Support the Arctic Sea Ice Forum and Blog

Author Topic: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)  (Read 54711 times)

AbruptSLR

  • ASIF Emperor
  • Posts: 16662
    • View Profile
  • Liked: 240
  • Likes Given: 63
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #600 on: February 15, 2019, 11:24:02 PM »
As I have been (/will be) traveling, the following are some random considerations as to why the WAIS may collapse sooner than even DeConto & Pollard estimate (see the first image, and I note that the second image indicates that SSP5-Baseline results in a faster rate of global warming than computed by DeConto & Pollard):

1. Finer mesh resolution typically result in faster ice mass loss projections from ice sheet models, and this is particularly true for models of the Thwaites Gateway, and I note that DeConto & Pollards mesh could be finer if they had access to more computational power.

2.  If I am correct that once the residual Thwaites Ice Tongue is cleared away (maybe within 5 to 20 years), that ice cliff calved icebergs will be able to float-out by traveling along the seafloor trench at the base of the Thwaites Ice Tongue, then an MICI mechanism should be able to develop for the Thwaites Glacier prior to the development of hydrofracturing in this area.

3. As climate change is currently increasing the frequency of cyclones in the Amundsen-Bellingshausen Sea Sector, increased storm surge activity will likely accelerate ice mass loss from this area.

4. The recently observed trend of accelerating ice flow velocities for both the Thwaites, and Pine Island, Glaciers (partially attributable to the loss of buttressing on the SW Tributary Glacier in 2018), results in increased friction-induced ice melting within the body of these glaciers; and such ice meltwater drips/rains down to create increased subglacial meltwater; which serves to accelerate the destabilization of such key marine glaciers.

5. The glacial beds for the WAIS marine glaciers are all more worn/scoured than was the case for all paleo-cases.  Thus, any ice mass models calibrated using paleo-data will consequently err on the side of least drama.

6. It is likely that glacial isostatic rebound will increase geothermal heat flux through the beds of key WAIS marine glaciers; which would serve to accelerate the destabilization of such glaciers.

7. Projections of increased snowfall in the coastal regions of the WAIS (with continued global warming), will increase the gravitational driving force associated with MICI and MISI ice mass loss in coming decades.

8. Projections of increased El Nino activity (with continued global warming) will increase the volume of warm CDW advected to the grounding lines of key WAIS marine glaciers, and will also increase the likelihood of hydrofracturing of key WAIS ice shelves in the coming decades.

9. DeConto & Pollard (& Hansen) used consensus values of ECS in their model projections; which indicates that their projections of ice mass loss err on the side of least drama.

10. The Eastern Thwaites Ice Shelf and the Pine Island Ice Shelf, both appear to be degrading faster than projected by DeConto & Pollard; which indicates that their ice mass loss projections err on the side of least drama.

11. The freshening of much of the surface waters of the Southern Ocean, due to both early ice mass loss from Antarctic ice shelves and increase precipitation onto the surface of the Southern Ocean, is accelerating the projected increased upwelling of warm CDW.

12. The early ice mass loss from the Greenland Ice Sheet is accelerating the bipolar seesaw mechanism, which is compounding the influence of the decadal slow down of the MOC.

13. At some point, sufficient ice mass loss from the WAIS will trigger increased seismic and volcanic activity, not evaluated by DeConto & Pollard.

14. Recent evidence indicates that the negative forcing associated with anthropogenic aerosols has been/is greater than previously assumed by consensus climate science; which implies that GMSTA will increase faster than projected as anthropogenic aerosol emissions are reduced and/or redistributed around the globe.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

RealityCheck

  • ASIF Lurker
  • Posts: 65
    • View Profile
  • Liked: 8
  • Likes Given: 3
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #601 on: February 16, 2019, 07:46:31 AM »
Thanks for this excellent summary of upside risks to Thwaites glacier, ASLR. And for your ongoing posting here - much obliged. Happy trails as you travel...
Sic transit gloria mundi

AbruptSLR

  • ASIF Emperor
  • Posts: 16662
    • View Profile
  • Liked: 240
  • Likes Given: 63
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #602 on: February 16, 2019, 05:22:59 PM »
A few key related points from Jonathan Bamber:

Title: "The Carbon Brief Interview: Prof Jonathan Bamber"

https://www.carbonbrief.org/the-carbon-brief-interview-prof-jonathan-bamber

Extracts: "On Arctic sea ice loss: “We could potentially have an ice-free Arctic Ocean in summer by 2035-2040, which is potentially in my lifetime, not so far away. That really is incredible.”

