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Comments 6401 to 6450:
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scaddenp at 13:57 PM on 30 October 2020A Skeptical Science member's path to an experiment on carbon sequestration
So now we can look forward to a published paper some day on the subject. Well done Scott. I hope the experiment proceeds smoothly.
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dana1981 at 13:06 PM on 30 October 2020Warmer climate and Arctic sea ice in a veritable suicide pact
Thanks Doug!
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Doug Bostrom at 08:41 AM on 30 October 2020Warmer climate and Arctic sea ice in a veritable suicide pact
What a good explanatory synthesis of a major heap of research looks like. Thanks!
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michael sweet at 18:13 PM on 29 October 2020Climate's changed before
This picture shows sunny day tidal flooding in St. Augustine, Florida this past September.
The Guardian article says that nusance flooding affects 60% of historical locations (the economy is based on historical tourism) and with 1.5 feet (about 45 cm) of additional rise all historical locations will be affected.
How can people live with regular flooding? You would never build a structure in a location that floods once a month. People everywhere refuse to accept the fact that these locations no longer are viable locations to live. Eventually they will have to retreat. Millions of people in Florida live within 1 meter of sea level.
In addition to tidal flooding, the increase in the water table underground makes it much harder to get rain to drain away and causes more flooding when it rains.
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michael sweet at 09:22 AM on 29 October 2020Climate's changed before
Daniel Bailey and MARodger:
I have not kept up on sea level rise as much as you have the past few years. Your data and posts help me a lot with most recent thinking. I note that every IPCC report they raise their estimates of future rise as more is known.
I remember about 10 years ago I wondered if I would live long enough to see damage from sea level rise (I am currently 62 years old). I now see damage from sunny day flooding recorded in many locations around the globe, including serious damage in my home state of Florida and city of Tampa. I now expect to see many homes in Florida abandoned from sea level rise.
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Daniel Bailey at 07:47 AM on 29 October 2020Climate's changed before
"Then the question is how long will it take for all that ice to melt"
Sea level rise from ice sheets continue to track worst-case (High scenario) climate change scenarios (discussion here, source paper here).
Which, charitably, means 2.0 meters SLR by 2100, given that the Greenland Ice Sheet has tipped into a negative mass balance state, Earth having lost 28 trillion tons of ice in the past 23 years and that Greenland is expected to exceed Holocene loss rates by 2100.
Typically, when climate scientists try to understand some of the expected future effects of global warming and climate change, they first look to the past. And in looking to the past, we can use the example of the climate transition from the icy depths of the Last Glacial Maximum into our current Holocene Interglacial to guide us. From about 21,000 years Before Present (BP) to about 11,700 years BP, the Earth warmed about 4 degrees C and the oceans rose (with a slight lag after the onset of the warming) about 85 meters.
However, the sea level response continued to rise another 45 meters, to a total of 130 meters (from its initial level before warming began), reaching its modern level about 3,000 BP.
This means that, even after temperatures reached their maximum and leveled off, the ice sheets continued to melt for another 8,000 years until they reached an equilibrium with temperatures.
Stated another way, the ice sheet response to warming continued for 8,000 years after warming had already leveled off, with the meltwater contribution to global sea levels totaling 45 additional meters of SLR.
Which brings us to our modern era of today: over the past 100 years, global temperatures have risen about 1 degree C…with sea level response to that warming totaling about 150 mm. Recently, accelerations in SLR and in ice sheet mass losses have been detected, which is what you’d expect to happen when the globe warms, based on our understanding of the previous history of the Earth and our understanding of the physics of climate.
Support for above:https://www.nasa.gov/feature/goddard/2019/study-predicts-more-long-term-sea-level-rise-from-greenland-ice/
https://advances.sciencemag.org/content/5/6/eaav9396https://climate.nasa.gov/news/2458/why-a-half-degree-temperature-rise-is-a-big-deal/
https://www.nature.com/articles/nclimate2923
https://www.nature.com/articles/ncomms9059
http://www.pnas.org/content/111/43/15296.short
https://www.carbonbrief.org/sea-level-research-says-only-a-brief-window-to-cut-emissionshttps://climate.nasa.gov/news/2869/antarcticas-effect-on-sea-level-rise-in-coming-centuries/
https://www.pnas.org/content/110/4/1209
https://science.sciencemag.org/content/364/6444/eaav7908
https://advances.sciencemag.org/content/5/1/eaau3433
https://www.pnas.org/content/116/30/14887 -
MA Rodger at 07:28 AM on 29 October 2020Climate's changed before
michael sweet @867,
The quote you cite from #866 is perhaps a little out of context for your purpose as within Miller et al (2015) it is embedded within a discussion of the relationship between sea level, temperature & CO2. With reference to features in its Fig 1, this passage runs:-
"Relationships among proxy records of CO2, climate, and sea level are not always clear. For example, large changes in Miocene [23Ma to 5Ma] cryospheric evolution and deep-water temperature occurred with only what appear to be modest changes in CO2. The Miocene Climatic Optimum [17Ma] is an interesting case in point where B isotopes indicate variations from 300 to 500 ppm [of CO2] during this interval of ~4°C warmer global temperatures above present. Our records that suggest nearly ice-free conditions occurred during the MCO ... are thus intriguing if this is an equilibrium state for warming levels that will be attained in this century or the next century under sustained greenhouse gas emissions. Similarly, the long-known mismatch between Eocene [56Ma to 34Ma] to Oligocene [34Ma to 23Ma] CO2 proxies (with the main CO2 drop in the later Oligocene) and the earliest Oligocene glaciation has been perplexing, although we show that decreases in CO2 during the Middle to Late Eocene are associated with bottom water cooling and ice growth. In all cases, we note that errors on pre-ice core CO2 values are large (hundreds of ppm) and could mask closer relationships. We look forward to more refined estimates of Eocene to Miocene CO2 to test these relationships in detail." [Geological dates added]
The MCO marks the point when global temperatures tipped down towards the Pleistocene era of glaciation/interglacial cycles. Through this time, the layout of the globe has changed enough I think to put into some doubt any direct comparison with the MCO and a +4°C world of today.
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michael sweet at 05:24 AM on 29 October 2020Climate's changed before
Daniel baily:
From your second link:
"Our records that suggest nearly ice-free conditions occurred during the MCO and are thus intriguing if this is an equilibrium state for warming levels that will be attained in this century or the next century under sustained greenhouse gas emissions."
Ice free conditions means sea level 60-65 meters higher than current!! Then the question is how long will it take for all that ice to melt. At a foot a decade it would not be too long before many cities were in troube. I live in Florida (at over 40 feet elevation) and parts of South Florida are already hurting from only 1 foot of sea level rise.
RrealClimate has several good discussions of potential sea level rise. 2013 article 2016 article In general, the IPCC estimates are at the low end of what expert opinion is. This is because of the method the IPCC uses to come to a consensus. The IPCC states what a consensus of experts feel is the lowest range of sea level rise. The average of experts is then higher than the IPCC reports. There is a lot of discussion on melting rates. It seems to me that knowledge of probable melting rates is still being developed.
