic polarity flipped twice in only 250 years, or about 125 years per flip.

Title: "An extremely brief reversal of the geomagnetic field, climate variability and a super volcano"

https://phys.org/news/2012-10-extremely-reversal-geomagnetic-field-climate.html

Extract: "41,000 years ago, a complete and rapid reversal of the geomagnetic field occurred.

What is remarkable is the speed of the reversal: "The field geometry of reversed polarity, with field lines pointing into the opposite direction when compared to today's configuration, lasted for only about 440 years, and it was associated with a field strength that was only one quarter of today's field," explains Norbert Nowaczyk. "The actual polarity changes lasted only 250 years.

Besides giving evidence for a geomagnetic field reversal 41,000 years ago, the geoscientists from Potsdam discovered numerous abrupt climate changes during the last ice age in the analysed cores from the Black Sea, as it was already known from the Greenland ice cores. This ultimately allowed a high precision synchronisation of the two data records from the Black Sea and Greenland. The largest volcanic eruption on the Northern hemisphere in the past 100 000 years, namely the eruption of the super volcano 39400 years ago in the area of today's Phlegraean Fields near Naples, Italy, is also documented within the studied sediments from the Black Sea. The ashes of this eruption, during which about 350 cubic kilometers of rock and lava were ejected, were distributed over the entire eastern Mediterranean and up to central Russia. These three extreme scenarios, a short and fast reversal of the Earth's magnetic field, short-term climate variability of the last ice age and the volcanic eruption in Italy, have been investigated for the first time in a single geological archive and placed in precise chronological order."
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1025 on: May 02, 2019, 06:52:53 PM »
While there is a lot of uncertainty as to when peak fossil fuel consumption with occur, the linked article makes it sound like there is plenty of commercially recoverable fossil fuel to follow SSP5-baseline for the rest of this century:

Title: "Is peak oil looming?"

https://www.cnbc.com/advertorial/2019/03/19/is-peak-oil-looming.html

Extract: "Odd as it may seem, we have no precise, official, complete picture of global oil reserves. Figures vary depending on technological and economic factors — or stakeholder perspectives. Forecasting remains a difficult art for the energy that shaped the planet over last century, and probably will over this century too. Meanwhile, pessimists and optimists argue back and forth, as they await peak oil. But which peak oil — production or consumption?

In the fossil fuel category, 95 million barrels of oil are consumed each day worldwide. That works out to more than 15 billion liters or 4.8 billion tons a day.

“It is estimated that 2,900 billion barrels worth of oil remain. Currently known conventional reserves should ensure more than 40 years of production. Further discoveries may increase this period to 60 years, while unconventional resources such as shale oil and heavy oil could translate into 90 years,” says Etienne Anglès d’Auriac in conclusion."
« Last Edit: May 02, 2019, 07:56:20 PM by AbruptSLR »
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1026 on: May 02, 2019, 10:13:42 PM »
.ons...

...Everyone in that business knows that CFC is still around and why it shouldn't be used, everyone.
The newer blends is a result of the refrigerant oligopoly defending patented blends.
There has been alternative refrigerants for as long as there has been heat pumps....


Shame they are using CFCs in foam in the building industry in China. Apparently they are very easy to export too, in the form of hydrogenated polyols.

https://www.bbc.com/news/science-environment-44738952
« Last Edit: May 02, 2019, 11:37:11 PM by RoxTheGeologist »

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1027 on: May 02, 2019, 11:08:24 PM »
I frequently read articles that there are too many other priorities (like fighting infectious diseases and/or terror/crime) to spend much money on climate action.  However, as climate change is a risk multiplier to virtually all of these other high priority matters; climate action likely offers the best way to reduce future risks; otherwise (for example) instead of drug resistant diseases killing 10 million people per year by 2050; this risk could be several times higher due to synergies with potential abrupt climate change in the coming decades:

Title: "Drug resistance could kill 10M people per year by 2050, experts say"

https://www.axios.com/drug-resistance-kill-10million-people-year-2050-4f048f02-8664-4000-8315-e4ca51c29ff7.html

Extract: "Infectious disease experts tell Axios they agree with a dire scenario painted in the UN report posted earlier this week saying that, if nothing changes, antimicrobial resistance (AMR) could be "catastrophic" in its economic and death toll.

