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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1950 on: November 18, 2019, 06:25:31 PM »
I appreciate Naomi Oreskes' insights in the linked article about the decades long energy companies' '… climate-change scam that beat science, big time.; including the insight that: 'Scientists working on the issue have often told me that, once upon a time, they assumed, if they did their jobs, politicians would act upon the information. That, of course, hasn’t happened.'

In a perfect world, consensus climate scientists would be immune to politics; but w.r.t climate-change, history has proven that this is far from the actual case:

Title: "Why science failed to stop climate change - How the energy companies took us all"

https://www.salon.com/2019/11/18/why-science-failed-to-stop-climate-change_partner/

Extract: "It’s a tale for all time. What might be the greatest scam in history or, at least, the one that threatens to take history down with it. Think of it as the climate-change scam that beat science, big time.

Scientists have been seriously investigating the subject of human-made climate change since the late 1950s and political leaders have been discussing it for nearly as long. In 1961, Alvin Weinberg, the director of the Oak Ridge National Laboratory, called carbon dioxide one of the “big problems” of the world “on whose solution the entire future of the human race depends.” Fast-forward nearly 30 years and, in 1992, President George H.W. Bush signed the U.N. Framework Convention on Climate Change (UNFCCC), promising “concrete action to protect the planet.”

Scientists working on the issue have often told me that, once upon a time, they assumed, if they did their jobs, politicians would act upon the information. That, of course, hasn’t happened. Anything but, across much of the planet. Worse yet, science failed to have the necessary impact in significant part because of disinformation promoted by the major fossil-fuel companies, which have succeeded in diverting attention from climate change and successfully blocking meaningful action."
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nanning

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1951 on: November 18, 2019, 06:42:40 PM »
<snip>
It is a small planet with limited resources to maintain life. That resource is in decline.

Thank you for that view gerontocrat.
"It is preoccupation with possessions, more than anything else, that prevents us from living freely and nobly" - Bertrand Russell
   Simple: minimize your possessions and be free and kind    It's just a mindset.       Refugees welcome

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1952 on: November 19, 2019, 12:32:29 AM »
Gavin Schmidt recently posted the first image indicating that 2019 will almost certainly be the second warmest year in the observed record, even though ENSO is currently neutral.



For what it is worth, I provide the two attached images that Gavin Schmidt provided in July 2019 (referenced to a 'pre-industrial' baseline) where based on January to June 2019 GISTEMP data he was projecting the 2019 would likely be tied for second place for the warmest year on record; while his November 2019 indicates that 2019 will most likely have second place all by itself.

Edit1: I note that in these images 2016 is shown as having an annual GMSTA with a 'pre-industrial' baseline of about 1.23C; while 2019 is likely to have an annual GMSTA with a 'pre-industrial' baseline of above 1.1C.

Edit2: For convenience, I provide the third image as a re-post of the quoted image.

Edit3: See also:

Title: "Assessing the Global Climate in October 2019:

https://www.ncei.noaa.gov/news/global-climate-201910

Extract: "The year-to-date globally averaged sea surface temperature was the second highest for January–October in the 1880–2019 record …"
« Last Edit: November 20, 2019, 05:39:46 PM by AbruptSLR »
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1953 on: November 19, 2019, 03:39:50 AM »
...
 Furthermore, the 40-year update of Limits to Growth provides projections very much inline with our current BAU situation, and which projects a coming major socioeconomic contraction very much inline with my proposed sixth family of IPCC forcing scenarios (see the last two images, respectively).

Not only did Limits to Growth project a socio-economic collapse circa 2050, but so have the Australians:

Title: "Climate Change Could End Human Civilisation as We Know It by 2050, Analysis Finds"

https://www.sciencealert.com/by-2050-climate-change-could-alter-human-civilisation-as-we-know-it

Extract: "The new report, co-written by a former executive in the fossil fuel industry, is a harrowing follow-up to the Breakthrough National Centre for Climate Restoration's 2018 paper, which found that climate models often underestimate the most extreme scenarios.

Endorsed by former Australian defence chief Admiral Chris Barrie, the message is simple: if we do not take climate action in the next 30 years, it is entirely plausible that our planet warms by 3°C and that human civilisation as we know it collapses.

