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Re: Sea Level Rise Pt. 2

Unread postPosted: Fri 26 May 2017, 09:08:26
by dohboi

Re: Sea Level Rise Pt. 2

Unread postPosted: Mon 29 May 2017, 15:05:51
by dohboi
At least for now, global sea level rise continues it's multi decade pattern of reverting to the trend of 3+ mm of rise per year.

https://www.aviso.altimetry.fr/en/data/ ... level.html

The little plateau in the slr graph over the last year or so must have something to do with El Nino, though I can't quite figure how or what. Any ideas out there?

Re: Sea Level Rise Pt. 2

Unread postPosted: Mon 29 May 2017, 16:20:08
by Subjectivist
dohboi wrote:At least for now, global sea level rise continues it's multi decade pattern of reverting to the trend of 3+ mm of rise per year.

https://www.aviso.altimetry.fr/en/data/ ... level.html

The little plateau in the slr graph over the last year or so must have something to do with El Nino, though I can't quite figure how or what. Any ideas out there?


When El Nino caused a lot of rain and snow far inland in 1997-98 it took three years for all that moisture to make its way to the sea so there was a pause IIRC.

Re: Sea Level Rise Pt. 2

Unread postPosted: Tue 30 May 2017, 07:32:56
by dohboi
Thanks, sub. That occurred to me just after I wrote it, but I wondered if anyone else would see it.

I guess all that extra sea surface warmth really kicks the hydrological cycle into overdrive!

I note that the extra water vapor in the atmosphere in the mean time (before it rains out) is a (mostly) positive feedback that makes el nino years even hotter than they would be without that feedback.

Re: Sea Level Rise Pt. 2

Unread postPosted: Tue 30 May 2017, 14:10:23
by Azothius
The Ghost of Climate-Change Future
As record-breaking high tides overwhelm Hawaii, people are getting a preview of what life will be like in the decades to come.

https://www.theatlantic.com/science/archive/2017/05/the-ghost-of-climate-change-future/528471/

The water is everywhere.

For the second time in a month, Hawaii’s coastlines have been swamped by epic tides. The phenomenon, known as a king tide, is actually a convergence of a few different factors: high lunar tides, rising sea levels associated with last year’s strong El Niño and climate change, swirling pockets of ocean eddies, and a robust south swell—that is, big waves rolling onto south-facing shores.

King tides happen routinely in the Hawaiian Islands—a few times a year, usually—but this year’s batch have been particularly extreme. Data from federal tide stations around Hawaii show that water levels have been up to six inches above predicted tidal heights since early last year. In April, levels peaked at more than nine inches above predicted tides and broke the record high for any water level around Hawaii since 1905. Scientists say the record is likely to be broken again in 2017.

Several Honolulu roadways have been submerged. Beaches have been washed out. Beachfront hotels have canceled shorefront entertainment and readied generators. Property owners living near the coasts were told to move electronics and other valuables up to the second floor of their houses and park their cars elsewhere. People photographed fish swimming down the streets. And all around the islands, small mountains of sand have been deposited in parking lots and other strange places—spots the waves should never reach.

For the people of Hawaii, alarm bells are ringing. King tides like this aren’t just a historic anomaly; they’re a sign of what’s to come. “Within a few decades this will be the new normal,” said Chip Fletcher, associate dean of the School of Ocean and Earth Science and Technology at the University of Hawaiʻi, in a university statement. “Hawaii should consider this a practice run, and reevaluate policies and development practices accordingly.”

Re: Sea Level Rise Pt. 2

Unread postPosted: Thu 17 Aug 2017, 10:51:13
by vox_mundi
A heads-up for Ibon ...

Florida Flood Risk Study Identifies Priorities for Property Buyouts

A study of flood damage in Florida by scientists at UC Santa Cruz and the Nature Conservancy proposes prioritizing property buyouts based on flood risk, ecological value, and socioeconomic conditions. Forecasters say an above-normal hurricane season is likely in the Atlantic Ocean this year, while a rising sea level is making Florida increasingly vulnerable to dangerous flooding.

The study shows the location of more than 15,000 repetitive loss properties in Florida which, collectively, filed more than 40,000 claims against the National Flood Insurance Program between 1978 and 2011 (more than 1,200 claims per year, on average). As of March 2016, the National Flood Insurance Program, which is up for reauthorization in 2017, owed the U.S. Treasury $23 billion.

"This study identified properties and surrounding land in Florida where buyouts can reduce future flood risk to socially vulnerable communities and simultaneously promote the restoration of the floodplain to a more natural condition," said lead author Juliano Calil. "We identified almost 150 properties in Miami-Dade County alone that are located in areas where these objectives are very well aligned."

Juliano Calil et al, Aligning Natural Resource Conservation, Flood Hazard Mitigation, and Social Vulnerability Remediation in Florida, Journal of Ocean and Coastal Economics (2017). DOI: 10.15351/2373-8456.1074

Image
https://www.researchgate.net/figure/319 ... -and-TNC's

Re: Sea Level Rise Pt. 2

Unread postPosted: Sat 19 Aug 2017, 10:58:55
by dohboi
Nice link and article, vox, but that map seems a bit...optimistic, perhaps?

Meanwhile:
Federal Flood Insurance Rebuilds Homes Over and Over, Trapping Residents in Flood-Prone Areas

"The National Flood Insurance Program was designed to help Americans recover from flood disasters, but it can also unintentionally trap homeowners who would prefer to move somewhere safer," the NRDC said on its website. "Instead of moving out of harm’s way, many policyholders find themselves rebuilding their homes again and again."

https://weather.com/amp/science/environ ... apped.html

Re: Sea Level Rise Pt. 2

Unread postPosted: Mon 04 Sep 2017, 07:53:00
by Zarquon
Drilling for oil, rising sea levels and the disappearing wetlands in Louisiana:

http://mondediplo.com/2015/11/11louisiana

Re: Sea Level Rise Pt. 2

Unread postPosted: Tue 26 Sep 2017, 13:56:20
by dohboi

Re: Sea Level Rise Pt. 2

Unread postPosted: Tue 26 Sep 2017, 17:30:41
by 35Kas
What needs to happen is that houses built on flood plains that get destroyed, and are insured under this retarded federal program, should get bought out under the terms and demolished, prohibiting re-development of such land.

Continuously wasting resources to re-build houses that get repeatedly damaged/destroyed under federal incentives is another stupid rule that must go.

Re: Sea Level Rise Pt. 2

Unread postPosted: Tue 26 Sep 2017, 18:04:15
by Plantagenet
35Kas wrote:What needs to happen is that houses built on flood plains that get destroyed, and are insured under this retarded federal program, should get bought out under the terms and demolished, prohibiting re-development of such land.

Continuously wasting resources to re-build houses that get repeatedly damaged/destroyed under federal incentives is another stupid rule that must go.


Once a benefit is bestowed by the federal government, it cannot be taken back.

Every benefit creates a constituency that demands that its special deal not be cut.

Just add flood insurance to long list of highly inefficient government programs and subsidies along with Obamacare, biofuels, charitable deductions, state income tax write-offs, etc. etc. that can be "reformed"....which almost always means expand it and add in more money----, but will never be repealed.

Cheers!

Re: Sea Level Rise Pt. 2

Unread postPosted: Tue 24 Oct 2017, 21:24:42
by dohboi
Possibly meters of sea level rise within decades?

https://www.nature.com/articles/s41467-017-00966-x

Re: Sea Level Rise Pt. 2

Unread postPosted: Tue 24 Oct 2017, 22:59:22
by dissident
dohboi wrote:Possibly meters of sea level rise within decades?

https://www.nature.com/articles/s41467-017-00966-x


But we have had very large and rapid melting events in the last 20,000 years. The current melting is slow in comparison.

Instead of looking to the past with sub 320 ppmv CO2, we have to deal with the looming cataclysms that advanced primates have never seen. Hansen's estimates of sea level rise are probably the most likely since there will be an acceleration of the melt between now and 2100. Unlike the transient spikes in melting and sea level rise after the last glacial maximum, the new regime is relentless melting and warming. There will not be decades and centuries of cooling. The cooling will have to wait for tens of thousands of years in order for the carbon reservoirs that are going to be released to deplete and for the CO2 to be chemically weathered to concentration levels where the ocean sink can re-appear.

Re: Sea Level Rise Pt. 2

Unread postPosted: Wed 25 Oct 2017, 14:49:35
by dohboi
Good points. The main thing I take away from the paper is that we should expect a smooth rate of srl going forward, or even a smoothly accelerating rate of sea level rise.

Rather, we will have periods of very rapid sea level rise. So complacency about our ability to gradually adjust to incremental slr over the decades and centuries is...misplaced, for this and other reasons.

But yeah, even these high historic rates should not be seen as the upper possible limit, more likely they are the least we can expect going forward, given the extreme forcings we are introducing into the system.

Re: Sea Level Rise Pt. 2

Unread postPosted: Thu 26 Oct 2017, 15:42:21
by dohboi
And...here's more on why sea level rise is likely to see some rather precipitous sudden increases at some point:

Evidence of paleoclimate Pine Island Glacier Cliff effect collapse during end of last ice age.

https://www.washingtonpost.com/news/ene ... 16ef3c6d1b

What’s critical about the markings, explains lead study author Matthew Wise of the University of Cambridge, is their maximum depth — 848 meters, or around 2,800 feet. Because ice floats with 10 percent of its mass above the surface and the remaining 90 percent below it, this suggests that when the ice broke from the glacier, close to 100 meters (over 3oo feet) of it was extending above the water surface.

That’s a key number, because scientists are converging on the belief that ice cliffs of about this height above the water level are no longer sustainable and collapse under their own weight — meaning that when you get a glacier this tall up against the ocean, it tends to crumble and crumble, leading to fast retreat and potentially fast sea level rise.

“If we think about how thick these icebergs would have needed to be considering these float with 90 percent of their mass and thickness beneath the sea,” Wise said, “we think of an ice cliff that was at the maximum thickness implied by the physics of the ice.”

The problem is that if it happened then, well, it could happen again. Both Pine Island glacier and its next door neighbor, Thwaites, are known to get thicker as one travels inland away from the sea, which means they are capable of once again generating ice cliffs taller than the critical size detected by the current study.

“If a cliff even higher than the ~100 m subaerial/900 m submarine cliffs were to form, as might occur with retreat of Thwaites Glacier in West Antarctica, it might break repeatedly with much shorter pauses than now observed, causing very fast grounding line retreat and sea level rise,” explained Richard Alley, a glaciologist at Penn State University, by email after reviewing the current study for the Post.
(my emphases)

More here:


Evidence of marine ice-cliff instability in Pine Island Bay from iceberg-keel plough marks


http://www.nature.com/nature/journal/v5 ... Y1MDUzNQS2

and an illustration of the concepts..
http://www.nature.com/nature/journal/v5 ... 58_F4.html

and all the figures at:
http://www.nature.com/nature/journal/v5 ... 58_ft.html

From the abstract...

From the planform shape and cross-sectional morphologies of iceberg-keel plough marks, we find that iceberg calving during the most recent deglaciation was not characterized by small numbers of large, tabular icebergs as is observed today which would produce wide, flat-based plough marks or toothcomb-like multi-keeled plough marks. Instead, it was characterized by large numbers of smaller icebergs with V-shaped keels.

'Our findings demonstrate the effective operation of Marine ice-cliff instability (MICI) in the past, and highlight its potential contribution to accelerated future retreat of the Antarctic Ice Sheet.

Re: Sea Level Rise Pt. 2

Unread postPosted: Fri 27 Oct 2017, 05:59:05
by Plantagenet
Good find Doh. Thx.

I really appreciate the time and work you put into finding and posting these new studies.

Cheers!

PS I’m down from Everest Base Camp and back in Kathmandu w access to internet again

Re: Sea Level Rise Pt. 2

Unread postPosted: Fri 27 Oct 2017, 06:35:05
by dohboi
You're welcome and thanks for noticing.

Stay safe, man

Re: Sea Level Rise Pt. 2

Unread postPosted: Fri 27 Oct 2017, 06:58:38
by Ibon
The accelerated movement of the Pine Island and Thwaites Galcier made it on the front page of the NYT today with animated graphics of the movement of ice.

Re: Sea Level Rise Pt. 2

Unread postPosted: Fri 27 Oct 2017, 08:07:18
by GHung
Plantagenet wrote:Good find Doh. Thx.

I really appreciate the time and work you put into finding and posting these new studies.

Cheers!

PS I’m down from Everest Base Camp and back in Kathmandu w access to internet again


The main Everest climbing season ended 4 months ago. What, pray tell, were you doing there? Fall viewing?

Re: Sea Level Rise Pt. 2

Unread postPosted: Fri 27 Oct 2017, 09:34:57
by Plantagenet
There’s another bit of good weather here in the high Himalayas in the early fall....After the monsoons end but before winter really settles in. We’ve had sunny weather every day on the trek up to Everest Base Camp—- even above 17000 feet it was pretty nice —- you could get by with a light down coat during the day

There was a small sign of global warming— a GLOF ie Glacial lake outburst flood down the Khumbu but it didn’t take out the bridges or trail.

Cheers!