Support the Arctic Sea Ice Forum and Blog

Author Topic: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE  (Read 479048 times)

Stephan

  • Nilas ice
  • Posts: 1513
    • View Profile
  • Liked: 539
  • Likes Given: 254
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3950 on: December 01, 2020, 09:03:35 PM »
I also see a hemisphere difference.
The western part (from a European perspective) has more "blue zones" (=colder) than the eastern part.
On the colder than average side:
Canada, parts of N Atlantic, East central Pacific, S Pacific, W Antarctica, Brasil, Central Asia
On the warmer than average side:
Europe, N and SE Asia, parts of Africa, Australia, parts of the US, E Antarctica
It is too late just to be concerned about Climate Change

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3951 on: December 01, 2020, 11:48:02 PM »
Just because I am never sure that readers see what I see in my prior posts, I have modified the first attached image (rotated 90 degrees for clarity) from Figure 3 of Jordan et al. (2020); where I annotate the location of the assumed ice cliff that I postulate could be abruptly exposed if/when the currently constrained icebergs floating over the top of the 'Big Ear' subglacial cavity float away some time in the 2030-2040 timeframe, likely due to a jökulhlaup event.  This annotated image of a sectional elevation along the Thwaites Ice Tongue alignment (cut from the second attached image) shows that this assumed ice cliff could have a freeboard as high as 300m (with a height above floatation, hf, of about 140m), with an upstream ice thickness gradient of over -0.03; which as shown in the third attached image from Bassis 2020 confirms that an MICI-type of failure would be initiated, and I believe sustained, down into the BSB.  For additional clarity, I attach the four image that indicates that ice cliffs with such high freeboard heights, result in icebergs with relatively shallow drafts that can float out of the ASE without becoming pinned.

Jordan, T. A., Porter, D., Tinto, K., Millan, R., Muto, A., Hogan, K., Larter, R. D., Graham, A. G. C., and Paden, J. D.: New gravity-derived bathymetry for the Thwaites, Crosson and Dotson ice shelves revealing two ice shelf populations, The Cryosphere Discuss., https://doi.org/10.5194/tc-2019-294, in review, 2020.

https://www.the-cryosphere-discuss.net/tc-2019-294/
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3952 on: December 02, 2020, 12:30:42 AM »
As a follow-on to my last post, I repost the first image (of the ice surface from 2018) showing the location of the 'Big Ear' subglacial cavity at the base of the Thwaites Ice Tongue (in orange outline from a 2017 survey); while the second image shows a November 21 2020 Sentinel-2 image of the ice surface at the base of the Thwaites Ice Tongue to which I have noted the location of a current crevasse at the location of my assumed ice cliff at the southern edge of the 'Big Ear' subglacial cavity where in MICI-type of failure may be initiated in the 2030 to 2040 timeframe (or sooner).
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3953 on: December 02, 2020, 04:51:25 PM »
I have previously discussed that the increasing frequency of atmospheric river events poses a threat to WAIS stability with continued global warming (see the linked reference); and it is also true that surface melt events during large El Nino events also contribute to the risk of hydrofracturing for the base of the Thwaites Ice Tongue as indicated by the attached image:

Jonathan D. Wille et al. (2019), "West Antarctic surface melt triggered by atmospheric rivers", Nature Geoscience,  12, 911–916, doi:10.1038/s41561-019-0460-1

https://www.nature.com/articles/s41561-019-0460-1

Abstract: "Recent major melting events in West Antarctica have raised concerns about a potential hydrofracturing and ice shelf instability. These events often share common forcings of surface melt-like anomalous radiative fluxes, turbulent heat fluxes and föhn winds. Using an atmospheric river detection algorithm developed for Antarctica together with surface melt datasets, we produced a climatology of atmospheric river-related surface melting around Antarctica and show that atmospheric rivers are associated with a large percentage of these surface melt events. Despite their rarity (around 12 events per year in West Antarctica), atmospheric rivers are associated with around 40% of the total summer meltwater generated across the Ross Ice Shelf to nearly 100% in the higher elevation Marie Byrd Land and 40–80% of the total winter meltwater generated on the Wilkins, Bach, George IV and Larsen B and C ice shelves. These events were all related to high-pressure blocking ridges that directed anomalous poleward moisture transport towards the continent. Major melt events in the West Antarctic Ice Sheet only occur about a couple times per decade, but a 1–2 °C warming and continued increase in atmospheric river activity could increase the melt frequency with consequences for ice shelf stability."
« Last Edit: December 03, 2020, 04:00:44 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

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3954 on: December 02, 2020, 05:23:33 PM »
Just because I am never sure that readers see what I see in my prior posts, I have modified the first attached image (rotated 90 degrees for clarity) from Figure 3 of Jordan et al. (2020); where I annotate the location of the assumed ice cliff that I postulate could be abruptly exposed if/when the currently constrained icebergs floating over the top of the 'Big Ear' subglacial cavity float away some time in the 2030-2040 timeframe, likely due to a jökulhlaup event.  This annotated image of a sectional elevation along the Thwaites Ice Tongue alignment (cut from the second attached image) shows that this assumed ice cliff could have a freeboard as high as 300m (with a height above floatation, hf, of about 140m), with an upstream ice thickness gradient of over -0.03; which as shown in the third attached image from Bassis 2020 confirms that an MICI-type of failure would be initiated, and I believe sustained, down into the BSB.  For additional clarity, I attach the four image that indicates that ice cliffs with such high freeboard heights, result in icebergs with relatively shallow drafts that can float out of the ASE without becoming pinned.

Jordan, T. A., Porter, D., Tinto, K., Millan, R., Muto, A., Hogan, K., Larter, R. D., Graham, A. G. C., and Paden, J. D.: New gravity-derived bathymetry for the Thwaites, Crosson and Dotson ice shelves revealing two ice shelf populations, The Cryosphere Discuss., https://doi.org/10.5194/tc-2019-294, in review, 2020.

https://www.the-cryosphere-discuss.net/tc-2019-294/

Just a reminder that the icebergs currently floating over the 'Big Ear' subglacial cavity described by Jordan et al. (2020) are only constrained by a few meters-worth of hf; and that once that hf is melted by warm modified CDW (see the attach image from the linked associated article), these constrained icebergs will be free to float away; which could abruptly expose an ice cliff face subject to an MICI-type of collapse leading into the BSB.

Title: "New maps show how warm water may reach Thwaites Glacier’s icy underbelly"


https://www.sciencenews.org/article/antarctica-thwaites-glacier-warm-water-sea-level-climate

Extract: "New seafloor maps reveal the first clear view of a system of channels that may be helping to hasten the demise of West Antarctica’s vulnerable Thwaites Glacier. The channels are deeper and more complex than previously thought, and may be funneling warm ocean water all the way to the underside of the glacier, melting it from below, the researchers found."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3955 on: December 03, 2020, 04:34:47 PM »
While I have previously posted links to the research cited in the linked article about how declining ice content in clouds makes relatively high climate sensitivities likely; I think that it is good to remember that most existing consensus climate models (including both in CMIP5 and CMIP6) are known to contain more ice content in their modelled clouds than what is observed in reality; which means that they incorrectly simulate too much negative cloud feedback with continued global warming.

Title: "How declining ice in clouds makes high ‘climate sensitivity’ plausible"

https://skepticalscience.com/declining-ice-clouds-high-sensitivity-plausible.html

Extract: "Even though CESM2 is only one example of models with high ECS, the mechanism described above must operate both in reality and in other global climate models. However, the importance of the effect depends on the model itself, how much ice it simulates in the mixed-phase clouds in the first place, and how quickly the Southern Ocean warms relative to the global average. As mentioned above, CESM2 correctly simulates a relatively low fraction of cloud ice in the mixed-phased clouds of the Southern Ocean. However, it is well known that most climate models simulate too much cloud ice compared to satellite observations and, therefore, would retain their negative cloud phase feedback longer than CESM2 does.

As for whether climate sensitivities above 5C are plausible, a complete answer to that question requires further testing of these models – for example, with respect to how well they reproduce past climate states both hotter and colder than the present. However, we have demonstrated that having the right cloud phase starting point for such simulations is critical – so far, a majority of climate models have not.

So, to answer the question of what happens if no ice is left and the clouds are already all liquid: It would mean that the climate system loses a natural cooling response. At that point it would enter a high-sensitivity state, which would make it even harder to slow the pace of global warming.

Bjordal, J. et al. (2020) Equilibrium climate sensitivity above 5C plausible due to state-dependent cloud feedback, Nature Geoscience, doi:10.1038/s41561-020-00649-1y"

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

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3956 on: December 03, 2020, 05:32:14 PM »
The linked reference presents findings of the E3SM calibration efforts for secondary organic aerosols (SOA).  Their findings indicate that the direct radiative forcing from SOAs are currently significant and that future levels of SOA radiative forcing is subject to potentially significant changes due to factors that influence the SOA lifetimes for different assumed future pathways.