Under this scenario, the authors explain, the world will be locked into a "hothouse Earth" scenario, where 35 percent of the global land area, and 55 percent of the global population, will be subject to more than 20 days a year of "lethal heat conditions, beyond the threshold of human survivability."

With a runaway event like this, climate change will not present as a normal distribution, but instead will be skewed by a fat tail – indicating a greater likelihood of warming that is well in excess of average climate models.
Under a business-as-usual scenario, the authors explain, warming is set to reach 2.4°C by 2050. If feedback cycles are taken into account, however, there may be another 0.6°C that current models do not assume.

"It should be noted," the paper adds, "that this is far from an extreme scenario: the low-probability, high-impact warming (five percent probability) can exceed 3.5–4°C by 2050.""

Edit: For ease of reference, I provide the two attached Limits to Growth images updated on its 40th anniversary
« Last Edit: November 19, 2019, 04:03:09 PM by AbruptSLR »
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1954 on: November 19, 2019, 05:20:02 PM »
The Pine Island Ice Shelf, PIIS, plays a major role in the future stability of the Pine Island Glacier, PIG, and as the first attached image of the PIIS for Nov. 19, 2019 indicates that the PIIS will sustain a major calving event any week/month now, I thought that it would be helpful to review some key issues regarding the PIIS, the PIG and their relationship to the Thwaites drainage basin, thus:

The second image shows the condition of the PIIS and the associated grounding line from March 2012, and the associated shear strains in the PIIS.

The third image shows the condition of the PIIS and associated grounding line from Mid-January 2014, showing both a retreat of the calving front and a retreat of the grounding line from 2012.

The fourth image shows a screen grab of the PIIS calving front retreat history from 1973 to 2018, which is close to the calving front configuration today.  Also, I note that the calving front is currently retreating faster than the grounding line; which suggests that in coming decades the PIG may have an un-buttressed ice cliff face subject to MICI-types of failure mechanisms
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1955 on: November 19, 2019, 05:34:02 PM »
As a follow-on to my last post about the retreat history of the PIIS and the PIG, the first attached image shows the PIG basal topography and the relationship of the PIG drainage basin to the Thwaites drainage basin; which indicates that a MICI-type of collapse in either basin would act to undermine the glacial ice in the other basin.

The second image shows a close-up of both the PIG and the Southwest 'SW' Tributary glacier basal topographies.

The third image shows the relations of the ice shear strains between the SW Tributary Glacier and the eastern shear margin of the Thwaites Glacier.  Further as the PIIS no longer blocks the flow path of the SW Glacier ice shelf; it is reasonable to assume that the SW Tributary Glacier ice flow velocity is increasing (& note that the upcoming major calving event for the PIIS may well trigger minor calving from the SW Tributary Glacier ice shelf), the shear margin for the SW Tributary Glacier may soon connect directly with the Thwaites eastern shear margin; which would likely cause the ice flow velocity for Thwaites to accelerate.

The fourth image shows a close-up of the ice flow velocities in the SW Tributary Glacier prior to 2016.
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1956 on: November 19, 2019, 05:49:36 PM »
As a follow-on to my last to posts, the first attached shows the ice velocity pattern for several key ASE marine glaciers prior to 2012.

The second image shows a representative water circulation pattern beneath the PIIS between 2009 and 2012, showing a gyre both in the front and the rear of the sub-ice-shelf cavity, that serve to periodically advection either warmer modified CDW or cooler modified CDW into this cavity.  Note that 2009 was associated with an introduction of warmer modified CDW (due to a moderate El Nino event) and that 2012 was associated with an introduction of cooler modified CDW (due to a moderate La Nina event).

The third image shows a profile view of that advection of warm modified CDW beneath the PIIS circa 2009 where the temperatures shown are the difference of the water temperature from that required to melt ice (which varies with depth).