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Daniel Bailey at 00:29 AM on 29 October 2020Climate's changed before
Since we are discussing sea level rise, recent sea level rise is unprecedented over the past 2,500 years (Kopp et al 2016):
Anthropogenic forcing dominates global mean sea-level rise since 1970 (Slangen et al 2016):
"the anthropogenic forcing (primarily a balance between a positive sea-level contribution from GHGs and a partially offsetting component from anthropogenic aerosols) explains only 15 ± 55% of the observations before 1950, but increases to become the dominant contribution to sea-level rise after 1970 (69 ± 31%), reaching 72 ± 39% in 2000 (37 ± 38% over the period 1900–2005)"
Causes of sea level rise since 1900, from NASA and Frederikse et al 2020:
Takeaways:
1. Glacier-dominated cryospheric mass loss has caused twice as much sea-level rise as thermal expansion since 1900
2. The acceleration since the 1970s is caused by the combination of thermal expansion and increased Greenland mass loss
3. Ocean mass increases from land-based ice losses dominated the early 20th and 21st Century sea level rise record; ocean heating was the dominant component from 1970-2000
4. The closure of the 20th-century sea-level budget derived here implies that no additional unknown processes, such as large-scale deep ocean thermal expansion or additional mass loss from the Antarctic Ice Sheet are required to explain the observed changes of global sea level
Additionally, new research (Miller et al 2020) affirms modern sea level rise is linked to human activities, and not to changes in Earth’s orbit:
"Surprisingly, the Earth had nearly ice-free conditions with carbon dioxide levels not much higher than today and had glacial periods in times previously believed to be ice-free over the last 66 million years, according to a paper published in the journal Science Advances.
“Our team showed that the Earth’s history of glaciation was more complex than previously thought,” said lead author Kenneth G. Miller, a Distinguished Professor in the Department of Earth and Planetary Sciences in the School of Arts and Sciences at Rutgers University-New Brunswick. “Although carbon dioxide levels had an important influence on ice-free periods, minor variations in the Earth’s orbit were the dominant factor in terms of ice volume and sea-level changes — until modern times.”
Sea-level rise, which has accelerated in recent decades, threatens to permanently inundate densely populated coastal cities and communities, other low-lying lands and costly infrastructure by 2100. It also poses a grave threat to many ecosystems and economies.
The paper reconstructed the history of sea levels and glaciation since the age of the dinosaurs ended. Scientists compared estimates of the global average sea level, based on deep-sea geochemistry data, with continental margin records. Continental margins, which include the relatively shallow ocean waters over a continental shelf, can extend hundreds of miles from the coast.
The study showed that periods of nearly ice-free conditions, such as 17 million to 13 million years ago, occurred when the concentration of atmospheric carbon dioxide — a key greenhouse gas driving climate change — was not much higher than today. However, glacial periods occurred when the Earth was previously thought to be ice-free, such as from 48 million to 34 million years ago.
“We demonstrate that although atmospheric carbon dioxide had an important influence on ice-free periods on Earth, ice volume and sea-level changes prior to human influences were linked primarily to minor variations in the Earth’s orbit and distance from the sun,” Miller said.
The largest sea-level decline took place during the last glacial period about 20,000 years ago, when the water level dropped by about 400 feet. That was followed by a foot per decade rise in sea level — a rapid pace that slowed from 10,000 to 2,000 years ago. Sea-level rise was then at a standstill until around 1900, when rates began rising as human activities began influencing the climate.
Future work reconstructing the history of sea-level changes before 48 million years ago is needed to determine the times when the Earth was entirely ice-free, the role of atmospheric carbon dioxide in glaciation and the cause of the natural fall in atmospheric carbon dioxide before humans."
From the source paper, Miller et al 2020:
"High long-term CO2 caused warm climates and high sea levels, with sea-level variability dominated by periodic Milankovitch cycles.
Sea level rose in the Early Pliocene ca. 4.7 Ma, reaching highs that had not been consistently seen since the MCO. From a sea-level perspective, the Pliocene is marked by three intervals with sea level well (~10 to 20 m) above modern: 4.6 to 4.1, 3.9 to 3.3, and 3.3 to 2.85 Ma.
GMSL higher than 12 m above modern requires loss of ice sheets in Greenland, West Antarctica, and sensitive areas of East Antarctica, the Wilkes, and Aurora Basins. This interval is of keen interest, because global temperatures were >2°C warmer than today at times when atmospheric CO2 concentrations were on the order of those in 2020 CE (~400 ppm), and thus, the equilibrium sea-level state is relevant to ice sheet trajectories in coming centuries. The peaks between 3.9 and 3.3 Ma were even higher, reaching a peak of ~30 m during Gi13, and thus requiring some melting of the EAIS.
The development of a permanent EAIS by 12.8 Ma resulted in a change from responding to precession, tilt, and eccentricity to subdued to absent response to eccentricity and precessional forcing that had previously been strong; the 41-ka tilt cycle dominated ice sheet and sea-level response from ca. 12.8 to 1.0 Ma following the development of a permanent EAIS. During the mid-Pleistocene transition, very large, 100-ka paced LIS were amplified by 100-ka changes in CO2 from ~180 (glacial) to 280 ppm (terminations).
During the last deglaciation (ca. 19 to 10 ka), GMSL rise exceeded 40 to 45 mm/year, providing an upper limit on known rates of GMSL rise. Rates before radiocarbon ages are less certain, although the sea-level rises exceeded 10 mm/year during terminations. Sea-level rise progressively slowed during the Holocene until the late 19th to early 20th century when rates began to rise from near 0 to 1.2 mm/year in the early 20th century to a late 20th and 21st century rise of 3.1 ± 0.4 mm/year.
Sea level follows long-term trends of atmospheric CO2, with high sea levels associated with high CO2 and warm climates. CO2 played an important role with high CO2 maintaining warmth in the Eocene (with values >800 to 1000 ppm; associated with largely ice-free conditions and high sea levels. Generally, decreasing CO2 values during Middle Eocene to Oligocene led to cooling and glaciation, although a secondary CO2 increase at ca. 35 to 36 Ma may be associated with the late Late Eocene warming. The cause of the CO2 decrease over the past 50 Ma has been widely discussed and debated but must be due to long-term (107-year) changes in CO2 sources (e.g., higher CO2 associated with inferred higher ocean crust production rates) or more likely the effectiveness of sinks CO2 (e.g., increased weathering associated with uplift of the Himalayas or exposure of basalts in tropical regions).
Our records that suggest nearly ice-free conditions occurred during the MCO and are thus intriguing if this is an equilibrium state for warming levels that will be attained in this century or the next century under sustained greenhouse gas emissions.
Our sea-level history constrains cryospheric evolution over the past 66 Ma, with ice-free conditions during most of the Early Eocene, MECO, latest Eocene, and possibly the MCO, with ice sheets (up to 40-m sea-level equivalent) in the Middle to Late Eocene greenhouse and with continental-scale Antarctic ice sheets beginning in the Oligocene.