Sijia Lou et al. (17 November 2020), "New SOA treatments within the Energy Exascale Earth System Model (E3SM): Strong production and sinks govern atmospheric SOA distributions and radiative forcing", JAMES, https://doi.org/10.1029/2020MS002266

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020MS002266

Abstract
Secondary organic aerosols (SOA) are large contributors to fine particle mass loading and number concentration and interact with clouds and radiation. Several processes affect the formation, chemical transformation and removal of SOA in the atmosphere. For computational efficiency, global models use simplified SOA treatments, which often do not capture the dynamics of SOA formation. Here we test more complex SOA treatments within the global Energy Exascale Earth System Model (E3SM) to investigate how simulated SOA spatial distributions respond to some of the important but uncertain processes affecting SOA formation, removal and lifetime. We evaluate model predictions with a suite of surface‐, aircraft‐ and satellite observations that span the globe and the full troposphere. Simulations indicate that both, a strong production (achieved here by multigenerational aging of SOA precursors that includes moderate functionalization) and a strong sink of SOA (especially in the mid‐upper troposphere, achieved here by adding particle‐phase photolysis) are needed to reproduce the vertical distribution of organic aerosol (OA) measured during several aircraft field campaigns; without this sink, the simulated mid‐upper tropospheric OA is too large. Our results show that variations in SOA chemistry formulations change SOA wet removal lifetime by a factor of 3 due to changes in horizontal and vertical distributions of SOA. In all the SOA chemistry formulations tested here, an efficient chemical sink i.e. particle‐phase photolysis, was needed to reproduce the aircraft measurements of OA at high altitudes. Globally, SOA removal rates by photolysis are equal to the wet removal sink, and photolysis decreases SOA lifetimes from 10 days to ~3 days. A recent review of multiple field studies found no increase in net OA formation over and downwind biomass burning regions, so we also tested an alternative, empirical SOA treatment that increases primary organic aerosol (POA) emissions near source region and converts POA to SOA with an aging timescale of 1 day. Although this empirical treatment performs surprisingly well in simulating OA loadings near the surface, it overestimates OA loadings in middle and upper troposphere compared to aircraft measurements, likely due to strong convective transport to high altitudes where wet removal is weak. The default improved model formulation (multigenerational aging with moderate fragmentation and photolysis) performs much better than the empirical treatment in these regions. Differences in SOA treatments greatly affect the SOA direct radiative effect, which ranges from ‐0.65 W m‐2 (moderate fragmentation and photolysis) to ‐2 W m‐2 (moderate fragmentation without photolysis). Notably, most SOA formulations predict similar global indirect forcing of SOA calculated as the difference in cloud forcing between present‐day and pre‐industrial simulations.

Plain language Summary
Secondary organic aerosols (SOA) are formed in the atmosphere by oxidation of organic gases emitted from natural biogenic, anthropogenic, and biomass burning sources. In many regions of the atmosphere, SOA greatly contributes to fine particle mass loadings and number concentrations and affects clouds and radiation. Integrating insights from global atmospheric modeling and measurements, we show that strong chemical production achieved here by multigenerational chemistry including moderate fragmentation of SOA precursors, and strong chemical sinks represented by particle‐phase photolysis are needed to explain the aircraft‐observed vertical profiles of SOA over multiple regions including North America, Equatorial Oceans and Southern Oceans. Photolysis reduces SOA simulated global SOA lifetimes from 10 days to 3 days. Within the same model physics and cloud treatments, we show that changes in SOA chemistry formulations change SOA wet removal lifetimes by a factor of 3. Simulations show that SOA exerts a strong direct radiative forcing in the present day ranging from ‐0.65 W m‐2 to ‐2 W m‐2. Future measurements and modeling are needed to better constrain the photolytic and heterogeneous chemical removal of SOA at high‐altitude atmospheric conditions.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3957 on: December 03, 2020, 06:43:24 PM »
I decided to add a couple of additional notes to the attached image originally posted in Reply #3951; to highlight that:

1. My proposed location of the first MICI-type of ice cliff immediately upstream of the Big Ear subglacial cavity is currently stable not only due to the buttressing from the confined icebergs floating over the top of the Big Ear subglacial cavity, but also due to buttressing from the Thwaites Eastern Ice Shelf; which results in a particularly high surface elevation relief that would resist ice creep after the constrained icebergs float away; which would maintain sufficient ice cliff freeboard to initiate a slumping type of ice cliff failure likely between 2030 & 2040.

2. The high ice surface relief discusses in item 1, provides the vertical pressure on the bed to form an ice plug that resists jökulhlaup events until a substantial subglacial hydrostatic pressure has built-up upstream, that when released (likely between 2030 and 2040) will likely flush the ice mélange downstream of the ice cliff face out into the ASE.

3. Virtually all ice sheet models assume that the Thwaites Ice Tongue consists of solid ice, and not a fractured mass of constrained icebergs that are likely to float away prior to 2030.

Edit: I previously neglected to mention that I suspect that the zone marked "correlated anomalies' on the attached image occurs due to an the assumed presence of a reservoir of basal subglacial meltwater upstream of the assumed ice plug.
« Last Edit: December 03, 2020, 06:56:51 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

Sciguy

  • Nilas ice
  • Posts: 1622
    • View Profile
  • Liked: 199
  • Likes Given: 157
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3958 on: December 03, 2020, 08:13:51 PM »
While I have previously posted links to the research cited in the linked article about how declining ice content in clouds makes relatively high climate sensitivities likely; I think that it is good to remember that most existing consensus climate models (including both in CMIP5 and CMIP6) are known to contain more ice content in their modelled clouds than what is observed in reality; which means that they incorrectly simulate too much negative cloud feedback with continued global warming.

Title: "How declining ice in clouds makes high ‘climate sensitivity’ plausible"

https://skepticalscience.com/declining-ice-clouds-high-sensitivity-plausible.html

Extract: "Even though CESM2 is only one example of models with high ECS, the mechanism described above must operate both in reality and in other global climate models. However, the importance of the effect depends on the model itself, how much ice it simulates in the mixed-phase clouds in the first place, and how quickly the Southern Ocean warms relative to the global average. As mentioned above, CESM2 correctly simulates a relatively low fraction of cloud ice in the mixed-phased clouds of the Southern Ocean. However, it is well known that most climate models simulate too much cloud ice compared to satellite observations and, therefore, would retain their negative cloud phase feedback longer than CESM2 does.

As for whether climate sensitivities above 5C are plausible, a complete answer to that question requires further testing of these models – for example, with respect to how well they reproduce past climate states both hotter and colder than the present. However, we have demonstrated that having the right cloud phase starting point for such simulations is critical – so far, a majority of climate models have not.

So, to answer the question of what happens if no ice is left and the clouds are already all liquid: It would mean that the climate system loses a natural cooling response. At that point it would enter a high-sensitivity state, which would make it even harder to slow the pace of global warming.

Bjordal, J. et al. (2020) Equilibrium climate sensitivity above 5C plausible due to state-dependent cloud feedback, Nature Geoscience, doi:10.1038/s41561-020-00649-1y"

You left out a key quote from that article:

Quote
So why does this happen? As the temperature increases, more and more of the ice crystals in the mixed-phase clouds over the Southern Ocean become liquid, until virtually no ice is left in the clouds. (In CESM2, this occurs when the global mean surface air temperature increase reaches 3-4C, but it is highly model dependent.) Without any ice left, the negative cloud phase feedback gets exhausted.

With the recent installations of renewable power plants and new stated climate policies from China, Japan, South Korea and a new policy from the US due in January 2021, global warming is expected to be limited to 2.1 C.  And with the energy transition occurring more rapidly than experts are predicting, 1.5 C is within reach.

https://www.rte.ie/news/environment/2020/1201/1181673-environment-climate-change/

Quote
Climate action pledges could curb global warming to 2.1C - analysis
Updated / Tuesday, 1 Dec 2020

Action to tackle climate emissions announced by countries in recent months could help limit global warming to 2.1C, analysis suggests.

A new assessment by Climate Action Tracker (CAT) found that if governments meet all their commitments to cut greenhouse gases to net zero by 2050 it could limit temperature rises to 2.1C above pre-industrial levels by 2100.

It puts the global climate goal in the Paris Agreement - to limit temperature rises to 1.5C - "within striking distance", the experts behind the analysis said.

And emissions aren't growing as fast as the IPCC projected.

https://www.sciencedaily.com/releases/2020/11/201130131404.htm

Quote
Emissions growth slower than worst-case projections

Date: November 30, 2020
Source: University of Colorado at Boulder
Summary: New research reveals that emissions are not growing as fast as the UN's Intergovernmental Panel on Climate Change's assessments have indicated -- and that the IPCC is not using the most up-to-date climate scenarios in its planning and policy recommendations.

Quote
The new study, published today in Environmental Research Letters, is the most rigorous evaluation of how projected climate scenarios established by the IPCC have evolved since they were established in 2005.

The good news: Emissions are not growing nearly as fast as IPCC assessments have indicated, according to the study's authors. The bad news: The IPCC is not using the most accurate and up-to-date climate scenarios in its planning and policy recommendations.


Tom_Mazanec

  • Young ice
  • Posts: 4292
  • Earth will survive AGW...but will Homo sapiens?
    • View Profile
    • Planet Mazanec
  • Liked: 630
  • Likes Given: 551
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3959 on: December 03, 2020, 10:04:10 PM »
AbruptSLR:
How again do you get the decade of 2030 to 2040 to be "It"? Could you be optimistic and it could actually occur in the 2020s? Or alternately could you be pessimistic and it actually occurs in the 2040s?
SHARKS (CROSSED OUT) MONGEESE (SIC) WITH FRICKIN LASER BEAMS ATTACHED TO THEIR HEADS

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3960 on: December 04, 2020, 12:35:16 AM »
I decided to add a couple of additional notes to the attached image originally posted in Reply #3951; to highlight that:

1. My proposed location of the first MICI-type of ice cliff immediately upstream of the Big Ear subglacial cavity is currently stable not only due to the buttressing from the confined icebergs floating over the top of the Big Ear subglacial cavity, but also due to buttressing from the Thwaites Eastern Ice Shelf; which results in a particularly high surface elevation relief that would resist ice creep after the constrained icebergs float away; which would maintain sufficient ice cliff freeboard to initiate a slumping type of ice cliff failure likely between 2030 & 2040.

