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Author Topic: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)  (Read 197143 times)

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1550 on: September 09, 2019, 05:13:05 PM »
The linked 2018 article indicates that China has plans to rapidly ramp-up its natural gas production from domestic shale sources:

Title: "China could be starting its own natural gas fracking revolution"

https://www.nextbigfuture.com/2018/06/china-could-be-starting-its-own-natural-gas-fracking-revolution.html

Extract: "China National Petroleum (CNPC), the largest state-owned producer of oil and natural gas in China, reportedly plans to nearly double natural gas production from shale sources this year and wants a five-fold increase in such production by 2020."
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1551 on: September 09, 2019, 06:05:00 PM »
All CMIP5 models fail to include climate feedback mechanisms from wildfires; but the linked article indicates that Arctic wildfires are occurring increasingly frequently and have significant climate feedback mechanisms from direct CO2 and black carbon emissions to decreasing the freezing resistance of many Arctic plants:

Title: "The Arctic is burning, and Greenland is melting, thanks to record heat"

https://www.sciencenews.org/article/arctic-burning-greenland-melting-thanks-record-heat

Extract: "Such Arctic wildfires are expected to become more common as the planet warms. There’s geologic precedent for that: Layers of black charcoal in sediments in the Canadian Arctic suggest that wildfires frequently raged across the region during the Pliocene Epoch, when global atmospheric CO₂ levels were between 350 and 450 parts per million — similar to today  (SN: 12/9/17, p. 24). In June, CO₂ levels averaged 413.92 ppm, according to data collected at the Mauna Loa Observatory in Hawaii.

Meanwhile, increasingly frequent winter warm spells, insect outbreaks and wildfires have also caused many Arctic plants to lose their resistance to freezing, dry out and die, turning large parts of the Arctic brown (SN: 4/13/19, p. 16). That, in turn, increases the region’s susceptibility to more wildfires: Normally, the icy peatlands are soggy enough to be fire-resistant, but they are thawing and drying out. Once set ablaze, the carbon-rich peat can burn for months, releasing large amounts of CO₂ back into the atmosphere and fueling the warming feedback loop (SN: 3/17/18, p. 20)."
“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 #1552 on: September 09, 2019, 07:14:46 PM »
The linked reference confirms that continued global warming will lead to projected increased frequency/extent of soil drought conditions; which the reference cited in Reply #1524, indicates will act as a positive feedback for increased global warming:

Sha Zhou, A. Park Williams, Alexis M. Berg, Benjamin I. Cook, Yao Zhang, Stefan Hagemann, Ruth Lorenz, Sonia I. Seneviratne, Pierre Gentine. Land-atmosphere feedbacks exacerbate concurrent soil drought and atmospheric aridity. PNAS, 2019 DOI: 10.1073/pnas.1904955116

https://www.pnas.org/content/early/2019/08/27/1904955116

Significance
Soil drought and atmospheric aridity can be disastrous for ecosystems and society. This study demonstrates the critical role of land–atmosphere feedbacks in driving cooccurring soil drought and atmospheric aridity. The frequency and intensity of atmospheric aridity are greatly reduced without the feedback of soil moisture to atmospheric temperature and humidity. Soil moisture can also impact precipitation to amplify soil moisture deficits under dry conditions. These land–atmosphere processes lead to high probability of concurrent soil drought and atmospheric aridity. Compared to the historical period, models project future frequency and intensity of concurrent soil drought and atmospheric aridity to be further enhanced by land–atmosphere feedbacks, which may pose large risks to ecosystem services and human well-being in the future.

Abstract
Compound extremes such as cooccurring soil drought (low soil moisture) and atmospheric aridity (high vapor pressure deficit) can be disastrous for natural and societal systems. Soil drought and atmospheric aridity are 2 main physiological stressors driving widespread vegetation mortality and reduced terrestrial carbon uptake. Here, we empirically demonstrate that strong negative coupling between soil moisture and vapor pressure deficit occurs globally, indicating high probability of cooccurring soil drought and atmospheric aridity. Using the Global Land Atmosphere Coupling Experiment (GLACE)-CMIP5 experiment, we further show that concurrent soil drought and atmospheric aridity are greatly exacerbated by land–atmosphere feedbacks. The feedback of soil drought on the atmosphere is largely responsible for enabling atmospheric aridity extremes. In addition, the soil moisture–precipitation feedback acts to amplify precipitation and soil moisture deficits in most regions. CMIP5 models further show that the frequency of concurrent soil drought and atmospheric aridity enhanced by land–atmosphere feedbacks is projected to increase in the 21st century. Importantly, land–atmosphere feedbacks will greatly increase the intensity of both soil drought and atmospheric aridity beyond that expected from changes in mean climate alone.
“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 #1553 on: September 09, 2019, 08:55:00 PM »
The linked reference (& associated article) indicates that consensus climate scientists currently underestimate the greenhouse gas potential of lakes, because they currently underestimate the amount of methane likely to be emitted from lakes with continued global warming:

Maciej Bartosiewicz et al. Hot tops, cold bottoms: Synergistic climate warming and shielding effects increase carbon burial in lakes, Limnology and Oceanography Letters (2019). DOI: 10.1002/lol2.10117

https://aslopubs.onlinelibrary.wiley.com/doi/full/10.1002/lol2.10117

Abstract
In this article, we challenge the notion that global warming stimulates organic matter mineralization and increases greenhouse gas emissions in lakes via direct temperature effects. We show that the interactive effects of warming and transparency loss due to eutrophication or browning overrides atmospheric warming alone. Thermal shielding enables a longer and more stable stratification that results in bottom‐water cooling, prolonged anoxia, and enhanced carbon preservation in a large proportion of global lakes. These effects are strongest in shallow lakes where an additional burial of 4.5 Tg C yr−1 increases current global estimates by 9%. Despite more burial, the net global warming potential of lakes will increase via enhanced methane production, related to prolonged periods of anoxia, rather than warming. Our understanding of how whole‐lake carbon cycling responds to climate change needs revision, as the synergistic influence of warming and transparency loss has much broader ecosystem level functional consequences.

Scientific Significance Statement
Lakes play a significant role in the global carbon cycle where inputs from watersheds and primary production are either stored in sediments or lost to the atmosphere through respiration. Climate change is anticipated to increase atmospheric losses as water overlying sediments warms, thus reducing carbon storage. Lakes worldwide, however, are not only warming but are also losing transparency through eutrophication or browning. The synergistic result is that heat is trapped in the surface layers of more colored lakes, which in turn isolates colder bottom waters and sediments experience longer periods without oxygen. This bottom‐water cooling increases overall carbon storage by reducing aerobic respiration, but stimulates methane production due to prolonged anoxia, thus potentially increasing the overall global warming potential of lakes.

See also:

Title: "Warm on top, cold below: Unexpected greenhouse gas effect in lakes"

https://phys.org/news/2019-09-cold-uexpected-greenhouse-gas-effect.html

Extract: "The increased differential warming in lakes has yet another effect: the pronounced thermal stratification entails that the deeper water layers do barely mix and are poorly ventilated, which can lead to prolonged anoxia. Under these oxygen-free conditions, methane production by anaerobic microorganisms is enhanced.