Threat level, per the report: By 2030, up to 24 million people could be forced into extreme poverty and annual economic damage could resemble that from the 2008–2009 global financial crisis, if pathogens continue becoming resistant to medications. By 2050, AMR could kill 10 million people per year, in its worst-case scenario."
&

Title: "Climate Change Is a Risk Multiplier for Terror and Crime"

https://unfccc.int/news/climate-change-is-a-risk-multiplier-for-terror-and-crime

Extract: "As the climate changes, so too do the conditions in which non-state armed groups operate. The complex risks presented by conflicts, climate change and increasingly fragile geophysical and socio-political conditions can contribute to the emergence and growth of non-state armed groups. Our new report examines the links between climate-fragility risks and non-state armed groups."
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1028 on: May 02, 2019, 11:09:35 PM »

.ons...

...Everyone in that business knows that CFC is still around and why it shouldn't be used, everyone.
The newer blends is a result of the refrigerant oligopoly defending patented blends.
There has been alternative refrigerants for as long as there has been heat pumps....


Shame they are using CFCs in foam in the building industry in China. Apparently they are very easy to export too, in the form of hydrogenated polyols.

https://www.bbc.com/news/science-environment-44738952

Just for the record, the quote above attributed to me was actually written by Sleepy.
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RoxTheGeologist

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1029 on: May 02, 2019, 11:35:12 PM »
Oh duh,... modified

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1030 on: May 03, 2019, 01:30:26 AM »
The linked reference indicates that under RCP8.5 reductions in anthropogenic aerosol emissions will likely result in more future heatwaves than currently assumed by consensus climate science:

Alcide Zhao, Massimo A. Bollasina & David S. Stevenson (30 April 2019), "Strong influence of aerosol reductions on future heatwaves", Geophysical Research Letters, https://doi.org/10.1029/2019GL082269

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL082269

Abstract
Using the Community Earth System Model Large Ensemble experiments, we investigate future heatwaves under the Representative Concentration Pathway 8.5 scenario, separating the relative roles of greenhouse gas increases and aerosol reductions. We show that there will be more severe heatwaves (in terms of intensity, duration and frequency) due to mean warming, with minor contributions from future temperature variability changes. While these changes come primarily from greenhouse gas (GHG) increases, aerosol reductions contribute significantly over the Northern Hemisphere. Furthermore, per degree of global warming, aerosol reductions induce a significantly stronger response in heatwave metrics relative to GHG increases. The stronger response to aerosols is associated with aerosol‐cloud interactions which are still poorly understood and constrained in current climate models. This suggests that there may exist large uncertainties in future heatwave projections, highlighting the critical significance of reducing uncertainties in aerosol‐cloud interactions for reliable projection of climate extremes and effective risk management.

Plain Language Summary
The past few years have seen record heatwaves worldwide, primarily driven by human activities. We used a state‐of‐the‐art climate model to investigate future changes in heatwave characteristics under the Representative Concentration Pathway 8.5 scenario, and seek to separate the roles of projected changes in anthropogenic greenhouse gases and aerosols. The model shows that there will be more severe heatwaves (in terms of intensity, duration and frequency) primarily because of global warming, while the internal variability of the climate system does not change much by 2100 and hence has limited influences. Also, these changes are mainly associated with greenhouse gas increases. However, anthropogenic aerosol changes have important influences, through their effects on clouds and radiation, and produce larger impacts comparing to GHGs per unit of warming. Effects of aerosols on clouds such as changes in cloudiness and other rapid adjustments (e.g. changes in vertical temperature profiles), however, are still poorly represented in present generation climate models, leading to large uncertainties in future heatwave projections. Therefore, we call the attention of the community to prioritize efforts into reducing uncertainties involved in aerosol‐cloud interactions, in order to get reliable projections of future climate extremes, as well as effective strategies for climate risk management.