From 34 to 13.8 Ma, the EAIS varied from larger than today (sea-level ~35 m below present) to nearly ice-free (~50 m above present) but became permanent during the MMCT ca. 12.8 Ma."
Miller 2020, Figure 4, rotated once:
And the past 40,000 years, from Miller 2020, Figure 4 above:
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Eclectic at 22:02 PM on 28 October 2020Climate's changed before
MA Rodger @864 , thanks for that info ~ you are a champion.
The study by Lambeck et al.(2010) was particularly interesting. I apologize for and withdraw my skepticism about the 0 - 2000.BP flatness of the sea level as shown on "your graph".
The lateness of the Holocene highstand seemed (to me) probably explicable by some lag effects of the H. Optimum's warmth. But if I understand it correctly, Lambeck favors a greater Southern Hemisphere effect lingering on and operating by melting some of the West Antarctica ice sheet up until fairly recent times (despite marginally greater NH cooling).
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Nick Palmer at 21:30 PM on 28 October 2020A Skeptical Science member's path to an experiment on carbon sequestration
Scott (Red Baron) made his target this morning, so can go ahead with the project.
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MA Rodger at 20:36 PM on 28 October 2020Climate's changed before
Eclectic @861,
"That graph" of Holocene SLR you reference (referenced also @860 & pasted in-thread @843) is a bold piece of work found within Wikipedia and is based on the following:-
- Fleming et al (1998) 'Refining the eustatic sea-level curve since the Last Glacial Maximumusing far- and intermediate-field sites',
- Fleming (2000) 'Glacial rebound and sea-level change : constraints on the Greenland ice sheet', a 300 page thesis with download PDF available from this webpage,
- Milne et al (2005) 'Modelling Holocene relative sea-level observations from the Caribbean and South America' [Abstract].
I say 'bold' as combining the messy Holocene SLR data into a simple grand global average is not entirely scientific although it does prove illustrative. The IPCC AR5 does present a graphic (within Fig 5.15) providing the same sort of image surrounded by a blizzard of other graphical SLR data. This IPCC Fig5.15f is essentially Fig 14 from Lambeck et al (2010) 'Palaeoenvironmental records, geophysical modelling and reconstruction of sea-leveltrends and variability on centennial and longer time scales'.
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scaddenp at 19:17 PM on 28 October 2020Climate's changed before
For more detail on "sea-level" budget (the various contributors and estimating their impact), try this paper from Church et al 2011. There may be more recent updates
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Eclectic at 16:41 PM on 28 October 2020Climate's changed before
Hal Kantrud @860 (continued)
The rise in sea level during the past 150 years or so is the result of oceanic "swelling" - roughly half from thermal expansion and half from increased mass (the contribution from melting of land ice). Land rebound is too small to make much difference over 150 years. Likewise the "oceanic siphoning" as the ocean floor slowly sags a bit, under the increased weight of total ocean.
In short, it's a matter of the observed global warming. If you are questioning the connection between the recent spike in Greenhouse Gasses [ GHG's ] and the recent spike in global warming . . . then you've come to the right place, here at SkS website. Loads of info available via the Home Page.
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Eclectic at 16:26 PM on 28 October 2020Climate's changed before
Hal Kantrud @860 , yes indeed what are we to make of all this !?!?
On that graph, my eye-crometer shows a MSL uptick of 1m from 3000 BP to 2000 BP, and then zero change 2000 BP to 0 BP (1950.AD).
I don't know the provenance of the graph - I gather it is displayed on Wikipedia, but I haven't looked to see where Wiki got it from.
How useful is that thick black line? You will note how the black line shows no rise in the final century, even though there has been a small measured rise 1850-1950.AD . . . so the line is "thick" . . . and the strange (i.e. unnatural) angulations over past millennia must be the result of some author "hand-drawing" an approximate fit. A fit to those many multicolored points scattered near the black line.
Look at the multicolored data points. Jamaica / Tahiti / Indonesia / Australia / New Guinea / Rio , and so on. A great scattering, and showing much vertical spread too. In other words, the black line is a rough approximation ~ and I advise not getting out your magnifying glass in order to fish for precise detail.
We know that there has been a huge ( over 100m ) MSL rise from the depths of the glacial 20,000 years ago until the Holocene Optimum [strange name!]. Search, and you will find different studies/graphs from different parts of the world - and depending on the local level of land uplift etcetera, you will find at least some indicating a small fall of sea level in the last few thousand years . . . a fall which you would expect as a result of the 0.7 degreesC cooling [0.7 is a rough figure too, but fairly well established].
Nevertheless, there are post-glacial local rebounds and ocean-floor depressions ["siphoning"] to be considered with every site measured. Basically, for practical purposes, I wouldn't be too fussed about it all. Simply stand back and look at the bigger picture.
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Hal Kantrud at 13:42 PM on 28 October 2020Climate's changed before
Eclectic I just drew a horizontal in my eye from 6000 YBP on Rodgers graph to 0 and it looked like about a 2m rise in sea level. I ignored the more recent plateau.
Is it accepted by most Earth scientists now that the recent spike in greenhouse gasses is the primary cause of the rise in sea levels, rather than land rebound or other factors?
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Eclectic at 08:09 AM on 28 October 2020CO2 effect is saturated
Aoeu - a small addition :-
Dr Happer's paper seems more than a tad confused about the meaning of "saturation" in regard to Greenhouse gasses & climate.
I am not sure that the WUWT editor actually managed to read the paper. Certainly many (most?) of the subsequent WUWT commenters didn't.
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Eclectic at 07:50 AM on 28 October 2020CO2 effect is saturated
Aoeu @587 , permit me to add my 2 cents as well.
The WUWT article is a "nothingburger" - and worse.
The WUWT editor has given a completely fallacious headline. (Typical for WUWT) The article is based on a paper - unpublished - by two scientists, one of whom is the eminent Dr Happer. It is claimed that Happer's paper has been knocked back by three major journals . . . and reading the paper soon shows why a scientific journal would not bother to publish this paper.
You will see from the above comments by MA Rodger and Tom Dayton, that the Happer paper comes out with a CO2-doubling Climate Sensitivity of 2.2 degreesC . . . a finding which is wildly misrepresented by the WUWT editor. This 2.2C sensitivity is slightly below the 3.0 figure which is a fairer "average" of sensitivity assessments (based on paleo and modern empirical evidence). So really nothing new there.
The paper has two weaknesses. It makes no allowance for cloud effects (the paper is a "clear sky" model). And as a minor point, it uses constant relative humidity in its modeling. Apart from that, I have no particular criticism to make . . . other than the humorous one where a typographical error shows "temperature region" where "temperate region" was meant ;-)
Clearly the Happer paper is not worth publishing.
Sadly, the blog WUWT is trumpeting this paper to the skies (excuse pun). WattsUpWithThat and its denialist clientele are always desperate to make much of anything at all which comes even within a million miles of casting some doubt on mainstream climate science.