On the west Antarctic ice sheet: “There were some papers…that suggest that we may even have passed that marine ice sheet instability threshold already for parts of west Antarctica.”

On Arctic permafrost: “When it melts, we believe most of that carbon will be emitted as methane, which is a much stronger greenhouse gas than CO2.”"
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • ASIF Emperor
  • Posts: 16662
    • View Profile
  • Liked: 240
  • Likes Given: 63
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #603 on: February 16, 2019, 05:55:29 PM »
The linked reference provides paleo evidence that the eastern equatorial Pacific (EEP) can release previously sequestered carbon from the ocean into the atmosphere in a relatively short-timespan.  Thus, ESM projections should be updated to include this potentially significant source of carbon emissions into the atmosphere over the coming decades, with continued global warming:

Lowell D Stott et al. (2019), "Hydrothermal carbon release to the ocean and atmosphere from the eastern equatorial Pacific during the last glacial termination", Environmental Research Letters,

https://iopscience.iop.org/article/10.1088/1748-9326/aafe28/meta

Abstract: "Arguably among the most globally impactful climate changes in Earth's past million years are the glacial terminations that punctuated the Pleistocene epoch. With the acquisition and analysis of marine and continental records, including ice cores, it is now clear that the Earth's climate was responding profoundly to changes in greenhouse gases that accompanied those glacial terminations. But the ultimate forcing responsible for the greenhouse gas variability remains elusive. The oceans must play a central role in any hypothesis that attempt to explain the systematic variations in pCO2 because the Ocean is a giant carbon capacitor, regulating carbon entering and leaving the atmosphere. For a long time, geological processes that regulate fluxes of carbon to and from the oceans were thought to operate too slowly to account for any of the systematic variations in atmospheric pCO2 that accompanied glacial cycles during the Pleistocene. Here we investigate the role that Earth's hydrothermal systems had in affecting the flux of carbon to the ocean and ultimately, the atmosphere during the last glacial termination. We document late glacial and deglacial intervals of anomalously old 14C reservoir ages, large benthic-planktic foraminifera 14C age differences, and increased deposition of hydrothermal metals in marine sediments from the eastern equatorial Pacific (EEP) that indicate a significant release of hydrothermal fluids entered the ocean at the last glacial termination. The large 14C anomaly was accompanied by a ~4-fold increase in Zn/Ca in both benthic and planktic foraminifera that reflects an increase in dissolved [Zn] throughout the water column. Foraminiferal B/Ca and Li/Ca results from these sites document deglacial declines in [ ] throughout the water column; these were accompanied by carbonate dissolution at water depths that today lie well above the calcite lysocline. Taken together, these results are strong evidence for an increased flux of hydrothermally-derived carbon through the EEP upwelling system at the last glacial termination that would have exchanged with the atmosphere and affected both Δ14C and pCO2. These data do not quantify the amount of carbon released to the atmosphere through the EEP upwelling system but indicate that geologic forcing must be incorporated into models that attempt to simulate the cyclic nature of glacial/interglacial climate variability. Importantly, these results underscore the need to put better constraints on the flux of carbon from geologic reservoirs that affect the global carbon budget."

Caption for the attached image: "Figure 1. Nearly pure CO2 bubbles emanating from sediments that blanket an active hydrothermal system in the western tropical Pacific. Photos by Roy Price, courtesy of Jan Amend."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • ASIF Emperor
  • Posts: 16662
    • View Profile
  • Liked: 240
  • Likes Given: 63
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #604 on: February 16, 2019, 06:09:21 PM »
The linked reference adds information to Bamber's observation that the Arctic Ocean could become seasonally sea ice free circa 2040 (which would accelerate the ice-climate positive feedback mechanism):

J. A. Screen & C. Deser (05 February 2019), "Pacific Ocean Variability Influences the Time of Emergence of a Seasonally Ice‐Free Arctic Ocean", Geophysical Research Letters, https://doi.org/10.1029/2018GL081393

