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Messages - AbruptSLR

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Research Reveals Past Rapid Antarctic Ice Loss Due to Ocean Warming

New research from the University of Otago has found the sensitive West Antarctic Ice Sheet collapsed during a warming period just over a million years ago when atmospheric carbon dioxide levels were lower than today.

Using biomarkers to reconstruct past ocean temperatures, and through ice sheet computer models, the study published in Quaternary Science Reviews shows that the accepted maximum global warming of 1.5°C under the Paris Agreement could lead to a runaway retreat of the West Antarctic Ice Sheet.

The study found that one million years ago in the ocean surrounding Antarctica, the summer ocean temperature was on average 5°C (±1.2°C) warmer than today.

"Using the data, the ice sheet simulation indicates a complete collapse of the West Antarctic Ice Sheet with additional melting of the East Antarctic Ice Sheet resulting in sustained global sea-level rise of centimetre to decimetres per decade."

The study proposes a two-step model for West Antarctic ice loss which initially involves mild ocean warming forcing ice margin retreat, followed by a rapid warming primarily driven by the extensively modified oceanic and hydrologic system following further ice sheet retreat.

Beltran Catherine et al. Southern Ocean temperature records and ice-sheet models demonstrate rapid Antarctic ice sheet retreat under low atmospheric CO2 during Marine Isotope Stage 31, Quaternary Science Reviews (2019)


• Quantification of the Southern Ocean warming during MIS31 using molecular temperature reconstructions at high latitudes.

• Sustained surface Southern Ocean warming & collapse of the sub-Antarctic ocean fronts under low atmospheric CO2 conditions.

• Use of sea surface temperature data to test scenarios for the AIS retreat using coupled ice-sheet/ice-shelf model.

• Two steps WAIS retreat: 1) mild ocean warming forcing ice margin retreat 2) rapid ocean warming as the ice sheet retreats.

We show that the Paris Agreement target temperature of 1.5°C is sufficient to drive runaway retreat of the WAIS.

Quote from: Lennart van der Linde link=topic=2205.msg239688#msg239688
Several recent interglacials had even a little less ice than the current interglacial (which by human interference has stopped being an interglacial, or turned into a super-interglacial of at least 50,000-100,000 years).

I myself didn't remember Ganopolski et al 2016 carefully enough:

They say:
"our analysis suggests that even in the absence of human perturbations no substantial build-up of ice sheets would occur within the next several thousand years and that the current interglacial would probably last for another 50,000 years. However, moderate anthropogenic cumulative CO2 emissions of 1,000 to 1,500 gigatonnes of carbon will postpone the next glacial inception by at least 100,000 years. Our simulations demonstrate that under natural conditions alone the Earth system would be expected to remain in the present delicately balanced interglacial climate state, steering clear of both large-scale glaciation of the Northern Hemisphere and its complete deglaciation, for an unusually long time."

So a natural super-interglacial has been turned by us into a super-super-interglacial, and maybe we're even tipping the planet into a Hothouse Earth state:

a lot of posters on this forum seem to think that we're doomed and it's too late to do anything.

My impression is that a lot of posters are concerned we're not doing as much as we can, and should, because powerful forces do not think it necessary and/or desirable to do more than we're doing (which has not been much so far).

Yes, we need to get off of fossil fuels as soon as possible.  However [...] we're making great progress in doing so [...] Even with the additional carbon being released in the Arctic due to warming, the reduction in CO2 and methane from eliminating those two sources of anthropogenic emissions will result in emissions closer to the RCP 2.6 scenario than the RCP 8.5 scenario.

Lenton et al 2019 say:
"If current national pledges to reduce greenhouse-gas emissions are implemented — and that’s a big ‘if’ — they are likely to result in at least 3 °C of global warming. This is despite the goal of the 2015 Paris agreement to limit warming to well below 2 °C. Some economists, assuming that climate tipping points are of very low probability (even if they would be catastrophic), have suggested that 3 °C warming is optimal from a cost–benefit perspective. However, if tipping points are looking more likely, then the ‘optimal policy’ recommendation of simple cost–benefit climate-economy models aligns with those of the recent IPCC report. In other words, warming must be limited to 1.5 °C. This requires an emergency response [...] Early results from the latest climate models — run for the IPCC’s sixth assessment report, due in 2021 — indicate a much larger climate sensitivity (defined as the temperature response to doubling of atmospheric CO2) than in previous models. Many more results are pending and further investigation is required, but to us, these preliminary results hint that a global tipping point is possible [...] Some scientists counter that the possibility of global tipping remains highly speculative. It is our position that, given its huge impact and irreversible nature, any serious risk assessment must consider the evidence, however limited our understanding might still be. To err on the side of danger is not a responsible option. If damaging tipping cascades can occur and a global tipping point cannot be ruled out, then this is an existential threat to civilization. No amount of economic cost–benefit analysis is going to help us. We need to change our approach to the climate problem. In our view, the evidence from tipping points alone suggests that we are in a state of planetary emergency: both the risk and urgency of the situation are acute."

Let's take the science seriously and recognize the urgency that Lenton et al, ASLR and others describe and justly emphasize as a planetary emergency and existential threat. Downplaying this inconvenient truth may be a natural impulse, but has been done for too long and is nog helping us. Let's face reality and the risks it entails and do what we have to do to minimize those risks, while we still can.

Hawkins lists various reasons why there is a discrepancy. Nr 3: "the real world may have a climate sensitivity towards the lower end of the CMIP5 range."
I guess he nailed it there.
If that was true for CMIP5, the CMIP6 models with much higher ECS around or above 5 will have an even tougher fight with reality.

Lewandowsky et al 2018  analyze data up until 2016. If you go back to the figure I attached in Reply #2016 the discrepancy looked less worrying with those data ending in 2016. But when we include 2017 and 2018 in the dataset and compare with the models, we get the impression that actual temperatures follow a lower trajectory, a lower trend, than the models. They write:
"...several biases in the observations and in model projections gave rise to the impression of a divergence between modeled and observed temperature trends. This impression was limited to the period 2011–2013, after which the ongoing debiasing eliminated any appearance of a divergence. During the period 2011–2013, the impression of a divergence could appear to be statistically significant, but only if the selection-bias issue was ignored. "

They might have been correct about selection bias, if it wasn't for a repeat of same in 2017-18. With two more years of data, the divergence seems to become only stronger.

