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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2950 on: March 28, 2020, 07:15:05 PM »
The linked reference indicates that climate sensitivity increases with increasing CO2 concentration faster than previously realized due to higher cloud feedback than previously assumed.

Jiang Zhu, Christopher J. Poulsen, Jessica E. Tierney. Simulation of Eocene extreme warmth and high climate sensitivity through cloud feedbacks. Science Advances, 2019; 5 (9): eaax1874 DOI: 10.1126/sciadv.aax1874

https://advances.sciencemag.org/content/5/9/eaax1874

Abstract
The Early Eocene, a period of elevated atmospheric CO2 (>1000 ppmv), is considered an analog for future climate. Previous modeling attempts have been unable to reproduce major features of Eocene climate indicated by proxy data without substantial modification to the model physics. Here, we present simulations using a state-of-the-art climate model forced by proxy-estimated CO2 levels that capture the extreme surface warmth and reduced latitudinal temperature gradient of the Early Eocene and the warming of the Paleocene-Eocene Thermal Maximum. Our simulations exhibit increasing equilibrium climate sensitivity with warming and suggest an Eocene sensitivity of more than 6.6°C, much greater than the present-day value (4.2°C). This higher climate sensitivity is mainly attributable to the shortwave cloud feedback, which is linked primarily to cloud microphysical processes. Our findings highlight the role of small-scale cloud processes in determining large-scale climate changes and suggest a potential increase in climate sensitivity with future warming.

See also:

Title: "Study of ancient climate suggests future warming could accelerate"

https://www.sciencedaily.com/releases/2019/09/190918142035.htm

Extract: ""We were surprised that the climate sensitivity increased as much as it did with increasing carbon dioxide levels," said first author Jiang Zhu, a postdoctoral researcher at the U-M Department of Earth and Environmental Sciences.

"It is a scary finding because it indicates that the temperature response to an increase in carbon dioxide in the future might be larger than the response to the same increase in CO2 now. This is not good news for us.""
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2951 on: March 28, 2020, 11:45:42 PM »
Apparently, the COVID-19 outbreak gave the Trump administration an excuse, last Thursday, to give the U.S. oil & gas industry 'an open license to pollute.'

Title: "Trump’s Move to Suspend Enforcement of Environmental Laws is a Lifeline to the Oil Industry"

https://insideclimatenews.org/news/27032020/coronavirus-covid-19-EPA-API-environmental-enforcement

Extract: "The American Petroleum Institute sought the EPA’s help for companies hurt by COVID-19. One former EPA official called the suspension “an open license to pollute.""
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2952 on: March 29, 2020, 11:23:40 PM »
'Banked' CFCs still represent a risk to accelerated climate change; and merit appropriate action:

Lickley, M., Solomon, S., Fletcher, S. et al. Quantifying contributions of chlorofluorocarbon banks to emissions and impacts on the ozone layer and climate. Nat Commun 11, 1380 (2020). https://doi.org/10.1038/s41467-020-15162-7

https://www.nature.com/articles/s41467-020-15162-7

Abstract
Chlorofluorocarbon (CFC) banks from uses such as air conditioners or foams can be emitted after global production stops. Recent reports of unexpected emissions of CFC-11 raise the need to better quantify releases from these banks, and associated impacts on ozone depletion and climate change. Here we develop a Bayesian probabilistic model for CFC-11, 12, and 113 banks and their emissions, incorporating the broadest range of constraints to date. We find that bank sizes of CFC-11 and CFC-12 are larger than recent international scientific assessments suggested, and can account for much of current estimated CFC-11 and 12 emissions (with the exception of increased CFC-11 emissions after 2012). Left unrecovered, these CFC banks could delay Antarctic ozone hole recovery by about six years and contribute 9 billion metric tonnes of equivalent CO2 emission. Derived CFC-113 emissions are subject to uncertainty, but are much larger than expected, raising questions about its sources.

See also:

Title: "Long Phased-Out Refrigeration and Insulation Chemicals Still Widely in Use and Warming the Climate"

https://insideclimatenews.org/news/17032020/cfc-ozone-layer-short-lived-climate-pollutants

Extract: "New study concludes that “banked” CFCs have greenhouse gas impacts equal to all registered U.S. cars and slow the shrinking of the ozone hole."
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2953 on: March 29, 2020, 11:30:28 PM »
The linked article indicates that many banks are still significantly supporting the fossil fuel industry via loans/finance:

Title: "Study: global banks 'failing miserably' on climate crisis by funneling trillions into fossil fuels"

https://www.theguardian.com/environment/2020/mar/18/global-banks-climate-crisis-finance-fossil-fuels

Extract: "Analysis of 35 leading investment banks shows financing of more than $2.66tn for fossil fuel industries since the Paris agreement"
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2954 on: March 29, 2020, 11:43:33 PM »
The linked article discusses the probability that the modern global socio-economic system is fragile to shocks whether from pandemics, climate change, or other perturbations from the norm:

Title: "Professor Sees Climate Mayhem Lurking Behind Covid-19 Outbreak"

https://www.bloomberg.com/news/articles/2020-03-28/professor-sees-climate-mayhem-lurking-behind-covid-19-outbreak

Extract: "“In modern industrial societies, the fallout from Covid-19 feels like a dress rehearsal for the kind of collapse that climate change threatens,” Bendell said in an interview. “This crisis reveals how fragile our current way of life has become.”