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL081393

Abstract

The Arctic Ocean is projected to become seasonally ice‐free before midcentury unless greenhouse gas emissions are rapidly reduced, but exactly when this could occur depends considerably on internal climate variability. Here we show that trajectories to an ice‐free Arctic are modulated by concomitant shifts in the Interdecadal Pacific Oscillation (IPO). Trajectories starting in the negative IPO phase become ice‐free 7 years sooner than those starting in the positive IPO phase. Trajectories starting in the negative IPO phase subsequently transition toward the positive IPO phase, on average, with an associated strengthening of the Aleutian Low, increased poleward energy transport, and faster sea‐ice loss. The observed IPO began to transition away from its negative phase in the past few years. If this shift continues, our results suggest increased likelihood of accelerated sea‐ice loss over the coming decades, and an increased risk of an ice‐free Arctic within the next 20–30 years.

Plain Language Summary
Manmade climate change is causing a rapid loss of Arctic sea ice. Summer Arctic sea ice is predicted to disappear almost completely by the middle of this century, unless emissions of greenhouse gases are rapidly reduced. The speed of sea‐ice loss is not constant over time, however. Natural climate variability can add to the manmade decline, leading to faster sea‐ice loss, or can subtract from the manmade decline, leading to slower sea‐ice loss. In this study, we looked at how natural climate variability affects the timing of an ice‐free Arctic. We found that a natural cycle called the Interdecadal Pacific Oscillation, or IPO for short, is particularly important. Arctic sea‐ice loss is faster when the IPO is moving from its cold to warm phase and slower when the IPO is moving from its warm to cold phase. This is because variations in the IPO cause changes in atmospheric wind patterns, which alter the amount of heat that is transported into the Arctic. Observations show that the IPO started to shift from its cold to warm phase in the past few years. If this shift continues, our results suggest that there is an increased chance of accelerated sea‐ice loss over the coming decades.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • ASIF Emperor
  • Posts: 16662
    • View Profile
  • Liked: 240
  • Likes Given: 63
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #605 on: February 16, 2019, 06:20:52 PM »
export from the Ross Sea sector in recent years; those who consider the impact of ice-climate feedback mechanisms realize that this observed increase in Antarctic sea ice, and associated freshening of the Southern Ocean, leads to increase upwelling of warm CDW and an associated acceleration of the destabilization of key Antarctic marine glaciers:

Ivana Cerovečki et al. (2019), "The effects of enhanced sea ice export from the Ross Sea on recent cooling and freshening of the Southeast Pacific", Journal of Climate, https://doi.org/10.1175/JCLI-D-18-0205.1

https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-18-0205.1

Abstract: "The top 2000 m of the Southern Ocean has freshened and warmed over recent decades. However, the high-latitude (south of 50°S) southeast Pacific was observed to be cooler and fresher in the years 2008-2010 compared to 2005-2007 over a wide depth range including surface, mode, and intermediate waters. The causes and impacts of this event are analyzed using the ocean—sea-ice data-assimilating Southern Ocean State Estimate (SOSE) and observationally based products. In 2008-2010, a strong positive Southern Annular Mode coincided with a negative El Niño Southern Oscillation and a deep Amundsen Sea Low. Enhanced meridional winds drove strong sea ice export from the eastern Ross Sea, bringing large amounts of ice to the Amundsen Sea ice edge. In 2008, together with increased precipitation, this introduced a strong freshwater anomaly that was advected eastward by the Antarctic Circumpolar Current (ACC), mixing along the way. This anomaly entered the ocean interior not only as Antarctic Intermediate Water, but also as lighter Southeast Pacific Subantarctic Mode Water (SEPSAMW). A numerical particle release experiment carried out in SOSE , showed that the Ross Sea sector was the dominant source of particles reaching the SEPSAMW formation region. This suggests that large-scale climate fluctuations can induce strong interannual variability of volume and properties of SEPSAMW. These fluctuations act at different time scales: instantaneously via direct forcing, and also lagged over advective time scales of several years from upstream regions."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • ASIF Emperor
  • Posts: 16662
    • View Profile
  • Liked: 240
  • Likes Given: 63
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #606 on: February 16, 2019, 06:30:39 PM »
The linked reference indicates that current IPCC carbon budgets only consider relatively fast Earth System responses; while slower Earth System responses like those associated with ENSO feedback mechanism are unstoppable by geoengineering, once triggered, and which will contribute to net global warming:

Xiao‐Tong Zheng et al. (05 February 2019), "Intensification of El Niño rainfall variability over the tropical Pacific in the slow oceanic response to global warming", Geophysical Research Letters, https://doi.org/10.1029/2018GL081414

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL081414

Abstract
Changes in rainfall variability of El Niño–Southern Oscillation (ENSO) are investigated under scenarios where the greenhouse gases (GHGs) increase and then stabilize. During the period of increasing greenhouse forcing, the ocean mixed layer warms rapidly. After the forcing stabilizes, the deeper ocean continues to warm the surface (the slow response). We show that ENSO rainfall variability over the tropical Pacific intensifies in both periods but the rate of increase per degree global mean surface temperature (GMST) warming is larger for the slow response because of greater relative warming in the base state as the mean upwelling changes from a damping to a driver of the surface warming. Our results have important implications for climate extremes under GMST stabilization that the Paris Agreement calls for. To stabilize GMST, the fast surface cooling offsets the slow warming from the prior GHG increase, while ENSO rainfall variability would continue to increase.

Plain Language Summary
The Paris Agreement calls for limiting global mean surface temperature (GMST) increase to well below 2 degrees at the end of the 21st century. This requires the greenhouse gas (GHG) concentration to peak and subsequently decline in next few decades. After the GHG concentration peak, the heat accumulated in the ocean surface layer continues to penetrate to the deeper ocean. This deeper ocean warming leads to a slow response of surface warming, further influencing the climate system. This study examines scenarios where GHGs increase and then stabilize to isolate the fast and slow responses of El Niño‐Southern Oscillation (ENSO) rainfall variability. We find intensification of ENSO rainfall variability both during the increase and after stabilization of GHG concentrations due to a persistent El Niño‐like mean warming pattern in the tropical Pacific. Furthermore, for unit GMST increase, the changes in the mean state temperature and ENSO rainfall variability in the eastern equatorial Pacific is larger during the slow response. These results imply that there is a need for GHG emission reduction in near future to avoid more extreme tropical rainfall during El Niño.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • ASIF Emperor
  • Posts: 16662
    • View Profile
  • Liked: 240
  • Likes Given: 63
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #607 on: February 16, 2019, 06:38:50 PM »
The linked reference finds that methane emissions are increasing faster in the NH than previously assumed.  I suspect that this trend will eventually result in greater Arctic Amplification than previously assumed by consensus climate science:

Sudhanshu Pandey et al. (29 January 2019), "Influence of Atmospheric Transport on Estimates of Variability in the Global Methane Burden", Geophysical Research Letters, https://doi.org/10.1029/2018GL081092

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL081092

Abstract: "We quantify the impact of atmospheric transport and limited marine boundary layer sampling on changes in global and regional CH4 burdens estimate using tracer transport model simulations with annually repeating CH4 emissions and sinks, but varying atmospheric transport patterns. We find the 1σ error due to the transport‐sampling effect on annual global CH4 increases to be 1.11 ppb/yr and on zonal growth rates to be 3.8 ppb/yr, indicating the transport‐sampling effect becomes more critical at smaller spatiotemporal scales. We also find that the trends in inter‐hemispheric and inter‐polar difference of CH4 are significantly influenced by transport‐sampling. Contrary to a negligible trend in the inter‐hemispheric difference of measurements, we find, after adjusting for the transport‐sampling, a trend of 0.37 ± 0.06 ppb/yr. This is consistent with the emission trend from a 3D inversion of the measurements, suggesting a faster increase in emissions in the Northern Hemisphere than in the Southern Hemisphere."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • ASIF Emperor
  • Posts: 16662
    • View Profile
  • Liked: 240
  • Likes Given: 63
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #608 on: February 17, 2019, 12:46:28 AM »
The linked SciAm article indicates that black carbon is currently contributing to high values of Arctic Amplification:

Title: "Scientists Track the Source of Soot That Speeds Arctic Melt"

https://www.scientificamerican.com/article/scientists-track-the-source-of-soot-that-speeds-arctic-melt/

Extract: "Research has found that black carbon emissions may be responsible for as much as half a degree Celsius of Arctic warming — that's about a quarter of the warming the Arctic has experienced over the last hundred years.