Edit, see also:

'The growing threat of heat disasters'

https://iopscience.iop.org/article/10.1088/1748-9326/ab0bb9/meta
« Last Edit: May 03, 2019, 03:06:27 AM by AbruptSLR »
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1031 on: May 03, 2019, 08:17:13 AM »
.ons...

...Everyone in that business knows that CFC is still around and why it shouldn't be used, everyone.
The newer blends is a result of the refrigerant oligopoly defending patented blends.
There has been alternative refrigerants for as long as there has been heat pumps....


Shame they are using CFCs in foam in the building industry in China. Apparently they are very easy to export too, in the form of hydrogenated polyols.

https://www.bbc.com/news/science-environment-44738952

Yeah, what's truly surprising (after decades...) is that the "experts" out there are still surprised, gobsmacked and shocked, that R11 is still in use and for sale. It's on frickin' youtube...

What's visible here is one nitrogen and one R22 canister, prior to that he used R11 to clean the pipes. All of it vented into the air.



Edit; correcting the URL.
« Last Edit: May 05, 2019, 07:02:27 AM by Sleepy »
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1032 on: May 04, 2019, 01:36:56 PM »
The attached images are from the linked IPCC AR5 Synthesis Report, and indicates that the WGIII Baseline Global Mean Surface Temperature Increase (above pre-industrial) that reflect the Cancun commitments are lower than that for the mean RCP 8.5 scenario by 2100 (remember that we are currently exceeding the mean RCP 8.5 emission rates).

http://www.ipcc.ch/pdf/assessment-report/ar5/syr/SYR_AR5_LONGERREPORT_Final.pdf

Note that I believe that these projections err on the side of least drama, particularly when considering the variability of climate sensitivity.

Also note that IPCC WG III states: "Baseline scenarios, those without additional mitigation, result in global mean surface temperature increases in 2100 from 3.7 °C to 4.8 °C compared to pre-industrial levels (median values; the range is 2.5 °C to 7.8 °C when including climate uncertainty, see Table SPM.1) (high confidence)."
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1033 on: May 05, 2019, 01:37:19 AM »
The GRACE satellite was an amazing tool from April 2002 until June 2017 & I look forward to seeing even better results from GRACE-FO:
Unfortunately there are serious problems on-board GRACE-FO, so the data-quality is likely to be a lot worse than for the original GRACE  :(

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1034 on: May 05, 2019, 05:15:16 AM »
You could replace "GRACE-FO" with "EARTH" in that ^ scentence.

--
Edit; if someone wish to explore the expanding refrigeration market a bit further here's a few useful links:
http://www.iifiir.org/medias/medias.aspx?instance=EXPLOITATION&SETLANGUAGE=EN
https://www.ejarn.com/news_list.php?c=home&t=eJARN-News
Also market report from last year:
https://www.grandviewresearch.com/industry-analysis/refrigerant-market
Leaving this now.

--
Since I usually try to follow up on older comments and check the number of views on posted videos, I'll crosspost this here where the interest might be higher.
Bunch-O-vids from the International Conference on Negative CO2 Emissions.
<snip>
Those were all from last years conference:
http://negativeco2emissions2018.com/
Instead of filling this thread with individual videos I'll simply add the url to all of them:
https://www.youtube.com/channel/UCirbz-iLdizsK2G7lmOgodw/videos?view=0&sort=dd&shelf_id=1
Very few views on all of them.
« Last Edit: May 05, 2019, 06:59:55 AM by Sleepy »
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1035 on: May 06, 2019, 02:10:25 AM »
In "Climatic Thresholds for WAIS Retreat: Onset of Widespread Ice Shelf Hydrofracturing and Ice Cliff Calving in a Warming World", Rob DeConto, David Pollard, Knut Christianson, Richard B. Alley & Byron R. Parizek only project widespread ice shelf hydrofracturing after GMSTA reaches about 2C above pre-industrial; which following SSP5-Baseline is projected to occur circa 2040.