The University of Cumbria social-science professor is well-known among environmentalists for his theory of “deep adaptation.” In a 2018 paper, Bendell said that time was up for gradual measures to combat global warming. Without an abrupt transformation of society, changes in the planet’s climate would bring starvation, destruction, migration, disease and war -- the collapse of civilization -- within a decade."
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2955 on: March 30, 2020, 01:01:24 AM »
The linked research '... suggests that substantial reductions or instabilities of the AMOC could also occur in a future warmer climate.'

Thomas F. Stocker ( 27 Mar 2020), "Surprises for climate stability", Science, Vol. 367, Issue 6485, pp. 1425-1426, DOI: 10.1126/science.abb3569

https://science.sciencemag.org/content/367/6485/1425

Summary
Instabilities in Earth's climate system have intrigued scientists ever since analyses from Greenland ice cores revealed climate variations over the last hundred thousand years (1, 2). Abrupt changes were not singular events but a pervasive feature of the last ice age. Studies pointed to the ocean, specifically the Atlantic Meridional Overturning Circulation (AMOC), as a possible origin of these large swings (3, 4). Their occurrence in the distant past of the last ice age and their absence in the past 8000 years suggested that we are living in times of relative climate stability. On page 1485 of this issue, Galaasen et al. (5) report that over the past 500,000 years, there were disruptions in the formation of the North Atlantic Deep Water mass—an essential driver of the AMOC—during interglacial periods. This suggests that substantial reductions or instabilities of the AMOC could also occur in a future warmer climate.

http://www.sciencemag.org/about/science-licenses-journal-article-reuse
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2956 on: March 30, 2020, 05:24:34 PM »
While currently 'Big Oil' is not leading the charge into renewable energy; however, their eventual adoption of more renewable energy would speed the transition to more sustainable power infrastructure.  Thus, 'Big Oil's currently wavering investments into sustainable energy is not good news.

Title: "Big Oil's interest in renewable energy investments expected to waver: report"

https://www.nsnews.com/big-oil-s-interest-in-renewable-energy-investments-expected-to-waver-report-1.24108471

Extract: "Budget cutting in response to the twin challenges of COVID-19 demand destruction and low oil prices mean the world's oil and gas industry will likely spend less on renewable energy going forward.

"In a US$60 per barrel oil price environment, most companies were generating strong cash flow and could afford to think about carbon mitigation strategies," said Valentina Kretzschmar, vice-president, corporate analysis, at Wood Mackenzie.

"But now ... all discretionary spend will be under review — that includes additional budget allocated for carbon mitigation. And companies that haven't yet engaged in carbon reduction strategies are likely to put the issue on the back burner.""
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2957 on: March 30, 2020, 07:14:36 PM »
The linked Nature article discusses an ozone hole that has currently formed over the Arctic, and that this hole is worse than what happened in 1997 and 2011.  While a temporary Arctic ozone hole would not likely have a meaningful impact on climate change; nevertheless, it is discomforting that this event is worse than all previous events, and that if it is prolonged, or if future such events happen more frequently, this might have an impact on Arctic wind patterns; which might then have an impact of Arctic sea ice flow patterns.

Title: "Rare ozone hole opens over Arctic — and it’s big"

https://www.nature.com/articles/d41586-020-00904-w

Extract: "Cold temperatures and a strong polar vortex allowed chemicals to gnaw away at the protective ozone layer in the north.

A vast ozone hole — likely the biggest on record in the north — has opened in the skies above the Arctic. It rivals the better-known Antarctic ozone hole that forms in the southern hemisphere each year.

Record-low ozone levels currently stretch across much of the central Arctic, covering an area about three times the size of Greenland (see ‘Arctic opening’). The hole doesn’t threaten people’s health, and will probably break apart in the coming weeks. But it is an extraordinary atmospheric phenomenon that will go down in the record books.

The Arctic experienced ozone depletion in 1997 and in 2011, but this year’s loss looks on track to surpass those. “We have at least as much loss as in 2011, and there are some indications that it might be more than 2011,” says Gloria Manney, an atmospheric scientist at NorthWest Research Associates in Socorro, New Mexico. She works with a NASA satellite instrument that measures chlorine in the atmosphere, and says there is still quite a bit of chlorine available to deplete ozone in the coming days."
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2958 on: March 30, 2020, 07:31:18 PM »
The linked reference (& associated article) indicate that recent studies of glacial earthquakes associated with Thwaites Glacier Calving events can help to improve projections of future ice mass loss from this key glacier:

J. Paul Winberry et al. (15 January 2020), "Glacial Earthquakes and Precursory Seismicity Associated With Thwaites Glacier Calving", Geophysical Research Letters, https://doi.org/10.1029/2019GL086178

https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL086178

Abstract
We observe two (~MS 3) long‐period (10–30 s) seismic events that originate from the terminus of Thwaites Glacier, Antarctica. Serendipitous acquisition of satellite images confirm that the seismic events were glacial earthquakes generated during the capsizing of icebergs. The glacial earthquakes were preceded by 6 days of discrete high‐frequency seismic events that can be observed at distances exceeding 250 km. The high‐frequency seismicity displays an increasing rate of occurrence, culminating in several hours of sustained tremor coeval with the long‐period events. A series of satellite images collected during this precursory time period show that the high‐frequency events and tremor are the result of accelerating growth of ancillary fractures prior to the culminating calving event. This study indicates that seismic data have the potential to elucidate the processes by which Thwaites Glacier discharges into the ocean, thus improving our ability to constrain future sea level rise.