The fourth (& final) image in this series, shows a schematic of typical primary stresses and associated crevasse patterns for ice shelves like the PIIS, and I note that the PIIS calving from is currently in the 'Compressive flow with shear at sides' zone, but that in coming decades this calving front will likely retreat thru the 'Shear at valley walls' zone into the 'Extending flow' zone where/when an un-buttressed ice cliff face may likely become exposed.
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1957 on: November 19, 2019, 06:39:25 PM »
The linked reference indicates that since 2009 nitrous oxide emissions have been increasing at about twice the rate assumed by the IPCC:

R. L. Thompson et al. (2019), "Acceleration of global N2O emissions seen from two decades of atmospheric inversion", Nature Climate Change, DOI: https://doi.org/10.1038/s41558-019-0613-7

https://www.nature.com/articles/s41558-019-0613-7

Abstract: "Nitrous oxide (N2O) is the third most important long-lived GHG and an important stratospheric ozone depleting substance. Agricultural practices and the use of N-fertilizers have greatly enhanced emissions of N2O. Here, we present estimates of N2O emissions determined from three global atmospheric inversion frameworks during the period 1998–2016. We find that global N2O emissions increased substantially from 2009 and at a faster rate than estimated by the IPCC emission factor approach. The regions of East Asia and South America made the largest contributions to the global increase. From the inversion-based emissions, we estimate a global emission factor of 2.3 ± 0.6%, which is significantly larger than the IPCC Tier-1 default for combined direct and indirect emissions of 1.375%. The larger emission factor and accelerating emission increase found from the inversions suggest that N2O emission may have a nonlinear response at global and regional scales with high levels of N-input."

Edit, see also:

Title: "Nitrogen fertilizers are incredibly efficient, but they make climate change a lot worse"

https://phys.org/news/2019-11-nitrogen-fertilizers-incredibly-efficient-climate.html

Extract: "In a paper published today in Nature Climate Change, we found global emissions are higher and growing faster than are being reported."
« Last Edit: November 20, 2019, 10:42:53 PM by AbruptSLR »
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1958 on: November 19, 2019, 09:30:56 PM »
The linked reference indicates that consensus climate science has previously seriously underestimated the amount of future GHG emission from freshwater lakes by up to a factor of 2.7 times:

Andrew J. Tanentzap et al. Chemical and microbial diversity covary in fresh water to influence ecosystem functioning, Proceedings of the National Academy of Sciences (2019). DOI: 10.1073/pnas.1904896116

https://www.pnas.org/content/early/2019/11/12/1904896116

Significance

Every drop of fresh water contains hundreds of different organic compounds, yet the biological role of this vast chemical diversity is largely a mystery. One hypothesis is that greater diversity may provide more opportunities for microbes to coexist, namely “diversity begets diversity.” Here we find a close association between mixtures of chemicals and both the diversity of microorganisms in lake sediments and their potential to decompose plant litterfall. Increases in chemical diversity also elevated greenhouse gas concentrations by an average of 1.5 to 2.7 times under scenarios that simulated future environmental change. Overall, our findings advance our understanding of how life is connected to the chemical environment in ways that can influence important processes, such as carbon cycling.

Abstract

Invisible to the naked eye lies a tremendous diversity of organic molecules and organisms that make major contributions to important biogeochemical cycles. However, how the diversity and composition of these two communities are interlinked remains poorly characterized in fresh waters, despite the potential for chemical and microbial diversity to promote one another. Here we exploited gradients in chemodiversity within a common microbial pool to test how chemical and biological diversity covary and characterized the implications for ecosystem functioning. We found that both chemodiversity and genes associated with organic matter decomposition increased as more plant litterfall accumulated in experimental lake sediments, consistent with scenarios of future environmental change. Chemical and microbial diversity were also positively correlated, with dissolved organic matter having stronger effects on microbes than vice versa. Under our experimental scenarios that increased sediment organic matter from 5 to 25% or darkened overlying waters by 2.5 times, the resulting increases in chemodiversity could increase greenhouse gas concentrations in lake sediments by an average of 1.5 to 2.7 times, when all of the other effects of litterfall and water color were considered. Our results open a major new avenue for research in aquatic ecosystems by exposing connections between chemical and microbial diversity and their implications for the global carbon cycle in greater detail than ever before.

See also:

Title: "Freshwater lakes already emit a quarter of global carbon—and climate change could double that"

https://phys.org/news/2019-11-freshwater-lakes-emit-quarter-global.html

Extract: "The amount of greenhouse gases released from lakes by microbes and sunlight is huge. Initial estimates were about 9% of the net carbon released from the Earth's surface to the atmosphere—that is, the amount released over and above the Earth's carbon-storing processes.