https://www.waisworkshop.org/sites/waisworkshop.org/files/webform/2018/abstracts/WAIS2018.pdf

However, this is a quick note to remind readers that the PIIS and Thwaites Eastern Ice Shelf could collapse earlier than when GMSTA reaches about 2C above pre-industrial; primarily due to (channelized) basal ice melting beneath these key ice shelves; which in my opinion could result in these ice shelves effectively disappearing as early at 2030; which might then trigger an MICI-type of collapse of the WAIS of the subsequent decades.  The first attached image (from MacGregor et al. 2012) indicates that as late as 2011 both the PIIS, the Thwaites Eastern Ice Shelf, and the Thwaites Ice Tongue were in much better condition than any of them are today.

Edit: I note that the ocean has been accumulating anthropogenic heat for at least the past two hundred and seventy years, and most of this excess ocean heat content has been advected to the Southern Ocean; where it represents a threat to the stability of Antarctic ice shelves.

Edit 2: The condition of the key ice shelves in the ASE is illustrated both by Schroeder et al. (2018), and by the recent retreat of the PIIS calving face to be upstream of the SW Tributary Glacier (see the second attached image {showing a recent crevasse in PIIS on May 5, 2019} & note that in Reply #931 I projected another major PIIS calving event still further upstream in July 2019).

Schroeder et al (2018) indicate that: "… thickness change of the Thwaites Eastern Ice Shelf between 1978 and 2009, revealing the loss of over half of its thickness over the past three decades."  As the Eastern Thwaites Ice Shelf continues to thin, its risk of abrupt collapse increases rapidly in coming decades:

https://www.waisworkshop.org/sites/waisworkshop.org/files/webform/2018/abstracts/SchroederD2018.pdf

Edit 3: Needless to say, but if key ASE ice shelves collapse simply due to the heat content that is already in the Southern Ocean, then no matter what radiative forcing pathway the global socio-economic system following in the coming decades, we may have already past the tipping point for a MICI-type of collapse for the WAIS this century.
« Last Edit: May 06, 2019, 07:27:49 PM by AbruptSLR »
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1036 on: May 06, 2019, 04:40:30 PM »
The linked reference discusses efforts to improve poorly constrained modeling of basal sliding friction for marine glaciers focused on the PIG.  The model under consideration only considers MISI, and not MICI, mechanisms.  Nevertheless, I note that:

a) As ice velocity accelerates, friction induced ice melting also accelerates; which increases basal meltwater supplies, and

b) Cases of relatively high basal friction would likely result in relatively tall ice cliff faces if/when the buttressing ice shelf is lost; which would promote MICI mechanisms:

Ian Joughin, Benjamin E. Smith & Christian G. Schoof (29 April 2019), "Regularized Coulomb Friction Laws for Ice Sheet Sliding: Application to Pine Island Glacier, Antarctica", Geophysical Research Letters, https://doi.org/10.1029/2019GL082526

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL082526

Abstract
The choice of the best basal friction law to use in ice‐sheet models remains a source of uncertainty in projections of sea level. The parameters in commonly used friction laws can produce a broad range of behavior and are poorly constrained. Here we use a time series of elevation and speed data to examine the simulated transient response of Pine Island Glacier, Antarctica, to a loss of basal traction as its grounding line retreats. We evaluate a variety of friction laws, which produces a diversity of responses, to determine which best reproduces the observed speedup when forced with the observed thinning. Forms of the commonly used power‐law friction provide much larger model‐data disagreement than less commonly used regularized Coulomb friction in which cavitation effects yield an upper bound on basal friction. Thus, adoption of such friction laws could substantially improve the fidelity of large‐scale simulations to determine future sea level.