Plain Language Summary
Thwaites Glacier is one of the largest sources of Antarctic ice mass loss; however, the physics of the processes that control its discharge into the ocean remains incomplete. The long‐term stability of glaciers, such as Thwaites, that discharge directly into the ocean is linked to the rate of calving, the process of iceberg production. Spaceborne observations are crucial to understanding the calving processes; however, the typical repeat time of a satellite imagery is much longer than the typical duration of a calving event (minutes to hours). Increasingly, the seismic signals generated during calving are being used to complement other observations. For larger calving events, seismic energy can be recorded by remote seismic observation (hundreds to thousands of kilometers away from a glacier). While these glacier earthquakes are now regularly used to study calving in Greenland, only a limited number of glacial earthquakes have been observed in Antarctica. We show that Thwaites Glacier has now begun generating glacial earthquakes similar to those observed in Greenland. Additionally, we show that enhanced rates of fracturing can be seismically observed before the event. Our observations open a new avenue for understanding the behavior of Antarctica's leading source of mass loss.

See also:

Title: "Thwaites Glacier in Antarctica is Now Causing Earthquakes"

https://glacierhub.org/2020/03/05/thwaites-glacier-in-antarctica-is-now-causing-earthquakes/

Extract: "Combing through seismograph readings collected in West Antarctica during a large calving event at Thwaites on February 8th 2014, a team of researchers found evidence of two low frequency earthquakes, each about 10-30 seconds long. Their hunch—that the quakes came from the calving—was confirmed when they matched the seismograph readings with satellite images taken on the same day.

They also discovered high frequency blips of seismic activity that chirped on and off in the week preceding the event. Glaciologist and lead author of the study, Paul Winberry, explained to GlacierHub that in these short bursts they were actually “hearing all these little cracks start to propagate.” It was the sound of countless cracks forming and popping apart, heralding the large break about to come.

Thwaites is the only known glacier in Antarctica to exhibit seismic behavior, whereas glaciers in Greenland have been recorded causing earthquakes for some time. This difference can be explained by the fact that the majority of Greenland’s icebergs capsize when they break off into the water. The result is a more boisterous form of calving that produces detectable earthquakes. Why Greenland’s icebergs capsize and Antarctica’s do not has to do with the physical makeup of each landmass’s ice sheets and where they start to float on the water."
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2959 on: April 01, 2020, 08:56:27 PM »
By itself, the heat wave recently recorded in East Antarctica means little, but if such heat waves become more frequent in the coming decades, it would not be good news.

Title: "Researchers record 1st-ever heat wave in East Antarctica"

https://theweek.com/speedreads/905968/researchers-record-1stever-heat-wave-east-antarctica

Extract: "This January, East Antarctica — an area that previously seemed to be spared from climate warming — experienced its first recorded heat wave.

The heat wave was recorded at the Casey Research Station between Jan. 23 and 26, marking the area's highest temperature ever at 48.6 degrees Fahrenheit, while minimum temperatures stayed above 32 degrees Fahrenheit, according to research in Global Change Biology.

A rarity in Antarctica, heat waves are known as "three consecutive days with both extreme maximum and minimum temperatures," according to the research."

Edit, see also:

Sharon A. Robinson  Andrew R. Klekociuk  Diana H. King  Marisol Pizarro Rojas  Gustavo E. Zúñiga  Dana M. Bergstrom (30 March 2020), "The 2019/2020 summer of Antarctic heatwaves", Global Change Biology, https://doi.org/10.1111/gcb.15083

https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.15083?af=R
« Last Edit: April 02, 2020, 07:05:19 PM by AbruptSLR »
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2960 on: April 02, 2020, 03:58:04 PM »
While the formation of temperate rainforests near the South Pole are not likely to occur in our children's lifetimes; if we do trigger an equable climate (say by the Equatorial Pacific SST increasing by 5oC due to a sufficient slowdown of the MOC and an increase of the CO2-equivant to between 700 ppm & 1,000 ppm), then history could repeat itself (see linked reference), within less than a thousand years (worse case):

Klages, J.P., Salzmann, U., Bickert, T. et al. Temperate rainforests near the South Pole during peak Cretaceous warmth. Nature 580, 81–86 (2020). https://doi.org/10.1038/s41586-020-2148-5

https://www.nature.com/articles/s41586-020-2148-5

Abstract: "The mid-Cretaceous period was one of the warmest intervals of the past 140 million years, driven by atmospheric carbon dioxide levels of around 1,000 parts per million by volume. In the near absence of proximal geological records from south of the Antarctic Circle, it is disputed whether polar ice could exist under such environmental conditions. Here we use a sedimentary sequence recovered from the West Antarctic shelf—the southernmost Cretaceous record reported so far—and show that a temperate lowland rainforest environment existed at a palaeolatitude of about 82° S during the Turonian–Santonian age (92 to 83 million years ago). This record contains an intact 3-metre-long network of in situ fossil roots embedded in a mudstone matrix containing diverse pollen and spores. A climate model simulation shows that the reconstructed temperate climate at this high latitude requires a combination of both atmospheric carbon dioxide concentrations of 1,120–1,680 parts per million by volume and a vegetated land surface without major Antarctic glaciation, highlighting the important cooling effect exerted by ice albedo under high levels of atmospheric carbon dioxide."
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2961 on: April 02, 2020, 07:18:26 PM »
The linked article indicates that the Keystone XL pipeline just received financial support from Alberta's United Conservative government:

Title: "Why Alberta is throwing billions behind the Keystone XL pipeline"

https://www.cbc.ca/news/business/analysis-alberta-invests-in-keystone-1.5516144

Extract: "With the energy sector still reeling from weeks of economic turmoil, Alberta's United Conservative government announced Tuesday it is throwing its financial heft behind the long-delayed Keystone XL pipeline.