Recent research has warned that unless global greenhouse gas emissions begin falling substantially within the next decade or two, winter temperatures in the Arctic could skyrocket by more than 10 C."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • ASIF Emperor
  • Posts: 16662
    • View Profile
  • Liked: 240
  • Likes Given: 63
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #609 on: February 17, 2019, 11:00:35 PM »
The linked reference provides calibrated simulations of Pliocene Earth Systems, to indicate that with continued warming Arctic Amplification will likely occur faster during the Arctic winter than during the Arctic Summer:

Zheng, J., Zhang, Q., Li, Q., Zhang, Q., and Cai, M.: Contribution of sea ice albedo and insulation effects to Arctic amplification in the EC-Earth Pliocene simulation, Clim. Past, 15, 291-305, https://doi.org/10.5194/cp-15-291-2019, 2019.

https://www.clim-past.net/15/291/2019/

Abstract
In the present work, we simulate the Pliocene climate with the EC-Earth climate model as an equilibrium state for the current warming climate induced by rising CO2 in the atmosphere. The simulated Pliocene climate shows a strong Arctic amplification featuring pronounced warming sea surface temperature (SST) over the North Atlantic, in particular over the Greenland Sea and Baffin Bay, which is comparable to geological SST reconstructions from the Pliocene Research, Interpretation and Synoptic Mapping group (PRISM; Dowsett et al., 2016). To understand the underlying physical processes, the air–sea heat flux variation in response to Arctic sea ice change is quantitatively assessed by a climate feedback and response analysis method (CFRAM) and an approach similar to equilibrium feedback assessment. Given the fact that the maximum SST warming occurs in summer while the maximum surface air temperature warming happens during winter, our analyses show that a dominant ice-albedo effect is the main reason for summer SST warming, and a 1 % loss in sea ice concentration could lead to an approximate 1.8 W m−2 increase in shortwave solar radiation into open sea surface. During the winter months, the insulation effect induces enhanced turbulent heat flux out of the sea surface due to sea ice melting in previous summer months. This leads to more heat released from the ocean to the atmosphere, thus explaining why surface air temperature warming amplification is stronger in winter than in summer.

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

AbruptSLR

  • ASIF Emperor
  • Posts: 16662
    • View Profile
  • Liked: 240
  • Likes Given: 63
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #610 on: February 18, 2019, 12:52:32 AM »
The linked reference provides paleo data (from the past 360,000 years) that the ENSO assumes a La Nina like pattern during glacial periods and assumes an El Nino like pattern during rapidly changing portions of interglacial periods.  As we are in the most rapidly changing interglacial period on record, this is not good news:

Zhang, S., Li, T., Chang, F. et al. Chin. J. (2017), "Correspondence between the ENSO-like state and glacial-interglacial condition during the past 360 kyr", Ocean. Limnol., 35: 1018. https://doi.org/10.1007/s00343-017-6082-9

https://link.springer.com/article/10.1007/s00343-017-6082-9#citeas

Abstract: "In the warming world, tropical Pacific sea surface temperature (SST) variation has received considerable attention because of its enormous influence on global climate change, particularly the El Niño-Southern Oscillation process. Here, we provide new high-resolution proxy records of the magnesium/calcium ratio and the oxygen isotope in foraminifera from a core on the Ontong-Java Plateau to reconstruct the SST and hydrological variation in the center of the Western Pacific Warm Pool (WPWP) over the last 360 000 years. In comparison with other Mg/Ca-derived SST and δ18O records, the results suggested that in a relatively stable condition, e.g., the last glacial maximum (LGM) and other glacial periods, the tropical Pacific would adopt a La Niña-like state, and the Walker and Hadley cycles would be synchronously enhanced. Conversely, El Niño-like conditions could have occurred in the tropical Pacific during fast changing periods, e.g., the termination and rapidly cooling stages of interglacial periods. In the light of the sensitivity of the Eastern Pacific Cold Tongue (EPCT) and the inertia of the WPWP, we hypothesize an inter-restricted relationship between the WPWP and EPCT, which could control the zonal gradient variation of SST and affect climate change."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • ASIF Emperor
  • Posts: 16662
    • View Profile
  • Liked: 240
  • Likes Given: 63
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #611 on: February 18, 2019, 01:16:49 AM »
The linked references indicate that at a global scale permafrost is degrading fasters than previously assumed by consensus climate science; which could accelerate the rate of climate change this century:

Title: "Some Arctic ground no longer freezing—even in winter"

https://www.nationalgeographic.com/environment/2018/08/news-arctic-permafrost-may-thaw-faster-than-expected/

Extract: "On January 16, 2019, a new global study published in Nature Communications confirmed that permafrost is thawing quickly across much of the world. Between 2007 and 2016, permafrost temperature increased by 0.29 ± 0.12 °C globally. The greatest warming was seen in parts of Siberia, up to 0.93 °C. Significant warming was also seen in Antarctica, and less in mountain regions. In much of the Arctic ground temperature increased because of rising average air temperatures, while increased snow thickness in some areas also contributed to warming the ground underneath."
&

Biskaborn et al. (2019), "Permafrost is warming at a global scale", Nature Communications 10, No. 264, https://doi.org/10.1038/s41467-018-08240-4

https://www.nature.com/articles/s41467-018-08240-4#Fig6
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • ASIF Emperor
  • Posts: 16662
    • View Profile
  • Liked: 240
  • Likes Given: 63
Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #612 on: February 18, 2019, 08:26:33 PM »
The paleo findings cited in the linked article confirms that Arctic Sea Ice loss can lead to abrupt increases in Arctic Amplification:

Title: "Arctic sea ice loss in the past linked to abrupt climate events"

https://www.sciencedaily.com/releases/2019/02/190211164033.htm

Extract: "A new study on ice cores shows that reductions in sea ice in the Arctic in the period between 30-100,000 years ago led to major climate events. During this period, Greenland temperatures rose by as much as 16 degrees Celsius.
...
"The summer time sea ice in the Arctic has experienced a 40% decline in the last few decades, but we know that about two thirds of that reduction is caused by human-induced climate change. What we now need to determine is, what can be learnt from these past sea ice losses to enable us to understand what might happen next to our climate.""

See also:

Louise C. Sime, Peter O. Hopcroft, Rachael H. Rhodes (February 13, 2019), "Impact of abrupt sea ice loss on Greenland water isotopes during the last glacial period", PNAS,   https://doi.org/10.1073/pnas.1807261116

https://www.pnas.org/content/early/2019/02/12/1807261116

Abstract: "Greenland ice cores provide excellent evidence of past abrupt climate changes. However, there is no universally accepted theory of how and why these Dansgaard–Oeschger (DO) events occur. Several mechanisms have been proposed to explain DO events, including sea ice, ice shelf buildup, ice sheets, atmospheric circulation, and meltwater changes. DO event temperature reconstructions depend on the stable water isotope (δ18O) and nitrogen isotope measurements from Greenland ice cores: interpretation of these measurements holds the key to understanding the nature of DO events. Here, we demonstrate the primary importance of sea ice as a control on Greenland ice core δ18O: 95% of the variability in δ18O in southern Greenland is explained by DO event sea ice changes. Our suite of DO events, simulated using a general circulation model, accurately captures the amplitude of δ18O enrichment during the abrupt DO event onsets. Simulated geographical variability is broadly consistent with available ice core evidence. We find an hitherto unknown sensitivity of the δ18O paleothermometer to the magnitude of DO event temperature increase: the change in δ18O per Kelvin temperature increase reduces with DO event amplitude. We show that this effect is controlled by precipitation seasonality.