It seems to me you're jumping to conclusions from hypotheses that have not been confirmed or not properly investigated yet. Hawkins lists several hypothetical explanations for the discrepancy between observations and simulations without saying which explanation he thinks is responsible for which part of the discrepancy, if at all. So your guess is as good as any, but needs to be properly investigated first. Lewandowsky et al give some first results from their investigation and do not confirm your guess. Maybe this is because they have not taken the latest years into account yet, but that remains to be seen. If two more years of data would indeed show a significant divergence, then two or more years of data after 2018 may change the picture once again. So it seems a little early to jump to the conclusion that the models are running hot, the more so as ASLR has shown several studies that indicate the ECS may be or may become higher with further warming. Proper risk management would take this possibility into account and demands a little more critical reasoning than you've been showing here so far, if you ask me.

Nothing peer reviewed, but prof. Ed Hawkins makes regular updates to evaluate model performance. Models evidently running hot.

It may be evident to you, but apparently not to Hawkins himself, and not to peer-reviewed Lewandowsky et al 2018 either.

Hawkins writes on his blog:
"The simulation data uses spatially complete coverage of surface air temperature whereas the observations use a spatially incomplete mix of air temperatures over land and sea surface temperatures over the ocean. It is expected that this factor alone would cause the observations to show smaller trends than the simulations."

He gives some other potential explanations for the apparent divergence as well:
"There are several possible explanations for why the earlier observations are at the lower end of the CMIP5 range. First, there is internal climate variability, which can cause temperatures to temporarily rise faster or slower than expected. Second, the radiative forcings used after 2005 are from the RCPs, rather than as observed. Given that there have been some small volcanic eruptions and a dip in solar activity, this has likely caused some of the apparent discrepancy. Third, the real world may have a climate sensitivity towards the lower end of the CMIP5 range. Next, the exact position of the observations within the CMIP5 range depends slightly on the reference period chosen. Lastly, this is not an apples-with-apples comparison because it is comparing air temperatures everywhere (simulations) with blended and sparse observations of air temperature and sea temperatures. A combination of some of these factors is likely responsible."

Lewandowsky et al 2018  elaborate on this:

"The impression of a divergence early in the 21st century was caused by various biases in model interpretation and in the observations, and was unsupported by robust statistics [...] IPCC Assessment Report (AR5)... stated that '...111 out of 114 realizations show a GMST trend over 1998–2012 that is higher than the entire HadCRUT4 trend ensemble... This difference between simulated and observed trends could be caused by some combination of (a) internal climate variability, (b) missing or incorrect radiative forcing and (c) model response error' (Flato et al 2013, p 769). The consensus view expressed by the IPCC therefore pointed to a divergence between modeled and observed temperature trends, putatively caused by a mix of three factors. Subsequent to the IPCC report, the role of these three factors has become clearer [...] We have established that several biases in the observations and in model projections gave rise to the impression of a divergence between modeled and observed temperature trends. This impression was limited to the period 2011–2013, after which the ongoing debiasing eliminated any appearance of a divergence. During the period 2011–2013, the impression of a divergence could appear to be statistically significant, but only if the selection-bias issue was ignored. We have shown that ignoring of the selection-bias issue can drastically inflate Type-I error rates, which renders the inferences unreliable and in this case erroneous."

See their full paper for further details.
What do you think of their conclusions?

The basic concept of LTG is that there are limited resources, and that mankind is depleting those resources in such a way that it triggers more or less uncontrollable dynamic developments regarding environment etc.
This concept is faulty. Resources will get higher relative prices the scarcer they become. But they won't be physically depleted. That was the first big modelling mistake they made.
The second big mistake was to disregard all technical development. This is also connected with the changing relative prices: when an essential resource gets a higher price due to scarcity, it will trigger developments to either replace that resource with substitutes or find ways to improve the extraction or production of the resource [...]
The third modelling mistake was to not include counteractions by TPTB.
That said, I agree with what you say about ecological boundaries. Capitalism needs regulation.

Below a few quotes from Limits to Growth 1972 and the 30-year update Limits to Growth 2004 that seem to contradict your assertions. Paraphrased Meadows et al say:
- dynamics only become uncontrollable if we wait too long to consciously limit material growth
- even when higher prices for scarcer resources lead to technological innovation and substitution in the short run the total supply of resources remains limited in the longer run
- counteractions by TPTB have been modelled in the several scenario's, including a scenario that avoids collapse by consciously limiting further material growth

Meadows et al argue that the longer we postpone implementing policies to limit material growth, the higher the risk of eventual collapse, without being able to predict exactly when this collapse may occur. In (most of) their scenario's this collapse would occur somewhere during this century, mainly depending on the exact ecological and technological limits.

The current climate crisis seems the ultimate illustration of the general accuracy of their analysis, with climate scientists showing we need extremely rapid emission reductions to avoid passing potentially catastrophic climate tipping points, while energy experts argue that such rapid reductions hardly seem possible without (in the short run) shrinking the global economy, or at least the material consumption in the richer economies.

So the crucial question seems to be: how long do we want to keep gambling with the future of our children? Or alternatively: how certain can we be that we're not risking their future by holding on to business-as-usual policies aimed at continued material growth?

If you reject the fundamental influence of market forces you always risk repeating the mistake of the Club of Rome report "Limits to growth".

Have you actually read "Limits to Growth"? If so, where exactly did you find the mistake?
As far as I know they didn't reject the fundamental influence of market forces at all, but maybe I missed it.
Even market forces cannot provide unlimited material growth on a finite planet.
Current market forces are already exceeding several planetary ecological boundaries.
The longer this overshoot lasts, the higher the risk of eventual collapse.
Only by governing market forces can we hope to still avoid this collapse, or at least make its impact less destructive.
This is how I understand the Club of Rome's warning of 1972 (updated several times since), which still seems very accurate to me.

[Are lower latitudes warming? No, see attached, we have a negative SST trend in Antarctic seas.

Antarctic seas are at higher latitudes, not lower. Lower latitudes are closer to the equator.