But, thanks to improved measurements, recent research has revised the figure to as high as 25%. These numbers are substantial given that that lakes only comprise about 4% of the global land surface."
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1959 on: November 19, 2019, 11:52:21 PM »
The linked January 24, 2019 article makes is clear that the Bulletin of Atomic Scientists' Science and Security Board believes that we are within 2 minutes on the Doomsday Clock to a hypothetical apocalypse associated with threats from both nuclear weapons and climate change and that the risks associated with these threats are amplified '… by the increased use of information warfare to undermine democracy around the world …":

Title: "A new abnormal: It is still 2 minutes to midnight"

https://thebulletin.org/doomsday-clock/current-time/

Extract: "Humanity now faces two simultaneous existential threats, either of which would be cause for extreme concern and immediate attention. These major threats—nuclear weapons and climate change—were exacerbated this past year by the increased use of information warfare to undermine democracy around the world, amplifying risk from these and other threats and putting the future of civilization in extraordinary danger."

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1960 on: November 20, 2019, 04:20:57 PM »
The linked reference indicates that stratospheric ozone trends have not been recovering as quickly as assumed by consensus climate models, indicating that:

'These decreases do not reveal an inefficacy of the Montreal Protocol; rather, they suggest that other effects are at work, mainly dynamical variability on long or short timescales, counteracting the positive effects of the Montreal Protocol on stratospheric ozone recovery.'

&

'However, this variability is not represented in current regression analyses.'

Ball, W. T., Alsing, J., Staehelin, J., Davis, S. M., Froidevaux, L., and Peter, T.: Stratospheric ozone trends for 1985–2018: sensitivity to recent large variability, Atmos. Chem. Phys., 19, 12731–12748, https://doi.org/10.5194/acp-19-12731-2019, 2019.

https://www.atmos-chem-phys.net/19/12731/2019/

Abstract: "The Montreal Protocol, and its subsequent amendments, has successfully prevented catastrophic losses of stratospheric ozone, and signs of recovery are now evident. Nevertheless, recent work has suggested that ozone in the lower stratosphere (< 24 km) continued to decline over the 1998–2016 period, offsetting recovery at higher altitudes and preventing a statistically significant increase in quasi-global (60∘ S–60∘ N) total column ozone. In 2017, a large lower stratospheric ozone resurgence over less than 12 months was estimated (using a chemistry transport model; CTM) to have offset the long-term decline in the quasi-global integrated lower stratospheric ozone column. Here, we extend the analysis of space-based ozone observations to December 2018 using the BASICSG ozone composite. We find that the observed 2017 resurgence was only around half that modelled by the CTM, was of comparable magnitude to other strong interannual changes in the past, and was restricted to Southern Hemisphere (SH) midlatitudes (60–30∘ S). In the SH midlatitude lower stratosphere, the data suggest that by the end of 2018 ozone is still likely lower than in 1998 (probability ∼80 %). In contrast, tropical and Northern Hemisphere (NH) ozone continue to display ongoing decreases, exceeding 90 % probability. Robust tropical (>95 %, 30∘ S–30∘ N) decreases dominate the quasi-global integrated decrease (99 % probability); the integrated tropical stratospheric column (1–100 hPa, 30∘ S–30∘ N) displays a significant overall ozone decrease, with 95 % probability. These decreases do not reveal an inefficacy of the Montreal Protocol; rather, they suggest that other effects are at work, mainly dynamical variability on long or short timescales, counteracting the positive effects of the Montreal Protocol on stratospheric ozone recovery. We demonstrate that large interannual midlatitude (30–60∘) variations, such as the 2017 resurgence, are driven by non-linear quasi-biennial oscillation (QBO) phase-dependent seasonal variability. However, this variability is not represented in current regression analyses. To understand if observed lower stratospheric ozone decreases are a transient or long-term phenomenon, progress needs to be made in accounting for this dynamically driven variability."