The investment of $1.5 billion, plus a $6-billion loan guarantee, aims to accelerate construction of the massive project and was warmly greeted by a sector desperate for some good news.

Still, the enormity of the investment will also raise many questions — including, why now?
 
But as with many things in Alberta over the years, the answer can often be found at the intersection of oil, government and politics. Now, the stakes feel higher than ever for an industry with an unsettled future."
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2962 on: April 03, 2020, 08:55:15 PM »
The linked reference indicates that consensus climate scientists have been assuming that phytoplankton absorbed more CO2 from the atmosphere than they actually do, which means that climate sensitivity is higher than previously assumed:

Bolaños, L.M., Karp-Boss, L., Choi, C.J. et al. Small phytoplankton dominate western North Atlantic biomass. ISME J (2020). https://doi.org/10.1038/s41396-020-0636-0

https://www.nature.com/articles/s41396-020-0636-0

Abstract
The North Atlantic phytoplankton spring bloom is the pinnacle in an annual cycle that is driven by physical, chemical, and biological seasonality. Despite its important contributions to the global carbon cycle, transitions in plankton community composition between the winter and spring have been scarcely examined in the North Atlantic. Phytoplankton composition in early winter was compared with latitudinal transects that captured the subsequent spring bloom climax. Amplicon sequence variants (ASVs), imaging flow cytometry, and flow-cytometry provided a synoptic view of phytoplankton diversity. Phytoplankton communities were not uniform across the sites studied, but rather mapped with apparent fidelity onto subpolar- and subtropical-influenced water masses of the North Atlantic. At most stations, cells < 20-µm diameter were the main contributors to phytoplankton biomass. Winter phytoplankton communities were dominated by cyanobacteria and pico-phytoeukaryotes. These transitioned to more diverse and dynamic spring communities in which pico- and nano-phytoeukaryotes, including many prasinophyte algae, dominated. Diatoms, which are often assumed to be the dominant phytoplankton in blooms, were contributors but not the major component of biomass. We show that diverse, small phytoplankton taxa are unexpectedly common in the western North Atlantic and that regional influences play a large role in modulating community transitions during the seasonal progression of blooms.
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sidd

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2963 on: April 04, 2020, 12:21:27 AM »
Re: phytoplankton absorbed more CO2 from the atmosphere than they actually do, which means that climate sensitivity is higher than previously assumed

I dont see the connection ?

sidd

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2964 on: April 04, 2020, 01:55:06 AM »
Sidd you left our The linked reference indicates that consensus climate scientists have been assuming that.

Some relevant snippets:

Quote
Diatoms, which are often thought to dominate phytoplankton blooms [8, 63], were infrequently a major fraction of the phytoplankton genetic profiles and, when diatoms were a relatively high fraction of the ASVs (subpolar spring stations 2 and 3), IFCB data showed that they were mostly small diatoms in the nano-phytoplankton or at the lower end of the micro-phytoplankton size category. Biogeochemical models are often influenced by the perception that North Atlantic phytoplankton blooms are composed of large cells that contribute massively to export carbon flux [64]. This perception has been perpetuated by models that assume that diatoms are uniformly large cells. However, diatoms are diverse in size, introducing substantial variation in their contribution to the export of carbon [63, 65]. Support for our findings can be found in previous reports that noted small phytoplankton cells are common components of the North Atlantic spring bloom [1, 66].


Notably, the profoundly contrasting composition of the winter community, and the diverse phytoplankton assemblages dominated by small taxa we found in the spring, are system features that alter our perspective and will likely set the stage for future research.

So basically we have been modelling this to our best knowledge but new research shows the actual situation is worse (which is a general theme among climate papers which should signal right tail! right tail! is probably the best bet for predictions especially with so many assholes still banking on oilriches and an outdated worldview).

They extrapolated what they knew:

Quote
Historically, diatoms have been recognized as the dominant taxa during the highest productivity stage of the North Atlantic bloom at high latitudes [5, 6]. Algorithms that predict carbon export from satellite-sensed chlorophyll often assign high export rates to phytoplankton blooms, on the assumption that large diatoms dominate at their climax [7]. A succession of coccolithophores, dinoflagellates, and pico-phytoplankton typically is expected to follow the diatom peak [8, 9]. This understanding of phytoplankton dynamics derives heavily from observations in eastern North Atlantic [10,11,12,13], but is extrapolated to the west, as if the North Atlantic region were a homogenous entity.

Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

sidd

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2965 on: April 04, 2020, 06:34:53 AM »
My point was:

Stipulated that phytoplankton absorb less CO2 that was thought. How does this affect climate sensitivity ?

sidd

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2966 on: April 04, 2020, 08:11:43 AM »
^^
sidd (and others), do you think this line of reasoning is correct?

Less CO₂ gets sequestered by the ocean (plankton) → more CO₂ stays in the atmosphere → antropogenic CO₂ (outside carbon cycle) has a greater warming effect because more stays in the atmosphere than earlier thought → higher climate sensitivity from our extra CO₂.
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2967 on: April 04, 2020, 09:50:49 PM »
My point was:

Stipulated that phytoplankton absorb less CO2 that was thought. How does this affect climate sensitivity ?

sidd
sidd,

The linked article explains how consensus science uncertainty about what the true climate sensitivity will be in coming decades is driven by uncertainty about the net combined impact of both positive, and negative, feedback mechanisms.  Thus, if negative feedback mechanisms are less negative than previously assumed then climate sensitivity will be higher than consensus climate scientists previously assumed.

Title: "Explainer: How scientists estimate ‘climate sensitivity’"

https://www.carbonbrief.org/explainer-how-scientists-estimate-climate-sensitivity

Extract: "The wide range of estimates of climate sensitivity is driven by uncertainties in climate feedbacks, including how water vapour, clouds, surface reflectivity and other factors will change as the Earth warms. Climate feedbacks are processes that may amplify (positive feedbacks) or diminish (negative feedbacks) the effect of warming from increased CO2 concentrations or other climate forcings – factors that initially drive changes in the climate."
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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2968 on: April 05, 2020, 06:34:33 PM »
The UN's WMO (World Meteorological Organization) "Statement on the State of the Global Climate in 2019", confirms that climate change is currently accelerating and that mankind is nowhere near to being on track to stall within the 'well below' 2C target.

Title: "Flagship UN study shows accelerating climate change on land, sea and in the atmosphere"

https://news.un.org/en/story/2020/03/1059061

Extract: "Writing in the foreword to the report, UN chief António Guterres warned that the world is currently “way off track meeting either the 1.5°C or 2°C targets that the Paris Agreement calls for”, referring to the commitment made by the international community in 2015, to keep global average temperatures well below 2°C above pre-industrial levels."

See also:

Title: "WMO Statement on the State of the Global Climate in 2019"

https://reliefweb.int/report/world/wmo-statement-state-global-climate-2019-enarru

Extract: "Multi-agency report highlights increasing signs and impacts of climate change in atmosphere, land and oceans"
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sidd

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2969 on: April 05, 2020, 10:00:42 PM »
Re: if negative feedback mechanisms are less negative than previously assumed then climate sensitivity will be higher than consensus climate scientists previously assumed.

Agreed. But those negative feedbacks also must explain past climate. If they were wrong, the model would not fit past climate. But we know that models do a good job simulating past climate. So there must be a) some other carbon drawdown mechanism or b) carbon emission in the past was smaller than previously assumed.

Which do you think it is ?

sidd

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2970 on: April 06, 2020, 12:05:16 AM »
Re: if negative feedback mechanisms are less negative than previously assumed then climate sensitivity will be higher than consensus climate scientists previously assumed.

Agreed. But those negative feedbacks also must explain past climate. If they were wrong, the model would not fit past climate. But we know that models do a good job simulating past climate. So there must be a) some other carbon drawdown mechanism or b) carbon emission in the past was smaller than previously assumed.

Which do you think it is ?

sidd

First of all I believe that your assumption the current consensus climate models do a good job of simulating relevant past climate is not correct.  Just search in this thread for either Holsteinian and/or MIS 11 and you will find numerous studies indicating that consensus climate models cannot replicate this highly relevant case.

Second, consensus climate models do not adequately simulate ice-climate feedback mechanisms (especially MICI mechanisms) and thus, in my opinion, cannot reasonably simulate climate risks in the coming decades.

Finally, you gloss over other well documented climate feedback uncertainties such as: a) aerosol-cloud feedbacks, b) cloud feedbacks and c) permafrost degradation.  Thus, how say that you know that if plankton feedbacks are less negative than previously assumed than some other mechanism must be compensating?
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sidd

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2971 on: April 06, 2020, 06:54:25 AM »
Because if any negative feedback were smaller in reality than in models, then temperature rise in the models would have been larger than observed, unless there was a compensating error. Where is that compensation ?

sidd

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2972 on: April 06, 2020, 07:49:13 AM »
Aerosols?
Everyone who can must self-isolate.

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2973 on: April 06, 2020, 06:12:17 PM »
Because if any negative feedback were smaller in reality than in models, then temperature rise in the models would have been larger than observed, unless there was a compensating error. Where is that compensation ?

sidd

sidd,

It sounds to me like you are referring to comparisons of consensus model projections to the observed record.  If so, the observed record is an extremely short period of time, and consensus model are subject to any number of factors that could temporarily mask the impacts of actual trends in climate feedback mechanisms, such as:
a) Boundary conditions of the models and initial start-up conditions,
b) Incorrect modeling of other feedback mechanisms that result in compensating errors (like aerosol feedback mechanisms, or a temporary spurt of growth of vegetation that ends abruptly when increases in GMSTA result in future losses of vegetation that return temporarily sequestered carbon to the atmosphere).
c) The fact that ECS increases with increasing GMSTA, thus looking at the recent past may not be appropriate for simulating the future.