Hansen et al 2016:

"Meltwater tends to stabilize the ocean column, inducing amplifying feedbacks that increase subsurface ocean warming and ice shelf melting. Cold meltwater and induced dynamical effects cause ocean surface cooling in the Southern Ocean and North Atlantic, thus increasing Earth's energy imbalance and heat flux into most of the global ocean's surface. Southern Ocean surface cooling, while lower latitudes are warming, increases precipitation on the Southern Ocean, increasing ocean stratification, slowing deepwater formation, and increasing ice sheet mass loss. These feedbacks make ice sheets in contact with the ocean vulnerable to accelerating disintegration. We hypothesize that ice mass loss from the most vulnerable ice, sufficient to raise sea level several meters, is better approximated as exponential than by a more linear response. Doubling times of 10, 20 or 40 years yield multi-meter sea level rise in about 50, 100 or 200 years. Recent ice melt doubling times are near the lower end of the 10-40-year range, but the record is too short to confirm the nature of the response. The feedbacks, including subsurface ocean warming, help explain paleoclimate data and point to a dominant Southern Ocean role in controlling atmospheric CO2, which in turn exercised tight control on global temperature and sea level. The millennial (500-2000-year) timescale of deep-ocean ventilation affects the timescale for natural CO2 change and thus the timescale for paleo-global climate, ice sheet, and sea level changes, but this paleo-millennial timescale should not be misinterpreted as the timescale for ice sheet response to a rapid, large, human-made climate forcing [...] The modeling, paleoclimate evidence, and ongoing observations together imply that 2°C global warming above the preindustrial level could be dangerous. Continued high fossil fuel emissions this century are predicted to yield (1) cooling of the Southern Ocean, especially in the Western Hemisphere; (2) slowing of the Southern Ocean overturning circulation, warming of the ice shelves, and growing ice sheet mass loss; (3) slowdown and eventual shutdown of the Atlantic overturning circulation with cooling of the North Atlantic region; (4) increasingly powerful storms; and (5) nonlinearly growing sea level rise, reaching several meters over a timescale of 50-150 years. These predictions, especially the cooling in the Southern Ocean and North Atlantic with markedly reduced warming or even cooling in Europe, differ fundamentally from existing climate change assessments."

Silvano et al 2018:

"Strong heat loss and brine release during sea ice formation in coastal polynyas act to cool and salinify waters on the Antarctic continental shelf. Polynya activity thus both limits the ocean heat flux to the Antarctic Ice Sheet and promotes formation of Dense Shelf Water (DSW), the precursor to Antarctic Bottom Water. However, despite the presence of strong polynyas, DSW is not formed on the Sabrina Coast in East Antarctica and in the Amundsen Sea in West Antarctica. Using a simple ocean model driven by observed forcing, we show that freshwater input from basal melt of ice shelves partially offsets the salt flux by sea ice formation in polynyas found in both regions, preventing full-depth convection and formation of DSW. In the absence of deep convection, warm water that reaches the continental shelf in the bottom layer does not lose much heat to the atmosphere and is thus available to drive the rapid basal melt observed at the Totten Ice Shelf on the Sabrina Coast and at the Dotson and Getz ice shelves in the Amundsen Sea. Our results suggest that increased glacial meltwater input in a warming climate will both reduce Antarctic Bottom Water formation and trigger increased mass loss from the Antarctic Ice Sheet, with consequences for the global overturning circulation and sea level rise."

1. You misinterpret my posts.  We need to get off of fossil fuels fast. 

What I'm saying is that we're doing that.
Your optimism is admirable but I have not seen any data to suggest the world is getting off fossil fuels fast. The only data I have seen suggests that fossil fuel consumption is rising year after year. This is borne out by the inexorable and accelerating climb in CO2 levels as shown by KiwiGriff.

Also, you tend to completely ignore facts that make the extreme right tail risks unlikely to occur.  Case in point, renewables have been less expensive than coal for almost two years now.  Investments in new coal plants have plummeted and retirements of coal power plants have accelerated.  Coal use is projected to peak within a few years and then rapidly decrease afterwards.  Even thought that's been pointed out, you seem to think that we'll still be on the RCP 8.5 scenario when there is no other source of greenhouse gas emissions that can make up for the missing coal emissions.
Alas, projections are not facts. And there are plenty of other sources of GHG emissions to replace coal.

In model pathways with no or limited overshoot of 1.5°C, global net anthropogenic CO2 emissions decline by about 45% from 2010 levels by 2030 (40–60% interquartile range), reaching net zero around 2050
And ........our present reality.


Second, per the following article, and associated Rignot et al (2019) reference, if DeConto when back and re-calibrated his model values for the EAIS to match Rignot et al. (2019)'s observed values; he would get significantly higher ice mass loss values at much earlier dates.

Title: "Polar Warning: Even Antarctica’s Coldest Region Is Starting to Melt"

Extract: "In January, Rignot and colleagues published a paper that looked back to 1979. Like the IMBIE study, they found an acceleration in ice loss over the continent as a whole: it went up six times over the four decades of their study. But, more strikingly, they could say that East Antarctica was a big player in that loss: from 2009 to 2017, they concluded, West Antarctica accounted for 63 percent of the continent’s ice loss, and East Antarctica accounted for 20 percent — more than the Antarctic Peninsula’s contribution of 17 percent.

In the face of rapid change and limited data, it is extremely challenging to predict what the Antarctic will do in the future. The models, says Rignot, “all have fundamental flaws. None of them are right.” Their resolution is coarse and they don’t include all the physics; plus they are lacking in critical input data. Very little is known, for example, about water temperatures and the seafloor shape off the coast of much of East Antarctica. That affects things like ocean currents and sea ice buildup, both of which affect glacier flow.

For now, DeConto says, his models show that “the East Antarctic is stable for a few decades, but in the high emissions scenarios it starts to become a player in the late 21st century.” But, he adds, “If I went back and put [Rignot’s] numbers in…” He trails off, waving his hands at the potentially large, unknown increase that would cause."

See also:

Eric Rignot, Jérémie Mouginot, Bernd Scheuchl, Michiel van den Broeke, Melchior J. van Wessem, and Mathieu Morlighem (January 22, 2019), "Four decades of Antarctic Ice Sheet mass balance from 1979–2017", PNAS, 116 (4) 1095-1103;
The Rignot et al paper (and its accompanying spreadsheet separated out melt from the annual mass gain from snowfall of about 1,100GT. They found that in many parts of the EAIS things had changed from annual snowfall in excess of melt, i.e. a net mass gain, to annual snowfall less than melt, .e. a net mass loss.

The GRACE + GRACE-FO data  seems to confirm this, especially in the EIS East of the Ross Ice Shelf (data to September 2019 attached).

Here are the projections for RCP 8.5 from DeConto and Pollard 2016:

Antarctica contributes 77 cm of GMSL rise by 2100, and continued loss of the Ross and Weddell Sea ice shelves drives WAIS retreat from three sides simultaneously (the Amundsen, Ross, and Weddell seas), all with reverse-sloping beds into the deep ice-sheet interior. As a result, WAIS collapses within 250 years. At the same time, steady retreat into the Wilkes and Aurora basins... adds substantially to the rate of sea-level rise, exceeding 4 cm yr−1 (Fig. 4c) in the next century, which is comparable to maximum rates of sea-level rise during the last deglaciation.