"All in all, global warming increases the greenhouse gas potential of lakes, as expected. However, this has less to do with the warming directly, and more to do with increased oxygen depletion at the bottom of these lakes," concludes Bartosiewicz."
“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 #1554 on: September 09, 2019, 11:26:50 PM »
The linked reference indicates that during the last deglaciation: "…, a positive imbalance of typically +0.2 W⋅m−2 is maintained for ∼10,000 y, however, with two distinct peaks that reach up to 0.4 W⋅m−2 during times of substantially reduced Atlantic Meridional Overturning Circulation."  As the Meridional Overturning Circulation is projected to slow rapidly if the WAIS were to collapse; these new paleo-finding support James Hansen's projections that ice-climate feedbacks associated with a slowing of the MOC (due to a collapse of the WAIS), would contribute abruptly to global warming:

Daniel Baggenstos, Marcel Häberli, Jochen Schmitt, Sarah A. Shackleton, Benjamin Birner, Jeffrey P. Severinghaus, Thomas Kellerhals, and Hubertus Fischer (July 8, 2019), "Earth’s radiative imbalance from the Last Glacial Maximum to the present", PNAS, 116 (30) 14881-14886; https://doi.org/10.1073/pnas.1905447116

https://www.pnas.org/content/116/30/14881.short

Significance
Earth’s radiative imbalance determines whether energy is flowing into or out of the ocean–atmosphere system. The present, anthropogenic, positive imbalance drives global warming. This study reconstructs the radiative imbalance for the last deglaciation, ∼20,000 to 10,000 y ago. During the deglaciation, a positive imbalance was maintained for several thousand years, which brought the climate system from the last ice age into the Holocene warm period. We show that the imbalance varied significantly during this time, possibly due to changes in ocean circulation that affect the radiative energy fluxes, highlighting the importance of internal variability in Earth’s energy budget.

Abstract
The energy imbalance at the top of the atmosphere determines the temporal evolution of the global climate, and vice versa changes in the climate system can alter the planetary energy fluxes. This interplay is fundamental to our understanding of Earth’s heat budget and the climate system. However, even today, the direct measurement of global radiative fluxes is difficult, such that most assessments are based on changes in the total energy content of the climate system. We apply the same approach to estimate the long-term evolution of Earth’s radiative imbalance in the past. New measurements of noble gas-derived mean ocean temperature from the European Project for Ice Coring in Antarctica Dome C ice core covering the last 40,000 y, combined with recent results from the West Antarctic Ice Sheet Divide ice core and the sea-level record, allow us to quantitatively reconstruct the history of the climate system energy budget. The temporal derivative of this quantity must be equal to the planetary radiative imbalance. During the deglaciation, a positive imbalance of typically +0.2 W⋅m−2 is maintained for ∼10,000 y, however, with two distinct peaks that reach up to 0.4 W⋅m−2 during times of substantially reduced Atlantic Meridional Overturning Circulation. We conclude that these peaks are related to net changes in ocean heat uptake, likely due to rapid changes in North Atlantic deep-water formation and their impact on the global radiative balance, while changes in cloud coverage, albeit uncertain, may also factor into the picture.
“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 #1555 on: September 10, 2019, 04:23:16 AM »

While the linked reference is over one and a half years old, it still presents post-CMIP5 model results that indicate high values for ECS and more significantly which indicate that: "... changed sea surface temperature pattern may be of equal importance" to cloud feedbacks in determining their higher than AR5 values for ECS:

D. Paynter  T. L. Frölicher  L. W. Horowitz  L. G. Silvers (26 January 2018), "Equilibrium Climate Sensitivity Obtained From Multimillennial Runs of Two GFDL Climate Models", JGR Atmospheres,  https://doi.org/10.1002/2017JD027885

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2017JD027885

Abstract
Equilibrium climate sensitivity (ECS), defined as the long‐term change in global mean surface air temperature in response to doubling atmospheric CO2, is usually computed from short atmospheric simulations over a mixed layer ocean, or inferred using a linear regression over a short‐time period of adjustment. We report the actual ECS from multimillenial simulations of two Geophysical Fluid Dynamics Laboratory (GFDL) general circulation models (GCMs), ESM2M, and CM3 of 3.3 K and 4.8 K, respectively. Both values are ~1 K higher than estimates for the same models reported in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change obtained by regressing the Earth's energy imbalance against temperature. This underestimate is mainly due to changes in the climate feedback parameter (−α) within the first century after atmospheric CO2 has stabilized. For both GCMs it is possible to estimate ECS with linear regression to within 0.3 K by increasing CO2 at 1% per year to doubling and using years 51–350 after CO2 is constant. We show that changes in −α differ between the two GCMs and are strongly tied to the changes in both vertical velocity at 500 hPa (ω500) and estimated inversion strength that the GCMs experience during the progression toward the equilibrium. This suggests that while cloud physics parametrizations are important for determining the strength of −α, the substantially different atmospheric state resulting from a changed sea surface temperature pattern may be of equal importance.
“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 #1556 on: September 10, 2019, 06:19:23 PM »
For those who are interested, I provide the following linked E3SM presentation without comment:

Title: "Carbon-Water Cycle Interactions: How do plant physiological responses to rising CO2 impact the water cycle and climate extremes in the tropics?"

https://e3sm.org/wp-content/uploads/2019/08/08272019_Kooperman_opt.pdf

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

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1557 on: September 10, 2019, 06:38:03 PM »
Thanks ASLR.
That's a prime example of very good communicating your science (these days).
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1558 on: September 10, 2019, 08:51:58 PM »
...
That's a prime example of very good communicating your science (these days).

I have said it before, but I say it again here, I believe that consensus climate scientists have done a poor job of communicating the true climate change risks to decision makers; for example:

1. This thread presents numerous positive feedback mechanisms the current consensus models either underestimate or do not consider entirely.  This results in demand PDFs that are too low.

2. Typically, decisions are made using something like a 95% confidence level for demand; while the IPCC presents 66% confidence levels.  Further, designs associated with public safety typically consider characteristic demand/load values together with a factor of safety for design while the IPCC emphasizes mean/average demand values and does not discuss what constitutes appropriate factors of safety for the public (see the first image, where the shades area represents the probability of failure).  Also, demands/loads for resilience civil designs are typically at least five time less likely to occur as compared to demands/loads for conventional civil designs; while the IPCC largely ignores long-tailed risks.

2. The second image reminds us that risk (consequence times probability) is dominated by long-tail climate change events; while the third image reminds us that feedback mechanisms with normal PDF distributions results in changes in mean global temperature that have PDFs with very long right-tails.
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1559 on: September 10, 2019, 10:08:33 PM »
As methane hydrates is a commonly discussed topic in this forum (including in this thread), I provide the information regarding new research findings on the formation conditions required for different methane hydrate polymorphs:

Arjun, Thom A. Berendsen, and Peter G. Bolhuis (September 9, 2019), "Unbiased atomistic insight in the competing nucleation mechanisms of methane hydrates", PNAS https://doi.org/10.1073/pnas.1906502116

https://www.pnas.org/content/early/2019/09/06/1906502116

Significance
Mixtures of methane gas and water can form ice-like solid methane hydrates via homogeneous nucleation at natural, moderate conditions. Understanding the formation of the different hydrate polymorphs, required for improved control of crystallization, is hampered by limited experimental resolution. Direct molecular dynamics simulations could provide insight, but it would require computation times beyond the age of the Universe for a single nucleation event to take place. Yet, the nucleation event itself, while rare, occurs fast. Therefore, we sample and examine ensembles of rare unbiased nucleation trajectories. Detailed analysis shows how selection between competing amorphous and crystalline polymorph formation mechanisms takes place. The conclusions shed light onto the formation of clathrate hydrates.

