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NotaDenier

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Global Mean Sea Level
« on: July 21, 2019, 03:42:50 PM »
https://sealevel.nasa.gov/understanding-sea-level/key-indicators/global-mean-sea-level

I found an interesting site this morning. It looks like they only update periodically. I wonder if we will see a more than usual rise in sea level after this NH summer with a greater than usual amount of melt from Greenland.

Tom_Mazanec

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Re: Global Mean Sea Level
« Reply #1 on: August 17, 2019, 04:51:39 PM »
Excellent site, thank you, NotaDenier.
Talking about Sea Level Rise, Paul Beckwith has just posted videos predicting 7 meters by 2070. Is he another Sam Carana, or is this actually within the realms of possibility?

https://paulbeckwith.net/2019/08/10/vulnerability-and-mayhem-greenland-blue-ocean-events-accelerating-sea-rise/
https://paulbeckwith.net/2019/08/16/accelerating-sea-level-rise-vacation-from-increased-extreme-weather-frequency-severity-duration/

In this video I expand upon my argument that global sea level will indeed rise 7 meters by 2070, as I originally discussed over 5 years ago in a video.

An Arctic Blue-Ocean Event (BOE) is likely by 2022 and will cause very large warming spikes that will further expose Greenland to:
accelerated, catastrophic ice loss with an abrupt increase in the frequency, severity, and duration of extreme weather events globally, as well as very rapid sea level rise.
As I said 5 years ago, I expect global sea level to: rise 7 m by around 2070, about 3.5 m by 2063, and about 1.75 m by 2055 or so.
———- ———- and
An Arctic Blue-Ocean Event (BOE) that is very likely by 2022 will cause very large Arctic warming. With no sea-ice left to melt, we lose our Arctic “refrigerator” and all that previous “latent heat” will now be “sensible heat” jacking up temperatures. This will further expose Greenland to accelerated, catastrophic ice loss with rapid sea-level rise and abrupt increases in frequency, severity, duration of extreme weather events globally.


fschmidt

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Re: Global Mean Sea Level
« Reply #2 on: August 18, 2019, 10:40:08 PM »
The arctic will be free in September and refreeze in winter. I don't see a fundamental change to the situation today as the amount of old ice is already very low.

oren

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Re: Global Mean Sea Level
« Reply #3 on: August 18, 2019, 10:49:19 PM »
He's certainly way out there.  His videos are not science.
I love how he back-end his promises. By 2055 he may still be considered a prophet. By 2070 his BS is exposed.

Tom_Mazanec

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Re: Global Mean Sea Level
« Reply #4 on: August 19, 2019, 01:29:34 PM »
He's certainly way out there.  His videos are not science.
I love how he back-end his promises. By 2055 he may still be considered a prophet. By 2070 his BS is exposed.

I have a feeling he won't be around to answer for his BS in 2070 anymore  ;D

Tom_Mazanec

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Re: Global Mean Sea Level
« Reply #5 on: August 19, 2019, 05:40:33 PM »
While Singapore hopes never to go to war, it cannot avoid taking on another threat to the country's existence: climate change.
Sea levels will rise, posing a grave threat to the low-lying island, said Prime Minister Lee Hsien Loong yesterday.
The only question is when. He estimates it will cost $100 billion or more, over 100 years, to protect the country against rising sea levels.
https://www.straitstimes.com/singapore/sea-level-rise-poses-threat-to-spore

Tom_Mazanec

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Re: Global Mean Sea Level
« Reply #6 on: November 19, 2019, 02:46:25 PM »
Sea Level: Gridded Average
https://tamino.wordpress.com/2019/11/08/sea-level-gridded-average/
Quote
I’ve formed a gridded composite sea level estimate and I’d like to share it. It’s quite crude, but some compensation is necessary because a simple average of stations is dominated by Europe and North America, there are so many tide gauge stations there. My regional breakdown was a first step; this is the next.
The graph on this article is...scary.

Stephen

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Re: Global Mean Sea Level
« Reply #7 on: December 09, 2019, 01:05:55 PM »
He's certainly way out there. 

James Hansen was quoting similar possible sea-level rises about 10 years ago. It presumes doubling of the rate of rise every 10 years.  He wasn't predicting it as a certainty, but putting it forward as a possibility for discussion  This is exactly what scientists should be able to do as a matter of course and they should not be criticized for it.
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kiwichick16

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Re: Global Mean Sea Level
« Reply #8 on: July 15, 2023, 07:57:30 AM »
this paper from Hansen et al suggests doubling times of 10, 20, or 40 years

0s.html#:~:text=We%20hypothesize%20that%20ice%20mass,50%2C%20100%20or%20200%20years.

kiwichick16

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Re: Global Mean Sea Level
« Reply #9 on: July 15, 2023, 07:58:43 AM »

kiwichick16

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oren

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Re: Global Mean Sea Level
« Reply #11 on: July 15, 2023, 02:00:21 PM »
Yes, it works now. BTW, this paper was discussed hereabouts a long time ago.

kiwichick16

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Re: Global Mean Sea Level
« Reply #12 on: July 15, 2023, 02:32:34 PM »
@  oren   yeah figured that    ...... just thought it was worth mentioning that the paper suggested 3 options for doubling times  .....the implication from my reading was that they needed more data

Espen

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Re: Global Mean Sea Level
« Reply #13 on: July 15, 2023, 04:25:41 PM »
Just another stupid Q? Why is this thread in "Glaciers" section?
Have a ice day!

oren

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Re: Global Mean Sea Level
« Reply #14 on: July 15, 2023, 06:05:21 PM »
Good point. It really shouldn't be in Cryo at all. I will try to move it to Kassy's domain.

John_the_Younger

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Re: Global Mean Sea Level
« Reply #15 on: July 15, 2023, 06:31:42 PM »
Why this section? I have no idea about its genesis, but the presence or absence of glaciers on this green, brown, white and blue ball is the single most important factor determining sea level.  (Ocean temperature, I believe, is second on a human time scale, and global tectonics is a [geological time] factor.)

oren

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Re: Global Mean Sea Level
« Reply #16 on: July 15, 2023, 06:42:52 PM »
True but I think it fits better in consequences.

gerontocrat

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Re: Global Mean Sea Level
« Reply #17 on: July 15, 2023, 08:45:04 PM »
I attach a graph of sea level rise since 1993 from the best data I can find buried in the Earthdata Cloud.

The acceleration in annual sea level rise has not happened - yet.

ps: Data is to 5 March 2023. Experience suggests we will see another 3 months data posted sometime next month, and at the same time Qu2 Ocean Heat data and maybe another 3 months Grace-FO data.
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oren

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Re: Global Mean Sea Level
« Reply #18 on: July 15, 2023, 08:49:10 PM »
I do see a slight acceleration in this chart, but it's still deep within the noise level.

CalamityCountdown

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Re: Global Mean Sea Level
« Reply #19 on: July 15, 2023, 10:09:48 PM »
While there is only a slight acceleration during the satelite era, coastal tide gage reports from 1900-2018 seems to indicate that there has been some accleration in sea level rise during the past two decades. Of course, this is only valid if the coastal tide gage data is accurate.

neal

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Re: Global Mean Sea Level
« Reply #20 on: July 17, 2023, 05:44:12 AM »
an oddity in sea level

...A vast expanse of the Indian Ocean is a staggering 100 meters lower than the global average sea level because of a major dip in Earth’s gravity. Scientists now think they know the cause...

https://www.scientificamerican.com/article/giant-gravity-hole-in-the-ocean-may-be-the-ghost-of-an-ancient-sea1/

anthropocene

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Re: Global Mean Sea Level
« Reply #21 on: July 17, 2023, 09:09:36 AM »
I attach a graph of sea level rise since 1993 from the best data I can find buried in the Earthdata Cloud.

The acceleration in annual sea level rise has not happened - yet.

ps: Data is to 5 March 2023. Experience suggests we will see another 3 months data posted sometime next month, and at the same time Qu2 Ocean Heat data and maybe another 3 months Grace-FO data.

Acceleration has happened. All you need is the correct data and correct statistical analysis. Tamino has covered this several times (mainly for US East coast stations) but this is a global/satellite data analysis they did: https://tamino.wordpress.com/2019/12/10/a-century-and-more-of-sea-level-acceleration/

Somebody mentioned Hansen's suggested doubling period. The doubling period was for mass-loss from major land based ice (Greenland and Antarctica). Since at the time of publication, thermal expansion was still a significant component to sea-level rise this was NOT a prediction for doubling period of speed of sea-level rise in the short term.

Renerpho

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Re: Global Mean Sea Level
« Reply #22 on: July 17, 2023, 10:08:59 AM »
A vast expanse of the Indian Ocean is a staggering 100 meters lower than the global average sea level because of a major dip in Earth’s gravity.

The phenomenon is real, the description in the article is possibly misleading. Of course the entire Indian Ocean is at sea level, not 100 meters below it, because that's part of what defines sea level. The "hole" is relative to a simple model of Earth's shape. By a similar argument, Earth's poles are tens of kilometers below sea level (due to the flattening of the Earth).

Incidentally, I explained the data behind that "geoid" model in my very first post in this forum. https://forum.arctic-sea-ice.net/index.php/topic,520.msg217893.html#msg217893
Before I came here I was confused about this subject. Having listened to your lecture I am still confused. But on a higher level.

John_the_Younger

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Re: Global Mean Sea Level
« Reply #23 on: July 17, 2023, 10:51:55 PM »
Indian Ocean as a hole...
I visited a steep Sri Lankan pebble beach once (yeah, on the Indian Ocean) and the rip tide appeared to be so strong that if someone stepped into the water to ankle depth (a large step from 'dry' shore) it would pull them in than out.  (I didn't test my theory.)

(I enjoyed studying aspects of the geoid in a techtonics class - I recall learning that the highest point of land above the geoid is in Hawaii, not Nepal/China.)

Renerpho

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Re: Global Mean Sea Level
« Reply #24 on: July 17, 2023, 11:00:18 PM »
I recall learning that the highest point of land above the geoid is in Hawaii, not Nepal/China.

I think that's a misunderstanding. The geoid defines the shape of mean sea level. The highest point of the geoid is actually in Iceland, at a staggering height of 85 meters. The lowest, as mentioned, is in southern India, at -106 meters. Gravity is equal everywhere on this shape (by definition), so tides are not affected by it. What you saw on Sri Lanka would have a different reason.



Maybe you mean the highest mountain, measured from the base, which is in fact Mauna Kea, Hawaii.

Before I came here I was confused about this subject. Having listened to your lecture I am still confused. But on a higher level.

John_the_Younger

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Re: Global Mean Sea Level
« Reply #25 on: July 18, 2023, 12:50:10 AM »
Sounds right - bad memory...