Maybe by CMIP7 we will have learned how to model ozone more accurately.
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1961 on: November 20, 2019, 04:48:49 PM »
The linked reference indicates that:

'These multiple lines of evidence lead to a 68% confidence interval for the total aerosol effective radiative forcing of ‐1.60 to ‐0.65 W m‐2, or ‐2.0 to ‐0.4 W m‐2 with a 90% likelihood. Those intervals are of similar width to the last Intergovernmental Panel on Climate Change assessment but shifted towards more negative values.'

Thus effective aerosol radiative forcing has been more negative than assumed by AR5; which, implies that it has been masking a higher ECS than assumed by AR5; and that as future aerosol emissions are decreased, GMSTA will increase faster than assumed by AR5:

N. Bellouin et al. (01 November 2019), "Bounding global aerosol radiative forcing of climate change", Reviews of Geophysics, https://doi.org/10.1029/2019RG000660

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019RG000660

Abstract
Aerosols interact with radiation and clouds. Substantial progress made over the past 40 years in observing, understanding, and modeling these processes helped quantify the imbalance in the Earth's radiation budget caused by anthropogenic aerosols, called aerosol radiative forcing, but uncertainties remain large. This review provides a new range of aerosol radiative forcing over the industrial era based on multiple, traceable and arguable lines of evidence, including modelling approaches, theoretical considerations, and observations. Improved understanding of aerosol absorption and the causes of trends in surface radiative fluxes constrain the forcing from aerosol‐radiation interactions. A robust theoretical foundation and convincing evidence constrain the forcing caused by aerosol‐driven increases in liquid cloud droplet number concentration. However, the influence of anthropogenic aerosols on cloud liquid water content and cloud fraction is less clear, and the influence on mixed‐phase and ice clouds remains poorly constrained. Observed changes in surface temperature and radiative fluxes provide additional constraints. These multiple lines of evidence lead to a 68% confidence interval for the total aerosol effective radiative forcing of ‐1.60 to ‐0.65 W m‐2, or ‐2.0 to ‐0.4 W m‐2 with a 90% likelihood. Those intervals are of similar width to the last Intergovernmental Panel on Climate Change assessment but shifted towards more negative values. The uncertainty will narrow in the future by continuing to critically combine multiple lines of evidence, especially those addressing industrial‐era changes in aerosol sources and aerosol effects on liquid cloud amount and on ice clouds.

Plain language summary
Human activities emit into the atmosphere small liquid and solid particles called aerosols. Those aerosols change the energy budget of the Earth, and trigger climate changes, by scattering and absorbing solar and terrestrial radiation and playing important roles in the formation of cloud droplets and ice crystals. But because aerosols are much more varied in their chemical composition and much more heterogeneous in their spatial and temporal distributions than greenhouse gases, their perturbation to the energy budget, called radiative forcing, is much more uncertain. This review uses traceable and arguable lines of evidence, supported by aerosol studies published over the past 40 years, to quantify that uncertainty. It finds that there are 2 chances out of three that aerosols from human activities have increased scattering and absorption of solar radiation by 14 to 29% and cloud droplet number concentration by 6 to 18% in the period 2005‐‐2015 compared to the year 1850. Those increases exert a radiative forcing that offsets between a fifth and a half of the radiative forcing by greenhouse gases. The degree to which human activities affect natural aerosol levels, and the response of clouds, and especially ice clouds, to aerosol perturbations remain particularly uncertain.
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1962 on: November 20, 2019, 05:19:16 PM »
The attached image from a French CMIP6 projections of GMSTA (with a pre-industrial baseline) for the different SSP scenarios, and indicate that by following either SSP5 8.5 or SSP3 7.0, GMSTA could be approaching 2.5C by 2040; which would likely be sufficient to trigger hydrofracturing on some key West Antarctic ice shelves, by that date:
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1963 on: November 20, 2019, 06:15:18 PM »
The linked reference indicates that since the industrial era the ocean has been accumulating more heat content then consensus climate scientists previously assumed.  Furthermore, the associate Fig. 2 (shown in two attached images for panel A and B, respectively), show that the Southern Ocean has been responsible for the lion's share of cumulative heat uptake (see the first image), while much of the heat accumulated in the Atlantic Ocean since 1950 has come from other regions.  This recent data suggests that many consensus climate models have likely underestimated the about of heat stored in the Southern Ocean; which is available for ice melting of key Antarctic marine glacial ice and ice shelf ice.