Abstract
Methane hydrates have important industrial and climate implications, yet their formation via homogeneous nucleation under natural, moderate conditions is poorly understood. Obtaining such understanding could lead to improved control of crystallization, as well as insight into polymorph selection in general, but is hampered by limited experimental resolution. Direct molecular dynamics simulations using atomistic force fields could provide such insight, but are not feasible for moderate undercooling, due to the rare event nature of nucleation. Instead, we harvest ensembles of the rare unbiased nucleation trajectories by employing transition path sampling. We find that with decreasing undercooling the mechanism shifts from amorphous to crystalline polymorph formation. At intermediate temperature the 2 mechanisms compete. Reaction coordinate analysis reveals the amount of a specific methane cage type is crucial for crystallization, while irrelevant for amorphous solids. Polymorph selection is thus governed by kinetic accessibility of the correct cage type and, moreover, occurs at precritical nucleus sizes, apparently against Ostwald’s step rule. We argue that these results are still in line with classical nucleation theory. Our findings illuminate how selection between competing methane hydrate polymorphs occurs and might generalize to other hydrates and molecular crystal formation

See also:

Title: "Molecular dynamics simulation sheds new light on methane hydrate formation"

https://phys.org/news/2019-09-molecular-dynamics-simulation-methane-hydrate.html

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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1560 on: September 10, 2019, 11:00:01 PM »
For your edification:

Carolyn W. Snyder (September 4, 2019), "Revised estimates of paleoclimate sensitivity over the past 800,000 years", Climatic Change, pp 1–18, DOI https://doi.org/10.1007/s10584-019-02536-0

https://link.springer.com/article/10.1007%2Fs10584-019-02536-0

Abstract: "This study evaluates paleoclimate sensitivity over the past 800,000 years from proxy-based reconstructions of changes in global temperature, ice sheets and sea level, vegetation, dust, and greenhouse gases. This analysis uses statistical methods that are not biased by the variable (heteroscedastic) uncertainty in the reconstructions, and applies a Monte Carlo-style probabilistic framework to quantify several sources of measurement and structural uncertainty. Not addressing the heteroscedastic uncertainty would result in regression results that underestimate paleoclimate sensitivity by over 30%, and not using a probabilistic framework could underestimate the credible interval by fivefold. A comparison of changes in global temperature (ΔT) and changes in radiative forcing from greenhouse gases, ice sheets, dust, and vegetation (ΔR[GHG,LI,AE,VG]) over the past 800 kyr finds that the two are closely coupled across glacial cycles with a correlation of 0.81 (0.6 to 0.9, 95% credible interval). The variation of ΔT with ΔR over the past 800 kyr is non-linear, with lower correlation and lower responsiveness at colder temperatures. The paleoclimate sensitivity parameter estimates (S[GHG,LI,AE,VG]) are 0.84 °C/W/m2 (0.20 to 1.9 °C/W/m2, 95% interval) for interglacial periods and intermediate glacial climates and 0.53 °C/W/m2 (0.08 to 1.5 °C/W/m2, 95% interval) for full glacial climates, 37% lower at the median. The estimates of S[GHG,LI,AE,VG] and the pattern of state dependence are similar across glacial cycles over the past 800 kyr. This analysis explicitly includes several sources of uncertainty and is still able to provide a strong upper bound for the paleoclimate sensitivity parameter for interglacial periods and intermediate glacial climates: over 1.5 °C/W/m2 is < 10% probability, 1.7 °C/W/m2 is < 5% probability, and over 1.9 °C/W/m2 is < 2.5% probability."

Note: AR6 will not only consider CMIP6 projections of climate sensitivity, but also paleo-determined values and values derived from observations.
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1561 on: September 10, 2019, 11:11:29 PM »
As ENSO teleconnections will likely be a key consideration in an likely abrupt climate change event this century, I provide the following linked reference:

Marie Drouard and Christophe Cassou (2019), "A modeling and process-oriented study to investigate the projected change of ENSO-forced wintertime teleconnectivity in a warmer world", Journal of Climate, https://doi.org/10.1175/JCLI-D-18-0803.1

https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-18-0803.1?af=R

Abstract: "Considerable uncertainties remain about the expected changes of ENSO and associated teleconnectivity as climate is warming. Two ensembles of pacemaker experiments using the CNRM-CM5 coupled model are designed in a perfect model framework to contrast ENSO-forced teleconnectivity between pre-industrial period versus a warmer background state (obtained from long stabilised simulation under late 21st century RCP8.5 constant forcing). The most notable sensitivity to the mean background state is found over the North Atlantic, where the ENSO-NAO teleconnection is considerably reinforced in a warmer world. We attribute this change to (i) a stronger and eastward-extended mean upper-level jet over the North Pacific, (ii) an eastward-shifted ENSO teleconnection over the North Pacific and (iii) an equatorward-shifted and reinforced mean jet over the North Atlantic. These altogether act as a more efficient waveguide, leading to a better penetration of synoptic storms coming from the Pacific into the Atlantic. This downstream penetration into the North Atlantic basin forces more systematically the NAO through wave breaking. The reinforcement in the teleconnection is asymmetrical with respect to the ENSO phase and is mainly sensitive to La Niña events. Even though the Pacific jet tends to retract westward and move northward during cold events, mean changes are such that both Pacific and Atlantic jets remains connected in warmer climate by contrast to pre-industrial period, thus ensuring preferred anticyclonic wave breaking downstream over the North Atlantic leading ultimately to NAO+ events."

See also:

Mandy B. Freund et al. (June 2019), "Higher frequency of Central Pacific El Niño events in recent decades relative to past centuries" Nature Geoscience, vol 12, 450-455, https://doi.org/10.1038/s41561-019-0353-3

https://www.nature.com/articles/s41561-019-0353-3.epdf?referrer_access_token=EkwhBweGmWeQafRwYrqexNRgN0jAjWel9jnR3ZoTv0O824PLTmnxWAGOnyIajby9UEpzPucKG_lC57mbCdt84v0aRk7adjIJvn9lrVRReSuYeOqA4xUGIjNEZmP3eywr6JDmcid9j5ChEeCNUpv3qETO54bpTDSzNNWYv-7dyR8eCvj1XfJ9uSSvYsEDyC0e-ntRw07iRL8VHRXKEr_Gj7L_jpHDD9r1cyQ5H3K8DCwYPjycC0JK_8cpmGufsbRYXwwYS9MkLB7aID5GlkEYFDxRP94NWHnbLwRxKQXow8m3jpKZ-StFAEtbOSeTw1GnQVB9FbxpaC-MmC8QS327QA%3D%3D&tracking_referrer=blogs.discovermagazine.com

Abstract: "El Niño events differ substantially in their spatial pattern and intensity. Canonical Eastern Pacific El Niño events have sea surface temperature anomalies that are strongest in the far eastern equatorial Pacific, whereas peak ocean warming occurs further west during Central Pacific El Niño events. The event types differ in their impacts on the location and intensity of temperature and precipitation anomalies globally. Evidence is emerging that Central Pacific El Niño events have become more common, a trend that is projected by some studies to continue with ongoing climate change. Here we identify spatial and temporal patterns in observed sea surface temperatures that distinguish the evolution of Eastern and Central Pacific El Niño events in the tropical Pacific. We show that these patterns are recorded by a network of 27 seasonally resolved coral records, which we then use to reconstruct Central and Eastern Pacific El Niño activity for the past four centuries. We find a simultaneous increase in Central Pacific events and a decrease in Eastern Pacific events since the late twentieth century that leads to a ratio of Central to Eastern Pacific events that is unusual in a multicentury context. Compared to the past four centuries, the most recent 30 year period includes fewer, but more intense, Eastern Pacific El Niño events."
« Last Edit: September 10, 2019, 11:40:09 PM by AbruptSLR »
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1562 on: September 11, 2019, 04:06:19 PM »
It looks like consensus climate science has been (& still is) under-reporting the amount of GHG emissions associated with the forestry industry:

Title: "Logging study reveals huge hidden emissions of the forestry industry"

https://www.newscientist.com/article/2215913-logging-study-reveals-huge-hidden-emissions-of-the-forestry-industry/

Extract: "The wood industry is a massive source of uncounted carbon emissions, according to a pioneering study in North Carolina. The same is probably true globally.