So in the worst case emissions scenario, which is no longer feasible because we aren't going to burn that much coal, the West Antarctic ice shelves collapse after the Larsen C, which collapses in the 2050s. The Wilkes and Aurora basins would contribute to sea level rise next century, after 2100.

And Rob DeConto has publicly backed off of these projections.

In new work, conducted with three other prominent glaciologists, DeConto and Pollard have lowered some of their worst-case projections for the 21st century. Antarctica may only contribute about a foot of sea-level rise by 2100, they now say. This finding, reached after the team improved their own ice model, is much closer to projections made by other glaciologists... Now their worst-case skyrocketing sea-level scenario seems extremely unlikely, at least within our own lifetimes.

Skeptical Science has a very good overview of MICI.

DeConto says he is not able to comment on it directly as it is undergoing peer review. However, he has presented some preliminary results at the Fall Meeting of the American Geophysical Union (AGU) in December.

So to recap:
- AbruptSLR continues to confuse the timeframes of the original MICI models published in 2016
- The authors of the original MICI models now state that the 2016 projections were too pessimistic
- Other studies have shown that ice flows instead of fails in a brittle manner, which casts doubt on the mechanism needed for MICI to occur.
- Past sea level rise could have occurred without needing the MICI mechanism
- MICI needs hydrofracturing to occur before MICI can occur and yet there are areas in Antarctica where water flows off the ice sheet rather than penetrating through it to create hydrofractures
- Coal is now more expensive than solar and wind power and coal use is expected to peak next decade, so the emission projections of RCP 8.5 from the 2020s through 2100 aren't possible.

Wilkes and Aurora reach their maximum rate of ice loss in the next century, but apparently start to contribute significantly already this century, in my understanding of your quotes of DeConto & Pollard.

And while their new results for 2100 seem to be lower than their earlier results, they also warned that after 2100 the rate of ice loss could be even higher than they found earlier, if I remember correctly. Richard Alley also warns for this possibility in this recent news item:

Alley noted that some research has suggested that, if global warming pushes West Antarctica's towering ice cliffs to collapse, it could raise sea level more than 3 feet by 2100, surging to 50 feet by 2500, from Antarctic ice melt alone.

"That model is sometimes treated as a worst-case scenario, but in fact the model used a maximum calving rate that has briefly been exceeded in Greenland already, and the possibility exists that even faster calving could occur from higher, wider cliffs that could develop in Antarctica," he said.

Even the most recent international assessment of ice loss relies on models that don't account for some of those ice shelf tipping points, he said. "If we're fortunate, and the ice shelves are retained, then these models may be accurate. If we do lose the ice shelves, the models may project less sea level rise than will occur, perhaps by a lot."

Everyone hopes we'll be lucky, but we can't count on that, so the strongest possible mitigation is urgent and preparing for strong adaptation is urgent as well. RCP8.5 may not be likely, but with people like Trump in power we can't be sure either that it will not come to pass. And also with lower RCP's the risks of rapid and large SLR remain substantial, so it seems reasonable to be very aware of those risks and to not underplay them, as has been done for decades now. It seems to me your posts have a tendency to "err on the side of least drama", like many IPCC reports so far, as argued by Brysse et al and others.

Asynchronous Antarctic and Greenland ice-volume contributions to the last interglacial sea-level highstand

    Eelco J. Rohling, Fiona D. Hibbert, Katharine M. Grant, Eirik V. Galaasen, Nil Irvalı, Helga F. Kleiven, Gianluca Marino, Ulysses Ninnemann, Andrew P. Roberts, Yair Rosenthal, Hartmut Schulz, Felicity H. Williams & Jimin Yu

Nature Communications volume 10, Article number: 5040 (2019)
Finally, we infer intra-LIG sea-level rises with event-mean rates of rise of 2.8, 2.3, and 0.6 m c−1. Such high pre-anthropogenic values lend credibility to similar rates inferred from some ice-modelling approaches51. The apparent reality of such extreme pre-anthropogenic rates increases the likelihood of extreme sea-level rise in future centuries.
This research reveals up to 2.8 meters/century sea level rise (without people mucking things up).

Edit:  LIG = The last interglacial


Changes in high-altitude winds over the South Pacific produce long-term effects on the Antarctic

“The study provides the first evidence of long-term changes in the high-altitude winds of the southern westerly wind belt over the South Pacific,” explains Dr Frank Lamy. “Our findings indicate closer atmospheric ties between the tropics and mid to high latitudes than in other sectors of the Southern Hemisphere, with consequences for global overturning circulation and the storage of atmospheric CO2 in the ocean.”

The team’s findings are also important with regard to understanding current and especially future large-scale climate mechanisms in the comparatively under-researched Southern Hemisphere. One crucial aspect is the coupling of the tropical Pacific with the source of the global climate phenomenon El Niño Southern Oscillation (ENSO) and the West Antarctic. The data shows that the West Antarctic Ice Sheet’s high sensitivity to ENSO in the Pacific sector, which can be seen in satellite observations made over the past few decades, is most likely also significant over much longer time scales. “A change in the high-altitude winds over the South Pacific in response to the increased frequency and intensity of El Niño events that many climate models predict would reduce the stability of the West Antarctic Ice Sheet, while also negatively impacting CO2 storage in the South Pacific,” says Lamy, putting the findings in perspective.

Link >>

(The study will be published on November 5, 2019 as an open access article in the online portal PNAS

The original title is: Frank Lamy, John C.H. Chiang, Gema Martínez-Méndez, Mieke Thierens, Helge W. Arz, Joyce Bosmans, Dierk  Hebbeln, Fabrice Lambert, Lester Lembke-Jene, Jan-Berend Stuut: Precession modulation of the South Pacific westerly wind belt over the past million years, Proceedings of the National Academy of Sciences of the United States of America (PNAS)  /


Countries that can increase co2 emissions
India - 1.83
Indonesia - 1.94
Vietnam - 2.29

China was at 7.72.... but they make a lot of stuff for the rich countries, I wonder if we removed the CO2 emissions for manufacturing our stuff whether it would be even half that value left over.

Rich countries are looking for ways to do as little as possible at the expense of those who
have not caused the problem and are doing their fair share while growing.

I am not certain the human nature (whether in the first, or third worlds) will allow modern global society to make the adjustments required to avoid a climate catastrophe in the coming decades:

Title: "Delhi air quality: Judges accuse authorities of 'passing the buck'"

Extract: "India's top court has accused state governments of "passing the buck" on air pollution and failing to take action to tackle Delhi's toxic smog.