2. The high ice surface relief discusses in item 1, provides the vertical pressure on the bed to form an ice plug that resists jökulhlaup events until a substantial subglacial hydrostatic pressure has built-up upstream, that when released (likely between 2030 and 2040) will likely flush the ice mélange downstream of the ice cliff face out into the ASE.

3. Virtually all ice sheet models assume that the Thwaites Ice Tongue consists of solid ice, and not a fractured mass of constrained icebergs that are likely to float away prior to 2030.

Edit: I previously neglected to mention that I suspect that the zone marked "correlated anomalies' on the attached image occurs due to an the assumed presence of a reservoir of basal subglacial meltwater upstream of the assumed ice plug.

The attached image roughly shows the location of the conceptual ice plug (see item 2 of the quote) that I  believe exists beneath the location of the proposed future MICI-type of ice cliff leading from the base of the Thwaites Ice Tongue directing into the BSB.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3961 on: December 04, 2020, 12:41:06 AM »
...
You left out a key quote from that article:

Quote
So why does this happen? As the temperature increases, more and more of the ice crystals in the mixed-phase clouds over the Southern Ocean become liquid, until virtually no ice is left in the clouds. (In CESM2, this occurs when the global mean surface air temperature increase reaches 3-4C, but it is highly model dependent.) Without any ice left, the negative cloud phase feedback gets exhausted.

...

To me the 'key quote' that you cite above means that from now until GMSTA reaches 3-4C, climate sensitivity will continuously increase due to reducing ice content in the mixed-phase clouds over the Southern Ocean.  This not mean that climate sensitivity only begins to increase, by this mechanism, once GMSTA reaches 3-4C.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3962 on: December 04, 2020, 01:14:12 AM »
AbruptSLR:
How again do you get the decade of 2030 to 2040 to be "It"? Could you be optimistic and it could actually occur in the 2020s? Or alternately could you be pessimistic and it actually occurs in the 2040s?

Again, I cite the decade from 2030 to 2040 as being the most likely decade for initiating an MICI-type of collapse from the base of the Thwaites Ice Tongue down into the Byrd Subglacial Basin for many reasons, including the following:

1. The last super El Nino occurred in the 2015-16 season and such events typically happen roughly every 20-years which would be the 2035-36 season; which is in the middle of the 2030-2040 range; and super El Nino event both advect more warm CDW into the ASE than average and they also increase the likelihood of surface ice melt at the base of the Thwaites Ice Tongue.

2. I believe that the last jökulhlaup event to occur in the Thwaites Gateway occurred in 2012; and it takes about 20 to 25 years to recharge the subglacial lakes associated with such events; which would most likely be between 2032 and 2037; and such an event would likely displace any retaining partially constrained icebergs that might be buttressing the MICI-ice cliff that I have proposed (see my prior posts on this location).

3. The icebergs currently floating above the 'Big Ear' subglacial cavity, are constrained by immediately downstream grounded icebergs with about 3 to 6m of ice height above floatation hf; and at the current rate of basal ice melt in this area and the current rate of thinning of the Thwaites Ice Tongue; I estimate that these partially grounded icebergs will be free to float away in the 2030 to 2040 timeframe; which could likely lead to the proposed future MICI-type of ice cliff at the base of the Thwaites Ice Tongue being abruptly exposed (without time to creep).

4. I estimate that due to basal ice melt that the Thwaites Eastern Ice Shelf will likely become ungrounded in the 2030-2040 timeframe; which in my opinion would relieve a buttressing action from the western base of the Thwaites Eastern Ice Shelf against the proposed ice plug just upstream of the 'Big Ear' subglacial cavity.

5. The first attached image of a computer model projection of CDW temperatures around Antarctica; shows a marked increase in this local CDW temperature in the 2030 to 2040 timeframe; which would increase basal ice melting beneath both the Thwaites Eastern Ice Shelf and the Thwaites Ice Tongue as well as within the Big Ear subglacial cavity.

6. The buttressing action of its ice shelf on the Pine Island SWT Glacier is rapidly deteriorating and I estimate that by 2030-2040 this buttressing action will be eliminated which would decrease the associated restraint on the Thwaites Eastern Shear Margin (see the second image).

7. I am concerned that the Beaufort Gyre will reverse itself sometime in the next twenty years; which in my opinion would increase the likelihood of an MICI-type of collapse of the Thwaite Glacier in the 2030-2040 timeframe; due to the bipolar seesaw mechanism.

Of course, I could be wrong about my projected timeframe; and if so you can criticize me in 2040.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

Tom_Mazanec

  • Young ice
  • Posts: 4292
  • Earth will survive AGW...but will Homo sapiens?
    • View Profile
    • Planet Mazanec
  • Liked: 630
  • Likes Given: 551
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3963 on: December 04, 2020, 01:40:08 AM »
I think I am at least as likely to criticize you in 2029 (or 2028, or 2027...).
SHARKS (CROSSED OUT) MONGEESE (SIC) WITH FRICKIN LASER BEAMS ATTACHED TO THEIR HEADS

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3964 on: December 04, 2020, 03:45:34 PM »
I think I am at least as likely to criticize you in 2029 (or 2028, or 2027...).

I guess in 2029 (or 2028, or 2027 ...) you can call me a 'Pollyanna' if any combination of the following triggers an MICI-type of collapse of the Thwaites Glacier before 2030:

1. A seasonally early (say December) sea ice loss in the ASE leading to an early loss of not only the grounded Iceberg B22-A (see the first attached animation by grixm from March 2020), but also the floating portion of the Thwaites Ice Tongue seaward of the current grounding line.

2. A major calving event (say to the bottom of the retrograde bed slope upstream of the cliff face shown in the second attached image) from the Jakobshavn Glacier might trigger a bipolar seesaw impact on Thwaites before 2030.

3. An early reversal of the Beaufort Gyre shown in the third image, might also trigger a bipolar seesaw impact on Thwaites before 2030.

4. An atmospheric river event could hit the coastal portion of the Thwaites Eastern Ice Shelf and Thwaites Ice Tongue before 2030.

5. A major volcanic, and/or seismic, event (see the fourth image) could hit the ASE region before 2030.

And while these are all long-tail events, that add to our collective risks, I do not consider them to be fat-tail events, that fall into the non-stationary 'likely' category before 2030.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3965 on: December 04, 2020, 03:50:46 PM »
For those who do not know, a Pollyanna is: "an excessively cheerful or optimistic person.
"what I am saying makes me sound like some aging Pollyanna who just wants to pretend that all is sweetness and light"" (see image)
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3966 on: December 04, 2020, 07:05:19 PM »
While the bipolar seesaw mechanism is much more involved than just considering RSLR contributions; nevertheless, the attached image shows the relative sea level contribution in different areas of the ocean from a 1mm eustatic sea level rise contribution from the Greenland Ice Sheet; which implies that the RSLR contribution from marine terminating glaciers in Southern Greenland (like Jakobshavn) would like result in about 30% more RSL in the ASE; which would help with the floatation of icebergs away from the Thwaites Gateway
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

Sciguy

  • Nilas ice
  • Posts: 1622
    • View Profile
  • Liked: 199
  • Likes Given: 157
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3967 on: December 04, 2020, 07:41:16 PM »
...
You left out a key quote from that article:

Quote
So why does this happen? As the temperature increases, more and more of the ice crystals in the mixed-phase clouds over the Southern Ocean become liquid, until virtually no ice is left in the clouds. (In CESM2, this occurs when the global mean surface air temperature increase reaches 3-4C, but it is highly model dependent.) Without any ice left, the negative cloud phase feedback gets exhausted.

...

To me the 'key quote' that you cite above means that from now until GMSTA reaches 3-4C, climate sensitivity will continuously increase due to reducing ice content in the mixed-phase clouds over the Southern Ocean.  This not mean that climate sensitivity only begins to increase, by this mechanism, once GMSTA reaches 3-4C.

Ice clouds provide a negative feedback until the ice is completely gone.  That occurs after a temperature increase of 3 to 4 C.  That's when the sensitivity would increase.

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3968 on: December 04, 2020, 07:47:42 PM »
The linked article indicates that a large Sahara dust storm the peaked from June 14 to 19, 2020 contributed Arctic sea ice loss this year.  If such large Sahara dust storm increase in frequency and/or magnitude, then this phenomena would likely contribute to future Arctic Amplification.