Plain Language Summary
Although much effort has gone into improving numerical simulations of ice‐sheet behavior for sea‐level projection, the best choice for the friction law that governs the sliding of ice over its bed remains poorly known. As a consequence, a wide range of friction laws is used by the ice‐sheet modeling community. Here we take advantage of several remotely sensed data sets to model the changes in speed of Pine Island Glacier (PIG), Antarctica, over nearly 2 decades, using a variety of existing friction laws. We find that the behavior of this glacier is simulated far more faithfully relative to observations when a “regularized Coulomb” friction law is used. This type of friction law accounts for the formation of pressurized basal water pockets (cavitation) that occur when ice slides rapidly over its bed, which limits friction in a way that may amplify ice‐sheet instability. By contrast, low‐order exponents in more traditional power‐law friction parameterizations yield unbounded basal friction as speed increases, placing a much stronger brake on unstable ice‐sheet behavior. Thus, these results make a strong case for adopting bounded regularized Coulomb friction laws in place of the more commonly used unbounded friction laws.
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1037 on: May 06, 2019, 05:09:51 PM »
Maybe the term 'Anthropocene' should be changed to 'Absurdocene':

Aarssen, Lonnie (2019). "Meet Homo absurdus--the only creature that refuses to be what it is", Ideas in Ecology and Evolution, 11, doi:10.24908/iee.2018.11.13.e.

https://ojs.library.queensu.ca/index.php/IEE/article/view/13137

Extract: "Homo sapiens sapiens ('wise human') may describe a distant human ancestor, but if it ever did, the name no longer suits us.  As Cribb (2011) put it, "An animal that imperils its own future and that of most other life forms and ecosystems does not merit a single 'sapiens', let alone the two we now bear." … Homo absurdus – human that spends its whole life trying to convince itself that its existence is not absurd.  As Albert Camus (1956) put it, "Man is the only creature who refuses to be what he is.

"The world of human aspirations is largely fictitious, and if we do not understand this, we understand nothing about man.  ...""

Edit, see also:

Title: "Earth hurtles toward extinction crisis — 1 million species at risk"

https://www.axios.com/earth-faces-accelerating-extinction-crisis-global-report-89444aef-901a-43ad-a9a8-548ba53396d0.html

Extract: "By the numbers:

- 8 million: Total estimated number of plant and animal species on Earth (includes insects).

- Up to 1 million: Total number of species threatened with extinction.

- Tens to hundreds of times: "The extent to which the current global rate of species extinction is higher compared to average over the last 10 million years." This rate is accelerating, the report finds.

..."
« Last Edit: May 06, 2019, 05:31:51 PM by AbruptSLR »
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1038 on: May 06, 2019, 06:05:15 PM »
Maybe the term 'Anthropocene' should be changed to 'Absurdocene':

Or 'Obcene' ?

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1039 on: May 06, 2019, 08:33:16 PM »
The linked reference finds that: "Turbulence-resolving models and emergent constraints provide probable evidence, supported by theoretical understanding, that the cooling cloud radiative effect (CRE) of low clouds weakens with warming: a positive low-cloud feedback." This indicates that ECS increases with warming:

Nuijens, L. & Siebesma, A.P. (2019), "Boundary Layer Clouds and Convection over Subtropical Oceans in our Current and in a Warmer Climate", Curr Clim Change Rep, https://doi.org/10.1007/s40641-019-00126-x

https://link.springer.com/article/10.1007%2Fs40641-019-00126-x

Abstract
Purpose of Review

We review our understanding of mechanisms underlying the response of (sub)tropical clouds to global warming, highlight mechanisms that challenge our understanding, and discuss simulation strategies that tackle them.

Recent Findings
Turbulence-resolving models and emergent constraints provide probable evidence, supported by theoretical understanding, that the cooling cloud radiative effect (CRE) of low clouds weakens with warming: a positive low-cloud feedback. Nevertheless, an uncertainty in the feedback remains. Climate models may not adequately represent changing SST and circulation patterns, which determine future cloud-controlling factors and how these couple to clouds. Furthermore, we do not understand what mesoscale organization implies for the CRE, and how moisture-radiation interactions, horizontal advection, and the profile of wind regulate low cloud, in our current and in our warmer climate.