Laure Zanna, Samar Khatiwala, Jonathan M. Gregory, Jonathan Ison, and Patrick Heimbach (January 22, 2019), "Global reconstruction of historical ocean heat storage and transport", PNAS, 116 (4), 1126-1131, https://doi.org/10.1073/pnas.1808838115

https://www.pnas.org/content/116/4/1126

Significance
Since the 19th century, rising greenhouse gas concentrations have caused the ocean to absorb most of the Earth’s excess heat and warm up. Before the 1990s, most ocean temperature measurements were above 700 m and therefore, insufficient for an accurate global estimate of ocean warming. We present a method to reconstruct ocean temperature changes with global, full-depth ocean coverage, revealing warming of 436 ×10 21  ×1021 J since 1871. Our reconstruction, which agrees with other estimates for the well-observed period, demonstrates that the ocean absorbed as much heat during 1921–1946 as during 1990–2015. Since the 1950s, up to one-half of excess heat in the Atlantic Ocean at midlatitudes has come from other regions via circulation-related changes in heat transport.

Abstract
Most of the excess energy stored in the climate system due to anthropogenic greenhouse gas emissions has been taken up by the oceans, leading to thermal expansion and sea-level rise. The oceans thus have an important role in the Earth’s energy imbalance. Observational constraints on future anthropogenic warming critically depend on accurate estimates of past ocean heat content (OHC) change. We present a reconstruction of OHC since 1871, with global coverage of the full ocean depth. Our estimates combine timeseries of observed sea surface temperatures with much longer historical coverage than those in the ocean interior together with a representation (a Green’s function) of time-independent ocean transport processes. For 1955–2017, our estimates are comparable with direct estimates made by infilling the available 3D time-dependent ocean temperature observations. We find that the global ocean absorbed heat during this period at a rate of 0.30 ± 0.06 W/m 2  m2 in the upper 2,000 m and 0.028 ± 0.026 W/m 2  m2 below 2,000 m, with large decadal fluctuations. The total OHC change since 1871 is estimated at 436 ± 91 ×10 21  ×1021 J, with an increase during 1921–1946 (145 ± 62 ×10 21  ×1021 J) that is as large as during 1990–2015. By comparing with direct estimates, we also infer that, during 1955–2017, up to one-half of the Atlantic Ocean warming and thermosteric sea-level rise at low latitudes to midlatitudes emerged due to heat convergence from changes in ocean transport.

Caption: "Fig. 2. Cumulative heat uptake from 1871 to 2017 (joules per year) shown for each patch (numbered here and shown in SI Appendix, Fig. S1), contributing to the integrated passive heat storage (A) globally and (B) in the Atlantic Ocean. Note the different scales for the two panels."

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1964 on: November 20, 2019, 07:27:03 PM »
The linked open access publication indicates that current consensus science estimates of right-tailed climate economic impacts are '… grossly underestimating many of the most serious consequences for lives and livelihoods because these risks are difficult to quantify precisely and lie outside of human experience.'  Obviously, as risk is equal to probability times consequences, this means that right-tailed risks are currently be grossly underestimated:

Title: "The missing economic risks in assessments of climate change impacts"

http://www.lse.ac.uk/GranthamInstitute/publication/the-missing-economic-risks-in-assessments-of-climate-change-impacts/
http://www.lse.ac.uk/GranthamInstitute/wp-content/uploads/2019/09/The-missing-economic-risks-in-assessments-of-climate-change-impacts-2.pdf

   Extract: "Economic assessments of the potential future risks of climate change have been omitting or grossly underestimating many of the most serious consequences for lives and livelihoods because these risks are difficult to quantify precisely and lie outside of human experience.

   Political and business leaders need to understand the scale of these ‘missing risks’ because they could have drastic and potentially catastrophic impacts on citizens, communities and companies.

   Scientists are growing in confidence about the evidence for the largest potential impacts of climate change and the rising probability that major thresholds in the Earth’s climate system will be breached as global mean surface temperature rises, particularly if warming exceeds 2°C above the pre-industrial level. These impacts include:
   Destabilisation of ice sheets and glaciers and consequent sea level rise
   Stronger tropical cyclones
   Extreme heat impacts
   More frequent and intense floods and droughts
   Disruptions to oceanic and atmospheric circulation
   Destruction of biodiversity and collapse of ecosystems
   
        Many of these impacts will grow and occur concurrently across the world as global temperature climbs.