The accounting rules were written by loggers for loggers,” he says. “That’s why you hear of agriculture as a big source of emissions, but not logging and wood products.”

Each year 80,000 hectares of trees in North Carolina are cut down to produce wood pellets that are then burnt in power plants in the UK, as well as for paper and timber. The state does not count the resulting emissions. But Talberth has calculated them based on data from the US Department of Agriculture’s Forest Inventory and Analysis Program."
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1563 on: September 11, 2019, 04:50:54 PM »
The following represents an example of one possible cascade of tipping points (not considered in consensus climate models) that could lead to a 'Hothouse Earth':

1. Emissions of ozone depleting substances in the 1970s-1980s creates an ozone hole over Antarctica, which accelerates circumpolar wind velocities, that induces the upwelling of relatively warm CDW (note that until 2019 consensus climate scientist disputed whether humans were responsible for this increase in upwell; however, it has now been proven that humans are responsible), which accelerates melting of Antarctic ice shelves; which freshens the Southern Ocean surface waters; which begins to slow the MOC since 1990s-2000s; which increases the tropical SST since 2015; which increases water evaporation from the tropical ocean surface; which increase atmospheric convection near the tropical; which increases high altitude cloud formation on both sides of the equator; which increases positive cloud feedback.

2. As the Pacific Ocean has the largest tropical belt in the world and as the Pacific's Western Warm Pool (or Western Pacific Warm Pool) is the warmest large body of water in the world; and the warming of this region of the ocean telecommunicates (both via the ocean and via the atmosphere) heat both into the Bering Sea area and into the Southern Ocean off the coast of West Antarctica; which has been accelerating the warming of these regions relative to the GMSTA; which has accelerated ice melting both in the Arctic and more particularly in the coastal regions of West Antarctica; which has weakened the buttressing action of key West Antarctic ice shelves such as from the Pine Island Ice Shelf (PIIS) and the Thwaites Ice Shelf (this has been confirmed this year) and Ice Tongue.

3. The observed (& projected) increase in extreme ENSO events has also accelerated the advection of warm CDW across the Antarctic continental shelf into the Amundson Sea Embayment (ASE) where it has periodically accelerated the weakening of the local ice shelves and accelerated the grounding line retreat for key marine glaciers in that area; which threaten MICI types of marine glacier failures in this region beginning around 2035 to 2040 (in my opinion) both due to potential collapse of buttressing action of key ice shelves, and due to a potential increasing in low elevation hydrofracturing of the marine glacial ice in the ASE.

4.  A potential MICI-type of collapse of the marine glaciers in the ASE beginning around 2035-2040, would likely send a decades long armada of icebergs into the Southern Ocean, thus cooling it and abruptly slowing down the MOC; which would abruptly increase the Earth planetary energy imbalance, by: a) abruptly increasing evaporation from the tropical oceans; b) abruptly poleward advecting energy from the tropical oceans thus accelerating Polar Amplification; and c) triggering the bipolar seesaw to accelerate ice mass loss from Greenland.

5.  As the tropical SST increases the atmospheric Hadley Cells would expand poleward, thus increasing the risk (depending on factors such as the true value of ECS over this period, anthropogenic radiative forcing, etc.) of a flip into an equable atmospheric pattern in the Northern Hemisphere by the end of this century; which would most likely lead to a hothouse condition for most of the planet.
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1564 on: September 11, 2019, 05:51:06 PM »
Some people have criticized the preliminary E3SM climate projections; while the linked reference (& associated article) discusses recent progress to reduce bias and to improve accuracy of this software platform; which will begin using Exascale computer in 2021:

Shaocheng Xie et al. (22 June 2019), "Improved Diurnal Cycle of Precipitation in E3SM With a Revised Convective Triggering Function", JAMES, https://doi.org/10.1029/2019MS001702

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019MS001702

Abstract: "We revise the convective triggering function in Department of Energy's Energy Exascale Earth System Model (E3SM) Atmosphere Model version 1 (EAMv1) by introducing a dynamic constraint on the initiation of convection that emulates the collective dynamical effects to prevent convection from being triggered too frequently and allowing air parcels to launch above the boundary layer to capture nocturnal elevated convection. The former is referred to as the dynamic Convective Available Potential Energy (dCAPE) trigger and the latter as the Unrestricted Launch Level (ULL) trigger. Compared to the original trigger in EAMv1 that initiates convection whenever CAPE is larger than a threshold, the revised trigger substantially improves the simulated diurnal cycle of precipitation over both midlatitude and tropical lands. The nocturnal peak of precipitation and the eastward propagation of convection downstream of the Rockies and over the adjacent Great Plains are much better captured than those in the default model. The overall impact on mean precipitation is minor with some notable improvements over the Indo‐Western Pacific, subtropical Pacific and Atlantic, and South America. In general, the dCAPE trigger helps to better capture late afternoon rainfall peak, while ULL is key to capturing nocturnal elevated convection and the eastward propagation of convection. The dCAPE trigger also primarily contributes to the considerable reduction of convective precipitation over subtropical regions and the frequency of light‐to‐moderate precipitation occurrence. However, no clear improvement is seen in intense convection and the amplitude of diurnal precipitation."

See also:

Shultz, D. (2019), One step closer to a milestone in climate modeling, Eos, 100, https://doi.org/10.1029/2019EO129065. Published on 24 July 2019.

https://eos.org/research-spotlights/one-step-closer-to-a-milestone-in-climate-modeling

Extract: "A pair of revisions to the Energy Exascale Earth System Model improves its ability to capture late afternoon and nocturnal rainfall as well as the timing and movement of convection.

With these two changes, E3SM did not improve in its predictions of the mean amount of precipitation across the entire globe, but it showed dramatic improvements in forecasting the timing of rainfall events, especially in its ability to accurately capture the diurnal cycle. The improvement represents an important advance and brings us one step closer to a milestone in climate modeling."
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1565 on: September 11, 2019, 09:54:16 PM »
The linked mechanism discusses another mechanism for Arctic Amplification (and consequently for increasing values of ECS), that have not yet been considered by consensus climate science:

Minjoong J. Kim et al. (August 2019), "Regional Arctic Amplification by a Fast Atmospheric Response to Anthropogenic Sulfate Aerosol Forcing in China", Journal of Climate, https://doi.org/10.1175/JCLI-D-18-0200.1

https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-18-0200.1

Abstract: "It is known that an increase of water vapor over the Arctic is one of most plausible causes driving Arctic amplification. However, debate continues with regard to the explanation of the underlying mechanisms driving the increase of moisture over the Arctic region in the observations. Here, we used the Community Atmosphere Model with prescribed sea surface temperature along with reanalysis datasets to examine the role of fast atmospheric responses to the increase of anthropogenic sulfate aerosol concentrations in China. We found that it plays an additive role in moisture transport from the midlatitudes, resulting in warming of the Arctic region, especially around the Barents–Kara Seas. Specifically, sulfate aerosol forcing in China reduces the meridional temperature gradient and leads to the increase of moisture transport into the Arctic by altering atmospheric circulation. The resulting increase of moisture then leads to surface warming through the enhancement of the downwelling longwave radiation. This implies that Arctic warming around the Barents–Kara Seas has been accelerated, at least in part, by a fast atmospheric response to anthropogenic sulfate aerosol emissions in China in the recent past."