Aoeu, have a look at the WUWT comments column below the article. There are all sorts of frothing-at-the-mouth comments . . . that this new paper overthrows all previous climate science / disproves the Greenhouse effect / exposes the incompetence & corrupt criminality of all the thousands of climate scientists worldwide. Etcetera. All the usual WattsUpWithThat nonsense and crackpot lunacy. But among all the madness, you will find a few pearls of wisdom by the genuine scientist Nick Stokes (who is thoroughly hated by the usual WUWT clientele).
We can expect the Happer paper will be a Nine Day Wonder in many parts of the bloggy Deniosphere . . . until they abandon it for the Next New Thing (by Lord Christopher Monckton or whoever). It is all very entertaining . . . but it ain't science.
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factotum at 06:12 AM on 28 October 2020The Debunking Handbook 2020: Debunk often and properly
Comments policy link DID NOT WORK!! I had to copy and paste.
Look up truth in, say wikipedia, and you will find little more than a large circle of words.
I would suggest that you use some form of
1. A statement about X must be able to be falsified, preferably by some form of observation or measurement. If it can not be falsified then it can be provisionally considered to be true. Like Newtons theory of gravity.
2. The statement must be measurable or refer to historical records of observations and measurements, or must make predictions accompanied by some reasonable time in which said prediction will be confirmed by observation
For example a statement about drought can be supported by records of published food prices.
Much better than this circular stuff from wikipedia: Thus, 'truth' involves both the quality of "faithfulness, fidelity, loyalty, sincerity, veracity",[7] and that of "agreement with fact or reality",
One has false statements, true statements, statements that are neither, and very often in discussions, statement that "are not even wrong!
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nigelj at 05:53 AM on 28 October 20202020 SkS Weekly Climate Change & Global Warming News Roundup #43
Odium @5
"I prefer a Trump reelection, the sooner we get close to a "point of no return" scenario the better, at least then, we could have a real informed discussion on a global scale."
If the climate is past the point of no return, what is it you think we should be discussing globally? Do we have a global last rites for the planet? Do we have a large mutual commiseration session? Do we say "oh well its all over we just have to go away and spend a fortune on adaptation"?
I meant there really would be nothing to discuss. Our goose would be cooked.
Given Trumps proven antipathy to international organisations, he won't want much of a global discussion and given his record its unlikely he will want to do much to help anyone. So electing him wont help. So have you actually thought about anything you just wrote before putting pen to paper? :)
But of course there is indeed no point of no return. Its never too late to make a difference.
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Philippe Chantreau at 04:06 AM on 28 October 2020How much has nuclear testing contributed to global warming?
Boston745 @ 37 above, the known cycles of the Earth orbit are in the order of 100,000 yrs (eccentricity), 26,000 yrs (axial precession), 112,000 years (apsidal precession) and 41,000 yrs (obliquity). Can you reference your 400,000 years cycle?
There is also ample evidence that the variations due to distance to the Sun are in fact minor factors in climate. All this can easily be found on NASA's web site.
Moderator Response:[DB] Unfortunately, user boston745 has recused themselves from further participation here.
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Tom Dayton at 03:20 AM on 28 October 2020CO2 effect is saturated
MA Rodger is correct, of course. Nick Stokes commented in WTFIUWTW: "They basically redid Manabe’s calc from 1967 and got a very similar answer. It has been known for that time that if you do a 1-D calc with just radiative, including simple hypotheses about the response of water vapor, you get CS in that range. But there is a lot more going on."
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MA Rodger at 03:16 AM on 28 October 2020CO2 effect is saturated
aoeu @587,
The paper you link-to is apparently co-authored by the physicist and climate change denier William Happer so if it did conclude with the message presented on the article you link-to on the rogue planetoid Wattsupia, there would be no real surprise. Happer has been the author of quite a bit of arrant ninsense on te subject of climatology.The Wattsupian take on the paper runs:-
"In plain language this means that from now on our emissions from burning fossil fuels could have little or no further impact on global warming. There would be no climate emergency. No threat at all. We could emit as much CO2 as we like; with no effect."
However, this account of the paper is total nonsense (so par for the course for Wattsupia). The paper actually concludes by saying it finds 2xCO2 without feedbacks would increase global temperature by +1.4ºC and with feedback (constant relative humidity) under clear-sky conditions by +2.2ºC, this finding close to other studies.
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One Planet Only Forever at 01:46 AM on 28 October 2020Arctic Sea Ice Minimum Volumes Video - 2020 edition
Presenting the reduction of Mimimum Volume since 1979 is a great way to show how dramatic the decline is. Presenting the Minimum volume captures the issue of reduction of multi-year ice.
But the amazing graphic image presentation of the minimum volume misses one very disturbing thing that the graph on the PIOMAS website shows. The Maximum volumes since the winter of 2008-09 have clearly been lower than any of the Minimum volumes before summer 2007.
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aoeu at 00:46 AM on 28 October 2020CO2 effect is saturated
To whom may be interested,
I've recently come across this physics study after running into it from this article.
The study's demonstrating the saturation argument with respect to thermal radiative flux from the earth to outer space when compared to varying CO2 and water vapor concentration, effectively countering the Greenhouse Effect argument being proposed in this page.
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One Planet Only Forever at 00:32 AM on 28 October 20202020 SkS Weekly Climate Change & Global Warming News Roundup #43
Odium,
The first, and most important point, regarding climate change impacts is that there is no 'point of no return'. There have already been significant harmful consequences for some regions of the planet. And the harm done will only continue to increase until the creation of the harm done is stopped. And for humanity to have a lasting and improving future 'human activities that cause harmful consequences for Others' must be ended. The Creed that "Harm Done is justified by Benefits Obtained" is wrong because it is "Us benefiting from Harm Done to Others". Until human activity stops making things worse the harm done will continue to increase.
The real informed discussion on a global scale started before the 1972 Stockholm Conference.
The understanding regarding the potential for many human activities to be harmful and ultimately unsustainable was being developed in the decades leading up to that 1972 conference. The first global attempt to do something was the League of Nations after WW1 which failed to stop WW2 from happening. The UN was then set up and its first formally estanblished Global Understanding is the Universal Declaration of Human Rights in 1948.
Trump represents the part of the USA that fights against the concept of Human Rights, fights against "No Harm Done", Fights for "Justifying Harm Done to Others". Fights to claim "They are the Victims - Others are the problem". Which is what MAGA is all about, reversing any and all Human Rights base advancements that have happened in the USA.
Though the USA is one of the least 'Human Rights advanced' nations among the supposedly advanced nations, its history is of a significant portion of the population liking the USA to be even less advanced. In the 1700's, after beating France to establish control of the eastern part of the USA, the King of England decreed that the settler colonies would be limited to the coast region east of the Allegheny Mountains. The Native population that had helped defeat the French but was displaced by the settlers would have the territory west of the Mountains as their Nation.
That thoughtful human rights based decision by the King of England in the 1700s was the trigger for the American Revolution against England. And the massacre of the Native population of the USA followed. The attitudes about slavery, also abolished in England, were a parallel case of the USA Manifest Destiny to maximize their Anglo Saxon Superiority.