Also, models have so many variables that modelers tweak them as the models run to ensure that they converge towards known parameters; and in this regard, CMIP6 matches many more parameters than does CMIP5; so you may be referring to out of date projections.

Edit: For those who do not know CMIP6 projects a significantly higher range of climate sensitivity values than did CMIP5; and my main criticism of the CMIP6 projections is that they do not adequately consider ice-climate feedback mechanisms (which have not yet become highly nonlinear)
« Last Edit: April 06, 2020, 06:43:12 PM by AbruptSLR »
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kassy

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2974 on: April 06, 2020, 07:30:51 PM »
Lets see.

Basically it means that the climate models overestimate the amount of carbon burial in some parts of the ocean.

Not sure how much data they got for all the other oceans and if this conclusion actually means much for the other oceans.

Models probably have bigger issues (clouds etc) and this is part of the ways in which ocean bury carbon. Not sure how much else is in the models (only looked at the land parts because that is easier).

But if we keep all else equal then the total sink becomes a bit smaller which means we get there quicker. That probably does not do anything for ECS in itself.

How will these populations develop at increasing temperatures? We have no clue and that might be more important. People have been growing all kinds of plants in future CO2 level but not algal blooms. You probably need a big pond...

Basically i would want to know the end of our push because that makes it easier to figure out ECS.

And it is too abstract for my liking anyway.

The whole the more important point is what happens on the way because that is where we live.
And there is this balance between what we could control and what we can not.

We either stop our contributions before we start a feedback we cannot control.
That point is somewhere between here and now and doubling CO2. Bit closer to here and now i bet.
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2975 on: April 07, 2020, 12:44:17 AM »
The linked reference (& associated article) indicate that flooding during 2019 delayed U.S. Midwest crop planting; which resulted in less carbon uptake.  If climate change trends result in more crop disruptions we can expect similarly reduced CO2 uptake by crops in the future:

Yi Yin, et al. (25 March 2020), "Cropland Carbon Uptake Delayed and Reduced by 2019 Midwest Floods", AGU Advances, https://doi.org/10.1029/2019AV000140

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019AV000140

Abstract
While large‐scale floods directly impact human lives and infrastructures, they also profoundly impact agricultural productivity. New satellite observations of vegetation activity and atmospheric CO2 offer the opportunity to quantify the effects of such extreme events on cropland carbon sequestration. Widespread flooding during spring and early summer 2019 induced conditions that delayed crop planting across the U.S. Midwest. As a result, satellite observations of solar‐induced chlorophyll fluorescence from TROPOspheric Monitoring Instrument and Orbiting Carbon Observatory reveal a 16‐day shift in the seasonal cycle of photosynthesis relative to 2018, along with a 15% lower peak value. We estimate a reduction of 0.21 PgC in cropland gross primary productivity in June and July, partially compensated in August and September (+0.14 PgC). The extension of the 2019 growing season into late September is likely to have benefited from increased water availability and late‐season temperature. Ultimately, this change is predicted to reduce the crop productivity in the Midwest Corn/Soy belt by ~15% compared to 2018. Using an atmospheric transport model, we show that a decline of ~0.1 PgC in the net carbon uptake during June and July is consistent with observed CO2 enhancements of up to 10 ppm in the midday boundary layer from Atmospheric Carbon and Transport‐America aircraft and over 3 ppm in column‐averaged dry‐air mole fractions from Orbiting Carbon Observatory. This study quantifies the impact of floods on cropland productivity and demonstrates the potential of combining solar‐induced chlorophyll fluorescence with atmospheric CO2 observations to monitor regional carbon flux anomalies.

Plain Language Summary
Widespread flooding and inundation across the U.S. Midwest during spring and early summer 2019 forced many farmers to delay crop planting. New satellite observations of vegetation photosynthesis and atmospheric CO2 offer the opportunity to quantify the effects of such events on cropland carbon sequestration. We show that the delayed planting resulted in a shift of 16 days in the seasonal cycle of the crop growth and a ~15% lower peak solar‐induced chlorophyll fluorescence value. We estimate a reduction of 0.21 PgC in the gross primary production during June and July, partially compensated in August and September (+0.14 PgC). The extension of the 2019 growing season into late September is likely to have benefited from increased water availability and late‐season temperature. Ultimately, this change is predicted to reduce the crop production over most of the Midwest Corn/Soy belt by 15%, based on the strong empirical correlation between 2018 growing season SIF and crop yield. The bottom‐up estimated net carbon uptake reduction of ~0.1 PgC in June and July is consistently supported by top‐down inferred CO2 anomalies from both aircraft and satellite observations. We anticipate that such a rapid event detection can benefit agricultural and natural resource management and ecological forecasting efforts.
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2976 on: April 07, 2020, 04:17:01 AM »
...

But if we keep all else equal then the total sink becomes a bit smaller which means we get there quicker. That probably does not do anything for ECS in itself.

...

Within Earth Systems Models, ESM, there is no parameter for ECS, TCR or other estimates of climate sensitivity; instead there are only the numerous separate positive and negative feedback mechanisms that result in a net change in warming/cooling for a given period of time.  Thus if we get 'there' (as in a warmer world) quicker then that means the climate sensitivity is a small amount higher than previously assumed.