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1566 on: September 11, 2019, 11:04:58 PM »
The attached image shows the Reference line (colored green) of processed mean sea level rise from the indicated satellite readings for the French Aviso program from Dec 9, 1992 to July 24, 2019.  This data indicates over 8.5cm of SLR has occurred in this period.


Footnotes for attached image:
"- for scientific and statistics reasons, period under 5 years are not significant.
- Default values are 2-month filtered data (green curve for "Reference Mission"). The trend value is based on these default values. The downloaded files correspond to these default values with 2-month filtered data.
 -"Reference" products are computed with the T/P-Jason-1-Jason-2-Jason-3 series for the time series and with merged datasets for the maps;
- "multi-mission" products include all the satellite time series overlaid after being adjusted from biases. The multi-mission time series are available only as images.
- Seasonal and annual signals are filtered when you select  "Seasonal Signal" "Removed"."

Edit: But most significantly the green Reference line shows that SLR is accelerating.
« Last Edit: September 11, 2019, 11:43:12 PM by AbruptSLR »
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1567 on: September 12, 2019, 07:00:01 PM »
It seems to me that most consensus climate scientists view themselves as the ones who are fighting the good fight, and that others (whether on the right or left) should fall in line with their way of thinking, with regards to systemic solutions to climate change.  While I actually do respect consensus climate scientist; I point out that if their 'systemic solutions' are not implemented, then they are not actually 'solutions' at all.

Unfortunately, one of consensus climate scientist do not appropriately convey true climate risks to the public, nor to policy makers.  For example, they hope to get climate denialist to shut-up by claiming that only consensus climate science (CMIP5, AR5, etc.) represents facts (truth) and that both right-tailed and left-tailed PDF extremes should be ignored or treated as 'unknown unknowns'.  Unfortunately, right-tailed climate change extremes carry many times the climate risks than do left-tailed climate extremes; so ignoring this reality represents both bad science and bad public policy.

For instance, CMIP5/AR5 assumed that characterizing cloud feedback carried so much uncertainty that they would ignore the 'known unknows' as well as the 'unknown unknows'; however, the preliminary findings from CMIP6 indicate that advances in characterizing the 'known unknows' of cloud feedback mechanism now allows them to be considered in their models, resulting in projections of average ECS well over 5C.  By the time that consensus science gets its collective act(s) together; the ensuing increase in climate risks may well invalidate most/all of their currently proposed 'systemic solutions'.

Title: "Lifestyle Changes Aren’t Enough to Save the Planet. Here’s What Could"

https://time.com/5669071/lifestyle-changes-climate-change/?xid=tcoshare

Extract: "If nobody is without carbon sin, who gets to cast the first lump of coal? If all climate advocates were expected to live off the grid, eating only what they could grow themselves and wearing only the clothes they’d knitted from scratch, there wouldn’t be much of a climate movement. That level of sacrifice is unacceptable to most.

The bigger issue is that focusing on individual choices around air travel and beef consumption heightens the risk of losing sight of the gorilla in the room: civilization’s reliance on fossil fuels for energy and transport overall, which accounts for roughly two-thirds of global carbon emissions. We need systemic changes that will reduce everyone’s carbon footprint, whether or not they care. The good news is we have tactics to bring environmentally friendly (and non-lifestyle-disrupting) options to fruition: pricing carbon emissions and creating incentives for renewable energy and reduced consumption. By putting a price on carbon, people can actually make money by reducing emissions, selling their services to corporations that are always looking for ways to cut costs. Never underestimate the resourcefulness of Americans when there’s a dime to be made! But a price on carbon needs to be designed such that marginalized communities most at risk from climate impacts aren’t adversely impacted economically as well.

This is why we really need political change at every level, from local leaders to federal legislators all the way up to the President. We need change not just at the breakfast table, but at the ballot box as well."

Edit: For a brief discussion of climate risks see Reply #1558; and I note that as most people are risk adverse it would help their case for consensus climate scientist's call for action, if they would publicly acknowledge that right-tailed risks are several times to many thousands of times greater than left-tailed risks.

Edit 2: To me it is unfortunate that the climate change issue has been caught in the 'culture wars' between the increasingly polarized right and left political wings.  To me it seems that both the extreme right and the extreme left are fundamentally exploitative (the extreme right thru 'crony capitalism' etc and the extreme left thru unending 'war communisms', see the linked article [from strategy for revolution in 21st century] below on 'war communism').  As the conflict/dynamic between the extreme right and the extreme left over who gets the right to exploit is not likely to be resolved anytime soon, this indicates to me that a true solution to climate change is not likely to be implemented before we have reached a tipping point w.r.t. the instability (MICI-type abrupt collapse) of the WAIS this century.

Title: "Lenin on War Communism, 1921-2"

http://sfr-21.org/war-communism.html

Extract: "At the time of the October Revolution in Russia, Lenin and others had hoped that workers throughout Europe would overthrow capitalist governments and achieve socialist revolutions. But when that did not take place, the Soviet Union found itself economically isolated and attacked on all sides by the invading armies of imperialism. Winston Churchill described the purpose of the attacks, involving over half a million soldiers, as "strangling" the revolution "at its birth."

While the Soviet Union fought back and defeated the invading armies by the end of 1920, the damage was done. Industry and machinery, already largely destroyed by the capitalists who fled during the revolution, were in shambles, many of the best workers had been killed or maimed at the front, agriculture, already hurt by war and demoralization of the farmers, was further damaged by crop failure in 1920. The people in the cities were starving.

To feed people in the cities, the Soviet government confiscated grain from the farmers without having money to pay them. As Lenin explained in his pamphlet, The Tax in Kind, "It was the war and the ruin that forced us into War Communism," and "Under this peculiar War Communism we actually took from the peasant all his surpluses - and sometimes even a part of his necessaries - to meet the requirements of the army and sustain the workers."

Lenin saw "war communism" as a temporary policy that must not be continued. At the Tenth Congress of the Russian Communist Party in March 1921, he called for a new policy: "Up to now we have been adapting ourselves to the tasks of war; we must now adapt ourselves to the conditions of peace. The Central Committee is faced with this task - the task of switching to the tax in kind in conditions of proletarian power ... With the Civil War on, we had to adopt war-time measures. But it would be a very great mistake indeed if we drew the conclusion that these are the only measures and relations possible. That would surely lead to the collapse of the Soviet power and the dictatorship of the proletariat ... We must recognise the need to grant concessions, and purchase machinery and equipment to satisfy agriculture, so as to exchange them for grain and re-establish relations between the proletariat and the peasants which will enable it to exist in peacetime conditions.

