Please support this Forum and Neven's Blog

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.


Messages - oren

Pages: [1] 2 3 ... 22
1
Arctic sea ice / Re: Stupid Questions :o
« on: Today at 02:38:34 AM »
sark someone with some knowledge will soon answer, but please make sure you know what you are asking:
Ice sheet covers land, in Greenland and Antarctica, is made of snow compressed over 1000s of years, and is therefore fresh water. Sea ice is made of frozen salt water, and over time and given cold temps becomes more and more fresh through brine rejection. Which one did you mean?

2
Arctic sea ice / Re: The 2017 melting season
« on: April 23, 2017, 10:07:25 AM »
Thanks for the animation. ~700 pixel width is the trick.
And, are you sure it's a current and not wind-driven? If it's a current it's really bad news.

3
The rest / Re: Russiagate
« on: April 23, 2017, 06:26:48 AM »
At the risk of posting though I'm not American, I agree with both previous posts,  I just need to add to Archimid's opportunity analysis the fact that the odds were similar between both sides to begin with. As the Republicans are for big business while the Democrats are supposedly for the little persons, who have been screwed repeatedly in past years even when ignoring climate change and all other "borrow from future little persons" schemes, one would naively expect the Democrats to achieve a decisive edge. They did not and thus were vulnerable to outside intervention, FBI intervention and so on.
Maybe lulling the differences between the parties is not working. Maybe some good-intentioned strongly-spoken populist like Bernie who could tear the masks from the political process is what they should have gone for. I wish they had. I wish my country had someone like that.
This is somewhat OT to this thread, but is the reason it could exist in the first place.
And yes, Putin could have done it.

4
Should Tesla indeed deliver 500k cars in 2018, or something close to that, all will be well. I am keeping my fingers crossed. But should they fail hard, I am afraid of a major reversal in the drive towards EVs, and potentially a long delay. The traditional automakers might be very happy to give this a quiet burial. A lot is hanging on Tesla and Musk here, which is why I am worried by Musk's seeming dispersion into various ventures which are possibly draining money and increasing the overall risk.

5
Arctic sea ice / Re: 2017 sea ice area and extent data
« on: April 22, 2017, 03:13:14 PM »
gerontocrat, absolutely. This year's extremely low winter volume makes me expect a record summer min volume even with average melt conditions.

6
Reasonings for such have already been posted by some, including myself, before your personal attack on people who happen to disagree with you. You are trolling the thread.

7
Arctic Background / Re: Arctic - territory of dialogue
« on: April 22, 2017, 02:10:45 PM »
Well, think of it: the way the arctic is going, ice-breakers might not be a good long-term investment...

8
people voted > 2090: denialists or essentially the same thing, trolls.
people voted 2030-2040: "lukewarmists", which is a special form of denialism
What I really don't get is why some people voted 2040-2050, 2050-2060 or 2060-2070.
I don't often post personal comments, but: This is disgusting. On a scientific forum you start name-calling like that to people who dare disagree with you. Who put you in the preacher's job? You are way out of line.
Bear in mind there are no denialists on this forum. Except maybe those who deny that randomness and variability exist in nature, and that unknowns exist in science.

9
Antarctica / Re: PIG has calved
« on: April 22, 2017, 08:42:12 AM »
Forum software decided to not animate it for some reason, just to let you know.
It's probably too large. If you limit to 700 pixel width it should work.
Edit: the last one works.

10
Arctic sea ice / Re: The 2017 melting season
« on: April 22, 2017, 08:39:39 AM »
This opening is very unusual up that high. I suspect warm SSTs and atlantification.
meddoc your suspicion is wrong, please read the "Nares Strait" thread in the Greenland section. There is an almost-constant surface flow from the Lincoln Sea southwest down the strait. When the thick ice gets stuck at the entrance it may form an "arch", as happened this year (more often an arch is created in Kane Basin at the other end of the strait). The surface flow then keeps clearing the area below the arch.
Also search the web for the "North Water Polynya".

11
As I understand it, JH lost its ice shelf some years back and is now grounded at the calving front.

12
Arctic sea ice / Re: 2017 sea ice area and extent data
« on: April 21, 2017, 04:47:24 PM »
Indeed there is a relation but the correlation does depend in some cases on the third variable, namely the annual loss. Had there been a 100% correlation between max volume and annual loss, there could be 0% correlation between max and min volume. Indeed this is what will happen when min volume is 0 every year.
In reality though, annual loss remained stable and then even increased as max volume decreased over the years. Therefore min volume, on average, is dropping even faster than max volume.

13
Arctic sea ice / Re: The 2017 melting season
« on: April 21, 2017, 01:19:28 PM »
The Bering and Chukchi from April 15-21 with april 19 2016 by way of comparison. Doesn't look good
Terrible. All heading towards the (Fram) exit.

14
Indeed, the problem with human-driven cars is the humans. With so many "human error" accidents, it is 100% certain that an automation/human combo will be better than human alone. This already works in real life today with low-level automation such as ABS, or the "rear warning" thing that beeps when my car backs up too close to another car or other object.
And it is highly probable that a pure automation system will be safer than pure human-operated, especially after enough time has passed using the combo approach.