   Some of these impacts involve thresholds in the climate system beyond which major impacts accelerate, or become irreversible and unstoppable.

   When a threshold is breached, it might cause one or more other thresholds to be exceeded as well, leading to a cascade of impacts.

   Many of these impacts could exceed the capacity of human populations to adapt, and would significantly affect and disrupt the lives and livelihoods of hundreds of millions, if not billions, of people worldwide.

   These impacts would also undermine economic growth and development, exacerbate poverty and destabilise communities.

   Economic assessments fail to take account of the potential for large concurrent impacts across the world that would cause mass migration, displacement and conflict, with huge loss of life.

   Economic assessments that are expressed solely in terms of effects on output (e.g. gross domestic product), or that only extrapolate from past experience, or that use inappropriate discounting, do not provide a clear indication of the potential risks to lives and livelihoods.

   It is likely that there are additional risks that we are not yet anticipating simply because scientists have not yet detected their possibility, as we have entered a period of climate change that is unprecedented in human history.

   Some advances are being made in improving economic assessments of climate change impacts but much more progress is required if assessments are to offer reliable guidance for political and business leaders on the biggest risks.

   The lack of firm quantifications is not a reason to ignore these risks, and when the missing risks are taken into account, the case for strong and urgent action to reduce greenhouse gas emissions becomes even more compelling."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1965 on: November 20, 2019, 08:18:29 PM »
The linked reference indicates that earlier models of methane (& CO2) fluxes from Arctic tundra ecosystems underestimate the importance of the temperatures of deeper layers of soil w.r.t. fluxes in non-summer seasons:

Howard, D., Agnan, Y., Helmig, D., Yang, Y., and Obrist, D.: Environmental controls on ecosystem-scale cold season methane and carbon dioxide fluxes in an Arctic tundra ecosystem, Biogeosciences Discuss., https://doi.org/10.5194/bg-2019-437, in review, 2019.

https://www.biogeosciences-discuss.net/bg-2019-437/

https://www.biogeosciences-discuss.net/bg-2019-437/bg-2019-437.pdf

Abstract. Understanding the processes that influence and control carbon cycling in Arctic tundra ecosystems is essential for making accurate predictions about what role these ecosystems will play in potential future climate change scenarios. Particularly, air–surface fluxes of methane and carbon dioxide are of interest as recent observations suggest that the vast stores of soil carbon found in the Arctic tundra are becoming more available to release to the atmosphere in the form of these greenhouse gases. Further, harsh wintertime conditions and complex logistics have limited the number of year-round and cold season studies and hence too our understanding of carbon cycle processes during these periods. We present here a two-year micrometeorological data set of methane and carbon dioxide fluxes that provides near-continuous data throughout the active summer and cold winter seasons. Net emission of methane and carbon dioxide in one of the study years totalled 3.7 and 89 g C m−2 a−1 respectively, with cold season methane emission representing 54% of the annual total. In the other year, net emission totals of methane and carbon dioxide were 4.9 and 485 g C m−2 a−1 respectively, with cold season methane emission here representing 82 % of the annual total – a larger proportion than has been previously reported in the Arctic tundra. Regression tree analysis suggests that, due to relatively warmer air temperatures and deeper snow depths, deeper soil horizons – where most microbial methanogenic activity takes place – remained warm enough to maintain efficient methane production whilst surface soil temperatures were simultaneously cold enough to limit microbial methanotrophic activity. These results provide valuable insight into how a changing Arctic climate may impact methane emission, and highlight a need to focus on soil temperatures throughout the entire active soil profile, rather than rely on air temperature as a proxy for modelling temperature–methane flux dynamics.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1966 on: November 20, 2019, 09:37:05 PM »
The linked report indicates that government plans for fossil fuel production leaves a large 'Production Gap' between associated global carbon dioxide emissions that the emissions required to meet the goals of the Paris Agreement (see the attached image).  Also, I note that this analysis does not consider the potentially much higher values of climate sensitivity indicated by many CMIP6 models:

Title: "The Production Gap"

http://productiongap.org/

http://productiongap.org/wp-content/uploads/2019/11/Production-Gap-Report-2019.pdf

Extract: "Governments are planning to produce about 50% more fossil fuels by 2030 than would be consistent with limiting warming to 2°C and 120% more than would be consistent with limiting warming to 1.5°C.