But with Lenin's death in 1923, war communism became the permanent policy of the Soviet Union. Already, Leon Trotsky had called for the "militarization of labor," organizing the entire country like the armies he commanded in the civil war. For example, in his 1920 book, "Terrorism or Communism", he argues that people are naturally lazy and strive to avoid labor and therefore the Soviet Union needed to base its economy on obligatory labor service, supplemented by compulsion to the point of "extremely severe." "No organization except the army has ever controlled man with such severe compulsion as does the State organization of the working class in the most difficult period of transition. It is just for this reason that we speak of the militarization of labor."
In the end, although Trotsky did not triumph, his policy of coerced labor was firmly established by Stalin, to the point of mass labor camps. Then, during World War Two, the entire country had to be mobilized for war once again, and afterwards, with the Cold War, the militarization of the society continued. The country was run in military fashion: hierarchical and authoritarian, secretive, exploitative (of people and the environment) and male-dominated, justified by the enemy which was Western imperialism. And, of course, the capitalist West did all it could to be such an enemy. The Soviet economy was dominated by the military and military production, as the country matched the West in military strength on the basis of an economy only half as large.

Discipline as strong as that of war communism will be needed to defend the revolution of the 21st century against the inevitable counter-revolutionary attacks of the capitalists. Gandhi and King teach us that active nonviolence requires and promotes such discipline. Time will tell if it can meet the challenge."
« Last Edit: September 14, 2019, 03:18:15 PM by AbruptSLR »
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1568 on: September 12, 2019, 08:11:29 PM »
While the linked article highlights the dangers associated with the rapid spread of hot zones around the world; it is also important to remember that the cool zones in both the North Atlantic, and the Southern Ocean, serve to slow the velocity of the MOC which can (and probably already is) increase the value of ECS with increasing glacial ice mass loss:

Title: "Dangerous new hot zones are spreading around the world"

https://www.washingtonpost.com/graphics/2019/national/climate-environment/climate-change-world/

Extract: "The South Atlantic blob is part of a global trend: Around the planet, enormous ocean currents are traveling to new locations. As these currents relocate, waters are growing warmer. Scientists have found similar hot spots along the western stretches of four other oceans — the North Atlantic, the North Pacific, the South Pacific, and the Indian.

A Washington Post analysis of multiple temperature data sets found numerous locations around the globe that have warmed by at least 2 degrees Celsius over the past century. That's a number that scientists and policymakers have identified as a red line if the planet is to avoid catastrophic and irreversible consequences. But in regions large and small, that point has already been reached."
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1569 on: September 12, 2019, 10:37:32 PM »
Not to beat a dead horse; but if the IPCC wanted to improve communication of their global surface temperature targets to the public, why don't they reference their targets to a modern baseline, like 1986-2005, and then leave their baseline alone (not only for their targets but also for their radiative forcing scenarios)?

Title: "Defining ‘pre-industrial’"

https://www.climate-lab-book.ac.uk/2017/defining-pre-industrial/

Extract: "The IPCC 5th Assessment Report used 1850-1900 as a historical baseline (but did not formally define this as ‘pre-industrial’), and estimated the warming from then to 1986-2005 at 0.61°C. The new analysis finds that this historical warming assumed by the IPCC is at the lower limit of what we assess is the true change since pre-industrial times."
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1570 on: September 13, 2019, 08:36:59 AM »
A reaction to the recent post by ALSR from 7PM.
https://forum.arctic-sea-ice.net/index.php/topic,2205.msg228282.html#msg228282

Thanks ASLR (I'm not specifically addressing you in this post).

I agree with what ALSR wrote but disagree with the article.

We NEED to lose the capitalist system asap. Not change it. Fundamental changes are paramount. We NEED to lose the concept of rich people (=all non-poor people). They are the culprits. They have the power (direct or via consuming choices) but are so deeply addicted and insane that they fight any fundamental change. They just don't want to change their behaviour.

In order to heal, many times you have to go through a painful phase.

The longer you postpone healing, the more painful it will get. In this metaphore it will not get more painful for just the non-poor (ie the rich), but for all life on Earth, not just humans.
If you could take a photograph of this low morality and insanity of rich people, you would get a very black and dirty picture. Stinking.


Quote
That level of sacrifice is unacceptable to most.

What is unacceptable to XR, Greta and me, is losing the future for all life on Earth and the likely extinction of the human species.
That is the real sacrifice! THE DESTRUCTION OF THE FUTURE OF ALL LIFE ON EARTH. In order for rich people to keep their high energy life styles today.

This real sacrifice is a couple of hops further on the inference chain, so less intelligent people don't 'see' it.
Well, of course they see the poor people around the world suffering from the consequences of their high energy lifestyles, but those poor people are not Real people like Us. They're just numbers. So they're not important...
Try telling a poor African about your imaginary sacrifices.


edit: improved wording of 2nd to last sentence
« Last Edit: September 13, 2019, 06:59:55 PM by nanning »
"It is preoccupation with possessions, more than anything else, that prevents us from living freely and nobly" - Bertrand Russell

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1571 on: September 13, 2019, 10:46:45 PM »
Hopefully, the up-coming SouthTRAC campaign will add to our understanding of the stability of Antarctica under continuing climate change:

Title: "Climate change in the Southern Hemisphere"

https://phys.org/news/2019-09-climate-southern-hemisphere.html

Extract: "On its mission "SouthTRAC," the German research aircraft HALO will investigate the southern atmosphere and its effects on climate change in September and November 2019. Researchers from Goethe University will also be on board."
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1572 on: September 14, 2019, 12:42:11 AM »
Per the linked article, sulfur hexafluoride, is the most powerful GHG known to man, and its emissions have been rising rapidly in recent years:

Title: "Climate change: Electrical industry's 'dirty secret' boosts warming"

https://www.bbc.com/news/science-environment-49567197

Extract: "It's the most powerful greenhouse gas known to humanity, and emissions have risen rapidly in recent years, the BBC has learned.

Sulphur hexafluoride, or SF6, is widely used in the electrical industry to prevent short circuits and accidents.

But leaks of the little-known gas in the UK and the rest of the EU in 2017 were the equivalent of putting an extra 1.3 million cars on the road."
« Last Edit: September 14, 2019, 03:26:54 AM by AbruptSLR »
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1573 on: September 14, 2019, 03:44:21 PM »
Just a reminder that continued climate change will reduce soil's ability to aborb water:

Title: "Climate change may cut soil's ability to absorb water"

https://www.sciencedaily.com/releases/2019/09/190911151204.htm

Extract: "Coasts, oceans, ecosystems, weather and human health all face impacts from climate change, and now valuable soils may also be affected. Climate change may reduce the ability of soils to absorb water in many parts of the world, according to a new study. And that could have serious implications for groundwater supplies, food production and security, stormwater runoff, biodiversity and ecosystems."
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1574 on: September 14, 2019, 05:27:58 PM »
While the implications of the linked reference (& associated article) is not clear; only possibility is that in the past Secondary Organic Aerosols (SOAs) may have masked the full strength of climate sensitivity; while in the future SOAs from stressed vegetation may be (may likely be) less effective as a negative feedback.  Only time will tell:

Celia L. Faiola, Iida Pullinen, Angela Buchholz, Farzaneh Khalaj, Arttu Ylisirniö, Eetu Kari, Pasi Miettinen, Jarmo K. Holopainen, Minna Kivimäenpää, Siegfried Schobesberger, Taina Yli-Juuti, Annele Virtanen. Secondary Organic Aerosol Formation from Healthy and Aphid-Stressed Scots Pine Emissions. ACS Earth and Space Chemistry, 2019; DOI: 10.1021/acsearthspacechem.9b00118

https://pubs.acs.org/doi/10.1021/acsearthspacechem.9b00118

Abstract: "One barrier to predicting biogenic secondary organic aerosol (SOA) formation in a changing climate can be attributed to the complex nature of plant volatile emissions. Plant volatile emissions are dynamic over space and time, and change in response to environmental stressors. This study investigated SOA production from emissions of healthy and aphid-stressed Scots pine saplings via dark ozonolysis and photooxidation chemistry. Laboratory experiments using a batch reaction chamber were used to investigate SOA production from different plant volatile mixtures. The volatile mixture from healthy plants included monoterpenes, aromatics, and a small amount of sesquiterpenes. The biggest change in the volatile mixture for aphid-stressed plants was a large increase (from 1.4 to 7.9 ppb) in sesquiterpenes—particularly acyclic sesquiterpenes, such as the farnesene isomers. Acyclic sesquiterpenes had different effects on SOA production depending on the chemical mechanism. Farnesenes suppressed SOA formation from ozonolysis with a 9.7–14.6% SOA mass yield from healthy plant emissions and a 6.9–10.4% SOA mass yield from aphid-stressed plant emissions. Ozonolysis of volatile mixtures containing more farnesenes promoted fragmentation reactions, which produced higher volatility oxidation products. In contrast, plant volatile mixtures containing more farnesenes did not appreciably change SOA production from photooxidation. SOA mass yields ranged from 10.8 to 23.2% from healthy plant emissions and 17.8–26.8% for aphid-stressed plant emissions. This study highlights the potential importance of acyclic terpene chemistry in a future climate regime with an increased presence of plant stress volatiles."

See also:

Title: "Aphid-stressed pines show different secondary organic aerosol formation"

https://www.sciencedaily.com/releases/2019/09/190911121946.htm

Extract: "Although the implications of these findings with regard to climate change are currently unclear, the experiments show that increased plant stress in a changing climate could influence SOA production, the researchers say."

Edit: In order to add some perspective about the possible implications of the Faiola et al. (2019) findings, I provide the following linked information that indicates that total global mean aerosol direct radiative forcing effect is about -2.40 +/- 0.6 W/m2; while anthropogenic global aerosol direct radiative forcing effect is about -0.50+/-0.3 W/m2:

Alexander V. Matus  Tristan S. L'Ecuyer  David S. Henderson (17 June 2019), "New Estimates of Aerosol Direct Radiative Effects and Forcing From A‐Train Satellite Observations",  https://doi.org/10.1029/2019GL083656

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019GL083656

Abstract: "Aerosol direct radiative effects are assessed using multi‐sensor observations from the A‐Train satellite constellation. By leveraging vertical cloud and aerosol information from CloudSat and CALIPSO, this study reports new global estimates of aerosol radiative effects and the component owing to anthropogenic aerosols. We estimate that the global mean aerosol direct radiative effect is −2.40 W/m2 with an error of ± 0.6 W/m2 owing to uncertainties in aerosol type classification and optical depth retrievals. Anthropogenic direct radiative forcing is assessed using new observation‐based aerosol radiative kernels. Anthropogenic aerosols are found to account for 21% of the global radiative effect, or −0.50 ± 0.3 W/m2, mainly from sulfate pollution (−0.54 W/m2) partially offset by absorption from smoke (0.03 W/m2). Uncertainty estimates effectively rule out the possibility that anthropogenic aerosols warm the planet, although strong positive forcing is observed locally where anthropogenic aerosols reside above clouds and bright surfaces."
« Last Edit: September 14, 2019, 06:18:49 PM by AbruptSLR »
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1575 on: September 14, 2019, 09:50:06 PM »
The Amazon likely is closer to a tipping point (in 20 to 30 years) than many people think:

Title: "Will Deforestation and Warming Push the Amazon to a Tipping Point?"

https://e360.yale.edu/features/will-deforestation-and-warming-push-the-amazon-to-a-tipping-point

Extract: "In an e360 interview, Carlos Nobre, Brazil’s leading expert on the Amazon and climate change, discusses the key perils facing the world’s largest rainforest, where a record number of fires are now raging, and lays out what can be done to stave off a ruinous transformation of the region.
...
“At the current rates of deforestation, we are 20 to 30 years off from reaching this tipping point.”"
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1576 on: September 15, 2019, 12:13:15 AM »
The linked article discusses the nature, and sources, of nitrous oxide and why it is an increasing climate threat:

Title: "What Is Nitrous Oxide and Why Is It a Climate Threat?"

https://insideclimatenews.org/news/11092019/nitrous-oxide-climate-pollutant-explainer-greenhouse-gas-agriculture-livestock

Extract: "Nitrous oxide is 300 times more potent than carbon dioxide, and it also depletes the ozone layer. Since it also has a shorter life span, reducing it could have a faster, significant impact on global warming.

But the largest source of nitrous oxide is agriculture, particularly fertilized soil and animal waste, and that makes it harder to rein in.

Like other greenhouse gases, nitrous oxide absorbs radiation and traps heat in the atmosphere, where it can live for an average of 114 years, according to the EPA. That puts it in a sort-of middle ground of super pollutants."
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1577 on: September 15, 2019, 07:01:21 PM »
Current consensus climate models like CMIP5 are largely linear and thus to not account for climate tipping points that can be triggered by relatively small perturbations to push one, or more, Earth Systems into a new/higher state (such as the increasingly positive cloud feedback mechanisms identified by preliminary CMIP6 projections).  Over the next four years the European 'Tipping Points in the Earth System' (TiPES) project will investigate this matter of nonlinear climate responses (which have been observed in the paleo-record):

Title: "Scientists Announce TiPES Project"

https://eos.org/articles/scientists-announce-tipes-project

Extract: "The European Tipping Points in the Earth System project is a multidisciplinary effort to clarify and explain the dynamics and thresholds of climate change tipping points.

With greenhouse gas emissions unabated, scientists are increasingly concerned that different components of the Earth system will be stressed to their “tipping points,” defined as critical thresholds at which small perturbations can qualitatively alter the state or development of a system. The collapse of the Antarctic ice sheet, leading to dramatic sea level rise, is one example of a tipping point in the Earth system.

At the recent General Assembly of the European Geosciences Union (EGU), a group of European climate scientists introduced a new 4-year project that will urgently advance current understanding and identify tipping point thresholds that scientists say, if crossed, would be very dangerous for life on Earth.

Boers identified the six real-time tipping point concerns for which TiPES will provide critical threshold and system dynamics data: the Atlantic Meridional Overturning Circulation; the Arctic and Antarctic ice sheets and sea ice; the Amazon rain forest ecosystem; the South American and Asian monsoons; the Mediterranean region, with its risk of desertification; and the alpine regions, which are already experiencing dramatic melting glaciers."