The Supreme Court said authorities were only interested in "gimmicks", rather than concrete measures to combat pollution levels.

Levels of dangerous particles in the air - known as PM2.5 - are at well over 10 times safe limits in the capital."

I agree with you about our inability to react in a way that will reduce the catastrophe that is coming our way.

I also agree that India is basically being stupid in regards to using coal for power. The pollution there is shocking.

My point was more about who needs to do the most work in regards to the actions that need to be taken.
In theory, it is not India or SE Asia.

Oddly, India in particular, need to stop using coal and fossil fuels not to reduce their CO2 emissions, they need to do it to vastly reduce their levels of air pollution.
This means they need to do it for local reasons that are unrelated to global CO2 levels, but rather pollution levels.
To me, this benefit is just one more reason to get rid of fossil fuels. Maybe there is motivation for change in this approach.

As an aside..... India looking to Russia is an indication that the Adani mine in Australia is entering the too hard basket. The Govt is getting rather extreme in their efforts to force the Adani mine to start. For example, making it illegal to protest environmental concerns when it affects mining, imprisoning protest organizers (I am aware or 3 protesters serving 2 years each) and looking to create laws that makes insurance companies and banks unable to refuse their business to fossil fuel companies.
Australia is as corrupt as hell.
It also is why I doubt we fail to do enough to avoid global civilizational collapse within the coming decades.

(I will hunt down the links for the above mentioned statements, I thought I had them saved but didnt do it)

Imprisonments for protesting
This is what they want to do -
This is what they have done so far -

In regard to the Guardian article of the Amazon tipping point.  I have gotten behind  in this thread, busy and one needs to delve and think deeply on this thread. 

From the author cited for her report on papers.  Oct 31

She cites the two primary papers she utilized and critiques the Bolsanaro government regime. 

Her "PIEE" chart is here (bad pun)

Her 7 page review that the Guardian cited is here

As always, with admiration to the posts here. 

Two more quotes from IPCC SROCC attached:

Note that these are the estimates from their 2016 study. They've since indicated that they are considerable over estimates.

There are summaries of many other studies in the chapter, including ones that address the recently discovered cavity under Thwaites Glacier.  They also address the feedbacks from huge increases in meltwater on ocean stratification.

None of the scenarios lead to the catastrophic consequences implied by AbruptSLR's musings.  All of them agree that if we can keep emissions in-line with the RCP 2.6 scenario, the future sea level rise is greatly reduced from the RCP 8.5 emissions scenarios.  Many agree (including DeConto and Pollard) that the WAIS will not collapse under the RCP 2.6 scenario.

As you cite, IPCC SROCC also refers to Kopp et al 2017 (including DeConto & Pollard) which shows a non-negligible risk of pretty fast SLR between 2100-2300 even at RCP2.6 (3m SLR in 2 centuries). See table 1 in Kopp et al attached below. When DeConto & Pollard will have published their lowered estimates for 2100, we may also learn their new estimates for 2200 and 2300, which may be even higher than before, if I've understood their earlier indications of those results correctly. None of these estimates will be as definitive as you seem to present them, which means they still imply risks that should not be ignored, as indicated by the quotes from IPCC SROCC attached below, and as ASLR fortunately does not tire of reminding us, as do experts as for example Dewi Le Bars, when he reflected last February on the implications of two recent papers for the projections by DeConto & Pollard and for ice-climate feedback modelling (as proposed by Hansen et al, amongst others):

On Edwards et al 2019:
'The claim that MICI is "not necessary" to reproduce past sea level high stands is both not really true and not really useful. The uncertainty range about what could have been the contribution of Antarctica to sea level during the Pliocene is 5-20 m and during the Last Interglacial it is 3.6-7.4 m. DeConto and Pollard’s model without MICI can reproduce up to 6 m and 5.5 m respectively for these two period (see Edwards et al. E.D. Fig. 4). So yes it can reproduce the lower part of the ranges. But most of the Pliocene range cannot be reproduced with the no-MICI assumption. What the figure shows is that the model with MICI covers a much bigger par of the possible Antarctic contribution for these periods. And still, even including MICI, the model can only explain a maximum of 12 m contribution for the Pliocene. Which means additional mechanisms would be necessary to cover the whole range of possible Antarctic contribution for that period. The claim that MICI is “not necessary” is also not very useful practically because projections with MICI are used to make high-end sea level scenarios. The important information is then is it possible or not? If it was not possible then it would be good news and decision makers wouldn't need to take it into account. "Not necessary" only has an impact on low-end scenarios, for which MICI would already not be used anyways.'

On Golledge et al 2019:
'Current state of the art (CMIP5 type) climate models do not include ice sheet models so the coupled effects between ice sheets and climate are a blind spot. In these climate models the ice sheets are just white mountains that do not change over time. They might have a snow layer on top of them but no ice. So snow falls on them accumulate a little bit and when it melts it is put in the nearest ocean grid box. If too much accumulates then it is put directly in the ocean to avoid infinite accumulation. What is missing is a model to transform the snow to ice and then transport it back to the sides of the ice sheet or to the ocean under the force of gravity. This is what ice sheet models do. Golledge et al. use the PISM ice sheet model for Greenland and Antarctica and couple them offline to LOVECLIM, an intermediate complexity climate model. Intermediate complexity means lower resolution and simpler physics compared to CMIP5 type climate models. It is the type of models generally used for long paleoclimate simulations.

What they find is that allowing feedbacks between the ice sheets and the climate model leads to strengthen both Antarctic and Greenland mass loss, by 100% and 30% respectively. For Antarctica this is not a surprise, although the magnitude is much bigger than I expected. Freshwater from the melting of ice leads to increase the ocean stratification, because it is is very light. This reduces vertical ocean mixing and as a result the surface of the ocean cools down while the subsurface warms up. Antarctica mostly looses mass from ice shelves basal melt and calving which is strengthened by warmer subsurface ocean temperature. For Greenland, it comes as a surprise to me that the feedback would increase the mass loss, because Greenland mostly looses mass from surface melt and a cooler atmosphere temperature would tend to reduce surface melt. Unfortunately the paper does not explain the mechanisms at play there (or did I miss it?).