Summary

Clouds in nature are more complex than the idealized cloud types that have informed our understanding of the cloud feedback. Remaining major uncertainties are the coupling of clouds to large-scale circulations and to the ocean, and mesoscale aggregation of clouds.
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1040 on: May 06, 2019, 09:44:47 PM »
For the first time the linked insurance industry survey found '… climate change ranked as both the top current risk and leading emerging risk ..':

Title: "Twelfth Annual Survey of Emerging Risks: Summary of Finding"

https://www.casact.org/cms/files/12th-Annual-Emerging_1.pdf

Extract: "For the first time in the survey’s history, climate change ranked as both the top current risk and leading emerging risk – breaking cyber risk’s four-year streak as number one – according to the Twelfth Annual Emerging Risks Survey of Risk Managers from the Joint Risk Management Section (JRMS) of the Canadian Institute of Actuaries (CIA), Casualty Actuarial Society (CAS) and the Society of Actuaries (SOA)."

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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1041 on: May 07, 2019, 03:53:17 AM »
The linked reference applies mathematical modeling to state change in a natural lake ecosystem and '...  resolves a previously unclear issue as to the nature of the tipping point involved.'  Hopefully, such lessons learned can be applied to abrupt climate state change.

Boettiger, C. & Batt, R. J. (2019), "Bifurcation or state tipping: assessing transition type in a model trophic cascade", Math. Biol., https://doi.org/10.1007/s00285-019-01358-z

https://link.springer.com/article/10.1007/s00285-019-01358-z

Abstract: "Ecosystems can experience sudden regime shifts due to a variety of mechanisms. Two of the ways a system can cross a tipping point include when a perturbation to the system state is large enough to push the system beyond the basin of attraction of one stable state and into that of another (state tipping), and alternately, when slow changes to some underlying parameter lead to a fold bifurcation that annihilates one of the stable states. The first mechanism does not generate the phenomenon of critical slowing down (CSD), whereas the latter does generate CSD, which has been postulated as a way to detect early warning signs ahead of a sudden shift. Yet distinguishing between the two mechanisms (s-tipping and b-tipping) is not always as straightforward as it might seem. The distinction between “state” and “parameter” that may seem self-evident in mathematical equations depends fundamentally on ecological details in model formulation. This distinction is particularly relevant when considering high-dimensional models involving trophic webs of interacting species, which can only be reduced to a one-dimensional model of a tipping point under appropriate consideration of both the mathematics and biology involved. Here we illustrate that process of dimension reduction and distinguishing between s- and b-tipping for a highly influential trophic cascade model used to demonstrate tipping points and test CSD predictions in silico, and later, in a natural lake ecosystem. Our analysis resolves a previously unclear issue as to the nature of the tipping point involved."
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1042 on: May 07, 2019, 02:46:02 PM »
Maybe the term 'Anthropocene' should be changed to 'Absurdocene':

Long ago A-Team made a fun graph of geologic ages. This included the Dumbassic as a subdivision of the Anthropocene...i often have the feeling we are in that era now.  :(
Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1043 on: May 07, 2019, 04:03:54 PM »
Might not be the proper thread but Earth Rights Conference coming up this weekend, this time with online participation.

http://www.earthrightsconference.org/
What idea is powerful enough to heal the relationship between humans and nature?

A space for dialogue and co-creation about the idea that nature, not just humans, have rights.