Title: "Godzilla Sahara dust storm linked to melting Arctic sea ice"

www.newscientist.com/article/2261073-godzilla-sahara-dust-storm-linked-to-melting-arctic-sea-ice/

The linked reference (& associate article) indicate that Arctic warming is contributing to the observed increase of major Saharan dust storms; and if so this would represent a positive feedback as some major Saharan dust storms contribute to Arctic warming:

Diana Francis et al. (01 December 2020), "The Atmospheric Drivers of the Major Saharan Dust Storm in June 2020", Geophysical Research Letters, https://doi.org/10.1029/2020GL090102

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GL090102
&
https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2020GL090102

Abstract
This study investigates the atmospheric dynamics of the major dust storm that occurred in June 2020 over the Sahara and during which dust clouds associated with the highest‐on‐record aerosol optical depths were transported towards the America. An anomalous atmospheric circulation pattern in the mid‐latitudes, linked to a circum‐global wavetrain, resulted in the development of a subtropical high‐pressure system to the west of the Saharan Heat Low. This created a pressure dipole and generated anomalously strong northeasterlies over the Sahara, which caused continuous dust emissions over 4 days. Occurring along the northern fringes of the Intertropical Discontinuity, the dust was transported to higher altitudes (6 km) by the strong updraft in this region. This injected the dust at the African Easterly Jet (AEJ) altitudes and favored a rapid westward long‐range transport. The AEJ was also anomalously strong, being strengthened by the anticyclonic circulation associated with the anomalous high.

Plain Language Summary
Dust is an important constituent of the Earth's atmosphere, with a wide range of impacts ranging from human health to effects on climate. In June 2020, massive amounts of dust were lifted from the Sahara, the major dust source region in the world, and transported all the way into the Americas across the tropical Atlantic Ocean. This event was caused by the development of a subtropical high‐pressure system over northwest Africa which resulted in sustained strong northeasterlies over the Sahara generating continuous dust emissions for 4 days. Due to the strong low‐level convergence along the intertropical discontinuity region, the dust was lifted to roughly 5‐6 km above the surface, and then transported westward by the stronger mid‐atmospheric winds (>20 m s‐1). At Cape Verde and over large swaths of the Atlantic Ocean, the amount of dust suspended in the atmosphere was associated with the largest aerosol optical depths on record.

&

Title: "Is Arctic warming behind a monster Saharan dust storm?"

https://www.preventionweb.net/news/view/75036

Extract: "The researchers found that the subtropical high was embedded in a circumglobal wavetrain, a chain of wind patterns that extended around the planet, and was present in the Northern Hemisphere for most of June 2020. This wavetrain may have been caused by record-low Arctic sea ice extent observed in June 2020 as well. The warming of the Arctic region is believed to be altering the course of wind patterns in the mid-latitudes and subtropics and causing severe weather events, though there is controversy among scientists about this concept."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3969 on: December 04, 2020, 07:53:59 PM »
...
Ice clouds provide a negative feedback until the ice is completely gone.  That occurs after a temperature increase of 3 to 4 C.  That's when the sensitivity would increase.

The linked reference indicates that as the ice cloud fraction decreases the negative cloud feedback weakens and a less negative cloud feedback means a higher climate sensitivity well before all of the ice in the clouds is completely gone.

Jiang Zhu and Christopher J. Poulsen (02 September 2020), "On the increase of climate sensitivity and cloud feedback with warming in the Community Atmosphere Models", Geophysical Research Letters, https://doi.org/10.1029/2020GL089143

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GL089143

Abstract
Modeling and paleoclimate proxy‐based studies suggest that equilibrium climate sensitivity (ECS) depends on the background climate state, though the reason is not thoroughly understood. Here we study the state dependence of ECS over a large range of global mean surface temperature (GMST) in the Community Atmosphere Model (CAM) versions 4, 5, and 6 by varying atmospheric CO2 concentrations. We find a robust increase of ECS with GMST in all three models, albeit at different rates, which is primarily attributed to strengthening of the shortwave cloud feedback (λcld) at both high and low latitudes. Over high latitudes, increasing GMST leads to a reduction in the cloud ice fraction, weakening the (negative) cloud‐phase feedback due to the phase transition of cloud ice to liquid and thereby strengthening λcld. Over low‐latitude regions, increasing GMST strengthens λcld likely through the nonlinear increase in water vapor, which causes low‐cloud thinning through thermodynamic and radiative processes.

Plain Language Summary
Equilibrium climate sensitivity (ECS) is defined as the equilibrium increase in global mean temperature as a result of a doubling of atmospheric CO2 concentration. The latest assessment by the Intergovernmental Panel on Climate Change reported a likely ECS range of 1.5–4.5°C. Narrowing the ECS range is of paramount importance for prediction of future warming. Earth’s surface has experienced prolonged periods of large magnitude warming in the geological past, which provide important empirical information on ECS. To quantitatively use the paleoclimate information, we need a complete understanding of how ECS may depend on the background climate. In this study, we investigate the physical mechanisms responsible for the state dependence of ECS using three climate models that have distinct model physics. In all three models, we find that ECS grows as the background climate warms, i.e., a warmer climate is more sensitive to external forcing. We attribute the increase of ECS to both high‐ and low‐latitude cloud processes. Over high latitudes, cloud ice fraction decreases with global warming, weakening the potential for mixed‐phase clouds to reflect solar radiation and amplifying surface warming. Over low latitudes, global warming enhances the efficiency of processes that make clouds less opaque, again, amplifying surface warming.

Key Points
•   ECS increases with CO2‐induced global warming in CAM 6, 5, and 4, and is primarily attributed to the strengthening of cloud feedback
•   High‐latitude λcld strengthens with warming due to a decrease of cloud ice fraction and a weakening of the negative cloud‐phase feedback
•   Low‐latitude λcld strengthening is linked to cloud thinning over subsidence regions likely caused by cloud interactions with water vapor
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

Tom_Mazanec

  • Young ice
  • Posts: 4292
  • Earth will survive AGW...but will Homo sapiens?
    • View Profile
    • Planet Mazanec
  • Liked: 630
  • Likes Given: 551
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3970 on: December 04, 2020, 08:27:45 PM »
Hurricane Sandy and the June Saharan dust storm hint open Arctic Ocean is starting to affect NH weather.
SHARKS (CROSSED OUT) MONGEESE (SIC) WITH FRICKIN LASER BEAMS ATTACHED TO THEIR HEADS

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3971 on: December 04, 2020, 10:22:55 PM »
For what it is worth, as illustrated by the attached image, virtually all of the ITGC program field work has focused on the Thwaites Eastern Ice Shelf and the scientists know full well that the Thwaites Ice Tongue (including the Big Ear subglacial cavity region) is too unstable to trust
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

Sciguy

  • Nilas ice
  • Posts: 1622
    • View Profile
  • Liked: 199
  • Likes Given: 157
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3972 on: December 04, 2020, 11:23:35 PM »
...
Ice clouds provide a negative feedback until the ice is completely gone.  That occurs after a temperature increase of 3 to 4 C.  That's when the sensitivity would increase.

The linked reference indicates that as the ice cloud fraction decreases the negative cloud feedback weakens and a less negative cloud feedback means a higher climate sensitivity well before all of the ice in the clouds is completely gone.

Jiang Zhu and Christopher J. Poulsen (02 September 2020), "On the increase of climate sensitivity and cloud feedback with warming in the Community Atmosphere Models", Geophysical Research Letters, https://doi.org/10.1029/2020GL089143

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GL089143


That paper is behind a paywall.  Can you link to an open access version of the full paper?

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3973 on: December 05, 2020, 03:52:32 AM »
...
Ice clouds provide a negative feedback until the ice is completely gone.  That occurs after a temperature increase of 3 to 4 C.  That's when the sensitivity would increase.

The linked reference indicates that as the ice cloud fraction decreases the negative cloud feedback weakens and a less negative cloud feedback means a higher climate sensitivity well before all of the ice in the clouds is completely gone.

Jiang Zhu and Christopher J. Poulsen (02 September 2020), "On the increase of climate sensitivity and cloud feedback with warming in the Community Atmosphere Models", Geophysical Research Letters, https://doi.org/10.1029/2020GL089143

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GL089143


That paper is behind a paywall.  Can you link to an open access version of the full paper?

I recommend that you try Science Hub:
https://sci-hub.tw/
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

Lennart van der Linde

  • Grease ice
  • Posts: 782
    • View Profile
  • Liked: 85
  • Likes Given: 6
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3974 on: December 05, 2020, 09:14:58 AM »
I recommend that you try Science Hub:
https://sci-hub.tw/

Currently Science Hub can be found here:
https://scihub.wikicn.top/

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3975 on: December 05, 2020, 04:55:07 PM »
I recommend that you try Science Hub:
https://sci-hub.tw/

Currently Science Hub can be found here:
https://scihub.wikicn.top/

Lennart,

Thank you for keeping me up to date.  The world is changing faster than I can keep up with.

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

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3976 on: December 05, 2020, 05:22:13 PM »
I decided to add a couple of additional notes to the attached image originally posted in Reply #3951; to highlight that:

1. My proposed location of the first MICI-type of ice cliff immediately upstream of the Big Ear subglacial cavity is currently stable not only due to the buttressing from the confined icebergs floating over the top of the Big Ear subglacial cavity, but also due to buttressing from the Thwaites Eastern Ice Shelf; which results in a particularly high surface elevation relief that would resist ice creep after the constrained icebergs float away; which would maintain sufficient ice cliff freeboard to initiate a slumping type of ice cliff failure likely between 2030 & 2040.

2. The high ice surface relief discusses in item 1, provides the vertical pressure on the bed to form an ice plug that resists jökulhlaup events until a substantial subglacial hydrostatic pressure has built-up upstream, that when released (likely between 2030 and 2040) will likely flush the ice mélange downstream of the ice cliff face out into the ASE.