The effort to increase the understanding of the many ways human activity was developing to be harmful and unsustainable has been happening for centuries, with people like Trump fighting against the understandings.
I hope you appreciate, that with that understanding, I am being extremely civil in responding to someone who has declared a powerful liking for Trump that includes the "We are the Victim - Others are the problem" pathetic argument (Oops, I couldn't keep it totally civil to the end - apologies for using the term pathetic - but it applies).
And that is the root of the problem with believing there can ever be a 'reasonable debate amng all people'. The Harmfully Selfish will always be a part of humanity. They will always need to be externally governed by more thoughtful responsible people 'like the King of England in the 1700s'. Negotiating with harmfully selfish people leads to compromises that do not end the harm being done.
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Odium at 20:41 PM on 27 October 20202020 SkS Weekly Climate Change & Global Warming News Roundup #43
I prefer a Trump reelection, the sooner we get close to a "point of no return" scenario the better, at least then, we could have a real informed discussion on a global scale.
Also it's not that i don't appreciate the bashing, but China emitted 2020 close to double the CO2 (10.06GT vs 5.41GT) not that one should take those number all to seriously as there is no sure way to independently verify whether national governments are telling the truth about their own emissions. And i honestly don't think that the worlds factory will stop pumping CO2 into Atmos, just becouse Trump didn't get re-elected. On the other hand, I'm pretty confident that a Biden Presidency would just motivate them to increase it even more.
Moderator Response:[DB] The latest full-year data are through 2018, with 2019 data still provisional. By definition, 2020 is incomplete. The US is by far the leader in both cumulative and per-capita emissions and thus by far the single biggest portion of the overall problem. Discussions on politics must also be tangential to climate change.
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Eclectic at 19:41 PM on 27 October 2020How much has nuclear testing contributed to global warming?
Boston745 , your "observations and associations" are just personal anecdotes. Not scientific evidence. They seem to be your "feelings". Contrarians have all sorts of "feelings" ~ often mutually contradictory. That's one of the reasons why they can't get their act together.
Yes, those "qualified scientists" (who are very, very, very few) do deserve to be completely dismissed, since they completely fail to provide any valid evidence to overthrow the mainstream climate science. They talk hot air ~ empty rhetoric.
Instances : Drs Lindzen, Spencer, Curry - failed ideas or vague blather based on religious beliefs. No actual backing from scientific observations. And even they don't bother to advocate "magnetospheres and cosmic rays".
Boston745 , have you other "qualified scientists" who are contrarian enough to disagree with the mainstream science - and what is their substantive evidence that they are right and the mainstream is wrong? And why haven't they published it? Major scientific journals would be enthusiastic & delighted to publish some really cutting-edge ground-breaking stuff ! But the contrarians can't come up with anything valid.
Genuine science exists in the collective summary of peer-reviewed scientific papers in reputable journals - it does not reside in fruitcake blogs such as WattsUpWithThat. (If you wonder why I use the label fruitcake, then just go and read through WUWT. )
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boston745 at 18:02 PM on 27 October 2020How much has nuclear testing contributed to global warming?
You failed to address a single observation Ive made. You completely dismiss qualified scientists who disagree with the mainstream. And you put your faith in climate models that do not factor in things like clouds nor weakening magnetosphere. I'm sorry but it doesn't seem like you're after honest dialog.
Atmospheric scientists have learned a great deal in the past many decades about how clouds form and move in Earth's atmospheric circulation. Investigators now realize that traditional computer models of global climate have taken a rather simple view of clouds and their effects, partly because detailed global descriptions of clouds have been lacking, and partly because in the past the focus has been on short-term regional weather prediction rather than on long-term global climate prediction. To address today's concerns, we need to accumulate and analyze more and better data to improve our understanding of cloud processes and to increase the accuracy of our weather and climate models.
Moderator Response:[DB] Sloganeering and moderation complaints snipped. Merely repeating a refuted assertion without citing credible sources to support your claims is sloganeering. Models do indeed factor in cloud effects. By definition, surface weather and climate are a product of phenomena and physical processes occurring primarily in the troposphere, with some effects occurring above the tropopause in the stratosphere. A weakening magnetosphere or changes in magnetic field strength or polarity have no effects on surface climate because, essentially, air is not ferrous. As for moderation complaints:
"Moderation complaints are always off topic and will be deleted"
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Eclectic at 17:30 PM on 27 October 2020How much has nuclear testing contributed to global warming?
Boston745 , you really should educate yourself by reading the large amount of scientific information available here on the SkS [SkepticalScience] website ~ included are links to peer-reviewed papers in respected scientific journals, and summaries given by NASA, NOAA, the American NAS, the UK Royal Society . . . in short, by all the peak scientific bodies internationally. No exceptions. Yes there are a few qualified scientists who disagree with the mainstream science ~ but those few "contrarian" scientists have only their opinions (They don't have any facts to back their opinions. They are just hot air.)
I reckon you're pulling my leg regarding: "I know it's not CO2 though".
Barking up the wrong tree . . . could be worse! Like: just barking . . . and no tree in sight.
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michael sweet at 17:22 PM on 27 October 2020Climate's changed before
Scaddenp:
Thanks for the reference. Exactly what I wanted to know. As expected, scientists have figured out a complex evolution of mountains in the ocean.
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Eclectic at 17:06 PM on 27 October 2020Climate's changed before
Hal Kantrud @857 , the wording of your second sentence is awkward, since it seems to suggest a steady rise in ocean levels during our most recent millennia. Surely that was not what you meant to say. As expected, the very modern temperature spike has led to a sea level rise.
Yet the 4-5000 previous years have been cooling ( roughly 0.7 degreesC) and, as you would expect from basic physics : more cooling overall means more land ice mass and therefore less ocean mass. Does less ocean mass necessarily mean lower sea level globally? MA Rodger's post #843 shows an almost flatline sea level for the last 2000 years . . . but as you have seen discussed, there are many factors & difficulties of measurement ~ so the illustrated "flatline" should be viewed as a rough approximation (and we get into comparing different criteria and even definitions of exactly what is meant by "global Mean Sea Level" and Relative Sea Level). However, that's all "past history" ~ and the problem we now have to tackle is the current & future sea level rise and associated CO2 problems.
Bob Loblaw @856 , thank you for that almost psychedelic picture of the world. I see that it is a model output, so I shouldn't look for granular detail along the coasts!
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Eclectic at 15:27 PM on 27 October 2020How much has nuclear testing contributed to global warming?
Boston745 :
With or without nuclear explosions, the Earth's magnetic field has negligible effect on climate. Magnetic "reversals" are also of trivial importance. The magnetosphere is very useful in protecting the planetary atmosphere from (geologically) rapid ablation . . . and useful for (partly) protecting your DNA from cosmic ray damage. Another plus, is producing the beautiful auroral lights displays . . . and helping ham-radio operators etc with their long-wave communications. But that's about it. You are barking up the wrong tree.