Can this idea be the foundation for a new dimension of respect and harmony between humanity and the planet? The legal and existential dimensions of this question are raised and examined, in dialogue with leading voices for Earth rights from different parts of the world. This is the second international conference on Earth rights arranged by the Sigtuna Foundation in cooperation with Lodyn and Cemus.
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1044 on: May 07, 2019, 06:35:58 PM »
In "Climatic Thresholds for WAIS Retreat: Onset of Widespread Ice Shelf Hydrofracturing and Ice Cliff Calving in a Warming World", Rob DeConto, David Pollard, Knut Christianson, Richard B. Alley & Byron R. Parizek only project widespread ice shelf hydrofracturing after GMSTA reaches about 2C above pre-industrial; which following SSP5-Baseline is projected to occur circa 2040.

https://www.waisworkshop.org/sites/waisworkshop.org/files/webform/2018/abstracts/WAIS2018.pdf

However, this is a quick note to remind readers that the PIIS and Thwaites Eastern Ice Shelf could collapse earlier than when GMSTA reaches about 2C above pre-industrial; primarily due to (channelized) basal ice melting beneath these key ice shelves; which in my opinion could result in these ice shelves effectively disappearing as early at 2030; which might then trigger an MICI-type of collapse of the WAIS of the subsequent decades.  The first attached image (from MacGregor et al. 2012) indicates that as late as 2011 both the PIIS, the Thwaites Eastern Ice Shelf, and the Thwaites Ice Tongue were in much better condition than any of them are today.

Edit: I note that the ocean has been accumulating anthropogenic heat for at least the past two hundred and seventy years, and most of this excess ocean heat content has been advected to the Southern Ocean; where it represents a threat to the stability of Antarctic ice shelves.

Edit 2: The condition of the key ice shelves in the ASE is illustrated both by Schroeder et al. (2018), and by the recent retreat of the PIIS calving face to be upstream of the SW Tributary Glacier (see the second attached image {showing a recent crevasse in PIIS on May 5, 2019} & note that in Reply #931 I projected another major PIIS calving event still further upstream in July 2019).

Schroeder et al (2018) indicate that: "… thickness change of the Thwaites Eastern Ice Shelf between 1978 and 2009, revealing the loss of over half of its thickness over the past three decades."  As the Eastern Thwaites Ice Shelf continues to thin, its risk of abrupt collapse increases rapidly in coming decades:

https://www.waisworkshop.org/sites/waisworkshop.org/files/webform/2018/abstracts/SchroederD2018.pdf

Edit 3: Needless to say, but if key ASE ice shelves collapse simply due to the heat content that is already in the Southern Ocean, then no matter what radiative forcing pathway the global socio-economic system following in the coming decades, we may have already past the tipping point for a MICI-type of collapse for the WAIS this century.

As I get the feeling that many readers still do not fully appreciate the risk that we may have already passed a tipping point for a MICI-type of collapse of the WAIS possibly initiating as early as around 2030, here & in the next few posts, I reiterate points that I have made on this matter in prior posts.

In this post, I reiterate that: The Antarctic ozone hole has intensified the westerly winds (that have also shifted southward); which has intensified upwelling of warm CDW to key ASE marine glaciers via deep channels in the ASE continental shelf (see the first & second images); which has both thinned key ice shelves and also freshened the local surface water salinity, which has already advected still more warm CDW towards the grounding lines of these key marine glaciers (see third image).  This advected warm CDW has already raised the sea-floor potential temperatures above the ice melting point in many key Antarctic marine glaciers (see the fourth image).