Significance

The Dansgaard–Oeschger events contained in Greenland ice cores constitute the archetypal record of abrupt climate change. An accurate understanding of these events hinges on interpretation of Greenland records of oxygen and nitrogen isotopes. We present here the important results from a suite of modeled Dansgaard–Oeschger events. These simulations show that the change in oxygen isotope per degree of warming becomes smaller during larger events. Abrupt reductions in sea ice also emerge as a strong control on ice core oxygen isotopes because of the influence on both the moisture source and the regional temperature increase. This work confirms the significance of sea ice for past abrupt warming events
« Last Edit: February 18, 2019, 08:38:39 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

  • ASIF Emperor
  • Posts: 16662
    • View Profile
  • Liked: 240
  • Likes Given: 63
This is just quick post to note that there a numerous paleo examples of abrupt (including multi-decadal) climate change; which projections from current Earth System Models (ESMs) cannot not match.  Thus climate science continues to investigate this issue such as the linked conference in Ireland later this year:

INQUA 2019 (July 25 to 31): Special Session Details

http://www.inqua2019.org/programme/special-sessions/


Title: "Abrupt changes in climate and ice sheets during glacial-interglacial cycles"

http://www.inqua2019.org/programme/special-sessions/#toggle-id-48

Ruza Ivanovic (Convenor)
Lauren Gregoire (Co-Convenor)
Laura Robinson (Co-Convenor)
Understanding how and why rapid environmental changes took place in the Quaternary remains a key challenge in the field of climate science. In particular, it remains difficult to reconcile the chain of events between recorded warming, cooling, iceberg calving, ice sheet melt and sea level rise. Many of these events have been linked with changing greenhouse gases, collapsing ice sheets and rapid reorganisations of ocean circulation. However, the fundamental questions remain: How can progressive climate trends trigger rapid changes? What are the internal instabilities and ice-ocean-atmosphere interactions that drove the sudden transitions? Are they stochastic responses in a variable Earth System or are the processes consistent across glacial-interglacial cycles? What was their environmental impact?
For this session, we invite contributions that seek to better constrain the chain of events surrounding abrupt changes in climate and ice sheets during glacial-interglacial cycles. We encourage submissions covering mechanistic-modelling, data acquisition and reconstructions of the events and their impact.
&

Title: "Abrupt climate changes: The view from lakes"

http://www.inqua2019.org/programme/special-sessions/#toggle-id-49

Jule Xiao (Convenor)
Jonathan Dean (Co-Convenor)
The Earth’s climate system has experienced a series of abrupt changes during the recent geological past. Abrupt climate changes occurring on centennial to multi-decadal scales could provide an analogue for what might happen with future global warming, thus have attracted increasing attention from paleoclimatologists. In this regard, lake records are of special importance due to the fact that they contain a diverse selection of proxies, respond sensitively to climate change and are highly resolved and geographically widespread. This session invites contributions of newly obtained high-resolution, multi-proxy data from lake sediments, to allow for the exchange of the latest results and ideas regarding changes in hydrology, ecology and climate recorded by lakes at different latitudes during the late Quaternary. This session will aim to identify the regional expression of different abrupt climate changes occurring in the past, thereby progressing our understanding of the mechanisms responsible for abrupt climate changes on different timescales and the possible environmental effects of future global warming in different regions.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

  • ASIF Emperor
  • Posts: 16662
    • View Profile
  • Liked: 240
  • Likes Given: 63
The findings of the linked research indicate that with continued global warming more of the increased heat will be advected by the atmosphere and proportionately less will be advected by the ocean.  This clearly implies that the relatively rapid poleward advection of heat energy through the atmosphere from the tropical oceans, will bring about more rapid climate change than expected by consensus climate science.  Furthermore, the disproportional concentration of ocean heat in the Southern Ocean, serves to destabilize Antarctic marine glaciers faster than assumed by consensus climate science:

Title: "Study: Climate change reshaping how heat moves around globe"

https://phys.org/news/2019-01-climate-reshaping-globe.html

Extract: " This is the first study to examine current changes in heat transfer and to conclude that warming temperatures are driving increased heat transfer in the atmosphere, which is compensated by a reduced heat transfer in the ocean. Additionally, the researchers concluded that the excess oceanic heat is trapped in the Southern Ocean around the Antarctic."

Chengfei He et al. The transient response of atmospheric and oceanic heat transports to anthropogenic warming, Nature Climate Change (2019). DOI: 10.1038/s41558-018-0387-3

https://www.nature.com/articles/s41558-018-0387-3

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