Likewise, with the idea of cosmic rays somehow altering climate. There's lots of empirical evidence (plus experimental evidence) that the cosmic ray effect on climate is approximately zero [see the appropriate thread ~ linked at #37 above]. Forget about the cosmic-ray / climate connection. It ain't there. You are completely wasting your time on these things.
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boston745 at 15:22 PM on 27 October 2020How much has nuclear testing contributed to global warming?
In this animation, the blue lines indicate a weaker magnetic field, the red lines a stronger one, and the green line the boundary between them, at 10-year intervals from 1910 to 2020. The field is weakening over South America, and the red area over North America is losing strength
The Magnetic Field Is Shifting. The Poles May Flip. This Could Get Bad.
Moderator Response:[DB] Please limit image widths to 450.
Earth’s magnetic field is powered by fluid movements in the Earth’s liquid iron outer core, a convective flow called a geodynamo and is powered by gravity and the rotation of the Earth itself. The solid iron inner core inhibits polarity reversals, with the result that such reversals seldom happen, even on geologic timescales.
https://www.nasa.gov/vision/earth/lookingatearth/29dec_magneticfield.html
https://neptune.gsfc.nasa.gov/gngphys/index.php?section=411
https://istp.gsfc.nasa.gov/earthmag/dynamos2.htm
https://www.nasa.gov/mission_pages/msl/multimedia/hassler02.html
https://websites.pmc.ucsc.edu/~glatz/geodynamo.html
http://news.mit.edu/2010/explained-dynamo-0325
While the Earth's magnetic field is weakening a bit and its magnetic axis is shifting somewhat, magnetic field polarity changes have no effects on climate on the timescale of human lifetimes because air isn’t ferrous. The effects on hand-held compasses are insignificant. For purposes of electronic navigation, changes in the position of the magnetic poles are constantly updated in navigational databases.
https://www.ncei.noaa.gov/news/tracking-changes-earth-magnetic-poles
https://www.ncei.noaa.gov/news/world-magnetic-model-out-cycle-release
https://www.ngdc.noaa.gov/geomag/GeomagneticPoles.shtml
https://www.ngdc.noaa.gov/geomag/faqgeom.shtml
"The last time that Earth's poles flipped in a major reversal was about 780,000 years ago, in what scientists call the Brunhes-Matuyama reversal. The fossil record shows no drastic changes in plant or animal life. Deep ocean sediment cores from this period also indicate no changes in glacial activity, based on the amount of oxygen isotopes in the cores. This is also proof that a polarity reversal would not affect the rotation axis of Earth, as the planet's rotation axis tilt has a significant effect on climate and glaciation and any change would be evident in the glacial record."
And
"The science shows that magnetic pole reversal is – in terms of geologic time scales – a common occurrence that happens gradually over millennia. While the conditions that cause polarity reversals are not entirely predictable – the north pole's movement could subtly change direction, for instance – there is nothing in the millions of years of geologic record to suggest that any of the 2012 doomsday scenarios connected to a pole reversal should be taken seriously."
https://www.nasa.gov/topics/earth/features/2012-poleReversal.html
https://science.nasa.gov/science-news/news-articles/earths-magnetosphere
"Reversals take a few thousand years to complete, and during that time--contrary to popular belief--the magnetic field does not vanish. "It just gets more complicated," says Glatzmaier. Magnetic lines of force near Earth's surface become twisted and tangled, and magnetic poles pop up in unaccustomed places. A south magnetic pole might emerge over Africa, for instance, or a north pole over Tahiti. Weird. But it's still a planetary magnetic field, and it still protects us from space radiation and solar storms."
https://www.nasa.gov/vision/earth/lookingatearth/29dec_magneticfield.html
Answers to many other related questions on that subject can be found here:
https://www.ngdc.noaa.gov/geomag/faqgeom.shtml
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boston745 at 12:49 PM on 27 October 2020How much has nuclear testing contributed to global warming?
I understand that cosmic rays aren't germain to the articlr directly. However a weakened magnetic field allows more CR energy in. Its possible that the nuclear testing accelerated that weakening.
The problem with compartmentalization by article topic is that no 1 thing is causing global warming. Multiple factors are at play. Thus its difficult to discuss.
The earths orbit around the sun has brought the earth as close to the sun as it gets in a 400,000 year cycle. Thus the earth is receiving about maximum solar radiation. With a weaker field, more solar radiation gets through and thus more absorption.
Cloud cover is also a factor, which is impacted by moisture in the air, aerosols, & CRs. Clouds can reflect energy or keep radiation in like a thermal blanket.
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Hal Kantrud at 12:05 PM on 27 October 2020Climate's changed before
Eclectic thanks for pointing that out. I just noted what looked like quite a marked temperature drop during the last 6000 years pre-spike was accompanied by at least a fairly steady rise in ocean levels. So the sea level data is questionable.
Since the Antarctic ice has stayed relatively stable, it looks like the temperature drop and recent rise has has so far involved only the smaller (less than continent-size) ice sheets. This would be expected if the smaller sheets were thinner, partly above the sea, and assisted by human agriculture, deforestation, and industrialization, as these occurred almost exclucively in the N. Hemisphere because of greenhouse gas emissions. Is an estimate of the proportion of these gasses attributed to the three human activities available? I know even a rough estimate would be extremely complicated because plants use CO2 and N, as well as sequester them, plus we might know little about the extent of hydrocarbon extraction during the last 200 years, forest utilization, etc., but I bet it could be done.
I have read that the entire subarctic zone continues to lift upwards after the glacial ice maximum and subsequent melt. Are there studies showing the contrubution of each to ocean depths?
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Bob Loblaw at 11:40 AM on 27 October 2020Climate's changed before
It looks like MA Rodgers image in comment 850 does work if you drop the as=webp part of the URL:
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boston745 at 11:04 AM on 27 October 2020How much has nuclear testing contributed to global warming?
BTW a decreasing magnetic field means increased cosmic radiation. Cosmic radiation can increase cloud cover, increase hurricane strength, and even lead to massive polar air moving to lower latitudes .
https://www.sciencedaily.com/releases/2017/12/171219091320.htm
https://ui.adsabs.harvard.edu/abs/2014AdSpR..54.2467V/abstract
Moderator Response:[BL] If you want to argue cosmic rays, it is on-topic on this thread:
https://skepticalscience.com/cosmic-rays-and-global-warming.htm
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boston745 at 10:44 AM on 27 October 2020How much has nuclear testing contributed to global warming?
Why would you remove my post about what chemtrails really are? A combination of airplane aerosol emissions with cosmic rays. A natural phenomenon caused when increase cosmic radiation is incoming from outside our solar system or our sun.
Moderator Response:[BL] Moderation complaints are a pretty fast way to get things deleted.
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boston745 at 06:27 AM on 27 October 2020How much has nuclear testing contributed to global warming?
Did nuclear testing cause current warming trends? Stop looking at the energy released and look at the impact of the energy.
https://www.nasa.gov/feature/goddard/2017/space-weather-events-linked-to-human-activity
Simply put, HANT impacted the magnetosphere in ways they are still trying to understand and was classified until recently. There's a reason this has been classified for the last 50 years.