3. Virtually all ice sheet models assume that the Thwaites Ice Tongue consists of solid ice, and not a fractured mass of constrained icebergs that are likely to float away prior to 2030.

Edit: I previously neglected to mention that I suspect that the zone marked "correlated anomalies' on the attached image occurs due to an the assumed presence of a reservoir of basal subglacial meltwater upstream of the assumed ice plug.

The attached image roughly shows the location of the conceptual ice plug (see item 2 of the quote) that I  believe exists beneath the location of the proposed future MICI-type of ice cliff leading from the base of the Thwaites Ice Tongue directing into the BSB.

The first image (adapted from Millian et al 2017 with a 2011 grounding line shown) shows the location of my proposed ice plug at my proposed MICI-type ice cliff location; which indicates that there are different bed slope pathways leading down into the BSB where the upstream ice thickness gradient is between -0.04 and -0.05; which is an indication of a high probability that an MICI-type of failure may occur in this area circa 2030 to 2040.

I repost the second image from the ITGC TARSAN project (showing a 2011 ice face); in order to emphasize that we are currently essentially have the conditions postulated for the third perturbation experiment with a pinned Thwaites Eastern Ice Shelf and essentially no Thwaites Ice Tongue; while sometime between 2030 and 2040 we are likely to abruptly transition to the second perturbation experiment with the Thwaites Eastern Ice Shelf unpinned and no Thwaites Ice Tongue (at all); which would abruptly end the current buttressing action of the Thwaites Eastern Ice Shelf on the ice plug that the MICI-type future ice cliff location that I propose (see the first image).

I repost the third image in order to remind readers that between January 2012 and January 2013 the ice surface elevation over the Little Ear subglacial cavity dropped by over 6m (& I believe that this occurred abruptly in September 2012 with a collapse of the roof of the Little Ear subglacial cavity); which (in my opinion) lead to an temporary abrupt loss of the buttressing from the Thwaites Eastern Ice Shelf on my proposed ice plug location (see the first image); which (in my opinion) lead to a jökulhlaup event that flushed a series of icebergs out from the base area of the Thwaites Ice Tongue from September 2012 until early 2014.  I repost this image to remind readers that the Big Ear subglacial cavity did not exist in 2012; and that by 2030 to 2040 it is likely that another jökulhlaup event is likely to occur that will flush all icebergs in front of my proposed MICI-type ice cliff location, thus abruptly exposing the bare ice cliff to a MICI-type failure before any significant ice creep could occur.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3977 on: December 05, 2020, 05:35:30 PM »
Per the attached Tweet, Haufather indicates that November 2020 will likely be the warmest November on record, even during La Nina conditions.  This increases the probability that 2020 may be the warmest year on record.

As it is likely that the final GMSTA for 2020 will be almost the same as that for 2016; and as the 2020-2021 ENSO season is very likely to be an official La Nina season; I have updated the first attached image of Hansen's La Nina trend vs GMSTA; with my purple lines indicating that the rate of increase of GMSTA is accelerating rapidly as compare to earlier trend lines.  This means that we are collectively more likely to pass the U.N.'s 2C limit sooner than consensus climate scientists have previously acknowledged.

In this regard, we are currently still essentially on the SSP 8.5 forcing pathway, and if the high-end (Wolf Pack) CMIP6 GMSTA projections are correct (see the second [by Hausfather 2020] and third [particularly the heavy black curve for UKESM1-0-LL] images) then we will likely pass the 2C limit around 2034; which per DeConto and Pollard would significantly increase the risk of an MICI-type of collapse of the Thwaites Glacier after 2034 (due to the increase risk of hydrofracturing).

Edit: Note that by extending my last purple La Nina vs GMSTA trendline (for from 2018 to 2020), this also indicates that GMSTA will reach 2C circa 2034 to 2035.
« Last Edit: December 05, 2020, 05:43:37 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

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3978 on: December 06, 2020, 05:35:21 PM »
The linked summary has a link to a pdf of a BIS report entitled 'The Green Swan'.  While in this thread I have focused on abrupt physical climate change threats/risks; this report focuses on socioeconomic/financial risks, including risks that too rapid implementations of measures to move towards sustainable economies could a collapse of global financial systems.  This 'transition risk' together with the 'physical risk' could produce what the BIS calls a 'Green Swan' event (see the first image) of a global financial collapse in the coming years (see the second image).  Regarding the second image, note that:

1. The BIS considers a GMSTA this century of 3C is the 'Business-as-Intended' scenario.

2. This graph (or risk) does not consider the very likely scenario that: 'Delayed actions followed by strong actions in an attempt to catch up would probably lead to high both physical and transition risks (not represented in Graph 5)'.

3. This graph focuses on risks associate with GMSTA and does not consider such physical scenarios as the Byrd Subglacial Basin initiating a MICI-type of collapse in the 2030-2040 timeframe leading a 2m rise in eustatic SLR by 2050; resulting in flooding of every ocean port and ocean bordering river delta simultaneously in the world (which would strongly/abruptly impact both global trade and global food production).

Title: "The green swan"

https://www.bis.org/publ/othp31.htm

Extract: "Climate change poses new challenges to central banks, regulators and supervisors. This book reviews ways of addressing these new risks within central banks' financial stability mandate. However, integrating climate-related risk analysis into financial stability monitoring is particularly challenging because of the radical uncertainty associated with a physical, social and economic phenomenon that is constantly changing and involves complex dynamics and chain reactions. Traditional backward-looking risk assessments and existing climate-economic models cannot anticipate accurately enough the form that climate-related risks will take. These include what we call "green swan" risks: potentially extremely financially disruptive events that could be behind the next systemic financial crisis. Central banks have a role to play in avoiding such an outcome, including by seeking to improve their understanding of climate-related risks through the development of forward-looking scenario-based analysis. But central banks alone cannot mitigate climate change. This complex collective action problem requires coordinating actions among many players including governments, the private sector, civil society and the international community. Central banks can therefore have an additional role to play in helping coordinate the measures to fight climate change. Those include climate mitigation policies such as carbon pricing, the integration of sustainability into financial practices and accounting frameworks, the search for appropriate policy mixes, and the development of new financial mechanisms at the international level. All these actions will be complex to coordinate and could have significant redistributive consequences that should be adequately handled, yet they are essential to preserve long-term financial (and price) stability in the age of climate change.

Transition risks are associated with the uncertain financial impacts that could result from a rapid low-carbon transition, including policy changes, reputational impacts, technological breakthroughs or limitations, and shifts in market preferences and social norms. In particular, a rapid and ambitious transition to lower emissions pathways means that a large fraction of proven reserves of fossil fuel cannot be extracted (McGlade and Elkins (2015)), becoming “stranded assets”, with potentially systemic consequences for the financial system (see Box 1). For instance, an archetypal fire sale might result if these stranded assets suddenly lose value, “potentially triggering a financial crisis” (Pereira da Silva (2019a)). As Mark Carney puts it: “too rapid a movement towards a low-carbon economy could materially damage financial stability. A wholesale reassessment of prospects, as climate-related risks are re-evaluated, could destabilise markets, spark a pro-cyclical crystallisation of losses and lead to a persistent tightening of financial conditions: a climate Minsky moment” (Carney (2016), p 2)."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3979 on: December 06, 2020, 08:53:22 PM »
The linked reference indicates that the projected decrease in anthropogenic aerosols will lead to a slowing of the AMOC.

Xiaofan Ma et al. (06 Nov 2020), "Dependence of regional ocean heat uptake on anthropogenic warming scenarios", Science Advances, Vol. 6, no. 45, eabc0303, DOI: 10.1126/sciadv.abc0303

https://advances.sciencemag.org/content/6/45/eabc0303

Abstract
The North Atlantic and Southern Ocean exhibit enhanced ocean heat uptake (OHU) during recent decades while their future OHU changes are subject to great uncertainty. Here, we show that regional OHU patterns in these two basins are highly dependent on the trajectories of aerosols and greenhouse gases (GHGs) in future scenarios. During the 21st century, North Atlantic and Southern Ocean OHU exhibit similarly positive trends under a business-as-usual scenario but respectively positive and negative trends under a mitigation scenario. The opposite centurial OHU trends in the Southern Ocean can be attributed partially to distinct GHG trajectories under the two scenarios while the common positive centurial OHU trends in the North Atlantic are mainly due to aerosol effects. Under both scenarios, projected decline of anthropogenic aerosols potentially induces a weakening of the Atlantic Meridional Overturning Circulation and a divergence of meridional oceanic heat transport, which leads to enhanced OHU in the subpolar North Atlantic.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3980 on: December 06, 2020, 11:54:47 PM »
As I have recently been focusing how the BSB might experience an MICI-type of collapse by 2050; I thought that I would present a few images of how I believe that a combination of relatively high ECS and abrupt sea level rise can lead to much higher climate change risk, thru 2120 (see the second image) as compared to the consensus climate science expectation such risk this century (see the first image).

The first attached image (by Sutton/Hawkins) shows a diagram relating probability & impact to climate change risk for the consensus climate science interpretation of climate ECS (this century) offered by AR5.