The global production gap is even larger than the already-significant global emissions gap, due to minimal policy attention on curbing fossil fuel production."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1967 on: November 20, 2019, 10:09:00 PM »
More bad news about projected nitrous oxide emissions:

Title: "Nitrous oxide emissions set to rise in the Pacific Ocean"

https://phys.org/news/2019-11-nitrous-oxide-emissions-pacific-ocean.html

Extract: "The acidification of the Pacific Ocean in northern Japan is increasing the natural production rate of N2O, an ozone-depleting greenhouse gas. That's the finding of a study carried out jointly by scientists at EPFL, Tokyo Institute of Technology and Japan Agency for Marine-Earth Science and Technology and appearing recently in Nature Climate Change."

See also:

Florian Breider et al. Response of N2O production rate to ocean acidification in the western North Pacific, Nature Climate Change (2019). DOI: 10.1038/s41558-019-0605-7

https://www.nature.com/articles/s41558-019-0605-7

Extract: "Collectively, these results suggest that if seawater pH continues to decline at the same rate, ocean acidification could increase marine N2O production during nitrification in the subarctic North Pacific by 185 to 491% by the end of the century."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1968 on: November 20, 2019, 10:24:33 PM »
The linked article/reference indicates that the Arctic Ocean could be seasonally ice free between 2044 and 2067, by constraining the relationship between sea ice extent and sea ice albedo feedback (SIAF) and found that: 'The relationship is strengthened when models with unrealistically thin historical ice are excluded.'  Obviously, this stronger relationship projects greater Arctic Amplification and consequently greater values of ECS than previously assumed by consensus climate science:

Title: "Arctic Ocean could be ice-free for part of the year as soon as 2044"

https://phys.org/news/2019-11-arctic-ocean-ice-free-year.html

Extract: "But according to a new study by UCLA climate scientists, human-caused climate change is on track to make the Arctic Ocean functionally ice-free for part of each year starting sometime between 2044 and 2067.

For their study, Thackeray and co-author Alex Hall, a UCLA professor of atmospheric and oceanic sciences, set out to determine which models are most realistic in how they weigh the effects of sea ice albedo feedback, which they figured would lead them to the most realistic projections for sea ice loss.

Thackeray and Hall assessed 23 models' depiction of seasonal ice melt between 1980 and 2015 and compared them with the satellite observations. They retained the six models that best captured the actual historical results and discarded the ones that had proven to be off base, enabling them to narrow the range of predictions for ice-free Septembers in the Arctic."

See also:

Chad W. Thackeray et al. An emergent constraint on future Arctic sea-ice albedo feedback, Nature Climate Change (2019). DOI: 10.1038/s41558-019-0619-1

https://www.nature.com/articles/s41558-019-0619-1

Abstract: "Arctic sea ice has decreased substantially over recent decades, a trend projected to continue. Shrinking ice reduces surface albedo, leading to greater surface solar absorption, thus amplifying warming and driving further melt. This sea-ice albedo feedback (SIAF) is a key driver of Arctic climate change and an important uncertainty source in climate model projections. Using an ensemble of models, we demonstrate an emergent relationship between future SIAF and an observable version of SIAF in the current climate’s seasonal cycle. This relationship is robust in constraining SIAF over the coming decades (Pearson’s r = 0.76), and then it degrades. The degradation occurs because some models begin producing ice-free conditions, signalling a transition to a new ice regime. The relationship is strengthened when models with unrealistically thin historical ice are excluded. Because of this tight relationship, reducing model errors in the current climate’s seasonal SIAF and ice thickness can narrow SIAF spread under climate change."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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gerontocrat

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1969 on: November 20, 2019, 11:08:57 PM »
I managed to find the original of the graphic in the above post by AbruptSLR.

You can download it from here :- http://newsroom.ucla.edu/releases/arctic-sea-ice-melting-2044

Attached is part of the full graphic that is, I hope, easier to read.
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