See also:

https://meetingorganizer.copernicus.org/EGU2019/EGU2019-18084.pdf

&

https://tipes.sites.ku.dk/
« Last Edit: Today at 03:37:55 AM by AbruptSLR »
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #1578 on: September 15, 2019, 11:07:52 PM »
I have not discussed the bipolar seesaw mechanism for a while, so I present the two linked references that present paleo-finding about the bipolar seesaw and the Southern Ocean.  These references confirm that cooling of the Southern Ocean surface (possibly/probably from an armada melting icebergs) leads to warming of the Northern Hemisphere over a period of more than a century.  Nevertheless, I suspect that possible future bipolar seesaw activity could happen this century for reasons including:

a) radiative forcing is currently increase at a rate of several hundreds to several thousands of times faster than in the paleo cases cited in the two references;

b) the current ozone hole was not extant in the cited paleo cases; which is upwelling relatively warm CDW faster now than in the past, and

c) rapid climate change (as is currently occurring) would give Antarctic marine glaciers less time to thin, which may well lead to taller ice cliffs in coming decades; which may likely result in faster MICI propagation in the WAIS in coming decades:

Andrew F. Thompson et al. (2019), "Southern Ocean Mechanism for the Interhemispheric Coupling and Phasing of the Bipolar Seesaw", JCLI, https://doi.org/10.1175/JCLI-D-18-0621.1

https://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-18-0621.1

Abstract: "The last glacial period is punctuated by abrupt changes in Northern Hemisphere temperatures that are known as Dansgaard–Oeschger (DO) events. A striking and largely unexplained feature of DO events is an interhemispheric asymmetry characterized by cooling in Antarctica during periods of warming in Greenland and vice versa—the bipolar seesaw. Methane-synchronized ice core records indicate that the Southern Hemisphere lags the Northern Hemisphere by approximately 200 years. Here, we propose a mechanism that produces observed features of both the bipolar seesaw and the phasing of DO events. The spatial pattern of sea ice formation and melt in the Southern Ocean imposes a rigid constraint on where water masses are modified: waters are made denser near the coast where ice forms and waters are made lighter farther north where ice melts. This pattern, coupled to the tilt of density surfaces across the Southern Ocean and the stratification of the ocean basins, produces two modes of overturning corresponding to different bipolar seesaw states. We present evolution equations for a simplified ocean model that describes the transient adjustment of the basin stratification, the Southern Ocean surface density distribution, and the overturning strength as the ocean moves between these states in response to perturbations in North Atlantic Deep Water formation, which we take as a proxy for Greenland temperatures. Transitions between different overturning states occur over a multicentennial time scale, which is qualitatively consistent with the observed Southern Hemisphere lag. The volume of deep density layers varies inversely with the overturning strength, leading to significant changes in residence times. Evidence of these dynamics in more realistic circulation models is discussed."

&

Svante Björck et al. (2019), "A south Atlantic island record uncovers shifts in westerlies and hydroclimate during the last glacial", Climate of the Past, https://doi.org/10.5194/cp-2019-65

https://www.clim-past-discuss.net/cp-2019-65/

Abstract. The period 36–18 ka was a dynamic phase of the last glacial, with large climate shifts in both hemispheres. Through the bipolar seesaw, the Antarctic Isotope Maxima and Greenland DO events were part of a global concert of large scale climate changes. The interaction between atmospheric processes and Atlantic meridional overturning circulation (AMOC) is crucial for such shifts, controlling upwelling- and carbon cycle dynamics, and generating climate tipping points. Here we report the first temperature and humidity record for the glacial period from the central South Atlantic (SA). The presented data resolves ambiguities about atmospheric circulation shifts during bipolar climate events recorded in polar ice cores. A unique lake sediment sequence from Nightingale Island at 37° S in the SA, covering 36.4–18.6 ka, exhibits continuous impact of the Southern Hemisphere Westerlies (SHW), recording shifts in their position and strength. The SHW displayed high latitudinal and strength-wise variability 36–31 ka locked to the bipolar seesaw, followed by 4 ka of slightly falling temperatures, decreasing humidity and fairly southern westerlies. After 27.5 ka temperatures decreased 3–4 °C, marking the largest hydroclimate change with drier conditions and a variable SHW position. We note that periods with more intense and southerly positioned SHW are correlated with periods of increased CO2 outgassing from the ocean. Changes in the cross-equatorial gradient during large northern temperature changes appear as the driving mechanism for the SHW shifts. Together with coeval shifts of the South Pacific westerlies, it shows that most of the Southern Hemisphere experienced simultaneous atmospheric circulation changes during the latter part of the last glacial.
« Last Edit: September 15, 2019, 11:13:11 PM by AbruptSLR »
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The question of climate tipping points, and cascades of climate tipping points is a complex matter, so I provide a link to the following Grist article on this topic, not because it is comprehensive (which it is not), but because it provides thoughtful color commentary on this somewhat emotional topic:

Title: "Will I be able to tell when we’ve reached a climate tipping point?"

https://grist.org/article/will-i-be-able-to-tell-when-weve-reached-a-climate-tipping-point/

Extract: "“All we can say, as loud as we can, is that every half degree matters, but especially regarding stability of polar ice sheets,” Cobb explains."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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The global military-industrial complex has a heavy carbon footprint:

Title: "War on the World"

https://theintercept.com/2019/09/15/climate-change-us-military-war/

Extract: "Industrialized militaries are a bigger part of the climate emergency than you know.

A recent study from Brown University’s Costs of War project surfaced this startling fact: The U.S. Department of Defense has a larger annual carbon footprint than most countries on earth."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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It seems to me that all consensus climate models (e.g.: CMIP5/AR5) assume essentially linear relationships between radiative forcing and climate change this century; thus when they believe that they are adequately addressing the risks of abrupt climate change this century by projecting to 2100 using RCP 8.5; which they believe is a low probability radiative forcing scenario, for this century.  Unfortunately, such simple-minded think most certainly does not adequately address our true climate risks this century for reasons including (but not limited to) the following:

1.  Several key tipping points are not exclusively driven by radiative forcing such as a MICI-type of collapse of the WAIS which is largely triggered by the Antarctic ozone hole upwelling warm CDW to degrade/eliminate ice shelf buttressing of key marine glaciers; following by gravity driven ice cliff failures propagating upstream.

2. Post-industrial era masking of key positive feedback mechanisms may likely have fooled consensus climate scientists into believing the climate sensitivity is lower than it actually is, for instance by: a) having anthropogenic aerosols temporarily slow increases in GMSTA; b) having a more active ENSO cycle (than assumed) more rapidly sequestering heat into the ocean (which has been measured), which largely ends-up in the Southern Ocean where it has been melting ice in key ice shelves faster than assumed; and c) a recent surge in the growth of vegetation (due to both an increase in warmth and CO2 levels) may be temporarily sequestering CO2 in organics that will likely be reactivated this century by both desiccation of the soil and deforestation.

3. Many tipping point mechanisms are subject to cascading due to ice-climate feedback mechanisms that consensus climate models downplay or ignore.  For instance, a MICI-collapse of the WAIS this century would not only slow the MOC which would increase evaporation of tropical sea water into the atmosphere but it would also: a) increase ice mass loss from key marine terminating glaciers in Greenland; b) increase positive cloud feedback by putting more moisture into higher clouds (thus increasing a positive feedback) thus reducing moisture available to lower altitude clouds (thus reducing a negative feedback); c) pushing clouds near the equator poleward (due to the expansion of the Hadley Cells) which exposes the tropical sea surfaces to more direct solar radiation; and d) the bipolar seesaw increases Arctic Amplification when the surface waters of the Southern Ocean cool due to an armada of icebergs from a collapsing WAIS.

4. For the above mechanisms to occur, we probably only need to follow the anthropogenic portion of the RCP 8.5 pathway through about 2030; after which the potential cascaded of ice-climate triggered tipping points could provide sufficient temporary additional radiative forcing to keep us on the RCP 8.5 radiative forcing pathway through 2100.
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
― Leon C. Megginson