The second attached image (adapted from Sutton/Hawkins by ASLR) show a diagram approximately relating my interpretation of probability & impact to climate change risk for the 'Wolf Pack' evaluation of ECS (this century) offered by CMIP6 up to 5.0C and thereafter by my interpretation of parameters related to feedback factors to Effective ECS including: slowing of the MOC; thermokarst (& other) methane emissions; albedo flip and changes in cloud feedback, thru 2120.

The third image shows how the PDF for ECS is related to various feedback factors; indicating how the PDF for ECS becomes right skewed (which increases climate risk).

The fourth image shows how increases in mean GMSTA and increases in GMSTA variance can significantly increase the risk of experiencing high GMSTA in the future with continuing climate change (which increases climate risk).
« Last Edit: December 07, 2020, 03:24:46 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

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3981 on: December 07, 2020, 03:43:06 PM »
The linked Copernicus article indicates that November 2020 (see attached images) was:

•   the  warmest November in this data record by a clear margin
•   0.13°C warmer than the previous warmest Novembers, which were in 2016 and 2019.


This increases the chances that 2020 might eventually be the warmest year to date in the modern record.

Title: "Surface air temperature for November 2020"

https://climate.copernicus.eu/surface-air-temperature-november-2020

Extract:
"Global-mean temperatures were substantially above average in November  2020. The month was:
•   0.77°C warmer than the 1981-2010 average for November
•   the  warmest November in this data record by a clear margin
•   0.13°C warmer than the previous warmest Novembers, which were in 2016 and 2019.
•   November 2020 was also the joint fourth most extreme month of any in terms of global warmth compared with the climatogical average for the month in question. Its temperature anomaly was on a par with that of January 2020. Only February and March 2016 and February 2020 were more extreme, with temperatures respectively 0.88°C, 0.82°C and 0.80°C above average."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3982 on: December 07, 2020, 06:39:11 PM »
While we will have to wait to see how December's surface temperatures unfold, the attached image of Hausfather's projection the GMSTA for 2020 based on Copernicus readings thru November 2020, indicates that 2020 may well be the warmest year in the modern records; while an active La Nina event is developing.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3983 on: December 07, 2020, 07:17:07 PM »
Currently, peatlands act as a carbon sink, but with continuing climate change such sinks could likely turn into carbon sources:

Loisel, J., Gallego-Sala, A.V., Amesbury, M.J. et al. Expert assessment of future vulnerability of the global peatland carbon sink. Nat. Clim. Chang. (2020). https://doi.org/10.1038/s41558-020-00944-0

https://www.nature.com/articles/s41558-020-00944-0

Abstract: "The carbon balance of peatlands is predicted to shift from a sink to a source this century. However, peatland ecosystems are still omitted from the main Earth system models that are used for future climate change projections, and they are not considered in integrated assessment models that are used in impact and mitigation studies. By using evidence synthesized from the literature and an expert elicitation, we define and quantify the leading drivers of change that have impacted peatland carbon stocks during the Holocene and predict their effect during this century and in the far future. We also identify uncertainties and knowledge gaps in the scientific community and provide insight towards better integration of peatlands into modelling frameworks. Given the importance of the contribution by peatlands to the global carbon cycle, this study shows that peatland science is a critical research area and that we still have a long way to go to fully understand the peatland–carbon–climate nexus."

See also:

Title: "Peatlands keep a lot of carbon out of Earth’s atmosphere, but that could end with warming and development"

https://www.dailyclimate.org/peat-carbon-storage-climate-change-2649347784.html

Extract: "We found that permafrost degradation, warming temperatures, rising sea levels and drought are causing many peatlands around the world to lose some of their stored carbon. This is in addition to rapid degradation caused by human activity.

Although they only occupy 3 percent of the global land area, peatlands contain about 25 percent of global soil carbon — twice as much as the world's forests.

For example, in many regions of the Arctic, rapid permafrost thawing promotes microbial activity that releases greenhouse gases into the atmosphere. These microbes feed off carbon-rich peats that were once frozen.

Massive peatland fires also contribute. Recent wildfires like those in Russia are known to release as much carbon in a few months as total human carbon dioxide emissions in an entire year. And these fires are especially tricky to put out. Embers within the dense organic matter can reignite many months or even years later.

Human activities are also increasing greenhouse gas releases from these carbon-rich ecosystems. In the United Kingdom, for example, extracting peat for use in gardening has caused peatlands to emit an estimated 16 million tons of carbon every year—roughly equivalent to the annual greenhouse gas emissions from more than 12 million cars.

In Indonesia and Malaysia, as fertile land becomes increasingly scarce, peatlands are being burned, drained, and repurposed. Already, most peatlands in Indonesia have been destroyed in order to build palm oil plantations. The World Resources Institute estimates that in Indonesia and Malaysia, peatland draining results in total annual emissions equal to those of nearly 70 coal plants. These activities also endanger vulnerable animal populations, such as orangutans and various species of freshwater fish. Peatland degradation due to human activity accounts for 5-10 percent of annual carbon dioxide emissions from human activity, despite these zones' tiny geographic footprint."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3984 on: December 07, 2020, 07:19:41 PM »
Currently, peatlands act as a carbon sink, but with continuing climate change such sinks could likely turn into carbon sources (which is not fully considered in most consensus climate science projections):

Loisel, J., Gallego-Sala, A.V., Amesbury, M.J. et al. Expert assessment of future vulnerability of the global peatland carbon sink. Nat. Clim. Chang. (2020). https://doi.org/10.1038/s41558-020-00944-0

https://www.nature.com/articles/s41558-020-00944-0

Abstract: "The carbon balance of peatlands is predicted to shift from a sink to a source this century. However, peatland ecosystems are still omitted from the main Earth system models that are used for future climate change projections, and they are not considered in integrated assessment models that are used in impact and mitigation studies. By using evidence synthesized from the literature and an expert elicitation, we define and quantify the leading drivers of change that have impacted peatland carbon stocks during the Holocene and predict their effect during this century and in the far future. We also identify uncertainties and knowledge gaps in the scientific community and provide insight towards better integration of peatlands into modelling frameworks. Given the importance of the contribution by peatlands to the global carbon cycle, this study shows that peatland science is a critical research area and that we still have a long way to go to fully understand the peatland–carbon–climate nexus."

See also:

Title: "Peatlands keep a lot of carbon out of Earth’s atmosphere, but that could end with warming and development"

https://www.dailyclimate.org/peat-carbon-storage-climate-change-2649347784.html

Extract: "We found that permafrost degradation, warming temperatures, rising sea levels and drought are causing many peatlands around the world to lose some of their stored carbon. This is in addition to rapid degradation caused by human activity.

Although they only occupy 3 percent of the global land area, peatlands contain about 25 percent of global soil carbon — twice as much as the world's forests.

For example, in many regions of the Arctic, rapid permafrost thawing promotes microbial activity that releases greenhouse gases into the atmosphere. These microbes feed off carbon-rich peats that were once frozen.

Massive peatland fires also contribute. Recent wildfires like those in Russia are known to release as much carbon in a few months as total human carbon dioxide emissions in an entire year. And these fires are especially tricky to put out. Embers within the dense organic matter can reignite many months or even years later.

Human activities are also increasing greenhouse gas releases from these carbon-rich ecosystems. In the United Kingdom, for example, extracting peat for use in gardening has caused peatlands to emit an estimated 16 million tons of carbon every year—roughly equivalent to the annual greenhouse gas emissions from more than 12 million cars.

In Indonesia and Malaysia, as fertile land becomes increasingly scarce, peatlands are being burned, drained, and repurposed. Already, most peatlands in Indonesia have been destroyed in order to build palm oil plantations. The World Resources Institute estimates that in Indonesia and Malaysia, peatland draining results in total annual emissions equal to those of nearly 70 coal plants. These activities also endanger vulnerable animal populations, such as orangutans and various species of freshwater fish. Peatland degradation due to human activity accounts for 5-10 percent of annual carbon dioxide emissions from human activity, despite these zones' tiny geographic footprint."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

gerontocrat

  • Multi-year ice
  • Posts: 10438
    • View Profile
  • Liked: 3937
  • Likes Given: 31
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3985 on: December 07, 2020, 08:14:31 PM »
Just for interest is the GRACE-FO data for AIS+GIS ice mass loss since 2002.

Total mass loss = over 17 mms of sea level rise (very close to 1 mm per year)
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3986 on: December 07, 2020, 09:57:27 PM »
Just a reminder that the Amazon rainforest tends to experience drought during El Niño events. The warm, dry weather that occurs as a result of El Niño increases the risk of forest fires over the entire Amazon Basin. The dryness caused by El Niño also reduces plant growth, which means that trees store less carbon; and such dry weather causes the soil to release carbon. The frequency of El Niño events is projected to increase, not only gradually with continued anthropogenic radiative forcing, but also with the possibly abrupt future slowdown of the MOC due to a Beaufort Gyre reversal and/or a MICI-type collapse of the WAIS, in coming decades.  Thus, we could see an abrupt collapse of the Amazon rainforest in the coming decades; which would likely increase the effective ECS this century.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

gerontocrat

  • Multi-year ice
  • Posts: 10438
    • View Profile
  • Liked: 3937
  • Likes Given: 31
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3987 on: December 07, 2020, 11:02:49 PM »
Just a reminder that the Amazon rainforest tends to experience drought during El Niño events. The warm, dry weather that occurs as a result of El Niño increases the risk of forest fires over the entire Amazon Basin. The dryness caused by El Niño also reduces plant growth, which means that trees store less carbon; and such dry weather causes the soil to release carbon. The frequency of El Niño events is projected to increase, not only gradually with continued anthropogenic radiative forcing, but also with the possibly abrupt future slowdown of the MOC due to a Beaufort Gyre reversal and/or a MICI-type collapse of the WAIS, in coming decades.  Thus, we could see an abrupt collapse of the Amazon rainforest in the coming decades; which would likely increase the effective ECS this century.
A strong El Niño combined with the open season policies of Bolsonaro plus the demand from China for meat + soya (if the US / China trade war heats up even more that demand could sky-rocket) could make a nightmare of a deforestation/fire season. And maybe even a modest El Nino is enough.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Tom_Mazanec

  • Young ice
  • Posts: 4292
  • Earth will survive AGW...but will Homo sapiens?
    • View Profile
    • Planet Mazanec
  • Liked: 630
  • Likes Given: 551
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3988 on: December 08, 2020, 12:00:58 AM »
Just for interest is the GRACE-FO data for AIS+GIS ice mass loss since 2002.