There are a few issues with the ice sheet models that reduce my confidence in the projections. For Greenland the model is not able to reproduce the recent fast mass loss acceleration. Therefore the authors artificially impose the mass loss on the model in two ways: (1) decrease the friction between the ice and the bed (basal traction) to have a faster flow between 2000 and 2015 and (2) reduce the snowpack refreezing between 2000 and 2025. Refreezing is important for the mass balance because on ice sheets more than half of the snow that melts in the summer refreezes locally. It never reaches the ocean. Michiel van den Broeke had a similar comments in Trouw (in Dutch). You can force the model to agree with observations but if the model does not have the proper dynamics to explain observations there is no reason it is doing a good job for the future. For Antarctica, the model starts with enormous mass accumulation (1000 Gt/year in 1900) and accumulates mass until the 1980th. This is clearly not possible, such an accumulation would have been seen by tide gauge measurements. In fact as I said in the last review it is expected that Antarctica was slowly loosing mass in the 20th century. Also, the internal variability of grounded ice is so large in the model (Fig. 1a-d) that I do not understand what is going on physically (please let me know if you do).

In conclusion, the paper’s goal is important and it is the first time that two high resolution ice sheet models are coupled to a climate model. This is a big step in the right direction. However, I am not convinced by the results because of the issues mentioned above concerning the ice sheet models. Nevertheless, it is very instructive as it shows the long way that is left for ice sheet models to reach the level at which we can trust their future projections.'

Yes but .
The error goes both ways .
You think because the models are not perfect you can discount the result .
Unfortunately there is plenty of evidence  that models underestimate the result of our unfortunate experiment in atmospheric physics.

Still think you should be banned for spreading denial  FUD .

That Stokes paper referenced in the conversation article is 


open access. I have commented implications for Amery at,2578.msg232196/topicseen.html#msg232196

That paper references and earlier paper by Alley et al.  (doi: 10.1016/j.rse.2018.03.025 )  who evalued antarctic ice shelf vulnerability to hydrofracture. The measure of vulnerability is the fraction of ice saturated firn. I attach a figure showing that most ice shelves are vulnerable.


earlier today
"... If the higher CMIP6 ECS estimates hold true as the archive fills out, this will represent a departure from over four decades of research. Higher-sensitivity climates experience a greater probability of long-term temperature pauses and short-term trends, which can translate to more warming hiatuses or periods of fast temperature increase."
very interesting, indeed.  More data for deniers ("pauses") and then ghost-white faces.  :'(

Thanks for another nice selection of articles.

Enjoyed the animal ones and i cross posted the CAA glaciers (to What is new in the Arctic) and the Cerrado article.

The linked article explains how the current (and relatively rare) sudden stratospheric warming event over Antarctica can push cold air away from the surface ice.
Is the attached graph connected with the SSW? The EU severe weather site shows the area of the SSW moving over the S Pole in the coming days.

I added fig 10 from Schroeder to the thwaites discussion thread. I attach here also.


The scientific method is the same regardless the phenomena. However it might be too late to define baseline and departure from baseline for a lot of ecosystems as they are changing rapidly.

Unfortunately the changes are faster than we can study them...

So Hawkins is redefining preindustrial to be 1720-1800 instead of 1850-1900. So of course it would show greater warming, but the underlying observations havent changed. That doesnt mean that sensitivity has gone up, it just means that we compare with a lower baseline.

One difficulty with Hawkins baseline is that measurements are scarcer the further back you go in time. So i can see why people use 1850-1900.


But Hawkins is working from a more sensible baseline because we know the the 1850-1900 period already includes human influences:

However, some anthropogenic warming is estimated to have already occurred by 1850 (Hegerl et al. 2007; Schurer et al. 2013; Abram et al. 2016) as greenhouse gas concentrations had started increasing around a century earlier (Fig. 1).

Sensitivity did not change but if you start from the wrong baseline it looks lower...

cross post (highlight added):  things are sometimes worse then modeled!
I think sometimes can replaced by usually.

It is just hard to accurately model the whole planet with many missing variables (trouble with clouds and many other things we just had not thought of before).

Once serious trouble in the Arctic was expected in the 2040s and nobody thought much about antarctica. Seemed to gain mass so probably ok for a long time after 2040.

Well that did not turn out to be true on both ends and i really can´t think of an example of a model that predicted things to be way worse.

First we are using a broad brush but we are painting the picture with missing details. So we did not know how warm the cold water coming up near the glaciers was or their topography which is relevant or the way they collapse.

And i think that rate of change is also doing something, maybe especially on land.

There was an interesting discussion in the science subforum about Tietsche et all 2011 and i read that paper then actually looked up the paper on the model they used. Lots of stuff in there. Quite detailed but so much is not in there.

The model mainly does land surface and temperatures and water level.

Every 20 years between 1980 and 2060, three such experiments are started in consecutive years (e.g., 2019,2020, 2021), so that we can analyze five different time slices with a three-member ensemble each.

What the model does not see is all the damage we do in the meantime (which is not that important for the paper i am quoting from but it is more important if you want to predict how much time we have to act.

So in between 1980 and now we have paved over many a grassland for parking lots and build many more roads. Added a couple of cities. Cut away some mangrove forests. Went fracking. Saw bark beetles eat whole forests. Indonesia had some nice fires while they were converting the local jungles to palm tree plantations. Now the Amazon is going to be a cattle ranch and then there is just the Congo left.

Basically you have to vary only some factors. But the models look at what current CO2 etc does in a natural world. It is a bit like the Houston 100 year flood maps. If you update the data you will get a refreshing new picture.

So basically the long term model is mostly run from the initial state while the changes between 1980 and now are quite large even if only looking at extra cities and decline of tropical forests.

Basic line: we are actively eating into all our carbon sinks so we might run out.

You didn't read the article. It is about how an increased vapor pressure deficit causes more water to be lost through the leaves, which causes plants to close their stomata to prevent water loss, which in turn reduces the amount of photosynthesis that takes place, so they grow more slowly. Nothing about the amount of water in total available to the plant.

The ozone hole has caused upper and middle stratospheric cooling which has contributed to the tightening of winds around Antarctica that led to the upwelling of CDW.

Of course, there are many other variables, but the damage to the ozone layer has cooled the stratosphere at both poles in the months of polar daylight.


I think if you really want to know where we are heading with emissions you simply have to follow the money, and investment banks have yet to actually stop funding oil, coal and gas infrastructure, and we have yet to control deforestation and industrial farming. It's not looking good.

That infrastructure has a long lead time to spend the money, 2 years or so, and then usually has a ROI over 10 years and thereafter it makes money. If the money is still flowing towards oil and gas how can we expect emissions to stop growing?

Those gravity studies of Antarctic geology are very interesting to me. It appears to me that the WARS is not inactive, but similar to the tectonic situation in the Arctic ocean where there's very slow spreading along ridge segments.

