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vox_mundi

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Tipping Points
« on: July 06, 2023, 06:22:07 PM »
June Extremes Suggest Parts of Climate System are Reaching Tipping Points
https://arstechnica.com/science/2023/07/june-extremes-suggest-parts-of-climate-system-are-reaching-tipping-points/

June 2023 may be remembered as the start of a big change in the climate system, with many key global indicators flashing red warning lights amid signs that some systems are tipping toward a new state from which they may not recover.

Earth’s critical reflective polar ice caps are at their lowest extent on record in the satellite era, with the sea ice around Antarctica at a record-low extent by far, spurring worried scientists to share dramatic charts of the missing ice repeatedly. In the Arctic, the month ended with the Greenland Ice Sheet experiencing one of the largest June melt events ever recorded, and with scientists reporting that June 2023 was the hottest June ever measured, breaking the 2019 record by a “staggering” 0.16° Celsius.

Globally, the oceans set records for warmth on the surface and down to more than 6,000 feet deep throughout the month, with temperatures so far above the norm that the conditions elicited more graphs showing the anomaly. They’ve been shared thousands of times by scientists, policymakers and the public. And in Canada, forest areas about the size of Kentucky have burned, choking huge swaths of central and eastern North America with acrid wildfire smoke, with some of the haze even reaching Europe.

There was record-breaking heat on nearly every continent during the month, according to independent climate statistician Maximilian Herrera. Along with the deadly late June heat in Mexico and the South-central United States, extreme readings have been widespread in remote Siberia, with hundreds of daily heat records, including readings higher than 95° Fahrenheit close to the Arctic Circle. “The heat will just get worse,” he posted on Twitter.

Herrera also tracks notable regional extremes, like a historic mountain heatwave in Iran, where temperatures in late June spiked to between 100° and 120° Fahrenheit at elevations between 1,500 and 5,000 feet above sea level that are normally far cooler.  During the first week of July, temperatures in Iraq are forecast to breach 120° Fahrenheit.

“These extraordinary extremes could be an early warning of tipping points towards different weather or sea ice or fire regimes,” said University of Exeter climate researcher Tim Lenton. “We call it ‘flickering’ when a complex system starts to briefly sample a new regime before tipping into it. Let’s hope I’m wrong on that.”

In the meantime, the tropical Pacific Ocean is shifting into the warm El Niño phase of a two- to seven-year Pacific Ocean cycle that can boost the average global temperature by 0.2° Celsius, enough to stoke the planet’s fever to a dangerous new high.

“I expect a step change to higher global mean temperatures starting this year,” said atmospheric scientist Kevin Trenberth, a distinguished scholar at the National Center for Atmospheric Research and honorary faculty at the University of Auckland. “And next year will be the warmest on record, either 1.4 or 1.5C above pre-industrial.”

The higher of those levels is the amount to which the United Nations’ 2015 Paris Agreement aspired to limit climate change, but the continued upward trajectory of global temperatures could make that goal impossible to reach.

“I expect it then to oscillate about that value and not come down again,” he said.

The persistence of the startling Antarctic sea ice decline may be one of the most puzzling and worrisome of the recent cluster of climate extremes. Until recently, researchers expected less sudden changes in Antarctica, because it’s such a vast reservoir of coldness, and surrounded by a continual swirl of ocean currents and winds that have buffered the continent to some degree.

But at the end of June, getting into the heart of the Southern Hemisphere winter, an area of ice about the size of Texas and Alaska, nearly 1 million square miles, was missing. As the Southern Hemisphere’s winter set in, the sea ice grew more slowly than ever observed in the satellite era.





https://zacklabe.com/global-sea-ice-extent-conc/

Other recent research shows that the Southern Ocean encircling Antarctica and extending northward to 60° south latitude, stored a disproportionately large percentage of the heat trapped in the atmosphere by greenhouse gases and then absorbed by the world’s oceans between 2005 and 2017. The study showed the Southern Ocean took up 45 to 62 percent of the heat absorbed by the world’s oceans, even though it makes up only 6.25 percent of the global ocean surface area.

In the absence of its reflective sea ice cover, the darker-colored ocean can absorb even more heat, potentially leading to earlier and more extensive melting during the next Austral summer. And as the fringe of ice around Antarctica gets smaller, warmer ocean water can more easily flow toward the floating ice shelves that buttress vast areas of inland ice that could start flowing into the sea faster to speed sea level rise.

At the top of the planet, scientists have been watching an extreme ocean heat wave in the North Atlantic just as carefully, because it could be a symptom of disruption to the Atlantic Meridional Overturning Circulation, a critical part of the global climate system that transports cold and warm ocean water between the poles. Sea surface temperatures about 9° Fahrenheit above average in the region could also contribute to heatwaves over adjacent land areas.

... “The pile of evidence linking a rapidly warming Arctic with extreme summer weather events continues to grow,” climate scientist Jennifer Francis wrote on Twitter on June 30, sharing a link to a new peer-reviewed study in Nature Communications that solidifies the hypothesis that changes in the Arctic can lead to a wavier jet stream that can trap heat domes in place.

In recent years, those patterns have sometimes persisted for months with only short pauses, including last summer, when a heat dome over Europe lasted several months and fueled that continent’s hottest summer on record.
“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” ― anonymous

Insensible before the wave so soon released by callous fate. Affected most, they understand the least, and understanding, when it comes, invariably arrives too late

nadir

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Re: Tipping Points
« Reply #1 on: July 06, 2023, 08:46:16 PM »
Not a single tipping point being probably reached is clearly explained in the article above, except maybe Jennifer Francis’ theory about more extreme weather with increasing high-latitude temperatures and Arctic sea ice loss.

I am not sure if anybody knows with certainty what drives Antarctic sea ice. It was sea ice “gain” just about eight years ago. Nobody knows for sure how Arctic sea ice declines either, but there is a better understanding of this.

Clear tipping points are those caused by Arctic amplification, like the irreversible MYI loss and the disruption of weather patterns due to ice loss. Also the AMOC decline which can lead to abrupt changes but nobody knows when.

The further desertification of the Amazon is also worrisome. Then we have the accelerating mass loss of Ice Sheets, but that seems something measurable in centuries rather than decades. For sure we have the permafrost loss, which can lead to a tipping point in acceleration in amount of greenhouse gases.

But again the article is vague, the relationship with real tipping points is not clearly shown, except maybe J Francis theory. Of course there are tipping points down the road, we already know, but June extremes suggest nothing and Antarctic sea ice suggests nothing about when and how these tipping points are being approached.


zenith

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Re: Tipping Points
« Reply #2 on: July 07, 2023, 12:01:08 AM »
the problem with tipping points is that we won't really understand them until they're in the rear view mirror. canaries in the coal mine are dying left and right though.
Where is reality? Can you show it to me? - Heinz von Foerster

kiwichick16

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Re: Tipping Points
« Reply #3 on: July 07, 2023, 01:56:51 AM »
@ Zenith  ..... +1 ....  the guys watching the WAIS , for example, think it is already at , or approaching its tipping point.
the GIS , the Arctic summer sea ice, the European Alpine glaciers and the Coral reefs are also set to go at between 1 - 3 degrees C warming

nadir

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Re: Tipping Points
« Reply #4 on: July 07, 2023, 02:04:00 AM »
the problem with tipping points is that we won't really understand them until they're in the rear view mirror. canaries in the coal mine are dying left and right though.

Exactly! The Arctic is, for me, the canary in the coal mine, already dead or on oxygen. No need of blue ocean event. Some tipping points are smoking guns already over Arctic. But Antarctic sea ice? Temp extremes in June 2023? No.

When I read the word “suggests” in one of these headlines it’s a “red flag” very often.

kiwichick16

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Re: Tipping Points
« Reply #5 on: July 07, 2023, 02:29:36 AM »
@  nadir  ...... the flags are waving alright  ....... but i don't think there is going to be much celebrating

nadir

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Re: Tipping Points
« Reply #6 on: July 07, 2023, 02:41:33 PM »
@  nadir  ...... the flags are waving alright  ....... but i don't think there is going to be much celebrating

I don’t think so too, but listen I simply dislike this kind of journalism around such serious problem. They create a melange of current events and known trends, use “suggest”, and equal to tipping points unknown being reached. The math equation in the head of the journalist is:

Max June T’s + Arctic ice loss + Antarctic ice+ heat wave in Iran ≈ some tipping points must surely have been reached.

This kind of journalism actually may prompt skepticism from people, especially on those that are can detect bullcrap from a mile away. There were a lot of predictions of imminent Arctic sea ice collapse after 2012 (even supported by scientific predictions of doom years being 2013 and 2016 by now debunked by reality itself). The constant alarmism since Gore’s documentary and before has done more harm than good, and I wonder if that’s the reason why the system allows it and promotes it. To actually sell oil and perpetuate it thanks to the skepticism generated around it.

kiwichick16

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Re: Tipping Points
« Reply #7 on: July 07, 2023, 05:55:03 PM »
@  nadir .....they do say that sunlight is the best sanitiser......and i would suggest, and no i don't have any data to wave about, that there hasn't been anywhere near enough sunlight. There was probably more media attention on a game of cricket last week , than there was on the potential for the current wave of extinction of species, happening as we tap away at keyboards, to include our own species extinction...... which is a possibility at least some scientists are pondering.

And Al Gore's  Noble prize winning  "Inconvenient Truth" did exactly what it said on the can ...... i was one of the people it slapped in the face.

kassy

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Re: Tipping Points
« Reply #8 on: July 07, 2023, 08:45:15 PM »
the problem with tipping points is that we won't really understand them until they're in the rear view mirror. canaries in the coal mine are dying left and right though.

For a whole lot of them we know they are there but we don´t do anything about it.

It always was a problem. If we need a BOE to wake up the masses then that is a problem because even the run up to that causes a big shift in global temperatures and the change in weather should be impressive because most of the teleconnections are.

The global fish stock has been moving away from the equator since about 1C over global. It has been mentioned here repeatedly but it has not generated that much discussion. It is a big hint of a change which is really hard to reverse.

Back in the day other ideas were preventing Arctic ice from melting. Of course Antarctica would only be a problem much much later. This Arctic tipping point is now scheduled for next decade so we get to see it.

There are more and of course when one triggers it changes the others.

We have long ago triggered most of them because we assumed we had more margin. A lot of paleo research comes back to huge CO2 numbers but those are wrong. We have a correction from stomata data for one time which shows it is a third lower. Data among geologic ages will vary.

Arctic permafrost went to a source instead of a sink a while ago so what tipping point are we waiting for anyway? The one that changes YOUR life forever? This is a general question.

And for clarity this only means we need more action. Hard caps and energy diets but of course that will not happen.
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Alexander555

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Re: Tipping Points
« Reply #9 on: July 08, 2023, 11:13:20 PM »
Today somebody was telling it takes 10 000 years to melt the entire Greenland ice sheet. But at some point it will start to collaps. The central part of Greenland is lowland, even below sea level. Today you have melt, that's  like an orderley retreat. That lowland invites to destabelise that ice sheet. And as soon you have a part of that ice sheet collapsing. Than what will prevend the entire ice sheet from collapsing ? From north to south, from east to west. Probably nothing. So that's a tipping point. And that you have places that are still a little bit below freezing in summer, is because of the high elevation, the ice is a few km thick. Last week in the north of Greenland, it was almost 20 C .

nadir

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Re: Tipping Points
« Reply #10 on: July 09, 2023, 02:22:10 AM »
Today somebody was telling it takes 10 000 years to melt the entire Greenland ice sheet. But at some point it will start to collaps. The central part of Greenland is lowland, even below sea level. Today you have melt, that's  like an orderley retreat. That lowland invites to destabelise that ice sheet. And as soon you have a part of that ice sheet collapsing. Than what will prevend the entire ice sheet from collapsing ? From north to south, from east to west. Probably nothing. So that's a tipping point. And that you have places that are still a little bit below freezing in summer, is because of the high elevation, the ice is a few km thick. Last week in the north of Greenland, it was almost 20 C .

The estimate of 10,000 years is not from “somebody that was telling”. It’s from scientists:

Moon, T. A. et al. Greenland Ice Sheet. Arctic Report Card: Update for 2021.
https://arctic.noaa.gov/Report-Card/Report-Card-2021/ArtMID/8022/ArticleID/946/Greenland-Ice-Sheet
Briner, J. P. et al. Rate of mass loss from the Greenland Ice Sheet will exceed Holocene values this century. Nature 586, 70–74 (2020).
https://doi.org/10.1038/s41586-020-2742-6
Dinneen, J. Next 10,000 years of Greenland ice sheet could be decided this century. New Scientist (2023).
https://www.newscientist.com/article/2366749-next-10000-years-of-greenland-ice-sheet-could-be-decided-this-century/

However there is consensus that ice mass loss acceleration could make this time significantly shorter, but improbable within next millenium.

Edit:
within the next  5000 (edit: 50,000) years or so the Earth will enter a new glaciation period.

« Last Edit: July 09, 2023, 03:03:28 AM by nadir »

nadir

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Re: Tipping Points
« Reply #11 on: July 09, 2023, 02:59:49 AM »
Today somebody was telling it takes 10 000 years to melt the entire Greenland ice sheet. But at some point it will start to collaps. The central part of Greenland is lowland, even below sea level. Today you have melt, that's  like an orderley retreat. That lowland invites to destabelise that ice sheet. And as soon you have a part of that ice sheet collapsing. Than what will prevend the entire ice sheet from collapsing ? From north to south, from east to west. Probably nothing. So that's a tipping point. And that you have places that are still a little bit below freezing in summer, is because of the high elevation, the ice is a few km thick. Last week in the north of Greenland, it was almost 20 C .

Also, since I am tired of unscientific alarmism:

The collapse of ice sheets is complex with many factors. Your post implies that the central lowland of Greenland would destabilize the entire ice sheet, which is an incredible unsupported oversimplification. Also, you suggest that if one part of the ice sheet collapses, the entire ice sheet would have to follow. Explain this cause-effect relationship. It's possible for parts of the ice sheet to retreat or collapse without triggering a “total” collapse.

While the concept of a "tipping point" is correct, it doesn't necessarily mean an immediate complete collapse. A tipping point is a threshold beyond which some system changes are irreversible. Parts of the Greenland ice sheet may have already passed such points but significant aggregate changes may not be detectable until over centuries or millennia.

Your mention a temperature of almost 20 C in the north of Greenland, they ARE NOT the norm and are still relatively rare. These temps cannot support the claim of an imminent total collapse.

Your post focuses on melting but doesn't mention that ice also accumulates on Greenland through snowfall. It’s true that melting is currently faster than accumulation, so that ice mass is lost, but how climate change affects this balance in the long term is not clear for scientists (not certainly by you).

Anyway… and this is all to contradict the scientific assessment that Greenland Ice Sheet will last probably for at least another 10,000 years, because real scientists are “too conservative”. It is what it is. Arctic sea ice minima post-2012 are a sobering example that, maybe, real scientists are not too conservative.

zenith

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Re: Tipping Points
« Reply #12 on: July 09, 2023, 03:23:49 AM »
the problem with tipping points is that we won't really understand them until they're in the rear view mirror. canaries in the coal mine are dying left and right though.

For a whole lot of them we know they are there but we don´t do anything about it.

It always was a problem. If we need a BOE to wake up the masses then that is a problem because even the run up to that causes a big shift in global temperatures and the change in weather should be impressive because most of the teleconnections are.

The global fish stock has been moving away from the equator since about 1C over global. It has been mentioned here repeatedly but it has not generated that much discussion. It is a big hint of a change which is really hard to reverse.

Back in the day other ideas were preventing Arctic ice from melting. Of course Antarctica would only be a problem much much later. This Arctic tipping point is now scheduled for next decade so we get to see it.

There are more and of course when one triggers it changes the others.

We have long ago triggered most of them because we assumed we had more margin. A lot of paleo research comes back to huge CO2 numbers but those are wrong. We have a correction from stomata data for one time which shows it is a third lower. Data among geologic ages will vary.

Arctic permafrost went to a source instead of a sink a while ago so what tipping point are we waiting for anyway? The one that changes YOUR life forever? This is a general question.

And for clarity this only means we need more action. Hard caps and energy diets but of course that will not happen.

climate scientists and other scientists that would bring up "faster than expected" and tipping points being crossed would be attacked by other climate scientists as alarmist so...

Faster than forecast, climate impacts trigger tipping points in the Earth system
https://thebulletin.org/2023/04/faster-than-forecast-climate-impacts-trigger-tipping-points-in-the-earth-system/

"Speaking in 2018, Steffen said that the dominant linear, deterministic framework for assessing climate change is flawed, especially at higher levels of temperature rise. Model projections that don’t include these feedback and cascading processes “become less useful at higher temperature levels… or, as my co-author John Schellnhuber says, we are making a big mistake when we think we can ‘park’ the Earth System at any given temperature rise – say 2°C – and expect it to stay there.”"

a few short years ago everything was still framed as 2100. i used to pay attention to all the latest counter-narrative science but once you watch so many dominoes fall and it's all still futuristic the headache isn't worth it.

these are the sci-fi tipping points the economists want to talk about:

Here's what you need to know about positive climate tipping points
https://www.weforum.org/agenda/2023/04/heres-what-you-need-to-know-about-positive-climate-tipping-points/

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Alexander555

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Re: Tipping Points
« Reply #13 on: July 09, 2023, 08:14:59 AM »
Also, since I am tired of unscientific alarmism:

The collapse of ice sheets is complex with many factors. Your post implies that the central lowland of Greenland would destabilize the entire ice sheet, which is an incredible unsupported oversimplification. Also, you suggest that if one part of the ice sheet collapses, the entire ice sheet would have to follow. Explain this cause-effect relationship. It's possible for parts of the ice sheet to retreat or collapse without triggering a “total” collapse.

It's maybe unscientific. But at some point your meltwater will not move to the sea anymore. And that's already happening. If you look at the central part, east and west. Or the north. The highest points are already ice free. So whats the meltwater going to do, it only has one way to go. And you will need more as just a miracle not to have locations were it will not damage your ice sheet from below. Like bottem melt, you get cracks in your ice, a crack is basically a cliff, potentially hundreds of meters high.....So that want be a cliff very long. You have pressure from the ice on the high ground in direction of the lowland all the time. That the ice sheet will collaps is for sure, as you descend further into that lowland. The question is more like, can it start to collaps today. I don't know the conditions of that area. What do you have below that ice sheet, rock, sand, gravel deposits.....

zenith

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Re: Tipping Points
« Reply #14 on: July 09, 2023, 08:53:13 AM »
we'll wait until it's in the rear-view mirror and then we won't have to argue.
Where is reality? Can you show it to me? - Heinz von Foerster

kiwichick16

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Re: Tipping Points
« Reply #15 on: July 09, 2023, 09:17:26 AM »
the northern Greenland ice sheet will exit via this canyon

https://www.nasa.gov/content/goddard/nasa-data-reveals-mega-canyon-under-greenland-ice

kassy

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Re: Tipping Points
« Reply #16 on: July 09, 2023, 09:21:37 AM »
Quote
we'll wait until it's in the rear-view mirror and then we won't have to argue.

That works for so many subjects! I´m all for it.  :)

The story of meltwater on Greenland is much more complex then Alexander thinks. Standing water on the ice is pretty normal and it has interesting effects but at some point it drains down into the ice sheet. For details see the cryo section.

For us it does not really matter what happens in the long run for Greenland melt or Antarctic melt because it is the first few metres of sea level rise that will drown cities.
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sidd

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Re: Tipping Points
« Reply #17 on: July 09, 2023, 10:23:28 AM »
Re: greenland melt timescale

500 yr is the fastest published that i know of, AbruptSLR posted Applegate 2015 a while ago

 https://doi.org/10.1007/s00382-014-2451-7

https://forum.arctic-sea-ice.net/index.php/topic,2444.msg180119.html#msg180119

sidd

etienne

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Re: Tipping Points
« Reply #18 on: July 09, 2023, 10:50:11 AM »
I wonder if we have reached a tipping point regarding trees in western Europe. It is getting very complicated to plant some without watering.

Self reproduction still seem to work, but creating an orchard without watering seems impossible.

kiwichick16

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Re: Tipping Points
« Reply #19 on: July 09, 2023, 11:49:03 AM »
@  kassy ..... it does matter if the Ice Sheets of greenland and antartica melt  , along with the Tibetan Plateau , glaciers worldwide and the sea ice , as they act as a significant part of the planets cooling system and 60 metres of sea level rise also takes out major ( current ) agricultural areas.

kassy

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Re: Tipping Points
« Reply #20 on: July 09, 2023, 11:38:46 PM »
But i said:

For us it does not really matter what happens in the long run for Greenland melt or Antarctic melt because it is the first few metres of sea level rise that will drown cities.

You don´t need to worry about 60 metres because you are dead long before that.
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nadir

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Re: Tipping Points
« Reply #21 on: July 10, 2023, 02:33:03 AM »
Re: greenland melt timescale

500 yr is the fastest published that i know of, AbruptSLR posted Applegate 2015 a while ago

 https://doi.org/10.1007/s00382-014-2451-7

https://forum.arctic-sea-ice.net/index.php/topic,2444.msg180119.html#msg180119

sidd

That’s assuming humans will keep dumping CO2 at current rates. It is clear that this is not going to happen. We’ll be late but not “never”. (Or so I hope).

We have to thank companies like Tesla for showing us a way ( I am not ironical or sarcastic, as much as I don’t believe on Mr. Musk’s missions and visions).

Solar energy boom is unstoppable, I can see it from my balcony, literally.

Next environmental challenge: recycling all the crap from solar panels and lithium batteries.

kiwichick16

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Re: Tipping Points
« Reply #22 on: July 10, 2023, 10:27:23 AM »
@  kassy  ..... sure i'll be dead  ..... but my grandchildren may still be alive ....and their grandchildren

etienne

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Re: Tipping Points
« Reply #23 on: July 10, 2023, 12:49:53 PM »
The first few meters might be so disruptive that the next ones might not matter anymore. The Rhine is only around 17 meters above sea level when it enters in the Netherlands.
If we loose the harbours, our economic model won't work anymore.
You need the low tide to be low enough to remove the rain water of the land without pumping, otherwise energy costs just get too high.

kiwichick16

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Re: Tipping Points
« Reply #24 on: July 10, 2023, 01:52:07 PM »
" eventual global warming due to todays GHG forcing alone - after slow feedbacks operate - is about 10 degrees C "

https://pubs.giss.nasa.gov/abs/ha09020b.html

The Walrus

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Re: Tipping Points
« Reply #25 on: July 10, 2023, 02:04:53 PM »
@  kassy  ..... sure i'll be dead  ..... but my grandchildren may still be alive ....and their grandchildren

Not unless they live for many centuries.

be cause

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Re: Tipping Points
« Reply #26 on: July 10, 2023, 02:27:15 PM »
so eat , drink and be merry , for tomorrow we die !
There is no death , the Son of God is We .

nadir

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Re: Tipping Points
« Reply #27 on: July 10, 2023, 03:16:37 PM »
" eventual global warming due to todays GHG forcing alone - after slow feedbacks operate - is about 10 degrees C "

https://pubs.giss.nasa.gov/abs/ha09020b.html

That’s an interesting paper, but sounds really misaligned with many other recent studies that limit max temperature increase over preindustrial from +2degC to +4degC, in scenarios where carbon emissions cease more or less rapidly but typically before 2050.

Should be noted that James Hansen has some earned fame for leaning towards the side of exaggeration.

Although I admit I have not read the paper thoroughly and probably wouldn’t understand it. They seem to be estimating warming sensitivity to emissions including “slow feedbacks” such as the melt of Ice Sheets. These effects are measured in centuries and milennia. What I don’t understand is how these slow feedbacks keep operating should the Earth start to recover in terms of greenhouse gases in, say, 100 years, especially the slowest one CO2, which would come back to ~300 ppm although it would take many more centuries to decline to preindustrial levels. Isn’t there a sensitivity of the climate to declining greenhouse gases? Only one direction? Something is off.

Chris83

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Re: Tipping Points
« Reply #28 on: July 10, 2023, 03:23:00 PM »
  Carbon sinks turning into carbon emitters is the pathway
  Amazon around 2040 ..becomes a savanna
  Arctic for loss of albedo (also near 2040)
  Boreal forests ..already ongoing  (and swamps and lakes)
  Land now emitting methane ..already ongoing
  Warning of oceans ....trapping less CO2 ....already ongoing

  Going to netzero (which we are not even doing ) doesn't solve the issue and gets us nowhere

  In 2023, we can add Antarctica as a surprise element

etienne

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Re: Tipping Points
« Reply #29 on: July 10, 2023, 04:04:18 PM »
It is like the melting season, it doesn't end June 21st when the sun intensity on the northern hemisphere starts going down.

nadir

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Re: Tipping Points
« Reply #30 on: July 10, 2023, 04:49:18 PM »
It is like the melting season, it doesn't end June 21st when the sun intensity on the northern hemisphere starts going down.
So this is an avalanche that even when the cause ceases it’s unstoppable for thousands of years bringing tens of C of global warming.

Now someone explain the exact mechanisms of that “slow-feedback”. The paper is very vague in explaining specific and detailed mechanisms to cause that.

kiwichick16

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Re: Tipping Points
« Reply #31 on: July 10, 2023, 04:58:45 PM »
@ the Walrus   ......my point exactly ....... my descendents won't get to live at all if we go beyond 2 - 3 degrees of average global warming because the positive feedbacks will overwhelm human efforts to stabilise the climate .......

and nadir ..... why don't you email Mr. Hansen and the 14 other co-authors of the paper and explain where they went wrong.... i'm sure they will be extremely interested in your hypothesis

kassy

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Re: Tipping Points
« Reply #32 on: July 10, 2023, 05:38:19 PM »
@  kassy  ..... sure i'll be dead  ..... but my grandchildren may still be alive ....and their grandchildren

As Etienne wrote they will have to handle severe disruptions. It is not only the loss of the harbors but the sea also pushes the rivers back inland and then you combine this with river levels that are low because of Alpine ice cover loss and internal bulk shipping becomes really problematic. Etc. Oh and farming around the coastal rivers becomes problematic because the salt intrudes.

If you have children you should really not worry about such abstract things as the whole of Antarctica melting. AGW will cause many really bad problems like multiple bread basket failures and depending on the temperature at the time huge swaths of land will not be inhabitable. 

And even if we assume one of the more rosy scenario´s painted about the future they will have to use a lot of their money to remove CO2 and for all kinds of other mitigation measures. 
Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

kassy

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Re: Tipping Points
« Reply #33 on: July 10, 2023, 05:51:45 PM »
It is like the melting season, it doesn't end June 21st when the sun intensity on the northern hemisphere starts going down.
So this is an avalanche that even when the cause ceases it’s unstoppable for thousands of years bringing tens of C of global warming.

Now someone explain the exact mechanisms of that “slow-feedback”. The paper is very vague in explaining specific and detailed mechanisms to cause that.

Eventual global warming due to today's GHG forcing alone — after slow feedbacks operate — is about 10°C. Human-made aerosols are a major climate forcing, mainly via their effect on clouds. We infer from paleoclimate data that aerosol cooling offset GHG warming for several millennia as civilization developed. A hinge-point in global warming occurred in 1970 as increased GHG warming outpaced aerosol cooling, leading to global warming of 0.18°C per decade. Aerosol cooling is larger than estimated in the current IPCC report, but it has declined since 2010 because of aerosol reductions in China and shipping.

...

3.3. Slow, fast and ultrafast feedbacks

Charney et al.4 described climate feedbacks without discussing time scales. At the 1982 Ewing
Symposium, water vapor, clouds and sea ice were described as “fast” feedbacks7
presumed to change promptly in response to global temperature change, as opposed to “slow” feedbacks or specified boundary conditions such as ice sheet size, vegetation cover, and atmospheric CO2 amount, although it was noted that some specified boundary conditions, e.g., vegetation, in reality may be capable of relatively rapid change.7

https://arxiv.org/ftp/arxiv/papers/2212/2212.04474.pdf

So it is every one in the bolded list.

Added direct link to article.
« Last Edit: July 10, 2023, 05:59:04 PM by kassy »
Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

nadir

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Re: Tipping Points
« Reply #34 on: July 10, 2023, 06:20:17 PM »
@ the Walrus   ......my point exactly ....... my descendents won't get to live at all if we go beyond 2 - 3 degrees of average global warming because the positive feedbacks will overwhelm human efforts to stabilise the climate .......

and nadir ..... why don't you email Mr. Hansen and the 14 other co-authors of the paper and explain where they went wrong.... i'm sure they will be extremely interested in your hypothesis

I’m saying that there are many other projections that don’t go beyond 2-4 degC.

Why don’t you go to all other scientists that are predicting much lower impact and tell them they are all wrong, that only Dr Hansen et al 2022 is correct because Kiwi Chick endorses them?

nadir

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Re: Tipping Points
« Reply #35 on: July 10, 2023, 06:41:57 PM »
It is like the melting season, it doesn't end June 21st when the sun intensity on the northern hemisphere starts going down.
So this is an avalanche that even when the cause ceases it’s unstoppable for thousands of years bringing tens of C of global warming.

Now someone explain the exact mechanisms of that “slow-feedback”. The paper is very vague in explaining specific and detailed mechanisms to cause that.

Eventual global warming due to today's GHG forcing alone — after slow feedbacks operate — is about 10°C. Human-made aerosols are a major climate forcing, mainly via their effect on clouds. We infer from paleoclimate data that aerosol cooling offset GHG warming for several millennia as civilization developed. A hinge-point in global warming occurred in 1970 as increased GHG warming outpaced aerosol cooling, leading to global warming of 0.18°C per decade. Aerosol cooling is larger than estimated in the current IPCC report, but it has declined since 2010 because of aerosol reductions in China and shipping.

...

3.3. Slow, fast and ultrafast feedbacks

Charney et al.4 described climate feedbacks without discussing time scales. At the 1982 Ewing
Symposium, water vapor, clouds and sea ice were described as “fast” feedbacks7
presumed to change promptly in response to global temperature change, as opposed to “slow” feedbacks or specified boundary conditions such as ice sheet size, vegetation cover, and atmospheric CO2 amount, although it was noted that some specified boundary conditions, e.g., vegetation, in reality may be capable of relatively rapid change.7

https://arxiv.org/ftp/arxiv/papers/2212/2212.04474.pdf

So it is every one in the bolded list.

Added direct link to article.

No specific and detailed physical mechanisms.

Also, no negative feedbacks. Particularly cloudiness, which can amplify or attenuate. In fact cloud modeling is far from perfect. Or CO2 trapping by oceans. Or in general the role of oceans to reduce abrupt atmospheric heating…

Richard Rathbone

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Re: Tipping Points
« Reply #36 on: July 10, 2023, 06:52:55 PM »
@ the Walrus   ......my point exactly ....... my descendents won't get to live at all if we go beyond 2 - 3 degrees of average global warming because the positive feedbacks will overwhelm human efforts to stabilise the climate .......

and nadir ..... why don't you email Mr. Hansen and the 14 other co-authors of the paper and explain where they went wrong.... i'm sure they will be extremely interested in your hypothesis

I’m saying that there are many other projections that don’t go beyond 2-4 degC.

Why don’t you go to all other scientists that are predicting much lower impact and tell them they are all wrong, that only Dr Hansen et al 2022 is correct because Kiwi Chick endorses them?

4 is the same as 10.



a: Hansen is including 2000 years worth of slow feedback in his 10 which is about a factor of 2 compared to those that don't.
b: Hansen is assuming that the GHGs stay the same but the aerosols go away over the next 2000 years which adds about 2 compared to assuming that the aerosols stay the same as well as the GHG.

(10-2)/2 = 4. He's at the upper end, but not way outside it.


Quote
Also, no negative feedbacks. Particularly cloudiness, which can amplify or attenuate. In fact cloud modeling is far from perfect. Or CO2 trapping by oceans. Or in general the role of oceans to reduce abrupt atmospheric heating…

You really ought to read the paper. All of those are included and several have substantial discussion on them.

nadir

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Re: Tipping Points
« Reply #37 on: July 10, 2023, 07:20:45 PM »
I said that I didn’t completely understand the paper, so,  thanks for the clarification.

Still, thousands of years and the Earth is gonna evolve as predictably as considered in this paper? Maybe that’s why so many other scientists practice caution and project toward more predictable time ranges.

But the 10C prediction is really flashy!! Wow!! And it had to be Hansen!!! I see how this becomes quickly the favorite paper around here.

The Walrus

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Re: Tipping Points
« Reply #38 on: July 10, 2023, 07:29:17 PM »
Is he saying that we will reach 10C in 2000 years, due to slow feedbacks?

etienne

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Re: Tipping Points
« Reply #39 on: July 10, 2023, 07:30:17 PM »
@ Nadir, it is not a prediction, it is a model. Everybody knows that models are wrong for so many reasons, the first one being that unexpected events can happen that have not been predicted in the model. (added) the second one is that all parameters are not taken into account, they probably are not all known, but it works fine enough to help people take decisions.

The aim of a model is to give an idea of what could happen if things would happen a certain way. Most models have different scenarios, but one running on 2000 years is in some aspects a fairy tale. I guess you know that even fairy tales help you to understand the truth.

Added : Models are just a mathematical projection, it doesn't mean that the concept behind it makes sense. So if you don't agree with one, it is better to discuss the starting point than the result.
« Last Edit: July 10, 2023, 08:04:42 PM by etienne »

kiwichick16

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Re: Tipping Points
« Reply #40 on: July 10, 2023, 10:47:47 PM »
@  etienne  .... it would seem obvious that Hansen et al don't want the planet to heat up by 10  degrees  ...... Hansen has repeatedly talked about his family  particularly his grandchildren ......see " Storms of my Grandchildren "  where he states he did not want to say his grandchildren to say that he (Hansen) knew but didn't make it (Global Warming ) clear.

So the paper is an outline of could happen if we don't get our act together , in the same way scientists outlined what would happen if we continued destroying the Ozone Layer. Thankfully since signing the Montreal Protocol the world has significantly reduced the production of ozone depleting gases.

nadir

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Re: Tipping Points
« Reply #41 on: July 10, 2023, 11:30:59 PM »
Is he saying that we will reach 10C in 2000 years, due to slow feedbacks?

I think the double digits are important because Hansen is a scientist-activist. Like the Indiana Jones hat is very important too. You never know where from Latin America he is coming from to unveil some paleoclimate mystery.

Richard Rathbone

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Re: Tipping Points
« Reply #42 on: July 11, 2023, 11:00:24 AM »
Is he saying that we will reach 10C in 2000 years, due to slow feedbacks?

If atmospheric concentrations of GHG stay flat at current composition for those 2000 years.

He's using the longest pipeline possible which leads to the biggest headline number for warming in the pipeline.

He's also using a constant composition rather than a zero emission pipeline, which again leads to the biggest headline number for warming in the pipeline.

He's taken an extreme view on paleo temperatures which leads to the biggest headline number for warming in the pipeline.

He's taken an extreme view on aerosols which leads to ... you guessed it yet? ... the biggest headline number for warming in the pipeline.

He criticises others scientists for taking the route of least drama, and he is deliberately being dramatic in his presentation.

He has arguments for all of these choices and they aren't obviously wrong. However its still a preprint and still being revised. He hasn't managed to convince a journal to publish it yet. Many of his criticisms of other models are long standing and IMO well founded, but I'm not as convinced by his view on paleo temperatures and want to see what that part of his argument looks like in the published version rather than a preprint.

Time will tell, and it won't take 2000 years, a decade or so should be enough to see whether the acceleration in warming he expects has happened or not. Two more Ninas and I expect there'll be enough difference between his plume and the consensus to call it one way or the other.

The Walrus

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Re: Tipping Points
« Reply #43 on: July 11, 2023, 01:27:47 PM »
Is he saying that we will reach 10C in 2000 years, due to slow feedbacks?

If atmospheric concentrations of GHG stay flat at current composition for those 2000 years.

He's using the longest pipeline possible which leads to the biggest headline number for warming in the pipeline.

He's also using a constant composition rather than a zero emission pipeline, which again leads to the biggest headline number for warming in the pipeline.

He's taken an extreme view on paleo temperatures which leads to the biggest headline number for warming in the pipeline.

He's taken an extreme view on aerosols which leads to ... you guessed it yet? ... the biggest headline number for warming in the pipeline.

He criticises others scientists for taking the route of least drama, and he is deliberately being dramatic in his presentation.

He has arguments for all of these choices and they aren't obviously wrong. However its still a preprint and still being revised. He hasn't managed to convince a journal to publish it yet. Many of his criticisms of other models are long standing and IMO well founded, but I'm not as convinced by his view on paleo temperatures and want to see what that part of his argument looks like in the published version rather than a preprint.

Time will tell, and it won't take 2000 years, a decade or so should be enough to see whether the acceleration in warming he expects has happened or not. Two more Ninas and I expect there'll be enough difference between his plume and the consensus to call it one way or the other.

Defnitely an extreme view for the future timeline.  There are way too many variables to make this kind of claim.  I understand he is being dramatic (always has been), but I feel that paople will read this and assume that he is talking about temperatures in the near (not distant) future.  This could be taken the wrong way, and then people will say this was just another false prediction.

kiwichick16

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Re: Tipping Points
« Reply #44 on: July 11, 2023, 02:05:11 PM »
@  the walrus   ... have you read "6 Degrees " by Mark  Lynas ?

The Walrus

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Re: Tipping Points
« Reply #45 on: July 11, 2023, 02:39:21 PM »
@  the walrus   ... have you read "6 Degrees " by Mark  Lynas ?

No, I tend to avoid anything written about science by nonscientists.

kassy

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Re: Tipping Points
« Reply #46 on: July 11, 2023, 02:46:33 PM »
Time will tell, and it won't take 2000 years, a decade or so should be enough to see whether the acceleration in warming he expects has happened or not. Two more Ninas and I expect there'll be enough difference between his plume and the consensus to call it one way or the other.

Yes. It´s the rate that is important and we should be able to tell by then. It would suck if it turns out he is right.

Quote
He's taken an extreme view on paleo temperatures which leads to the biggest headline number for warming in the pipeline.

They just use the existing numbers for two comparisons. I don´t see the extreme view there. One can argue about the choices but that is another thing.



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

Richard Rathbone

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Re: Tipping Points
« Reply #47 on: July 11, 2023, 04:14:27 PM »

Defnitely an extreme view for the future timeline.  There are way too many variables to make this kind of claim.  I understand he is being dramatic (always has been), but I feel that paople will read this and assume that he is talking about temperatures in the near (not distant) future.  This could be taken the wrong way, and then people will say this was just another false prediction.

Its not a prediction, its an assessment of how far out of balance the earth's climate is now.

His predictions for the near future are:
its going to warm up even faster than you now think over the next decade,
weather is going to be even more extreme than you think due to being so far out of balance as well as being warmer.

His warnings are that unless something is done to stop it, the ice caps will entirely melt, sea level rise is going to be 60m, and there'll be a sustained period where the rate of rise is substantial
(based on other publications of his as well as this one I put that at an acceleration to a rate of 5-10cm/year taking 50-200 years to get there and then gradually dropping over the centuries as the ice caps melt away over the next 2000 years.)

Quote from: kassy
They just use the existing numbers for two comparisons. I don´t see the extreme view there. One can argue about the choices but that is another thing.

They select from a range of existing numbers and select at the extreme of James Annan's range.  In James' opinion Tierney found the LGM colder than everyone else did because they implicitly assumed it was colder.
https://bskiesresearch.wordpress.com/2022/05/24/egu-2022/

kiwichick16

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Re: Tipping Points
« Reply #48 on: July 11, 2023, 05:59:53 PM »
@ the walrus  ...... a basic search on Mark Lynas's book would have shown you that it is essentially a summary of scientific papers  . It won the Royal Society prize for science books in 2008 ; Stephen Hawking won the same prize in 2002.

nadir

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Re: Tipping Points
« Reply #49 on: July 11, 2023, 07:22:00 PM »
@ the walrus  ...... a basic search on Mark Lynas's book would have shown you that it is essentially a summary of scientific papers  . It won the Royal Society prize for science books in 2008 ; Stephen Hawking won the same prize in 2002.
And Al Gore won the Nobel Prize, almost back to back with Obama. 👍