Also, I note that while it is difficult for people to keep track of such small incremental changes; but if the ESMs sum thousands and thousands of such small incremental changes in the coming decades they may very likely push us all over a possible irreversible tipping point, such as a possible MICI-type of collapse of the WAIS in the coming decades.
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kassy

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2977 on: April 07, 2020, 05:28:42 PM »
Adding this here for fun.

1 The ocean captures twice as much carbon dioxide as previously thought

The biological carbon pump (BCP) contributes to the role of the ocean in taking up and storing carbon dioxide (CO2) by removing the gas from the atmosphere, changing it into living matter, and distributing it to the deeper ocean layers. Without the BCP, the atmospheric concentration of CO2 would be much higher.

...

Researchers set out to measure the depth of the ocean’s sunlit surface area or euphotic zone, using a technique known as chlorophyll fluorescence detection that looks for the presence of photosynthetic phytoplankton in the deeper layers of the ocean.

The found the depth of the euphotic zone, which is where most of the marine species live, to significantly vary throughout the world.

Combining their findings with data from previous studies of the BCP, the authors were able to estimate the rate at which carbon particles are sinking. They found that about twice as much carbon sinks into the ocean per year than previously estimated.

https://www.sciencefocus.com/news/the-ocean-captures-twice-as-much-carbon-dioxide-as-previously-thought/

Metrics that matter for assessing the ocean biological carbon pump

https://www.pnas.org/content/early/2020/04/03/1918114117

2 Upper ocean water masses shrinking in changing climate: Less efficient CO2 sink

The oceans help buffer the Earth from climate change by absorbing carbon dioxide and heat at the surface and transporting it to the deep ocean. New research indicates the North Atlantic Subtropical Mode Water, an upper ocean water mass, is shrinking in a changing climate and becoming a less efficient sink for heat and carbon dioxide.

One particular layer in the North Atlantic Ocean, a water mass called the North Atlantic Subtropical Mode Water (or STMW), is very efficient at drawing carbon dioxide out of the atmosphere. It represents around 20% of the entire carbon dioxide uptake in the mid-latitude North Atlantic and is an important reservoir of nutrients for phytoplankton -- the base of the marine food chain -- at the surface of the ocean.

...

Using data from two of the world's longest-running open-ocean research programs -- the Bermuda Atlantic Time-series Study (BATS) Program and Hydrostation 'S' -- the team found that as much as 93% of STMW has been lost in the past decade. This loss is coupled with a significant warming of the STMW (0.5 to 0.71 degrees Celsius or 0.9 to 1.3 degrees Fahrenheit), culminating in the weakest, warmest STMW layer ever recorded.

"Although some STMW loss is expected due to the prevailing atmospheric conditions of the past decade, these conditions do not explain the magnitude of loss that we have recorded," said Professor Nick Bates, BIOS senior scientist and principal investigator of the BATS Program. "We find that the loss is correlated with different climate change indicators, such as increased surface ocean heat content, suggesting that ocean warming may have played a role in the reduced STMW formation of the past decade."

https://www.sciencedaily.com/releases/2020/04/200406112530.htm
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AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2978 on: April 07, 2020, 10:39:35 PM »
While it is still uncertain how much carbon will be emitted from the degradation of permafrost into the atmosphere, the linked article discusses the fact that such emissions will be irreversible:

Title: "The irreversible emissions of a permafrost ‘tipping point’"

https://www.skepticalscience.com/irreversible-emissions-permafrost-tipping-point.html

Extract: "Tipping points
This article is part of a week-long special series on “tipping points”, where a changing climate could push parts of the Earth system into abrupt or irreversible change

•   Explainer: Nine ‘tipping points’ that could be triggered by climate change
•   Guest post: Could the Atlantic Overturning Circulation ‘shut down’?
•   Guest post: The irreversible emissions of a permafrost ‘tipping point’
•   Guest post: Could climate change and deforestation spark Amazon ‘dieback’?
•   Guest post: How close is the West Antarctic ice sheet to a ‘tipping point’?

Yet, what is irreversible is the escape of the carbon that has been – and is being – emitted. The carbon released from permafrost goes into the atmosphere and stays there, exacerbating global warming."
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Lennart van der Linde

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2979 on: April 07, 2020, 11:00:06 PM »
Maybe some good news for a change, on methane eating bacteria:
https://e360.yale.edu/digest/methane-eating-bacteria-could-help-decrease-greenhouse-gas-emissions-from-thawing-arctic-tundra

Quote
net greenhouse gas emissions from the Arctic may be much smaller than previously modeled due to the increased productivity of a type of bacteria known as high affinity methanotrophs, or HAMs. “This group of bacteria utilizes atmospheric methane as an energy source,” Qianlai Zhuang, lead author of the study, said in a statement. “The emissions from wetlands will potentially be quite large, but if you consider the uplands, then the area-aggregated net emissions will be much smaller than previously thought.”