The magnetosphere is weakening folks and maybe accelerating. Thats established science. That means greater amounts of radiation is able to penetrate into the atmosphere. What happens when you increase energy input of an object? It heats up. It also means more potential cloud cover. Clouds were thought to increase cooling, well thats true but clouds can also increase warming. Clouds can work as either a reflective blanket or thermal blanket depending on type. Consider for a minute the desert. It absorbs the most energy heating up. It also releases that energy into space which is why deserts experience biggest temperature swings. Add cloud cover, less energy gets in but also less energy escapes. Studies have shown that we are experiencing surface warming but cooling troposphere which correlates with an effect clouds can do. Hold energy in reflecting incoming energy back to space.
Moderator Response:[DB] Space weather is not surface weather. That NASA link does not support your claims.
From 1945-2009 there were 2,402 surface and underground nuclear weapon tests. Of those, 527 were conducted above-ground. Of those, some 458 were conducted in the first 20 years of nuclear weapons testing.
Looking at those peak years of testing, the forcing from those 20 years of peak tests of the nuclear weapons on the Earth came to about one eight-millionth of a Watt per square meter (8 x 10-6 W m-2) of power.
For comparison, the 1.8 Watts per square meter (1.8 W m-2) of CO2 radiative forcing as of 2011 generates approximately twenty nine billion, trillion Joules of energy (29 x 1021 J) over the Earth's surface in a single year, or more than ten thousand times as much energy in a year than the entire combined nuclear weapons program of the world had generated in those 20 years.
http://railsback.org/FQS/FQSNuclearWeaponsTesting01.jpg
http://www.johnstonsarchive.net/nuclear/nuctestsum.html
http://www.unscear.org/docs/reports/2008/09-86753_Report_2008_Annex_B.pdf
http://www.laradioactivite.com/site/pages/RadioPDF/unscear_artificielle.pdf
https://www.esrl.noaa.gov/gmd/aggi/ -
scaddenp at 05:32 AM on 27 October 2020Climate's changed before
Michael - see here perhaps. This is hydro-isotasy at work as opposed to rebound from weight of ice. Extra weight of water from ice melt deepening the ocean basins, dropping sea level slowly.
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michael sweet at 03:45 AM on 27 October 2020Climate's changed before
A long time ago someone at SkS suggested that sea level in the Pacific ocean peaked about 3-5,000 years ago and then went down about 1.5-2 meters. This explained how atolls formed and why they have coral rock above current sea level.
I do not see this change in MARodgers graph at post 843 but it seems consistant with his post at 850. Is sea level change the current understanding of how atolls came to be above current sea level? (Most atolls in the Pacific have 1-2 meters of coral stone at their core which cannot form above sea level. Sea level could have changed more than that.)
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One Planet Only Forever at 03:18 AM on 27 October 20202020 SkS Weekly Climate Change & Global Warming News Roundup #43
nigelj,
The following is my current understanding of the problems faced by efforts to develop sustainable improvements for the future of humanity. Better understanding a problem, and the desired outcome, is one of the most important steps in developing sustainable solutions, as every Engineer is very aware.
Regarding reactions to climate science and climate change information and misleading claims, a major difference between the USA and NZ is probably that, relative to NZ, the USA has more powerful wealthy people who have their wealth and power because of fossil fuels. They would lose status if the changes of how people live that are required to limit the climate change harm done to future generations are actually achieved. Increased awareness and understanding of the need to meet the Paris limits makes these powerful wealthy people more likely to lose their status. And that threat of losing their perceived status causes some of them to mentally 'lose it' and double down on harmful misleading marketing rather than striving to honestly change to be less harmful and more helpful.
Other possible reasons for the difference regarding harmful populism in the USA and NZ could be:
- The USA is the least Socialist of the supposedly more advanced nations. I use 'supposedly' because it highlights that 'impressions of advancement' may be misleading. Increased wealth or increased technological development that does not result in sustainable improvements of the living conditions for the poorer portion of the population is not 'advancement'.
- The USA, since its foundation, has been a nation of Anglo Saxon Colonists pursuing ever expanding Superiority for 'Their Tribe' relative to all 'Others' (the reason I pointed to "White Fragility" as a book to read). Books like "The End of the Myth" by Greg Grandin present an accurate and unflattering history of the formation and expansion of the USA (violent disregard for Others is a powerful part of the USA's history). And many Americans are still powerfully motivated by their collective lack of social development on acceptance of diversity and the related need to systemically more equitably treat the diversity of humanity.
- In the USA the 'pursuit of freedom' has been about the more freedom for powerful wealthy property-owning people (with property including Other people) to become more powerful and wealthier (small government having no role in regulating economic activity, not limiting the harm it does). It includes protection of the ability of likely unjustly acquired wealth to be passed to children who may be even less deserving of having that wealth and power. The wealthier a person is the more helpful and less harmful to Others that person needs to be, or the advancement of society is slowed or reversed.
- The USA has a 2 party system which makes it easier for the greedy and intolerant people to gather together and claim that 'The Other is the enemy'. And the history of the USA explains why the 2 Parties in the USA substantially share the objective of protecting the wealth of the wealthy. However, currently the Democrats are leaning towards being more Socially Sharing and Caring due to their party including the Social Democrat thinking. Multi-party systems may make people more aware of diversity rather than seeing things as Black-White Us-Them. In Canada there is only one party heavily focused on promoting greed and intolerance, the merged Right-Wing Conservatives. There used to be a Progressive Conservative Party that was centrist, but it disappeared when it merged with social conservatives and increased appeals to greed (which used to be in fringe parties). The inability of the hard Right-wing Party to get along with a diversity of Other Parties may make more people aware that it is the uncooperative party that is the problem, rather than a 2 party system where 'The Other' can always be blamed.
Another difference between the USA and NZ is that the Separation of Church and State has been removed by the current Republican pursuit of popular support from fundamentalist religious groups, because there is such a large population of fundamentalist evangelical religious people (and those people appear easily inclined to believe conspiracy theories about 'Those Others - Their Enemies').
A related difference between the USA and NZ may be that the USA has also amplified the power of wealth in government. It is clear that democracy requires a separation of Wealth and State (read Thomas Piketty's "Capital and Ideology") so that the State can act as the Responsible Governor of what is going on to limit harm done and help develop sustainable improvements for the least fortunate.
In summary, Social Democracy that effectively limits the influence of Religion and Wealth on the actions of Government may powerfully inoculate populations against populist autocracy. Note that anti-Socialism is part of the misleading marketing attacks by the greedy and intolerant portions of many populations that have joined forces to try to win the power to do as they please. Selfish people are more inclined to be harmful to Others, and less inclined to be helpful to Others. They easily dislike the idea of being 'forced to share and care by Government'. Any government that would do that is part of the 'Others'. They want the freedom to 'Win higher status any way they can get away with'. To them 'Harm Done is justified by Benefits Obtained'.