Total mass loss = over 17 mms of sea level rise (very close to 1 mm per year)
I thought annual rise was ~3 mm. What is the other two...thermal expansion? Glacier melt?
SHARKS (CROSSED OUT) MONGEESE (SIC) WITH FRICKIN LASER BEAMS ATTACHED TO THEIR HEADS

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3989 on: December 08, 2020, 12:34:19 AM »
BAS (British Antarctic Survey) sponsored 'Antarctica Week' zoom sessions for school children recently & I captured some screen shots associated with the Thwaites Offshore Research (THOR) project (for the 2019-2020 field season) from the two videos linked below.

The first image shows the various activities undertaken by THOR.

The second image shows the bathymetry from multibeam surveys taken by THOR.

The third image shows a higher resolution image of the bathymetry near the Thwaites Eastern Ice Shelf and the Thwaites Ice Tongue.

The fourth image shows that this new bathymetry indicates the amount of ocean heat reaching the grounding line for Thwaites maybe twice what was previously assumed; which is causing the grounding line to retreat faster than previously assumed by consensus climate science.

Title: "Antarctica Week: The Footprint of Past Ice" for grade school students.

https://ukri.zoom.us/rec/play/K4TbEcb-MlekVGG5p06bPEkgemwCPUFoj2fu-0-_Pb4VVEZc85jtHQSpZtd4cjWaBJEJa8GzTN7qh4F4.kVW6rmW87iE9Uilb?continueMode=true&_x_zm_rtaid=1vNhwyEtTaWyiNACxF1qEg.1607376296525.3379f134b6803e8299f750f456a2877b&_x_zm_rhtaid=570

&

Title: "Antarctica Week: Mapping deep channels under Thwaites Glacier"

https://ukri.zoom.us/rec/play/v4uuAcgxoqydvWdaz9N1yH6TSZPllzg6VlxWTxULoQO-ydEXs5Q9XJmLFxbEInWxg7wVeu2aUOfmF5IX.n74i27qalR7At6I5?continueMode=true&_x_zm_rtaid=1vNhwyEtTaWyiNACxF1qEg.1607376296525.3379f134b6803e8299f750f456a2877b&_x_zm_rhtaid=570

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

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3990 on: December 08, 2020, 01:13:02 AM »
Just for interest is the GRACE-FO data for AIS+GIS ice mass loss since 2002.

Total mass loss = over 17 mms of sea level rise (very close to 1 mm per year)
I thought annual rise was ~3 mm. What is the other two...thermal expansion? Glacier melt?

The linked references answer your question as other contributions (both negative and positive) to eustatic SLR include:

1. Terrestrial water storage (TWS) both natural and manmade;
2. Thermostatic;
3. Ice caps and mountain glaciers;
4. Groundwater depletion
5. Dam Impoundments
6. Barystatic.

Also, I note that there is a glacial isostatic adjustment (GIA) factor.

Frederikse, T., Landerer, F., Caron, L. et al. The causes of sea-level rise since 1900. Nature 584, 393–397 (2020). https://doi.org/10.1038/s41586-020-2591-3

https://www.nature.com/articles/s41586-020-2591-3

Abstract: "The rate of global-mean sea-level rise since 1900 has varied over time, but the contributing factors are still poorly understood. Previous assessments found that the summed contributions of ice-mass loss, terrestrial water storage and thermal expansion of the ocean could not be reconciled with observed changes in global-mean sea level, implying that changes in sea level or some contributions to those changes were poorly constrained. Recent improvements to observational data, our understanding of the main contributing processes to sea-level change and methods for estimating the individual contributions, mean another attempt at reconciliation is warranted. Here we present a probabilistic framework to reconstruct sea level since 1900 using independent observations and their inherent uncertainties. The sum of the contributions to sea-level change from thermal expansion of the ocean, ice-mass loss and changes in terrestrial water storage is consistent with the trends and multidecadal variability in observed sea level on both global and basin scales, which we reconstruct from tide-gauge records. Ice-mass loss —predominantly from glaciers—has caused twice as much sea-level rise since 1900 as has thermal expansion. Mass loss from glaciers and the Greenland Ice Sheet explains the high rates of global sea-level rise during the 1940s, while a sharp increase in water impoundment by artificial reservoirs is the main cause of the lower-than-average rates during the 1970s. The acceleration in sea-level rise since the 1970s is caused by the combination of thermal expansion of the ocean and increased ice-mass loss from Greenland. Our results reconcile the magnitude of observed global-mean sea-level rise since 1900 with estimates based on the underlying processes, implying that no additional processes are required to explain the observed changes in sea level since 1900."

&

Gregory, J.M., Griffies, S.M., Hughes, C.W. et al. Concepts and Terminology for Sea Level: Mean, Variability and Change, Both Local and Global. Surv Geophys 40, 1251–1289 (2019). https://doi.org/10.1007/s10712-019-09525-z

https://link.springer.com/article/10.1007/s10712-019-09525-z
« Last Edit: December 08, 2020, 01:18:21 AM by AbruptSLR »
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3991 on: December 08, 2020, 04:53:40 PM »
Just a reminder that the Amazon rainforest tends to experience drought during El Niño events. The warm, dry weather that occurs as a result of El Niño increases the risk of forest fires over the entire Amazon Basin. The dryness caused by El Niño also reduces plant growth, which means that trees store less carbon; and such dry weather causes the soil to release carbon. The frequency of El Niño events is projected to increase, not only gradually with continued anthropogenic radiative forcing, but also with the possibly abrupt future slowdown of the MOC due to a Beaufort Gyre reversal and/or a MICI-type collapse of the WAIS, in coming decades.  Thus, we could see an abrupt collapse of the Amazon rainforest in the coming decades; which would likely increase the effective ECS this century.
A strong El Niño combined with the open season policies of Bolsonaro plus the demand from China for meat + soya (if the US / China trade war heats up even more that demand could sky-rocket) could make a nightmare of a deforestation/fire season. And maybe even a modest El Nino is enough.

I also remind readers that during El Nino events, energy from the Tropical Pacific can be directly  telecommunicated via atmospheric Rossby Waves to the coastal areas of West Antarctica, and specifically to the coastal ASE area; where this energy can promote surface ice melting and potentially to associated hydrofracturing of key ice features (including ice shelves and ice cliffs).
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

Sciguy

  • Nilas ice
  • Posts: 1622
    • View Profile
  • Liked: 199
  • Likes Given: 157
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3992 on: December 09, 2020, 01:50:50 AM »

As it is likely that the final GMSTA for 2020 will be almost the same as that for 2016; and as the 2020-2021 ENSO season is very likely to be an official La Nina season; I have updated the first attached image of Hansen's La Nina trend vs GMSTA; with my purple lines indicating that the rate of increase of GMSTA is accelerating rapidly as compare to earlier trend lines.  This means that we are collectively more likely to pass the U.N.'s 2C limit sooner than consensus climate scientists have previously acknowledged.

In this regard, we are currently still essentially on the SSP 8.5 forcing pathway, and if the high-end (Wolf Pack) CMIP6 GMSTA projections are correct (see the second [by Hausfather 2020] and third [particularly the heavy black curve for UKESM1-0-LL] images) then we will likely pass the 2C limit around 2034; which per DeConto and Pollard would significantly increase the risk of an MICI-type of collapse of the Thwaites Glacier after 2034 (due to the increase risk of hydrofracturing).

Edit: Note that by extending my last purple La Nina vs GMSTA trendline (for from 2018 to 2020), this also indicates that GMSTA will reach 2C circa 2034 to 2035.



In 2020 RCP 2.5 forecasts a CO2 concentration of 412.1 ppm while RCP 8.5 forecasts 415.8 ppm.  The global average concentration in 2019 was 409.85.  With an estimated growth rate of 2.5 ppm, the 2020 concentration would be 412.35, much closer to RCP 2.6 then 8.5.

And the energy transition has made RCP 8.5 extremely unlikely. Coal consumption peaked in 2013 and in 2019 more coal fired power plant capacity was retired globally than was started.  Yet RCP 8.5 projects huge increases in coal use for eight more decades.