It's impossible to do typical GPS land based tectonic studies there because the ice moves much faster than the rifting. However, the ongoing volcanic activity, while not definitive, is evidence supportive of ongoing activity along the long rift/transform fault system that crosses Antarctica.

Of course, this tectonic situation is relevant to glacial melting, isostatic adjustment and sea level rise. This rift zone will be a potential region of increasing volcanism as glaciers retreat and depressure deep magma reservoirs. Yes, this is a potential positive feedback.

How hazardous algae blooms respond to changing oceans conditions may be illustrative of how microbial life responds. Here is an abstract for a webinar by Dave Hutchns that our ocean acidification group ( C-CAN )is sponsoring .
"How ocean acidification works hand-in-hand with warming and other global change stressors to promote toxic Pseudo-nitzschia harmful algal blooms along the West Coast
Toxic harmful algal blooms are an increasing problem globally, and the West Coast of the U.S. is no exception. In particular, massive neurotoxic blooms of the domoic acid-producing diatom Pseudo-nitzschia have recently appeared that are larger, more frequent, longer lasting, and much more toxic than any that have been historically recorded.  In recent years, these blooms have caused extensive damage to our Dungeness crab fishery, and they pose an increasing threat to other shellfish and finfish industries. It has become clear that this unprecedented intensification of toxic domoic acid events is very likely linked to ocean environmental change.  For instance, research in my laboratory has shown that ocean acidification can benefit the growth and increase the toxicity of many harmful algal bloom species, including Pseudo-nitzschia. At present day atmospheric CO2 concentrations, obtaining enough dissolved CO2 from the water to support growth can be a problem for Pseudo-nitzschia, which can thus be “carbon dioxide-limited”, and so it may actually directly benefit from higher CO2 levels. There is a definite potential for future CO2 fertilization of more frequent and more intense toxic algal blooms. However, we are now realizing that to understand and predict how ocean acidification will influence harmful algal blooms, we also need to consider a number of other interacting global change impacts. These other direct and indirect human disturbances include sea surface warming, losses of dissolved oxygen, stratification of the surface ocean, and modification of natural nutrient cycles by urban and agricultural pollution. For instance, in addition to ocean acidification, we have also shown that ocean warming strongly promotes domoic acid production by Pseudo-nitzschia.  I will discuss the complex network of interactions between ocean acidification and these many other global change multiple stressors that my lab group is currently working to understand, in order to help predict and perhaps mitigate the tremendously damaging toxic algal blooms that increasingly threaten our coastal fisheries and marine food webs."

A 2016 paper (Rising atmospheric methane: 2007–2014 growth and isotopic shift   -   summarizedhere) indicated the 2014 'large' increase in atmospheric methane appeared to be largely from tropical wetlands.  I couldn't find a more recent study of methane fingerprinting.

Which of course goes alongside this.
Ocean winds blowing harder
Two frequently asked questions about how climate warming will affect the environment are whether windiness might change and what effects that might have on ocean waves. Young and Ribal analyzed global satellite data over the period from 1985 to 2018 to determine if there are any trends in oceanic wind speed and wave height. They found small increases in both quantities, with the strongest increases in extreme conditions and in the Southern Ocean. These findings are important for understanding air-sea exchange of energy and carbon dioxide and for projecting sea levels during storms.

Science, this issue p. 548

In this study, global satellite data were analyzed to determine trends in oceanic wind speed and significant wave height over the 33-year period from 1985 to 2018. The analysis uses an extensive database obtained from 31 satellite missions comprising three types of instruments—altimeters, radiometers, and scatterometers. The analysis shows small increases in mean wind speed and significant wave height over this period, with larger increases in extreme conditions (90th percentiles). The largest increases occur in the Southern Ocean. Confidence in the results is strengthened because the wind speed trends are confirmed by all three satellite systems. An extensive set of sensitivity analyses confirms that both the mean and 90th percentile trends are robust, with only small impacts caused by satellite calibration and sampling patterns.

The higher sea states are  already impacting on west coast erosion rates here in NZ along with the anomalous regional rise in sea level.

James Hansen gave us an initial target of 350ppm for atmospheric CO2... Carbon capture is required and has been for well over a decade.

With sea level rise it will be higher storm surge that has significant impacts first.
We have already seen New York badly impacted with tropical cyclone  sandy.
It will not be the slow  rise of sea level that causes eventual retreat it will be weather events causing catastrophic damage and sane evaluation of the costs and futility of repeated repair. The developed world is far more susceptible to such costly events than the poor regions of Bangladesh.

Seeing as I have commented on this thread.
Thanks ASLR I have been reading your output for years and appreciate the immense amount of effort  your do in constructing your well supported narrative.

There are many factors contributing to inundation risks besides eustatic SLR, and storm surge, as illustrated by the attached three images.

Edit: I also note that recent research finds that for Hurricane/Typhoon cases, wave run-up is worse than previously assumed due to larger (than previously assumed) infragravity waves.

I would propose one small change to that first chart. Under tidal range, it suggests a "daily-yearly" cycle. Maximum tidal values occur during along an 18.6 year orbital cycle.  The cycle last peaked in 2015 and is declining. The next peak will be in 2034. King tides then in places like Miami Beach and Norfolk will be epic.

With sea level rise it will be higher storm surge that has significant impacts first.
We have already seen New York badly impacted with tropical cyclone  sandy.
It will not be the slow  rise of sea level that causes eventual retreat it will be weather events causing catastrophic damage and sane evaluation of the costs and futility of repeated repair. The developed world is far more susceptible to such costly events than the poor regions of Bangladesh.

Seeing as I have commented on this thread.
Thanks ASLR I have been reading your output for years and appreciate the immense amount of effort  your do in constructing your well supported narrative.


Title: "PP11A-05: Absence of the West Antarctic ice sheet during the last interglaciation" Carlson et al (2018)

Summary: "During the last interglaciation (LIG; ~129-116 ka), global mean sea level (GMSL) was >6 m above present. Based on evidence of only modest LIG Greenland ice-sheet retreat, Antarctic ice sheets may also have contributed to LIG GMSL, but direct data for a contribution is lacking. Here we investigate the LIG extent of the West Antarctic (WAIS) and Antarctic Peninsula (APIS) ice sheets using Sr-Nd-Pb isotopes of silt from ODP Site 1096 in the Bellingshausen Sea. Based on our shelf Sr-Nd-Pb provenance data and a stable-isotope age model, we document WAIS-APIS erosion of all radiogenically-discernable terranes from the latter part of marine isotope stage (MIS) 5 up through the Holocene, consistent with independent ice-margin chronologies showing ice presence on all of these terranes from MIS 2 through the Holocene. For the LIG/early MIS 5, we only find evidence of silt sourced from the erosion of the APIS and the mountain ranges that rim the northern modern WAIS, with an absence of silt from Pine Island glacier. Ice-sheet models link Pine Island glacier absence to full WAIS collapse into ice caps on mountains. Our record thus provides the first direct indication of a much smaller LIG WAIS, providing paleo-context for the susceptibility of the WAIS to collapse."

