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Wol at 08:58 AM on 4 November 2020How you can help to keep Climate misinformation on Twitter in check
I don't "do" Twitter, Facebook or any of the so-calld "social" media so can't comment on those. However the anti-science brigades are pretty active on online newspaper comments columns, which amounts to the same thing.
Frankly I think it's pointless entering into debates in any internet sites: because you are not face to face any debunking you put forward is either ignored, the subject is changed to another and/or often a heap of abuse is thrown.
A TV debate is better - but even here it's usually the science versus (for balance, you understand) an equal number consisting of of a genuine scientist denier and a crowd of pseudoscience deniers.
Even then you can see how rational argument is up against ignorance: Brian Cox talking to Malcolm Roberts on Australian TV's Q and A is a good example.
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Nick Palmer at 08:36 AM on 4 November 2020How you can help to keep Climate misinformation on Twitter in check
Ermm... The climate scientists I mentioned, that Botsentinel identifies as problematic or disruptive, are not tweeting 'sceptic' stuff! They are defending the science against deniers! That's why I suggested that Botsentinel is next to useless - it identifies 'Friends of Science' as 'normal' fer chrissakes...
link to wiki on FoS -
BaerbelW at 08:02 AM on 4 November 2020New Slideshow on Myth Debunking for Educators and Science Communicators
Melanie Harwood @15
Can you please send us a message via the Contact Us form about the apparently broken link for the PPTX? We can then more easily check with the authors by forwarding your question via email Thanks!
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nigelj at 05:41 AM on 4 November 2020How you can help to keep Climate misinformation on Twitter in check
The public get bombarded with messages on the climate issue with some being sceptical, and people are trying to sort fact from fiction while living busy lives. I can appreciate its frustrating.
This website gives some good tips on logical analysis, but if people are too busy to do this, its worth noting that the sceptical material most probably comes from a small group of hired guns. Its not coming from hordes of climate scientists. Studies show between 90 - 95% of climate scientists say we are warming the climate, eg Verheggen et al., 2014, Powell, 2013, John Cook et al., 2013 ,Farnsworth and Lichter, 2011 Anderegg, Prall, Harold, and Schneider 2000, Doran and Kendall Zimmerman, 2009, Bray and von Storch, 2008, Oreskes, 2004.
So any climate scientists tweeting scepticism are in a very small minority if there are any at all. Instead its more likely that the scepticism originates with lobby groups with powerful vested interests in keeping fossil fuels going, people whos self worth is very much tied to status and making money at all costs, people with libertarian very small government views, and scientific cranks. They certainly dont seem worried about distorting the truth.
The people who actually tweet sceptical information could be hired guns desperate for money, and with personalities that are not troubled by distoring the truth or they just dont know much about the issues. They remind me of the internet and phone scammers / fraudsters.
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Philippe Chantreau at 04:27 AM on 4 November 2020New rebuttal to the myth 'Holistic Management can reverse Climate Change'
Nice to see a vigorous debate where people actually substantiate their arguments. From what I read, it seems there is a lot of good to be said about holistic management from the non climate point of view.
However, looking quantitatively at the bigger picture I have the following questions: is it realistic to imagine the entire world cattle inventory managed under such regime? How much CO2 storage can actually be accomplished? How does that compare to emissions in a BAU scenario (we're not that far from what was considered BAU a few years ago)?
In other words, can HRM make that much difference without using all the other "wedges" already known? Should HRM not be treated as another "wedge"?
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Nick Palmer at 00:56 AM on 4 November 2020How you can help to keep Climate misinformation on Twitter in check
Actually should have written 'BotSentinel'...
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Nick Palmer at 00:40 AM on 4 November 2020How you can help to keep Climate misinformation on Twitter in check
I don't think Sentinelbot is of much use for this at all! I put myself @NickAPalmer into Sentinelbot and discovered that I was "questionable". I'm currently in a very active Twitter group of 49 that sometimes includes Robert '1000frolly' Holmes (questionable) and Ned Nikolov (normal) also the highly deceptive 'Friends of Science' is, unbelievably, 'normal'. Skepsci's own Rob Honeycutt is 'disruptive'. Most of the actual scientists, or those who quote them are 'disruptive' or even 'problematic'...