Closing back to climate change and climate science. The belief in conspiracy is strong in people who have developed preferred beliefs that are contradicted by expanded awareness and improved understanding of how to be less harmful and more helpful to Others. To maintain their perceptions of status and related beliefs, they accept anything that appeals to them, including the ability to declare themselves to be the Victims - of conspiracies, which requires the belief that there is no Objective Reality as a basis for Common Sense, every belief is equally valid - because of the barage of falsehoods they have developed a liking for but have been unable to make sense of.
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Bob Loblaw at 01:16 AM on 27 October 2020Climate's changed before
Eclectic:
A direct link to MA Rodger's figure is:
I notice that it is formatted to display is as a webp object, which might be breaking things for you if that format is not supported in your browser. It seems to be a Google format. YOu might try dropping the "as=webp" part.
As for isostatic rebound: keep in mind that it is a local effect. The crust is depressed where ice weighs on it, and rebounds when ice is removed. Areas around the ice do the opposite - they flex upwards when the ice pushes downwards, and move back down when the ice is removed. Think of what happens when someone places an object on a waterbed.
Interpreting sea level changes due to glaciation is rather complex, and evidence is difficult to find.
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Eclectic at 00:14 AM on 27 October 2020Climate's changed before
Correction :- not Peltier (2002) , but Khan et al. (2015) as per link in #850
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Eclectic at 00:05 AM on 27 October 2020Climate's changed before
MA Rodger @850 ,
sorry, but your diagram [relative sea level map] is not loading for me. (And yes, Nigelj, I have tried 3 computers!! ) I will take a stab, and presume the diagram is from Peltier (2002) .
If I understand you correctly, then relative sea level (disregarding the "short term" alterations from thermal volume effect and total mass change) during the Holocene interglacial . . . ought to receive a major influence from isostatic rebound of subpolar land regions, as well as from the more general land "rebound" secondary to oceanic siphoning. And both of these rebounds should produce a late-Holocene fall in relative sea level (i.e. measured at shore-lines). Perhaps excepting special cases like southern Britain.
To all of which, we can add in some extra fall secondary to late-Holocene cooling that reduced ocean temperatures and also deposited more ice on land ~ an amount of ice presumably rather less than the 30-meter deposit I mentioned in last paragraph of #849 . . . (a deposit too marginal to really decrease the land rebound).
I guess the whole question comes back to the nett result on "Mean Sea Level", from all these various factors. In view of all the difficulties in local measurement of millennial changes, I am not surprised by the scatter of results from different studies on this topic.
Almost - but not quite - it is enough to feel some sympathy for that remarkable outlier, the (recently) late Dr Moerner.
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MA Rodger at 20:27 PM on 26 October 2020Climate's changed before
Eclectic @849,
In the past, I do recall SLR free of significant tectonic movement being claimed as a good indicator of global SLR and that it usually concerns Australian data but I'm not sure such claims usually attach to late Holocene SLR. Lewis et al (2008) and indeed Lewis et al (2013) and Lewis et al (2015) are concerned with the late Holocene and more so the Australian record than establishing a global record. And their findings are not so clear cut although a significant drop in sea level post-7,500y bp has been established. The 2013 paper concludes:-
"A clearer understanding of past sea-level changes and their causes is urgently needed to better inform our ability to forecast future changes. A concerted effort is required ... to address the issues of whether there have been oscillations of the sea surface and if so, of what magnitude. The pattern and rate of fall from the Holocene highstand to modern levels, and of the contributions of the various factors to this change, both global ‘eustatic’ or ‘steric’ components and local geophysical, tectonic and land instability issues also need to be addressed."
The work to unravel the late Holocene global SLR record is far from complete and I see no evidence of the Australia (Oceania) data providing a short-cut to providing a conclusion. Thus, the conclusion from, for instance, Khan et al (2015):-
"Far-field Relative SL records exhibit a mid-Holocene highstand, the timing (between 8 and 4 ka) and magnitude (between <1m and 6 m) of which varies among South America, Africa, Asia, and Oceania regions."
And on the reasons:-
"The Relative SL signal of many far-field locations is characterized by a mid-Holocene sea-level maximum, or highstand, at the time meltwater production decreased. The fall in Relative SL to present is due to hydro-isostatic loading (continental levering) and a global fall in the ocean surface due to both hydro- and glacio-isostatic loading of the Earth’s surface (equatorial ocean siphoning). Perturbations to Earth’s rotation driven by mass redistribution also cause Relative SL changes in far-field regions to depart from the eustatic value. These processes occur during the deglacial period but are not manifested in far-field RSL records until the early to mid-Holocene because the eustatic signal is dominant prior to this time. Far-field locations are characterized by present-day rates of Relative SL change that are near constant or show a slight fall (<0.3 mm/a) in [rate of] Relative SL (Fig 1)."
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takamura_senpai at 17:18 PM on 26 October 2020The Debunking Handbook 2020: Debunk often and properly
People say what is profitable/gainful, NOT they realy think. USA produce more CO2 than whole Africa + S America + ...much more, if we look on goods which USA consume. Latin America + half Africa + others is a USA colonies, so MUST produce huge CO2, they must supply USA with many things.
For example: Brasil paid > 1 trillion to USA in last 20 years, and debt is higher and higher - colony. -
nigelj at 15:49 PM on 26 October 20202020 SkS Weekly Climate Change & Global Warming News Roundup #43
OPOF, I have a copy of Post Truth, by Evan Davis so that is another one to add to the list.
Your explanations sound quite good, although I'm still puzzled why we haven't seen quite the same extent of problems in NZ, ( we have seen some and it is growing a bit) but it may partly relate to geography and size and location, in that we are very small and very reliant on trade and international alliances which does open the mind and make people more tolerant of 'foreigners' and international organisations, and very aware of what happens in other countries. Fake news and xenophobia finds it harder to gain traction in that sort of environment.
America is so large it's almost self contained, and certainly trades less on a per capita basis than us, all of which might create a little bit of a bubble where fake news can gain traction along with anti foreigner sentiments, and if you tap into that racial dimension with appropriate falsehoods and emotive rhetoric, you pretty much have people under your control. We have had politicians like that and our share of xenophobes, but they are getting less and less traction. It was actually a free trade agreement with China around 2006 that got us through the GFC, and people are grateful.
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Eclectic at 13:34 PM on 26 October 2020A Skeptical Science member's path to an experiment on carbon sequestration
RedBaron @22 ,
thanks for that info. I did see that a charge would not be made until 28 Oct . . . but I wasn't clear whether that applied only to donations which were in excess of the official target. The wording was a touch ambiguous ( I thought ). I am guilty of overthinking the wording.
BTW my original computer has still shown the defective pop-up window on the Experiment.com website. Perhaps my software is not as up-to-date as I had believed. All the same, it might be worth dropping a word to the site Administrator, to check that the donation "mechanism" is functional for a wide range of operating systems (both ancient and modern) ~ if such is possible in a secure way. Every fishing line should have a hook on it!
2nd BTW ~ and thanks, RedBaron, for the Widow's Mite tale you had mentioned earlier. No reply from Mr Keithy, I see.
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