Some direct evidence of the collapse that is shown by the genetic distribution of octopi found in 2012.  At the time this was a primary indication that WAIS will collapse sooner under global warming than was thought at the time.
Scientists at the University have found that genetic information on the Antarctic octopus supports studies indicating that the West Antarctic Ice Sheet could have collapsed during its history, possibly as recently as 200,000 years ago.

Dr Phill Watts, from the University's Institute of Integrative Biology, explains: "We looked at information gathered by the Census of Antarctic Marine Life, which allowed us to examine genetic data on a scale that had not been done before in this area of the world. We expected to find a marked difference between Turguet's octopuses living in different regions of the ocean, particularly between areas that are currently separated by approximately 10,000km of sea. These creatures don't like to travel and so breeding between the populations in the Ross and Weddell Seas would have been highly unusual.

"We found, however, that they were genetically similar, suggesting that at some point in their past these populations would have been in contact with each other, perhaps at a time when the oceans were connected and not separated by the West Antarctic Ice Sheet. These findings agree with climate models indicating repeated periods in history when the climate was warmer, which would have released water from the ice and increased the sea levels, allowing dispersal of creatures between the Ross and Weddell Seas."

"While glaciovolcanism (defined as “the interactions of magma with ice in all its forms, including snow, firn and any meltwater”), may still be in its infancy; nevertheless, I provide the following links to relevant information (& two images about geomagnetism), and I note that there is more information in the 'Antarctic Tectonics' thread in the Antarctic folder; for those who are interested in learning more about this topic:

J.L. Smellie (2018), "Chapter 10 – Glaciovolcanism: A 21st Century Proxy for Palaeo-Ice",
Past Glacial Environments (Second Edition), Pages 335–375,

Abstract: "Glaciovolcanism is a young science that has undergone a major transformation during the last 15 years. It is important for a variety of reasons but it is set to play a major role in deriving critical parameters of past ice sheets and thus greatly improve the accuracy of their reconstruction. Glaciovolcanic studies can deduce a wider range of parameters than any other methodology currently existing, including: establishing the presence of ice, its age, ice thickness, ice surface elevation, and basal thermal regime. These attributes can be acquired routinely for many glaciovolcanic sequences and, uniquely, several are quantifiable. Most glaciovolcanic terrains provide punctuated rather than continuous records of the coeval ice sheet, i.e., with numerous time gaps. Despite the gaps, glaciovolcanic studies of ice sheets have been completed successfully in the three major glaciovolcanic regions of the Earth: mainly Antarctica, but also Iceland and British Columbia (Canada). Future studies in these and other glaciovolcanic regions will considerably improve our knowledge of Earth’s water inventory and contribute to a better understanding of past ice dynamics and the impact of the cryosphere on global climate."


Title: "Antarctic Glaciovolcanism:
A dedicated topic would be great, but where would it fit in?


See attached image for potential glaciovolcanism hot spots, via 2018 REVIEW by Cooper etal. . However, active faults possibly with submarine landslides could become apparent too, hence not only about volcanoes.

See my recent blog here with related studies Study: Enhanced Seismic Activity Observed in Alaska Due To Climate Change

Attempt to capture this topic in video format, for sources see

Maybe this terminology should be dubbed


Maybe not the first, being rich enough to postpone being hit before some poorer parts of the world. But we'll be hit eventually, or that risk seems substantial, at least.

Knowing how and knowing when: unpacking public understanding of atmospheric CO2 accumulation

One image split in two (snipped out the top and bottom parts) says it all (although current numbers are higher).

Roughly twelve years late or so... Remember beeing highly annoyed a decade ago about scientific reticence. Still someone told me just a few days ago, that I can't say that RCP2.6 is dead. A trip down memory lane:

Hansen on scientific reticence and sea level rise. (2007)

Van Vuuren from 2007 (a paper preceeding the RCP2.6 one from 2011...).
Stabilizing greenhouse gas concentrations at low levels: an assessment of reduction strategies and costs

Adding Fig. 3:  Global CO 2 -eq. emissions (all sources) for the B2 baseline emission and pathways to stabilization at a concentration of 650, 550 and 450 ppm CO 2 -eq.

Edit; also adding Fig. 12 from the Van Vuuren 2011 paper. Emissions for the IMAGE (IM) alternative RCP scenarios.

Thanks again AbruptSLR for this research.

Crossposting this by ivica along with my comments.

An effort to raise public awareness about sea level rise, The Royal Institution, published on 2019-05-29, filmed at the Ri on 2019-02-11:

   Sea Level Rise Can No Longer Be Stopped, What Next? - with John Englander

   Q&A part
Thanks ivica.

Edit; What's not discussed in the future part at the end is sustainability and resource use. Nothing really new around SLR and glaciers (for those who follow this) but other than that, it's all sound and a worthwhile watch. Adding the key messages below.

Yup, and then we also have the worst and unfortunately still present hysteresis, maybe best depicted with Meadows bathtub analogy? First an old quote by Donella and then Dennis version from last year in one image.
–August 23, 1990–
The real issues here, the underlying fears that trigger our anger, are that on the one hand a bunch of environmental alarmists will force unnecessary changes in our fossil-fuel-powered way of doing things, and that on the other hand a bunch of technological conservatives with heavy stakes in fossil-fuel industries will drive the climate and the earth’s ecosystems into overheated chaos.

I just had a thought...
Could SLR (and other AGW effects) have a hysteresis? So say CO2e doubles (to 560 ppm) and these effects occur, then through superhuman effort we get the CO2e back down to 280 ppm, but the effects don't go back to "normal"?
I was looking at an ice shelf that collapsed, Larsens B I believe, and they said the last time their wasn't a shelf was something like 10,000 years ago. In some parts of the antarctic is over a mile thick! I would think some of that ice is much older. So any damage done is permanent in the short to medium term.

I just had a thought...
Could SLR (and other AGW effects) have a hysteresis? So say CO2e doubles (to 560 ppm) and these effects occur, then through superhuman effort we get the CO2e back down to 280 ppm, but the effects don't go back to "normal"?

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