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Melanie Harwood at 00:11 AM on 4 November 2020New Slideshow on Myth Debunking for Educators and Science Communicators
Please can you make the slideshow available.
I would like to share this with the eduCCate Global Sustainability & Climate Change Teachers (currently 329,000 in 43 countries) so that they can deliver this to their pupils in their schools.
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Geoffrey Cruickshank at 15:08 PM on 3 November 2020New rebuttal to the myth 'Holistic Management can reverse Climate Change'
Yesterday domestic livestock were occupying one 138th of the area of my farm. Today when I moved them, based on observing yesterday's grazing, I allowed them one 145th. Depending on the next few days, I'll be revisiting the overall plan shortly as it is rapidly departing from the last iteration. Hard to see how you could plan a comparison grazing study with this going on.
on the matter of hooves, I was sceptical myself. However I have observed that where I have single wire electric fences permanently set up, the stock graze under them, but don't trample. These narrow strips are not benefitting to the same extent, and tend to be poorer in species and in growth. So unless the electric fence is somehow causing that, I would say that Mr Savory is right about the hooves.
On infiltration. Last autumn we had a dry period followed by a four inch rain one afternoon. My neighbour had a lot of runoff and one of his small dams failed. My paddocks absorbed the rain almost too well- I could have done with a little more run off to freshen the storage.
Don't judge Mr Savory purely on the twenty minute TED talk. Go and find someone who is doing this And open your eyes.
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Geoffrey Cruickshank at 14:42 PM on 3 November 2020New rebuttal to the myth 'Holistic Management can reverse Climate Change'
As this is your first post, Skeptical Science respectfully reminds you to please follow our comments policy. Thank You!
I am one of thousands of farmers who have taken on holistic management. It has been absolutely astonishing to watch new species taking hold and the increase in perennial grasses over the past five years. I find it rather sad that you set out to debunk a management process that you plainly have not seen in action and don't understand enough about to make an intelligent analysis.
Farmers don't actually need your approval to continue holistic management. But it is sad that you are actually working against a bunch of people who have converted to running farms with regard to ecological outcomes, all the birds and native animals, and trying their best to store some carbon deep in the soil.
In holistic management, a plan is made for the season ahead, but this will be varied as the season develops. Hence it would be impossible to design a controlled experiment in advance and stick to it. Thus it an only really be studied by means of case studies.
There are plenty of these. It works.
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michael sweet at 07:31 AM on 3 November 2020CO2 effect is saturated
ChezProvence:
As you can see if you read the comments directly above yours, this paper was rejected from peer reviewed ournals and is poorly written. I doubt anyones mind will be changed.
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One Planet Only Forever at 01:07 AM on 3 November 20202020 SkS Weekly Climate Change & Global Warming News Roundup #44
Prometheus 1962 appears to be a victim of, or perpetrator of, attempts to 'raise doubt about and smear the Other Leaders' by claiming they are just like the 'type of Leader they like' - a version of the False Equivalency scam.
The full set of evidence differentiating the Leadership candidates makes it hard for them to defend what they like. That can be especially true if the general population is becoming more aware that Leaders should be pursuing increased awareness and understanding applied to help develop sustainable improvements for the part of humanity they lead that does not negatively impact any other parts of global humanity (and understanding that the global future generations are the biggest part of humanity to avoid harming).
Those harmfuly selfish people, liking harmful actions they hope to benefit from, have to claim the Others are the same, are equally bad. They even try to create the appearance that the Others are worse by making-up scandalous gossip where there is little evidence or where they fabricate the evidence and the story by Cherry-Picking or taking bits out of context.
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ChezProvence at 23:37 PM on 2 November 2020CO2 effect is saturated
Oops. I was on the wrong page … Happer's work is already logged in.
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ChezProvence at 23:30 PM on 2 November 2020CO2 effect is saturated
So now we have this: https://arxiv.org/pdf/2006.03098.pdf
Change anyone's mind? It probably should cause deep reflection at a minimum.
Moderator Response:[DB] In order to facilitate a proper dialog, it is incumbent upon you to first provide your synthesisized interpretation of that paper for others to then weigh in on. What-about-this-ism does not advance the conversation.
Further, operating multiple accounts here is forbidden by this site's Comments Policy.
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ubrew12 at 12:58 PM on 2 November 20202020 SkS Weekly Climate Change & Global Warming News Roundup #44
Prometheus 1962@1 said "To think a Democratic administration would... be... interested in saving our climate..." They've already expressed that interest, and the GOP has just as firmly expressed its disinterest. So the only thing we really know, is that no solution will come from the GOP (because interest is a necessary, incomplete condition for solution). Meanwhile, here's a quote from the guy who wants to lead the Democratic Party, speaking of the climate challenge: "A time of real peril but also a time of extraordinary possibilities. We've seen the light through the dark smoke. We never give up. Always, without exception, we succeed... when we try."
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nigelj at 05:58 AM on 2 November 20202020 SkS Weekly Climate Change & Global Warming News Roundup #44
"If Bill McKibben thinks Joe Biden and the DNC are ever going to put the Green New Deal into a bill and put it up for a vote, he must be...."
Forgive me I dont live in America so may have this all wrong, but I do recall the democrats did actually put a version of the GND to a senate vote here but sadly it lost. This may have been because of the socioeconomic content, as opposed to the climate content.
However it does show the democrats are interested in advancing this GND, so its not clear why it wouldnt happen again with Biden. Only time will tell of course. If we want him to advance the issue, encouragement and some nagging might be better than implying hes a useless fool
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Eclectic at 23:01 PM on 1 November 20202020 SkS Weekly Climate Change & Global Warming News Roundup #44
Prometheus @1,
you might care to check this website's Comments Policy.
IIRC, the Comments Policy was somewhat against Concern Trolling.
Besides ~ "concern trolling" is very boring, doncha think?
Moderator Response:[BL] Please think twice before responding to baiting, and leave the moderation to the moderators.
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Prometheus 1962 at 21:10 PM on 1 November 20202020 SkS Weekly Climate Change & Global Warming News Roundup #44
If Bill McKibben thinks Joe Biden and the DNC are ever going to put the Green New Deal into a bill and put it up for a vote, he must be on some serious mind-altering drugs.
The Democrats conspired to destroy the one Democratic candidate who was pushing the GND, not once but twice. To think a Democratic administration would even be mildly interested in saving our climate is wildly delusional.
Moderator Response:[BL] Accusations of this sort really aren't appropriate.
Thank you for taking the time to share with us. Skeptical Science is a user forum wherein the science of climate change can be discussed from the standpoint of the science itself. Ideology and politics get checked at the keyboard.
Please take the time to review the Comments Policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.
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John Hartz at 09:45 AM on 31 October 2020Warmer climate and Arctic sea ice in a veritable suicide pact
Recommended supplemental reading including three stunning graphs...
Why the record low Arctic sea ice this October is so alarming by Lili Pike, Energy & Environment, Vox, Oct 28, 2020
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RedBaron at 07:29 AM on 31 October 2020A Skeptical Science member's path to an experiment on carbon sequestration
the DOI will be
DOI: 10.18258/15503
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RedBaron at 07:13 AM on 31 October 2020A Skeptical Science member's path to an experiment on carbon sequestration
Thanks very much to all who helped, either with donations, or information! I couldn't have done it without your support!
Sorry it took so long to reply, but Oklahoma got hit with a record breaking ice storm this week! over 300,000 without power and the roads were full of broken tree limbs. I couldn't even check on my own project myself! But my friends came through in the end and I am eternally grateful!
First order of business is grab a chainsaw and finish clearing a path of the tangled mess of tree limbs so I can safely enter my front door. Then when I finally get finished thanking everyone, I will get to work on the project.
Thanks again everyone.
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nigelj at 06:05 AM on 31 October 2020Warmer climate and Arctic sea ice in a veritable suicide pact
Prometheus, one of the problems with the current pace of climate change is its very rapid compared to most past periods, and we are not adapted to those rapid rates of change. We have a lot of expensive fixed infrastructure, like buildings and these are not designed to be moved like a tent, and they are designed to last at least 50 years.
If we trigger the worst outcome such as multi metre sea level rise this century, which is entirely possible, many buildings will be abandoned well before their "use by" dates and there will be far more rebuilding work that we humans normally undertake. This means we have less economic resources to do other things. Building construction is slow and very expensive.
Some small buildings can be relocated, at a cost but peoples investments in the land have been wiped out and that land cost forms the majority of the price of many house purchases! The loss of land will also add up over time especially alluvial plains used for farming.
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Eclectic at 22:07 PM on 30 October 2020Warmer climate and Arctic sea ice in a veritable suicide pact
Prometheus, as you are probably thinking yourself, the Eemian interglacial of 120,000 years ago had warm conditions extending further south than the Arctic sea. Fortunately for the plants animals and humans of those times, the Eemian interglacial's peak temperature came and went very slowly ~ unlike the rocket speed of today's anthropogenic global warming. Eemian global human population was not today's 7,000+ million, but probably around a quarter million or less . . . and they were hunter-gatherers, easily able to move their territory, as conditions gradually changed. (Slightly different from today ~ when potatoes complain about having to move from their couches when the remote's battery goes flat.)
The rapid AGW from fossil fuel usage which ( judging by the swift decisive action of today's politicians ) will continue to cause more acidification of the oceans . . . leading to greater ecological deterioration of oceans, with accompanying major reduction of fish stocks & other marine foodstocks for humans.
Eemian conditions had a global sea level 5 or more meters above current level. We could get there in a few centuries, and possibly rather faster than that. Which will lead to massive migration of refugees.
And massive loss of fertile farmland.
Resultant colossal financial & social costs (spread over several centuries, though).
Extinction of large swathes of plant & animal species (but this may not be of interest to the fiery mind of Prometheus).
# Please place a cross against any of the above points which seem unimportant.
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Prometheus 1962 at 20:52 PM on 30 October 2020Warmer climate and Arctic sea ice in a veritable suicide pact
Great article! So now I'm wondering if the record will be broken next year.
Can someone explain to me why it was okay for the Arctic to have no sea ice in summer 120,000 years before the last ice age, but it's not okay now? After all, if the Earth could cool naturally after such an event, surely it could do so now, if we were to stop warming the planet (and I realize that's easier said than done). What was the big difference (other than the fact that the current warming is happening much faster and is caused by human activity and not by other natural forces) that makes our current situation a major cause for concern?
Moderator Response:[DB] 2016 temperatures had exceeded those of the Eemian interglacial. Further warming this century, all driven by human activities, takes us far beyond those of the past several million years. Earth has lost 28 trillion tons of ice in just the past 23 years.
Hansen 2006, updates to 2020:
Under all foreseeable greenhouse gas emissions pathways society might follow over the next hundred years, a remnant portion of the Antarctic Ice Sheet endures even 10 thousand years from now, albeit greatly reduced in area, thickness and volume.
Under all emissions pathways, including Low emissions pathways, the Greenland Ice Sheet disappears entirely (ranging from between 1 to 6 thousand years to entirely waste away).
This implies that global sea levels will eventually rise from between 25 and 52 meters (82 to 170 feet) over the next 10,000 years, with most of that rise in global sea levels occurring during the next 3,000 years.
https://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.nature.com/articles/s41558-019-0466-0
https://www.carbonbrief.org/sea-level-research-says-only-a-brief-window-to-cut-emissions
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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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