And SSP 8.5 is even worse in its projections on energy use than RCP 8.5:

https://www.carbonbrief.org/explainer-the-high-emissions-rcp8-5-global-warming-scenario



Quote
With global coal use having declined slightly since its peak in 2014, it is hard to envision a world where coal expands this dramatically in the future even in the absence of new climate policies. This is particularly true given the falling prices of alternative energy technologies in recent years. A forthcoming “expert elicitation” – where energy experts were asked to assess the likelihood of various outcomes – gives RCP8.5 only a 5% chance of occurring among all the possible no-policy baseline scenarios.

The reality is that renewables are taking over from fossil fuels at a pace that hadn't been expected in 2007 when the RCP scenarios were created.  Since renewables are much more efficient than fossil fuels (around 1/3 of the energy from fossil fuels goes up the smokestack as waste heat), they lead to a huge decrease in primary energy needed.

The IEA's World Energy Outlook 2020 has more realistic scenarios, even though the IEA is known for underestimating the growth of renewables.

https://energycentral.com/c/ec/world-energy-outlook-weo-2020-glance

Quote
In its annual WEO, the IEA models the long-term developments on the global commodity and energy markets up to 2070. This year’s WEO focuses on the next decade. In particular, the effects of the COVID-19 pandemic on the energy sector are examined in more detail. Particularly in this year, the WEO 2020 contains four scenarios.
WEO 2020 outlines four scenarios

Their respective characteristics are briefly summarised below:

    COVID-19 will be brought under control next year in the “Stated Policies Scenario” (STEPS) and the world economy will reach pre-crisis levels.
    In contrast, the “Delayed Recovery Scenario" (DRS) assumes that the pandemic will not have any impact only after 2023. This would make this the decade with the lowest growth rate in energy demand since the 1930s.
    Thirdly, the focus in the “Sustainable Development Scenario” (SDS) is on compliance with the Paris Agreement by 2050.
    Last but not least, the new “Net Zero Emissions by 2050 case” (NZE2050) even surpasses the SDS and describes which changes are necessary in the next 10 years to reach the target of net zero emissions by 2050.

Figure 1 shows the course of CO2-emissions from energy use and industry and different reduction levers for three scenarios until 2030.



Quote
Renewable energies cover majority of additional energy consumption

In all four scenarios of the WEO 2020, coal demand falls continuously, but only in the SDS and NZE2050 coal-fired power generation falls significantly. This is also shown in Figure 3. Especially in Europe and the US, coal demand is projected to fall sharply.




Quote
Figure 4: Global primary energy demand by fuel, millions of tonnes of oil equivalent, between 1990 and 2040. Future demand is based on the STEPS (solid lines) and SDS (dashed). Other renewables includes solar, wind, geothermal and marine. (source: CarbonBrief)


AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3993 on: December 09, 2020, 09:05:48 AM »
NOAA uses a conservative formula for converting methane into its CO2 equivalent; nevertheless, the attached NOAA image indicates that as of the end of 2019 CO2 equivalent reached 500ppm.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3994 on: December 09, 2020, 03:33:29 PM »

As it is likely that the final GMSTA for 2020 will be almost the same as that for 2016; and as the 2020-2021 ENSO season is very likely to be an official La Nina season; I have updated the first attached image of Hansen's La Nina trend vs GMSTA; with my purple lines indicating that the rate of increase of GMSTA is accelerating rapidly as compare to earlier trend lines.  This means that we are collectively more likely to pass the U.N.'s 2C limit sooner than consensus climate scientists have previously acknowledged.

In this regard, we are currently still essentially on the SSP 8.5 forcing pathway, and if the high-end (Wolf Pack) CMIP6 GMSTA projections are correct (see the second [by Hausfather 2020] and third [particularly the heavy black curve for UKESM1-0-LL] images) then we will likely pass the 2C limit around 2034; which per DeConto and Pollard would significantly increase the risk of an MICI-type of collapse of the Thwaites Glacier after 2034 (due to the increase risk of hydrofracturing).

Edit: Note that by extending my last purple La Nina vs GMSTA trendline (for from 2018 to 2020), this also indicates that GMSTA will reach 2C circa 2034 to 2035.

...

In 2020 RCP 2.5 forecasts a CO2 concentration of 412.1 ppm while RCP 8.5 forecasts 415.8 ppm.  The global average concentration in 2019 was 409.85.  With an estimated growth rate of 2.5 ppm, the 2020 concentration would be 412.35, much closer to RCP 2.6 then 8.5.

And the energy transition has made RCP 8.5 extremely unlikely. Coal consumption peaked in 2013 and in 2019 more coal fired power plant capacity was retired globally than was started.  Yet RCP 8.5 projects huge increases in coal use for eight more decades.
...

My quote references SSP 8.5, and the attached plot shows Energy and Industry CO2 emissions thru December 2019 vs the SSP scenarios, and which indicates that we are relatively close to SSP 8.5.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

Tor Bejnar

  • Young ice
  • Posts: 3831
    • View Profile
  • Liked: 669
  • Likes Given: 491
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3995 on: December 09, 2020, 03:37:43 PM »
Quote
NOAA image indicates that as of the end of 2019 CO2 equivalent reached 500ppm.
So in around 7 or 8 years NOAA's CO2e will be double the pre-industrial value of 275ppm.  :'(

As in the Grant Peeples (satirical) song about luring people to Florida, "That's gotta count for somethun' ."
Arctic ice is healthy for children and other living things.

Sciguy

  • Nilas ice
  • Posts: 1622
    • View Profile
  • Liked: 199
  • Likes Given: 157
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3996 on: December 09, 2020, 06:16:11 PM »
My quote references SSP 8.5, and the attached plot shows Energy and Industry CO2 emissions thru December 2019 vs the SSP scenarios, and which indicates that we are relatively close to SSP 8.5.

It's interesting that energy and industry CO2 emissions were on the RCP 8.5 pathway yet the CO2 concentrations are closer to the RCP 2.6 pathway.  That suggests that either natural emissions are lower or the carbon sinks absorb more CO2 than consensus science estimates.

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3997 on: December 09, 2020, 06:52:44 PM »
The linked article discusses methane leaks from abandoned offshore oil/gas wells and makes it clear that some of these abandoned wells are super emitters that represent an under reported source of methane emissions into the atmosphere.  Furthermore, as more and more offshore oil/gas wells are abandoned, this will represent an increasing threat for continued global warming.

Title: "Unplugged: Abandoned oil and gas wells leave the ocean floor spewing methane"

https://www.ehn.org/oil-and-gas-wells-methane-oceans-2649126354.html

Extract: "The Gulf of Mexico is littered with tens of thousands of abandoned oil and gas wells, and toothless regulation leaves climate warming gas emissions unchecked."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

kassy

  • Young ice
  • Posts: 3006
    • View Profile
  • Liked: 1265
  • Likes Given: 1165
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3998 on: December 09, 2020, 08:58:39 PM »
One thing that bugs me is that the scenarios are just our emissions. The total temp rise is of course a sum of our emissions + trends in feedbacks.

There are lots of hints that we are underestimating those.

No matter how happy you are with the rate of change in the energy mix it will be a while before we get to zero CO2 growth from emissions and after that the atmospheric CO2 needs to go down a lot.

At the current levels the loss of Arctic ice is projected in the 2040s, could be 2030s too. It would not even surprise me if it happens in the current decade. Regardless of when that happens that will kick temperatures up a bit especially north with all extra feedbacks.

Another thing. To find out what practical doubling of CO2 does we need to work out what the actual planets response is. All well known data we have is from an icehouse state world. When looking at paleo data you have some historic parameters which we use with our models.

We do not have proper snapshots of the transitions.

We know that the Holocene Climate Optimum had less ice then today. That was due to orbital forcing.

Also there is this nagging detail of our current warming push being different. Milankovitch cycle warming changes the focal point of heating but if there is relatively more warming north there should be less south (obviously it is a bit more complicated) but our current push ramps up temperatures everywhere and disturbs climate systems everywhere.

And there is the small detail of our anthropogenic earth being different from the natural world.
Our penchant for hydro dams changed the input into sea level enough to mess up SLR predictions for a while. 

We know from historic records that arctic climates can flip quickly. How does this happen? Well local sea ice (and near land ice change for the focal point example) gets lost. The sea ice change is more important because those changes last (due to removal of fresh water lens etc). This in turn changes all kind of teleconnections in the atmosphere leading to a strong localized decline.

With the current CO2 push we have both that effect and more heat/vapour transferring which leads to faster change.

We have possibly already locked in changes in Antarctica which the IPCC rates as irreversible at current rates so avoiding dangerous climate change might just be political blah blah.

And if that is true then it is not important on which pathway we are but we need to be 100% certain that we are near 2,6 or below that and aiming lower.
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.

AbruptSLR

  • Multi-year ice
  • Posts: 19207
    • View Profile
  • Liked: 2130
  • Likes Given: 263
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE
« Reply #3999 on: December 09, 2020, 11:41:13 PM »
...
We have possibly already locked in changes in Antarctica which the IPCC rates as irreversible at current rates so avoiding dangerous climate change might just be political blah blah.

And if that is true then it is not important on which pathway we are but we need to be 100% certain that we are near 2,6 or below that and aiming lower.

kassy,

I like your post; however, I note that the IPCC only recognizes MISI type of Antarctic behavior; while I believe that an MICI-type of failure will occur in the Byrd Subglacial Basin between 2030 and 2040; when GMSTA may only be around 2C.  But we will not know whether I am correct until it is too late to do anything about such an MICI-type of behavior, but the more we cut back on emissions now the better life will be for future generations no matter what.

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