Oh et al 2020, Reduced net methane emissions due to microbial methane oxidation in a warmer Arctic:
https://www.nature.com/articles/s41558-020-0734-z

Abstract
Methane emissions from organic-rich soils in the Arctic have been extensively studied due to their potential to increase the atmospheric methane burden as permafrost thaws1,2,3. However, this methane source might have been overestimated without considering high-affinity methanotrophs (HAMs; methane-oxidizing bacteria) recently identified in Arctic mineral soils4,5,6,7. Herein we find that integrating the dynamics of HAMs and methanogens into a biogeochemistry model8,9,10 that includes permafrost soil organic carbon dynamics3 leads to the upland methane sink doubling (~5.5 Tg CH4 yr−1) north of 50 °N in simulations from 2000–2016. The increase is equivalent to at least half of the difference in net methane emissions estimated between process-based models and observation-based inversions11,12, and the revised estimates better match site-level and regional observations5,7,13,14,15. The new model projects doubled wetland methane emissions between 2017–2100 due to more accessible permafrost carbon16,17,18. However, most of the increase in wetland emissions is offset by a concordant increase in the upland sink, leading to only an 18% increase in net methane emission (from 29 to 35 Tg CH4 yr−1). The projected net methane emissions may decrease further due to different physiological responses between HAMs and methanogens in response to increasing temperature19,20.
« Last Edit: April 07, 2020, 11:07:43 PM by Lennart van der Linde »

AbruptSLR

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Re: Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE (narrated video)
« Reply #2980 on: April 07, 2020, 11:06:43 PM »
The linked article discusses how poorly planned mass planting of trees could do more harm than good:

Title: "Climate change: UK forests 'could do more harm than good'"

https://www.bbc.com/news/science-environment-52200045

Extract: "Mass tree planting in the UK could harm the environment if not planned properly, a report warns."
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AbruptSLR

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Please note that consensus climate scientists are not promising that decision makers will be given adequate warning before an abrupt change in climate might occur this century; as discussed in the linked article.

Title: "We climate scientists won’t know exactly how the crisis will unfold until it’s too late"

https://theconversation.com/we-climate-scientists-wont-know-exactly-how-the-crisis-will-unfold-until-its-too-late-133400

Extract: "When we hold on to things for too long, change can come about abruptly and even catastrophically. While this will ring true for many from personal experience, similar things can happen at large scales as well. Indeed, the history of Earth’s climate and ecosystems is punctuated by frequent large-scale disruptive events.

When the air warmed and the last ice age was coming to an end, the continent-size glaciers – or ice sheets – stayed around for much longer than the climate would allow. Then parts of them collapsed in spectacular fashion. One such collapse – we still don’t know of which ice sheet – caused at least four metres of sea level rise per century and possibly also the following abrupt transition to a much warmer climate, only to be followed by an equally abrupt flip-flop between warm and cold conditions, before the onset of the stable climate we have enjoyed until recently."
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Ken Feldman

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The linked paper from Science Magazine indicates that the subset of CMIP6 models with high climate sensitivities are not able to reproduce the temperature trends over the past few decades.  They tend to show higher temperatures over the recent warming period and thus are likely biased "hot" for future warming.  In contrast, models with lower climate sensitivities tend to reproduce the recent warming accurately.

https://advances.sciencemag.org/content/advances/6/12/eaaz9549.full.pdf

Quote
Past warming trend constrains future warming  inCMIP6 models
Katarzyna B. Tokarska, Martin B. Stolpe, Sebastian Sippel, Erich M. Fischer,  Christopher J. Smith, Flavio Lehner, Reto Knutti

Future  global  warming  estimates  have  been  similar  across  past  assessments,  but  several  climate  models  of  the  latest Sixth Coupled Model Intercomparison Project (CMIP6) simulate much stronger warming, apparently inconsistent with past assessments. Here, we show that projected future warming is correlated with the simulated warming trend during recent decades across CMIP5 and CMIP6 models, enabling us to constrain future warming based on consistency with the observed warming. These findings carry important policy-relevant implications: The observationally constrained CMIP6 median warming in high emissions and ambitious mitigation scenarios is over 16 and 14% lower by 2050 compared to the raw CMIP6 median, respectively, and over 14 and 8% lower by 2090, relative to 1995–2014. Observationally constrained CMIP6 warming is consistent with previous assessments based on CMIP5 models, and in an ambitious mitigation scenario, the likely range is consistent with reaching the Paris Agreement target.

Quote
DISCUSSIONOur results show that most models with high climate sensitivity (outside the AR5 likely range) or high transient response over-estimate recent warming trends, with differences that cannot be explained  by  internal  variability.  This  probably  leads  to  future  warming projections being biased high. Thus, the raw ensemble median and spread of future warming in CMIP6 (and therefore most other variables that scale to first order with global mean tem-perature) are not representative of a distribution constrained by observed trends, even if some of those models show a more realistic representation of processes in individual components than their CMIP5 predecessors (20–22). Conversely, CMIP6 models with climate sensitivity values that are within the IPCC AR5 likely range show warming trends much more consistent with the observations.

Quote
Despite the expectation that the constraint should be weaker in emission scenarios where non-CO2 forcings such as aerosol reduction have a substantial contribution to the future temperature evolution, the SSP1-2.6 warming is also highly correlated with warming during the past decades. Constrained warming in SSP1-2.6, with respect to the 1850–1900 baseline consistent with the Paris Agreement (35), by mid-century (years 2041–2060) is estimated at 1.36° to 1.86°C (likely range), and by the end of the century (years 2081–2100) is estimated at 1.33° to 1.99°C (likely range). Our results thus suggest that this ambitious mitigation scenario is consistent with meeting the Paris Agreement target based on the observationally constrained CMIP6 models, while the Paris Agreement target would be exceeded by several high ECS models.