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1045 on: May 07, 2019, 06:48:50 PM »
As a follow-on to my last post, here I reiterate that: The first image shows that through 2015 key Antarctic ice shelves have already provided (& continue to provide) significant quantities of freshwater to the coastal Antarctic surface water without contributing to measured SLR. The second image shows how during El Nino events (which are becoming more frequent with continued global warming) and negative SAM conditions, atmospheric heat is advected from the Tropical Pacific to the coastal West Antarctic. This second image also shows how El Nino conditions lead to a low pressure system (the blue blob in the image) off of coast of the Bellingshausen-Amundsen Seas; which pins the Amundsen Sea Low (ASL) off this coast; which as indicated in the third image blows wind landward, which drags still more warm CDW into the ASE.  Once the warm CDW is beneath the key ASE ice shelves, the fourth image shows how this warm water 'burns' upward through basal crevasses in these ice shelves, which leads to early calving events such as we are observing for the PIIS.
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1046 on: May 07, 2019, 07:14:03 PM »
As a follow-on to may last two posts, here I reiterate that: The first image shows the location of about a 6m abrupt drop in the ice surface elevation at the base of the Thwaites Ice Tongue in 2012, which has subsequently been attributed to a local & partial collapse of the subglacial cavity at this location.  This local cavity collapse seems to have triggered an acceleration of ice flow velocities in this area for a couple years after 2012, which appears to have trigger the drainage of subglacial lakes beneath the Thwaites Glacier from June 2013 to January 2014 as shown in the second image.  As these subglacial lakes drain every 15 to 25 years, and as Super El Ninos occur every 15 to 25 years; it seems reasonable to assume that there is a significant risk,  circa 2030, of another El Nino driven surge of warm CDW into the ASE, which might trigger another local cavity collapse at the base of the Thwaites Ice Tongue, leading to a surge of local ice velocities, that would trigger another subglacial lake drainage event.  If the Thwaites Eastern Ice Shelf has collapsed circa 2030 this would level a clear pathway for local icebergs to float-out of the deep water channel at the base of the Thwaites Ice Tongue as shown in the third image. Furthermore, the fourth image, of a cross-sectional profile of the Thwaites Ice Tongue, shows that once the residual ice tongue is lost and icebergs are free to float-out of the local deep channel (in the seafloor) the exposed ice cliff face would have a height exceeding 100m, which indicates that subsequent ice-cliff local failures would occur ala Pollard, DeConto, Alley and Bassis.
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1047 on: May 07, 2019, 07:27:21 PM »
As a follow-on to my last three posts, I reiterate that: The first image shows that if the PIIS were lost circa 2030 the exposed ice cliff height at the grounding line would also exceed the 90 to 100m height limit for an ice cliff failure mechanism to form.  Thus icebergs would be calving off from both the PIG and the area around the base of the Thwaites Ice Tongue; which per the second image would float out of the ASE and would follow the Antarctic Coastal Current moving counter clockwise around Antarctica to 'Iceberg Alley' in the Weddell Sea.  This armada of coastal icebergs would decrease the local seawater salinity along the entire coastal iceberg route, which would upwell more warm CDW to all the known locations of AABW formation (see the third image); which would slow the global meridional overturning current as indicated in the fourth image.
“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: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1048 on: May 07, 2019, 07:40:14 PM »
As a follow-on to my last four posts, I reiterate that: The first image shows how the formation of Antarctic Bottom Water, AABW, is associated with the global meridional overturning current, where a slowdown in AABW production leads to a slowing of the global meridional overturning current.  The second image shows that gyres are located at most of the AABW production areas and the third image shows how such gyres pull more warm CDW into these AABW production areas, which leads to more ice melting and a further reduction in AABW production.  The fourth image shows how this advection of warm CDW occurs in the Totten Ocean upwelling zone (which illustrates what would also happen in the Weddell and Ross Seas, which would destabilize the FRIS and RIS ice shelves).
« Last Edit: May 08, 2019, 04:34:35 PM by AbruptSLR »
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1049 on: May 07, 2019, 07:51:03 PM »
As a follow-on to my last five posts, I reiterate that: The first image shows key marine glacial basins in Antarctica (focused on the Totten Glacier catchment basin), and the second image shows seaways that could form in the WAIS basin due to MICI-type failures in this areas in the decades from circa 2030 to circa 2100.  The associated slowing of the meridional overturning current would advect more warm Atlantic water to key marine terminating glaciers in Southern and Northeast Greenland (see the third and fourth images) via the bipolar seesaw mechanism; which would accelerate ice mass loss from the GIS.

Finally, I remind readers that this possible scenario is not dependent upon GMSTA reading 2C above pre-industrial (as cited by Alley, Pollard, DeConto etc 2018), and is largely dependent only upon heat content that is already in the ocean.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson