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Messages - Susan Anderson

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Antarctica / Re: Thwaites Glacier Discussion
« on: January 23, 2020, 10:47:12 PM »
The latest Sentinel picture gave insight into the further development on the "peeling-off" of the Thwaites Ice Tongue.
The flow direction remains the same as it has been on Dec 24 (see my posting above) and is indcated by blue arrows. Therefore the gap has widened massively (large pale green circle) and lengthened in S direction (small pale green circle). A newly developed crack SE of it (red lines) seems to indicate that the "peeling off line" will march further southeast and probably include all the ice west of that N-S crack.
The NW directed movement also makes the gap between the Thwaites Ice Tongue and the icebergs west of it smaller, because they move in NNE direction.

In addition I still see the mini polynya which I had "explained" by the sunk iceberg (pale magenta circle)  ;)

See attached picture

Antarctica / Re: Thwaites Glacier Discussion
« on: October 19, 2019, 08:09:34 AM »
A quick update.  I was able to fairly easily (details below) add the grounding lines through late November 2017 (2017.91 in decimal years) as a very faint (30% opacity) overlay.  It's a very busy diagram, but I hope at some point to be able to mask out the extraneous details and increase the opacity.

In general, I was quite surprised at the size of the ground line retreat.  Seeing it laid on top of the satellite images I have grown quite familiar with was a bit of a shock.  Also, at first glance, it would appear that there has been some additional grounding line retreat in the last two years.  In particular, the West side of the "Butterfly" looks like it is no longer grounded, although it should probably be compared to older satellite images to see if it is a new feature or not.

Edit: Added an annotated version.

This is Figure 1(B) from Milillo 2019 "Heterogeneous retreat and ice melt of Thwaites Glacier, West Antarctica"

The only way I found to obtain a high resolution image of the figure was to click on the "View this article with LENS" button, then click on "Figures" and click on Figure 1.  I cropped and masked the figure to just get the bathymetry, then rotated it clockwise 70 degrees and scaled it down 4% (0.96 scaling.)  The 1996 grounding lines then lined up quite nicely, yellow in Milillo and Red in Millan.

Antarctica / Re: Where is D-26 headed?
« on: October 17, 2019, 08:20:23 PM »
An iceberg as big as D-26 will stick down 300 m or more into the sea.  Currents at that depth are not necessarily going where the wind is blowing.  As for thinning, the temperature at 300 m is most likely warmer than the surface water, so most melting will occur from the bottom. However, being a tabular berg, it will just sink lower--the freeboard will remain about 10% of the total thickness.

Antarctica / Re: Thwaites Glacier Discussion
« on: October 14, 2019, 08:45:51 PM »
I think it's time for an overview of the whole ice front of Thwaites Glacier so the discussion of various areas can be put in context.  The image below is from October 4 and I discuss the major sections from top to bottom (East to West.)  The image size is 112 km on a side and the width of the front as a whole is about 120 km.

Eastern Calving Front:  This is my designation.  It is usually considered to be part of the Eastern Ice Shelf, but this section does not seem to be directly pinned to the offshore ridge.  However it is slow moving because the ice behind it is probably affected by the pinned ice shelf.

Eastern Ice Shelf:  Ice that is caught directly between the glacier behind it and the undersea ridge in front of it.  This shelf was found to have thinned from 10 to 33 percent between 1978 and 2009 after early films of ice penetrating radar were recently digitized.

Melange:  Irregularly shaped ice that has calved from a transition zone between the slow moving Eastern Shelf and the fast moving Tongue.  It tends to stay trapped between the shelf and the tongue before reaching open water after 5-10 years.

Tongue:  Ice that calves from the fasting moving part of Thwaites Glacier, often called the Main Trunk, and tends to stay in formation until it passes over the submerged offshore ridge.  The trunk and the tongue move at about 5 km/year.  The ice tends to calve in long transverse pieces about 10 km long and 1 km wide, which then breakup into roughly 1km squares and get glued to each other with sea ice over many winters before finally breaking up.

Western Calving Front:  This used to be a slower moving part of the Tongue, but now the calving ice tends to float free although it doesn't always move away quickly.  There is usually a lot of ice just offshore combined with ice from the neighboring Haynes Glacier and the Crosson Ice Shelf fed by the Pope and Smith Glaciers.  The Western Calving Front is very close to the Thwaites grounding line in this sector, about a km at points.  The worst case scenario for Thwaites would be if the entire front were to degrade into a calving front like this sector, just dumping icebergs out near the grounding line and providing no buttressing to the glacier.

Antarctica / Re: Thwaites Glacier Discussion
« on: October 13, 2019, 10:53:10 PM »
Is there any order of magnitude how long a Thweites collapse would take?
A month, a year, a decade, a century?

Let me try to rephrase my answer.  Once the collapse "starts" it could take decades to wipe out most of the West Antarctic Ice Sheet.  But best guesses for WHEN it starts, is on the order of centuries and maybe millenia.

But on the other hand, things are happening at Thwaites.  The Tongue is much shorter and narrower than it was.  It is moving much faster and the ice is thinner.  Frankly, the Tongue could be gone after this Antarctic Summer.  Once the Tongue goes, the melange will probably float off also, exposing the Western side of the TEIS to open water during the summers.  We will see calving on both the western and eastern sides of the TEIS narrowing the ice shelf until it becomes unstable.  Collapse of the TEIS will speed up the ice on the Eastern half of Thwaites, pushing back the grounding line.  Then it will be just a matter of time.

Of course, the events above could be delayed for years or even decades.  Or the Tongue and TEIS may reform after collapsing.  The point is that there is plenty to watch for on the remote sensing front, and plenty of academic papers in the pipeline.  Things may happen slowly, but it won't be boring.

Antarctica / Re: Thwaites Glacier Discussion
« on: October 13, 2019, 08:03:37 PM »
Respectable scientists try not to be alarmists.  I got interested in Thwaites when I heard Richard Alley say it was something like "50 years give or take 50 years."  Maybe it was somewhere in this talk: but he has moderated his language somewhat since then to say that there is a risk that it could happen in decades but it may never happen.  More of a risk analysis rather than a prediction.

On the other hand, a paper published last December tried to model the collapse of Thwaites and it didn't see anything major for 30 years and the 100 year predictions were for something like a contribution of only 8 inches of sea level.

But if you read the paper, under section 4.6 "Limitations of the model study" you find "Another limitation is that the ice shelf front migration is not included in our simulations. We assume that the ice shelf front position of TG remains fixed" and later "The eastern ice shelf has been thinning and retreating, which means that the ice shelf could disintegrate in the coming decades."

It is hard to understand exactly what they are saying here.  They are making 100 year predictions assuming that the Eastern Ice Shelf remains fixed, yet they freely admit that the Eastern Ice Shelf could disintegrate in the coming decades.

Anyone who looks closely, knows that the Thwaites Eastern Ice Shelf (TEIS) is doomed to collapse in the next ten years.  The ice is visibly sliding eastward off the forward buttress which is at an angle to the current ice movement and not in a position to stop the forward progress.  (See GIF below.)  Meanwhile, the ice on the Western side of the TEIS has broken away (including the "cork" above) leaving no new ice to form a replacement TEIS.  It's impossible to say if the ice further inland might reform TEIS a few years after the collapse, but in my mind it is hard to find solace in these 100 year models based on the "stability" of the TEIS.

The models say that the Eastern half of Thwaites is the one most likely to collapse first, but the Eastern half is currently buttressed by the TEIS.  If the TEIS collapses and the Eastern half starts moving as fast as the Western half is currently, about 5km/year, I don't see how these 100 year predictions are worth anything.

The academic push has been to say "let's really study Thwaites" and they've done one season of observations so far.  Over the next 5 years expect to see a lot more papers published, but in the mean time, all we can do is watch the ice.

Arctic sea ice / Last Stand of The Fossil Fools
« on: October 06, 2019, 02:24:38 AM »
The topic might seem OT for this part of the forum, but it is quite literally (verbally in the video) about the Russian Arctic Sea (but also the Oklahoma State Seismologist).

Since quite some time I've been saying this. Not only on the polit threads here. Meanwhile Rachel Maddow seems to have written the (i.e. first) magisterial book about it. (Out right now, not yet ordered.)

What Lawrence O'Donnell couldn't make sense of (5:40) and let Rachel M read out herself is exactly what I mean when I try to explain the Trumputin nexus. It is where Post Truth Age meets fossil economics meets Arctic Sea Ice:

The politics / Re: The Media: Examples of Good AND Bad Journalism
« on: September 29, 2019, 06:33:37 PM »
No, Klein's point in the passage is that the term "neoliberal" gets used loosely, vaguely, and over-flexibly.  It's true.  One example is that Warren's stated policy positions cannot remotely be called neoliberal by any clear definition of the term.

So you disagree with the Wikipedia definition of the word. Why is that?

The definition is fine.  It doesn't describe Warren's stated policy positions.

The rest / Re: Systemic Isolation
« on: September 29, 2019, 05:58:18 PM »

Antarctica / Sea Ice in Amundsen Sea / Pine Island Bay
« on: September 29, 2019, 05:32:03 PM »
I start this topic to discuss the different patterns of sea ice and its melting during austral summer which should be separated from Thwaites Glacier / Pine Island Glacier calving events (see the individual threads).
I compared the last for years (see attached pictures from EOSDIS Worldview), which differ widely in extent and structure of the sea ice. I chose clear days, so all pictures are from around end September, but not at the same date. In this time of the year the changes from day to day can be relevant.
2016 saw in general a low sea ice cover in that area, 2017 had the closest ice cover. All pictures show the SE→NW flow of the ice.

The politics / Re: The Koch Watch Thread
« on: September 29, 2019, 10:26:11 AM »

The politics / Re: Russia, Russia, Russia
« on: September 29, 2019, 06:41:31 AM »
Did I say "information warfare" somewhere on this thread?
(Here is some engineering quality manager's delight: A Soviet system switchboard, with a ladder ready-to-hand (*), in a Ukrainian power station hacked by Russians. Much safer than American power stations (apropos Rachel Maddow being hysterical hahaaaaaaaaaaahahaha... :) ))
(Plus, some paradigmatic specimens of hackerz (autism spectrum, psychopathy, ?)...)
{ca. 35m}

Possibly the first instance when I turned down YouTube playback speed. And it was for Putin (1h16m ff. standing next to a grinning Macron) pondering cyberspace and the atom bomb.

This one is in German, but there's also a French version somewhere.

{Should be cross-posted in the "Examples of ... Journalism" thread here, which I promise to not touch.}


The politics / Re: The Koch Watch Thread
« on: September 28, 2019, 10:09:04 PM »

The politics / Re: The Koch Watch Thread
« on: September 28, 2019, 10:50:00 AM »
Alec Energy Task Force Members Uncovered

The American Legislative Exchange Council (ALEC) and its Energy, Environment and Agriculture (EEA) task force has been the source of a number of “model” bills and resolutions introduced in state legislatures across the country that benefit the fossil fuel industry and weaken environmental protections. A registration list obtained by Documented from a FOIA provides a rare glimpse at the fossil fuel corporations, utilities, industry trade associations, right-wing think tanks and legislators behind many of these policies.

Link >>

Antarctica / Re: Thwaites Glacier Discussion
« on: September 27, 2019, 06:53:15 PM »
Another possibility is that we are seeing an artifact of instrument calibration or image alignment associated with stitching together pixels captured from different angles by a moving instrument. Perhaps the next image will offer a useful comparison.

I know my immediate thought was that it was an artifact, but on closer look there is no evidence for it.  As for waiting for another image, here is a comparison of two images, different from the previous two, taken on 9/22 and today, 9/27.  They are from wider view images and are therefore at a lower resolution than the previous images, but they show they same separation.

The politics / Re: The Koch Watch Thread
« on: September 27, 2019, 06:01:04 PM »
Thanks, for contributing, Susan! :)

Antarctica / Re: The Amery Ice Shelf Thread
« on: September 26, 2019, 07:11:03 PM »
And to make the collection complete, here is the Sentinel radar, 20. vs 25.

Antarctica / Re: Thwaites Glacier Discussion
« on: September 02, 2019, 11:31:36 PM »
Vintage Film Shows Thwaites Glacier Ice Shelf Melting Faster Than Previously Observed

Newly digitized vintage film has doubled how far back scientists can peer into the history of underground ice in Antarctica, and revealed that an ice shelf on Thwaites Glacier in West Antarctica is being thawed by a warming ocean more quickly than previously thought. This finding contributes to predictions for sea-level rise that would impact coastal communities around the world.

... The researchers made their findings by comparing ice-penetrating radar records of Thwaites Glacier with modern data. The research appeared in Proceedings of the National Academy of Sciences Sept. 2.

"By having this record, we can now see these areas where the ice shelf is getting thinnest and could break through," ... "This is a pretty hard-to-get-to area and we're really lucky that they happened to fly across this ice shelf."

The researchers identified several features beneath the ice sheet that had previously only been observed in modern data, including ash layers from past volcanic eruptions captured inside the ice and channels where water from beneath the ice sheet is eroding the bottom of ice shelves. They also found that one of these channels had a stable geometry for over 40 years, information that contrasts their findings about the Thwaites Glacier ice shelf, which has thinned from 10 to 33 percent between 1978 and 2009.

Dustin M. Schroeder el al., "Multidecadal observations of the Antarctic ice sheet from restored analog radar records," PNAS (2019)

Antarctica / Re: SH Polar Vortex
« on: August 25, 2019, 04:35:45 AM »
There is now a Sudden Stratospheric Warming event in place over the Antarctic. Judging by the effects these have in the northern hemisphere we will be seeing effects on the polar vortex and decreased ice extent over the coming months. These SSW's are very rare in the southern hemisphere but we are likely to be seeing more and more of them.

The politics / Re: Russia, Russia, Russia
« on: August 24, 2019, 07:42:13 AM »
'stupid niggers vote against their best interests because they are brainwashed by Moscow'
Can you explain what your point is here, or maybe evidence of anyone saying something like this?
 (I get that the quoted passage is not a representation of your thoughts)

I'm referring to this insanity. Russiagate isn't just used as smoke and mirrors to hide systemic defects and personal failure of Democrats in high positions, but also to kneecap any left-of-center movements that could successfully question and thus change the system.

Let's do some fact-checking on that statement.

The 'insanity' you are referring to is a NYT article :
which quotes two studies that conclude that Russian 2016 Influence Operation Targeted African-Americans on Social Media more than other ethnic groups.

One study is from the University of Oxford :

Here are some of the statements from that report :

Russia's IRA activities were designed to polarize the US public and interfere in elections by:
o campaigning for African American voters to boycott elections or follow the wrong voting
procedures in 2016, and more recently for Mexican American and Hispanic voters to
distrust US institutions;
o encouraging extreme right-wing voters to be more confrontational; and
o spreading sensationalist, conspiratorial, and other forms of junk political news and
misinformation to voters across the political spectrum.


We can see from Table 4 that the African American segment was targeted with the most ads. White users were divided into liberal and conservative segments and targeted differently. A number of other ethnic segments, including Latin Americans and Muslim Americans, were targeted with smaller campaigns.


The top five posts by known IRA accounts are overtly political and polarizing, and details about the content and engagement by social media users is described in Appendix B. On Twitter, of the five most-retweeted IRA accounts, four focused on targeting African Americans.

This solidly confirms the NYT report that Russian 2016 Influence Operation Targeted African-Americans on Social Media more than other ethnic groups.

So now that the facts are clear, could you please clarify what you mean with 'insanity' regarding these studies, and please explain why you think these studies findings are just "smoke and mirrors", or that somehow these facts even "kneecap any left-of-center movements that could successfully question and thus change the system" ?

The politics / Re: Russia, Russia, Russia
« on: August 21, 2019, 10:22:15 AM »
OK, guys, I see that since I left, fact-based reasoning is still in short supply at the ASIF and ad-hominum is still the preferred way of communicating here.

Back to the facts :
This is a Princeton University study.
Not a tweet from the liar in chief.
Please know the difference.

How much % is from US?

The study did not find any Foreign Influence Effort (FIE) from the US.
Foreign Influence Effort needs to satisfy three criteria :

FIEs are defined as: (i) coordinated campaigns by one state to impact one or more specific aspects of politics in another state, (ii) through media channels, including social media, by (iii) producing content designed to appear indigenous to the target state. To be included in the data an FIE must meet all three criteria.

So if you find any effort from the US that satisfies all three criteria, please let us know.

The politics / Re: Russia, Russia, Russia
« on: August 20, 2019, 04:47:11 PM »
I can't believe this useless thread is undergoing a revival. Hope it dies back again.

The politics / Re: Russia, Russia, Russia
« on: August 20, 2019, 10:10:27 AM »
Not surprising, but a new study shows that Russia is the leading global offender of foreign disinfo influence operations around the world, accounting for a whopping 72% of total operations. Study by Princeton's @ESoConflict :

A massive calving happened over the last 24 hours at Helheim Gletscher the action including a new record (satelite) retreat:

Glaciers / Re: North Cascade glaciers Disastrous conditions
« on: August 09, 2019, 07:19:29 PM »
Massive Boulders, Floodwater Rush Down Mount Rainier After Glacial Outburst

A glacial outburst at about 6:50 p.m. Monday at the Mount Rainier’s South Tahoma Glacier sent debris and boulders as big as pickup trucks flowing down the mountain, said Mount Rainier National Park geologist Scott Beason.

The debris flow registered on seismic monitors and ran for more than 8 miles, Beason said.

Beason suspects warm, sunny weather filled the glacier with melt, rearranged the “internal plumbing” at the glacier’s base, caused water to blast a new channel through the glacier, and then flooded glacial melt into Tahoma Creek.

A glacial blowout on Mount Rainier sent debris as big as a pickup truck flowing for miles.

“The event lasted an hour and had four separate surges,” Beason said of the outburst flooding. “The outlet channel definitely shifted. It picked up a lot of loose material just below the glacier and carried it downstream and mobilized it into a debris flow.”

As the world warms and Mount Rainier’s glaciers thin and retreat over time, these massive debris flows have become a common occurrence on the mountain’s south side. The park is building systems to forecast massive debris flows and send alerts to park staff when they’re triggered, Beason said.

A view of a cavern in the terminus of the South Tahoma Glacier, from where floodwaters burst, carrying debris miles down.

The park has recorded some 32 debris flows along Tahoma Creek. The South Tahoma Glacier that feeds the creek began to retreat in the 1960s, Beason said.

Those gravity studies of Antarctic geology are very interesting to me. It appears to me that the WARS is not inactive, but similar to the tectonic situation in the Arctic ocean where there's very slow spreading along ridge segments.

It's impossible to do typical GPS land based tectonic studies there because the ice moves much faster than the rifting. However, the ongoing volcanic activity, while not definitive, is evidence supportive of ongoing activity along the long rift/transform fault system that crosses Antarctica.

Of course, this tectonic situation is relevant to glacial melting, isostatic adjustment and sea level rise. This rift zone will be a potential region of increasing volcanism as glaciers retreat and depressure deep magma reservoirs. Yes, this is a potential positive feedback.

Antarctica / Re: Sea Ice Extent around Antarctica
« on: July 21, 2019, 11:08:59 AM »
JAXA ANTARCTIC Sea Ice Extent :  15,628,582 km2(July 20, 2019)

July so far saw a run of high to extreme extent gains. And in the last 3 days crashed to an extent loss for 2 days in a row. This happens, not often, but it does happen. It happens more frequently as maximum ice approaches, probably due to the violent weather** and storms that can shift large amounts of thin ice at the fringes about.

2019 is now 2nd lowest in the satellite record, just 49 k above 2017 and 187 k below 2018.

- Extent loss on this day 48 k, a variation of 123 k from the average gain of 75 k on this day.
- Extent gain from minimum is 13.204 million km2, 0.250 million km2 (1.9%) less than the average of 13.454 million km2 by this day,
- 84.4% of average extent gain done, with 58 days to the average date of maximum (16 Sept).

The Perils of Projections
Remaining average freeze of the last 10 years gives a max of 18.13 million km2, 3rd lowest in the satellite record, and 0.07 million km2 greater than 2017 (the record low maximum year).

Despite the last 3 days, this is still a significant upwards change in extent from the end of June.  Still a large chance of significant change - either way. ______________________________________________________________________
** apparently weather is not a forbidden word on this thread (yet).

Antarctica / Re: SH Polar Vortex
« on: July 19, 2019, 03:40:14 AM »
I think that your concerns about fire are justified. Places with Mediterranean climates have fire problems that have gone from bad to worse. Spain and Greece, California and Australia have all had extreme fire storms in recent years that are worse than they used to be because of warmer and drier weather.

Antarctica / Re: SH Polar Vortex
« on: July 17, 2019, 06:03:32 PM »
The SH polar vortex has been impacted by the loss of ozone in the upper stratosphere, especially in the early spring. Cooling at high levels by the loss of ozone caused a tightening of the vortex and may also be causing instabilities such as sudden stratospheric warmings which are not common events in the SH.

For more details you need to read papers and reports by actual meteorologists. Paul Beckwith is not a good information source for Antarctic meteorology. The combined effects of ocean heating and ozone loss are affecting Antarctic weather, but it's very complicated because it also involves ocean currents, fresh water layers and deep convection of cold salty water. Hansen's papers get into some of the complexities of climate change in Antarctic waters. Hansen is a legitimate expert on atmospheric physics.

Antarctica / Re: PIG has calved
« on: July 16, 2019, 03:08:35 PM »
Hi-res (10m/pix) detail of the two big cracks. I'd say that they have widened considerably in the 12 days between the two images.  Any time now...

Images have been aligned with the movement of the ice upstream of the cracks.

Greenland and Arctic Circle / Re: Greenland 2019 Melt Season
« on: June 14, 2019, 06:51:11 PM »
The early melt action this week is very interesting as 2019 attempts to keep pace with 2012.  However, the longer term context is even more important. 

A new paper was published yesterday by Dr. Ruth Mottram from the Danish Meteorological Institute tracking three decades of observational data regarding the loss of ice sheet mass and how it compares to modeled projections.

Observations show surface lowering across virtually all regions of the ice sheet and at some locations up to −2.65 m year −1 between 1995 and 2017 based on radar altimetry analysis. In addition, calving fronts at 28 study sites, representing a sample of typical glaciers, have retreated all around Greenland since the 1990s and in only two out of 28 study locations have they remained stable. During the same period, two of five floating ice shelves have collapsed while the locations of grounding lines at the remaining three floating ice shelves have remained stable over the observation period. In a detailed case study with a fracture model at Petermann glacier, we demonstrate the potential sensitivity of these floating ice shelves to future warming. GRACE gravimetrically-derived mass balance (GMB) data shows that overall Greenland has lost 255 ± 15 Gt year −1 of ice over the period 2003 to 2016, consistent with that shown by IMBIE and a marked increase compared to a rate of loss of 83 ± 63 Gt year −1 in the 1993–2003 period.     

The rapid increase in the annual loss of ice during the period 2003 to 2016 compared to the period 1993 to 2003 is particularly troubling. 

Paper is open access at the link below:


Arctic sea ice / Re: Arctic Image of the Day
« on: June 14, 2019, 06:17:10 PM »
This is the largest "melt pond" I have ever seen on the internet. This photo was taken on the NW coast of Greenland. Stunning.
@SteffenMalskaer got the difficult task of retrieving our oceanographic moorings and weather station on sea ice in North West Greenland this year. Rapid melt and sea ice with low permeability and few cracks leaves the melt water on top.

2. Yes, ice has been declining since the end of the last ice age. The rate of decline is now many times that of the historical average.

Sorry to disagree but this is not correct - the ice has been increasing for the last 8000 years, something that only turned around some decades ago and is now going rapidly in the other direction.

The ice declined rapidly between 11.000 and 8.000 years ago, but then started to increase again. This is a very important point to make, the current changes are not "the same but bigger", but do in fact go against the recent trend, and against all the exptected changes caused by changes in  all the natural causes.
Since the climatic maximum, some 8000 years ago, glaciers have advanced and receded several times.  Exactly how many times this has occurred varies among scientists, as global glacial advance has not been in sync.  Most recently, glaciers were receded until the start of the 14th century, when European and Asian glaciers began advancing.  North American glaciers did not start their advance until about a century later.  The Himalayan glaciers were the first to stem their advance sometime in the 17th century.  The Canadian Rockies and Alaska appear to be the last, holding out until the end of the 19th century.  Individual glaciers can buck this trend, due to factors other than temperature.  Hubbard glacier in Alaska receded during the entire Little Ice Age, but has been advancing for the last century.

Not sure where you have your information from but you seem to be talking about short term fluctuations. In Iceland it is well established that over the last 8000 years, glaciers have grown from practically non-existent to covering some 10.000 km2. Absolute maximum extent was reached around 1930.

And this of course fits in with a world that is generally getting colder - by a massive 0.5C over 8000 years up to the middle of the 19th century. Since then, of course, the world has warmed by at least 1 degree.

Yes, they are short term in geologic time, lasting less than a millennium.  It has been an even shorter time since 1930 (although many glaciologists state 1850 as the maximum glacial extent during the LIA).

The whole discussion was about whether there had been a steady decrease in the amount of ice since the end of the last Ice age, or not. Some people seem to think that this is/has been the case, i.e. that once the last glacial ended, the world has been getting progressively warmer.

Many people, both deniers and not, seem to think that the world would be warming anyway, and that AGW is just adding increasing the speed of warming.

This is obviously not the case - the maximum was reached 8000 years ago and since then it has been getting progressively colder, with a fairly constant (although fluctuating) growth in ice, both as glaciation and as sea ice.

As for whether the last maximum glaciation was reached in 1850 or 1930 is not really important.

When Iceland was settled in the middle ages, a large valley in the south of Iceland was given the name "the big forest". In the 1300s and 1400s the inland glacier slowly advanced over farmland and by the end of the middle ages, the area was no longer habitable. By the early 1900s the glacier tongue had almost reached the sea, lacking only a few tens of meters. Since then, that glacier tongue has retreated some 10 kilometers inland.

So the constant and relentless growth of glaciers was a stark reality until the beginning of the 20th century. Today the glaciers are shrinking extremely fast, and may be all but disappeared in 200 years or so.

Antarctica / Re: PIG has calved
« on: June 13, 2019, 06:48:32 PM »
Time for an update. Cracks are developing slowly and are becoming visible in the modes with lower resolution. Here is is EW, medium resolution: 40m. The higher resolution modes have a basis resolution of 10m.

The animation is 80m/pix resolution. Horizontal and vertical polarization of the reflected microwave radiation are code as Green and Blue.

Antarctica / Re: What's new in Antarctica ?
« on: June 13, 2019, 06:19:17 PM »
Warming Waters in Western Tropical Pacific May Affect West Antarctic Ice Sheet

Warming waters in the western tropical Pacific Ocean have significantly increased thunderstorms and rainfall, which may affect the stability of the West Antarctic Ice Sheet and global sea-level rise, according to a Rutgers University-New Brunswick study.

Since the mid-1990s, West Antarctica—a massive ice sheet that sits on land—has been melting and contributing to global sea-level rise. That melting has accelerated this century. Wind and weather patterns play a crucial role in governing the melting: Winds push warm ocean water toward the ice sheet and melt it from below, at the same time as winds bring warm air over the ice sheet surface and melt it from above.

The study, in the journal Geophysical Research Letters, found that the South Pacific Convergence Zone, a region of the western tropical Pacific, is a major driver of weather variability across West Antarctica.

Rutgers researchers studied how warming ocean temperatures in the western tropical Pacific influence weather patterns around West Antarctica. This century, the Antarctic Peninsula and interior West Antarctica have been cooling while the Ross Ice Shelf has been warming—a reversal of what happened in the second half of the 20th century. From the 1950s to the 1990s, the Antarctic Peninsula and interior West Antarctica were the most rapidly warming regions on the planet, and the Ross Ice Shelf was cooling.

The temperature trends flipped at the start of this century. Coinciding with the flip in West Antarctic temperature trends, ocean temperatures in the western tropical Pacific began warming rapidly. Using a climate model, the researchers found that warming ocean temperatures in the western tropical Pacific have resulted in a significant increase in thunderstorm activity, rainfall and convection in the South Pacific Convergence Zone. Convection in the atmosphere is when heat and moisture move up or down.

A rainfall increase in the zone results in cold southerly winds over the Antarctic Peninsula and warm northerly winds over the Ross Ice Shelf, consistent with the recent cooling and warming in those respective regions. So the West Antarctic climate, although isolated from much of the planet, is profoundly influenced by the tropics. The findings may help scientists interpret the past West Antarctic climate as recorded in ice cores.

Kyle R. Clem et al, Role of the South Pacific Convergence Zone in West Antarctic Decadal Climate Variability, Geophysical Research Letters (2019).

Greenland and Arctic Circle / Re: Greenland 2019 Melt Season
« on: June 13, 2019, 07:27:06 AM » as at 12 June 2019

Melt was much stronger and well above average, and it snowed in the SE. Hence SMB was a mass loss but not by much, but increasing again the difference between the SE coastal fringe accumulated +ve SMB anomaly and the -ve anomaly for the rest of Greenland.
[/b]My prediction that belongs to me is now that today -Thursday - will see a strong melt and less snow in the SE, and in the days after melt moderating considerably, i.e. somewhat less of a major event than I thought a few days ago.

There is some serious melting going on way upstream. The two images in this animation are from the 5th and the 12th. The latest one looks like a large river system has formed and is draining down into the glacier.,B02,B03&maxcc=31&gain=1.0&gamma=1.0&time=2018-12-01%7C2019-06-12&atmFilter=&showDates=false&evalscript=cmV0dXJuIFtCOEEqMixCMDMqMSxCMDIqMV0%3D&showImage

Antarctica / Re: Sea Ice Extent around Antarctica
« on: June 10, 2019, 11:41:26 PM »
And for those who like to see where things are, here is a nice map of the various seas in Antarctica as used in these graphs.

Antarctica / Re: Antarctic Icebergs
« on: June 10, 2019, 05:55:58 PM »
A68-A is rotating around a different center now.  I thought it would be closer to the island/peninsula, but it is also 'moving out'.  New PolarView image ('added' to the previous GIF) is from June 8.

Developers Corner / Re: Test space
« on: June 09, 2019, 05:28:38 PM »
I am testing below for differences between U Bremen's SMOS vs SMOS-SMAP maps for ice thinness. Recall the M in both stands for soil moisture; their data (like Ascat's) has been re-purposed for sea ice. The latter brings in synergistic data from a second satellite to correct and enhance the former.

Since the advent of v205 of SMOS-SMAP, there seems to be no justification for using plain SMOS, other than it has a much longer consistent archive (ie same algo versioning) and a one day  shorter lag-to-archive posting. SMOS is riddled with flash artifacts. Both are observational data that have been vetted in the field, unlike Piomas.

SMOS-SMAP is provided at a vastly better resolution (2.83x), measured as Gimp pixel counts on the (polar stereographic) line between St Lawrence Island in the Bering Sea and Bear Island in the Barents (these are consistently visible in both pure imagery and in archival base maps).

That distance is 4738 km (2558 nm) as measured in WGS84 on Google Earth Pro. Accurate pixel counts are the key to re-sizing images to matching overlays:

satellite      pxl       %      ~km/pxl    ~km^2/pxl
SMOS          397.5    75.815   11.92      5.06
Ascat         524.3   100.000    9.04      6.67
OsiSaf       1075.5   204.711    4.41     13.66
SMOS-SMAP    1146.0   218.577    4.13     14.59
AMSR2        1197.6   228.419    3.96     15.24

Both satellites max out (to beige) in the central Arctic during the freeze season, as the ice pack quickly thickens beyond their 0.5m sensing capability. However, certain peripheral areas do not thicken to this depth at any time during recent winters. Thus SMOS-SMAP provides nuanced data during months when AMSR2, Ascat and WorldView see nothing but ice surface.

It's not possible yet to see how the two thinness maps compare during melt season, nor is it clear what they measure or conflate in summer, the possibilities being ice thinness, melt ponds, rafted ice, refrozen melted snow, slushy floes, liquid cloud water, or artifacts from passing storms.

Rather than throw the baby out with the bathwater (not use in summer), it might be better to take (locationally consistent) SMOS-SMAP colors as the thin or dodgy ice, that ice most vulnerable to melt-out. This interpretation interpret very well with the peripheral location of thinness colors both during fall freeze-up of 2018 and into early June of 2019.

The mp4 below is a 266-day hybrid map showing SMOS from 15 Sep to 31 Dec 2018 concatenated to SMOS-SMAP from 01 Jan to 07 June 2019. I originally made it to 700 pixel width but because the center stays so dark and is so large, it views better at 550 width. While moderately difficult to make, the final product only takes up 4-5 MB at 16-20 fps frame rate.

Note the very rapid expansion of dodgy ice in the last few days in the Beaufort-Chukchi and above the Svalbard-FJL-SZ line.

The freeze/melt cycle is largely a story of peripheral ice freezing, moving with the wind, and then melting to an extent determined by whatever weather summer brought. In most years the sub-central ice pack is not noticeably affected (though in fact multi-year ice is on a disappearing trend).

This year the lower CAB has experienced unusual displacement towards the CAA, Fram and Beaufort arm. The area has been cloudy enough that the main region of thick old ice has rarely been visible in Worldview, though intact ice with brittle healed leads can be seen after enhancement.

The contribution of SMOS-SMAP is thus to the near-miss zone: ice that thinned to 0.5m and below but did not quite melt out (or become visible as low concentration by AMSR2) by end of season. It is likely more informative than sketchy albedo and melt pond products earlier in the season as these do not measure either top or bottom melt.

The last three weeks of Ascat are also showing weather streaking across the scene, sometimes leaving permanent effects on radar brightness (ice near-surface dielectric), both lightning (less polarizable constituents) and darkening (more saline or more liquid).

Permafrost / Re: Arctic Methane Release
« on: May 22, 2019, 11:48:41 PM »
This should be good!
Any publicity of the mess we are in is good. But I cannot resist the temptation to....

"Methaneggedon!!!!" the Hollywood disaster movie to end all disaster movies.

Our young, brilliant, but difficult scientist (with a raft of personal problems) warns the scientific establishment that there are vast pools of liquid methane close to the surface along the Arctic Ocean fringe. Global warming means that channels are opening up from the surface down to and between these vast deposits- and ignition of just one of these surface channels could......

He/she is discredited and humiliated at the IPCC meeting.

But MegaCorp has stolen her/his  research, and blindly seeks to drill to capture the methane. A careless mechanic, an electrical short - ignition, rapidly spreading. The tundra and the ocean are on fire. Lots of exploding icebergs and LNG container ships.

Can the planet be saved?

Permafrost / Re: Permafrost general science thread
« on: May 03, 2019, 05:25:08 AM »
Permafrost is Thawing in the Arctic So Fast Scientists are Losing Their Equipment

Permafrost in some areas of the Canadian Arctic is thawing so fast that it's gulping up the equipment left there to study it.

"The ground thaws and swallows it," said Merritt Turetsky, a University of Guelph biologist whose new research warns the rapid thaw could dramatically increase the amounts of greenhouse gases released from ancient plants and animals frozen within the tundra.

...  "We've put cameras in the ground, we've put temperature equipment in the ground, and it gets flooded. It often happens so fast we can't get out there and rescue it.

"We've lost dozens of field sites. We were collecting data on a forest and all of a sudden it's a lake."

Nearly one-fifth of Arctic permafrost is now vulnerable to rapid warming, Turetsky's paper suggests. Plenty of it is in Canada, such as in the lowlands south of Hudson Bay.

Soil analysis found those quickly thawing areas also contain the most carbon. Nearly 80 per cent of them hold at least 70 kilograms of carbon per cubic metre.

That suggests permafrost is likely to release up to 50 per cent more greenhouse gases than climate scientists have believed. As well, much of it will be released as methane, which is about 30 per cent more efficient at trapping heat than carbon dioxide.

Open Access: Merritt R. Turetsky et al. Permafrost collapse is accelerating carbon release, Nature (2019)

Policy and solutions / Re: Extinction Rebellion
« on: May 01, 2019, 10:17:24 PM »
There's plenty more of that vileness here, I won't go into that, rather display her incredibly privileged background. Yes, her mother and grandfather are well known here but beware, this is scary stuff for grown up men:

Olof Thunberg is, for many here, the voice of "Bamse" The world's strongest bear (cartoon since 1966) and the most scary thing he probably ever did was the voice of Grumpy in Snow White and the Seven Dwarfs. He will be 94 this month.

But the Earth might tremble if Greta shares her mothers voice. My place on Earth:

Antarctica / Re: PIG has calved
« on: April 29, 2019, 08:12:07 PM »
Six days later, and now the development can be even seen on this short time interval. Things are speeding up.

Higher resolution -> need a click to start the animation.

EDIT: subscript showed "Sentinel 2", it is "Sentinel 1" of course

Antarctica / Re: What's new in Antarctica ?
« on: April 28, 2019, 08:44:35 PM »


... Such resolution bounds are incompatible with capturing the complex geometry of WAIS ice streams that are vulnerable to rapid retreat. For example, Pine Island Glacier (PIG) is 20-30 km wide at the grounding line, with complex grounding-line geometry that can only be resolved spatially at the 1-2 km level (10). In addition, a resolution of 25-100 km is inherently too coarse to capture short wavelength elastic uplift generated by fast grounding-line retreat and associated mass loss. As shown in Fig. 1, elastic uplift generated by a 2 km grounding-line retreat, modeled as loss of 100 m thick ice from a disk of 2 km radius, can reach 52 mm near the grounding line (centroid of the equivalent disk). At coarser resolutions (say, 16 km) the same model generates uplift one order magnitude lower. This implies that uplift generated in simulations such as (5, 6, 20) might underestimate how much uplift is generated during ungrounding of active areas of Antarctica such as TG or PIG, where highly complex grounding line geometries and associated retreat are observed over short time scales on the order of years. Some models such as (22) have attained resolutions down to 6 km, however in such cases GLD has not been considered interactively but prescribed offline, which precluded extensive negative feedback from manifesting themselves during the simulations. Our goal here is to carry out a sensitivity study of sea-level and ice-flow related processes by incorporating kilometer scale resolutions and global processes that involve solid-Earth dynamics. The ice-flow model robustly captures grounding line dynamics at high resolution (1 km) and over very short time scales (2 week"

There seems to be no support for 'short wavelength elastic response'. The earth does respond to loads elastically, the classic work being done on the loading of the Hawaii by A. B. Watts, but the wavelength of the response being dependent on the effective elastic thickness of the lithosphere (Te). My work on Africa showed that the continental lithosphere elastic loading response is more constrained by the current heat flow through the lithosphere rather than it's age. You would expect an elastic response to unloading, and the Antarctic rift would more than likely have a low Te, so relatively short wavelength. However, elastic and loading and unloading is constrained by how quickly rock can respond, and fails by brittle failure at the surface or undergoes ductile flow at the base of the elastic plate. The authors saying that there will be 5cm uplift by the movement of the grounding line as the ice melts, and that this response is on a decade timescale.. If we were seeing an elastic response at short wavelengths such of this, rapidly generating large rates of uplift with high curvature I would think you would see seismic activity all along the the grounding line as the upper crust fails and undergoes normal faulting. It would be interesting to know what effective Te was used to model this uplift, but it isn't mentioned in the paper. This might be happening, but if the earth was responding that fast I think it would be observable.

Permafrost / Re: Permafrost general science thread
« on: April 23, 2019, 03:06:30 PM »
A new study says the release of methane and carbon dioxide from thawing permafrost will accelerate global warming and add up to $70tn (£54tn) to the climate bill. Tried to find the article and failed. See summary from the guardian way down below or go to ...

But I did find instead that shows worrying increases in the temperature of permafrost all over the Arctic

Permafrost is warming at a global scale
Permafrost warming has the potential to amplify global climate change, because when frozen sediments thaw it unlocks soil organic carbon. Yet to date, no globally consistent assessment of permafrost temperature change has been compiled. Here we use a global data set of permafrost temperature time series from the Global Terrestrial Network for Permafrost to evaluate temperature change across permafrost regions for the period since the International Polar Year (2007–2009). During the reference decade between 2007 and 2016, ground temperature near the depth of zero annual amplitude in the continuous permafrost zone increased by 0.39 ± 0.15 °C. .....
Carbon release resulting from permafrost degradation will potentially impact the Earth’s climate system because large amounts of carbon previously locked in frozen organic matter will decompose into carbon dioxide and methane. This process is expected to augment global warming by 0.13–0.27 °C by 2100 and by up to 0.42 °C by 2300. Despite this, permafrost change is not yet adequately represented in most of the Earth System Models14 that are used for the IPCC projections for decision makers. One major reason for this was the absence of a standardized global data set of permafrost temperature observations for model validation.

Melting permafrost in Arctic will have $70tn climate impact - study
Study shows how destabilised natural systems will worsen man-made problem

Jonathan Watts Global environment editor

The release of methane and carbon dioxide from thawing permafrost will accelerate global warming and add up to $70tn (£54tn) to the world’s climate bill, according to the most advanced study yet of the economic consequences of a melting Arctic.

If nations fail to improve on their current Paris agreement commitments, this feedback mechanism combined with a loss of heat-deflecting white ice will cause a near 5% amplification of global warming and its associated costs, says the paper, which was published on Tuesday in Nature Communications.

The authors say their study is the first to calculate the economic impact of permafrost melt and reduced albedo – a measure of how much light that hits a surface is reflected without being absorbed – based on the most advanced computer models of what is likely to happen in the Arctic as temperatures rise. It shows how destabilised natural systems will worsen the problem caused by man-made emissions, making it more difficult and expensive to solve.

They assessed stocks of CO2 and methane trapped in the permafrost by using samples taken from a depth of three metres at multiple points across the Arctic. These were run through the world’s most advanced climate simulation software in the US and at the UK Met Office to predict how much gas will be released at different levels of warming. Even with supercomputers, the number crunching took weeks because the vast geography and complex climate interactions of the Arctic throw up multiple variables. The researchers then applied previous economic impact models to assess the likely costs.

Permafrost melt is the main concern. Greenhouse gases, which have been frozen below the soil for centuries, have already begun to escape at the current level of 1 degrees Celsius of global heating. So far the impact is small. Ten gigatonnes of CO2 have been released from the ice but this source of emissions will grow rapidly once temperatures rise beyond 1.5C.

On the current trajectory of at least 3C of warming by the end of the century, melting permafrost is expected to discharge 280 gigatonnes of carbon dioxide and 3 gigatonnes of methane, which has a climate effect that is 10 to 20 times stronger than CO2.

This would increase the global cost of destruction, adaptation and emissions reduction by $70tn between now and 2300. This is 10 times higher than the projected benefits from a melting Arctic, such as easier navigation for ships and access to minerals, says the paper.

Greenland and Arctic Circle / Re: The Nares Strait thread
« on: April 18, 2019, 06:48:08 PM »
The 'nose' of the largest floe to enter Nares Strait recently is going faster than its tail.  The nose section moved nearly 50 km in one day, while the tail moved 10 km less [i.e., it broke].  (The little island next to the nose, by the way, is Joe Is. [map]  Hans Is. is nearly 70 km downstream, and the channel's width between Hans Is. and the side of Judge Daly Promontory (Elsmere Is.) appears to be less than the width of the nose at its widest.  The tail, of course, is wider still.)

Edit: Floes in Kane Basin and Smith Sound moved 45-50 km between April 16 and 17 DMI images (not pictured).

Arctic sea ice / Re: The 2019 melting season
« on: April 17, 2019, 05:59:39 PM »
There has been a major shift in the atmospheric circulation pattern around the Arctic. The ridging which persisted over Alaska in February and March has ended while a strong ridge has set up over Scandinavia. This has allowed for an apparent recovery on the Alaskan side of the Arctic, although the reformed ice is very thin and won't last long. The heat on the Atlantic side won't show large effects on metrics because it is going over thick ice that was piled up at the exit to the Fram strait.

One not so good thing for sea ice about this atmospheric circulation pattern is that the coldest anomaly is focused on Baffin bay with strong north winds down the bay. This will enhance the circulation of warm salty water into the bay along the coast of Greenland and the flow of icy fresh water out of the bay into the Labrador sea. This will favor continued overturning in the Labrador sea and the release of oceanic heat to atmosphere over the far north Atlantic and subpolar seas.

Greenland and Arctic Circle / Re: The Nares Strait thread
« on: April 17, 2019, 05:38:20 PM »
The Nares Strait is, I believe, bordered by extremely hard limestones and dolomites.
This is "true" as far as it goes. 
Here is a partial 'grab' of rock types associated with each group of formations identified on first map from Denmark (yes, lots of dolomite, some of it 'hard') [some great photographs showing examples of outcrops]:
  • ‘Ellesmere Island – Inglefield Land belt’:  used to describe occurrences of the same gneiss, supracrustal and igneous suites on both sides of Smith Sound (Dawes 1988).
  • The Thule Basin is defined by a thick sedimentary-volcanic succession.  K-Ar ages of 676 and 627 Ma
  • Palaeozoic Franklinian Basin
    • Dallas Bugt Formation: Red to purple-brown arkosic sandstones with con-glomerates form the basal strata, overlain by white to pale yellow weathering, crossbedded sandstones, and topped by finer grained sandstones interbedded with green bioturbated mudstones
    • Humboldt Formation: basal fluvial sandstones and conglomerates, are succeeded by cross-bedded, bioturbated, shallow marine clastics of tidal origin, with the upper interbedded sandstone and mudstone
    • Ryder Gletscher Group: carbonate and siliciclastic deposits:  cliff-forming dolomites, crossstratified dolomites, hard grey dolomite, grey dolomites, with some thin silty horizons, mottled lime mudstones with silty laminations and horizons, together with dolomite-filled burrows and small mounds, locally dolomitised burrowed lime mudstones and minor conglomerates with some interbeds of grey, often glauconitic, calcareous finegrained sandstones; in the south-west glauconitic sandstones and siltstones dominate, with some more resistant limestone beds, uniform and hard, locally dolomitised oolitic limestone, bedded platy lime mudstone with silty laminae, and laterally extensive beds of intraformational flat-pebble conglomerate, massive thin bedded dolomites, stromatolitic mounds, siltstones and bituminous limestones, grainstones and white, brown-weathering sandstones, cliff-forming, burrow-mottled, grey lime mudstones with subordinate intermixed stromatolitic to thrombolitic limestones, sponge mounds and flat-pebble conglomerates, shaly dolomites, laminated lime mudstones and shales with both algal and wave-formed lamination, and dolomitic sandstones. Conspicuous beds of laminated to massive anhydrite and gypsum.
    • Morris Bugt Group: cliff-forming dolomitic limestones, with one distinctive recessive argillaceous unit
    • Washington Land Group: reef-derived deposits, lime mudstones, dolomitic limestones, dolomites and resedimented limestone conglomerates, together with subsidiary siltstones and shales.
    • Peary Land Group: siltstone and sandstone turbidites

The second map is from a Geologic Map of the Arctic from Canada with a few place names added in red.  A plate-boundary transverse fault (with complications) runs through the Strait.

Greenland and Arctic Circle / Re: Greenland 2019 Melt Season
« on: April 17, 2019, 11:07:05 AM » as at 16 April 2019

I was wrong - again. The melting event has persisted into the 16th April.
The 13th April melting event has continued to 15th April, only a little one but a bit stronger on the 15th. It may well be the last such event for at least 10 days

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