15
Arctic sea ice / Re: The 2017 melting season
« on: April 20, 2017, 07:52:15 PM »
gerontocrat, if you check the regional AMSR2 extent chart at https://14adebb0-a-62cb3a1a-s-sites.googlegroups.com/site/arctischepinguin/home/amsr2/grf/amsr2-extent-regional.png you will see that Barents + Greenland Sea (victims of Fram export) and Baffin (southbound drift) are running high in extent - this is ice on its way to hell - while the Pacific side (Bering, Okhotsk, Chukchi) is running low. The ice is weak, thin and broken but is still covering the same extent. All this setup will have a lot to say when the actual melting season begins (now it's just the very southern edges). Patience will be rewarded unfortunately.

16
Consequences / Re: Places becoming less livable
« on: April 20, 2017, 03:03:25 PM »
I liked this quote:
He described South Florida’s real estate market as “pessimists selling to optimists,”

17
Arctic sea ice / Re: The 2017 melting season
« on: April 19, 2017, 11:38:46 PM »
Reminder that a recent thread exists somewhere on the forum dealing with snow cover anomalies and new glaciation.

18
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: April 19, 2017, 11:30:57 PM »
Here's a quick animation of Apr 18 and 19. The ice is more broken, the cracks are getting closer to the "arch" while the newer ice inside the arch falls away.
I would not be surprised to see the arch crumbling within a few days under the stresses.  It's not a given but quite possible. And if it does go, I don't expect a new arch to form and stabilize as temps are going up already and the strait itself has been flushed away.

19
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: April 19, 2017, 12:31:51 PM »
Nares has suddenly cleared.

20
Arctic sea ice / Re: The 2017 melting season
« on: April 19, 2017, 01:10:52 AM »
Some major cracks north of Ellesmere Island and Nares Strait have appeared overnight. Currently there are stronger winds (15 m/s) and warmer temps approaching as well.
I think the Beaufort Gyre is back, looking at the various recent animations. And Hycom Nowcast https://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn_nowcast_anim30d.gif shows the thick ice north of Ellesmere suddenly pulling westward in the last few days, after being swept towards the east for a long time. I bet this is what caused the sudden cracks, as the Ellesmere part pulled west while the Greenland part continued east.
I wonder if this could cause an early collapse of the Lincoln Sea "arch" blocking export to Nares Strait.

21
Policy and solutions / Re: But, but, but Germany ....
« on: April 18, 2017, 09:01:21 PM »
Bob, I like your last series of posts (though somewhat OT here) but - it will take more than a few years, and it only applies to the "developed" countries. Globally it might take several decades if it happens at all.

22
Arctic sea ice / Re: Glossary ... for newbies and others
« on: April 18, 2017, 08:42:36 PM »
Hi can can anyone define "torching", from what i can tell its when ice changes albedo and starts looking darker on filtered satellite images?  What are the implications of this for the melt?
I will try though I'm no expert:
Torching - slang for when a significant amount of heat, typically anomalous temps and/or clear sunny sky, is applied to the ice. Terminology to keep the spirits going as we watch the melting season.
"Torching" as Wipneus uses it in his AMSR2 thread - when the ice loses 100% concentration over large areas of the AMSR2 animation. Remember it's a radar "image" so it's not albedo and actual darkening - but possibly concentration drops due to surface wetness, actual meltwater or even rain, or cloud interference. "Torching" is not necessarily the result of actual torching. The implications are that the ice is not in a perfect condition, and might melt sooner than 100% concentration ice.

23
Arctic sea ice / Re: The 2017 melting season
« on: April 18, 2017, 08:27:49 PM »
Definitely last year there was an stagnation of ice around the Chukchi/ESS sector of the CAB and the ESS that is not present this year. Perhaps the fact that during april there has been such a massive drift toward Atlantic/Fram while last year the flow was a bit different.
Yes, the non-stop export towards the Atlantic gutted the arctic ocean leaving behind what seems like the same area and extent, but in reality thinner and weaker .

24
Thank you Neven!
AndrewB - Each thread has its own subject. If you feel we should be discussing other stuff instead, why not post about it in the thread related to that subject?
(I generally do agree that the disaster is upon us, but I still like to post about a variety of subjects, which probably won't save us but are interesting nevertheless).
For the record, I have changed my vote form 2020-2030 to 2030-2040, as I expect some variablity to continue. A cold winter such as 2013 could come along again.

25
I find my poll choice is not editable. Could Neven work his magic here?

26
Arctic sea ice / Re: The 2017 melting season
« on: April 18, 2017, 06:52:14 AM »
What Archimid said. Also, someone earlier gave the rule of thumb that seawater won't freeze above -10C due to mechanical effects. And ice will get thicker faster the lower the temperature goes.
The main effect is ice not thickening enough, in the central arctic ice continues to thicken until May if I am not mistaken, and at -15oc it will thicken less and more slowly than at -30oc.

27
The forum / Re: Closed forum or mailing list
« on: April 18, 2017, 12:00:07 AM »
I too think a separate forum for invitees only, or a mailing list, will be less effective. However, perhaps threads with guest scientists discussing their work (and hopefully there will be more like that) may need stronger moderation than usual.
As the forum is a collective authority/knowledge base on sea ice and other adjacent subjects, it could become the right place for forward-minded scientists to discuss their research, maybe even use the forum as a sounding board as part of a review process. But such a discussion must be scientific, to the point and respectful, or it won't happen a whole lot.
Musing over  :-X

28
Policy and solutions / Re: Renewables Reach a Tipping Point...
« on: April 17, 2017, 11:42:59 PM »
I think that you are greatly underestimating the cost and complexity of building out a Europe-wide smart grid to deal with these issues. Also, the rate of change required is accelerating as reductions in emissions are delayed year after year. I feel that Kevin Anderson will be proved correct, at 8-10% per year reductions the transitional problems will start occurring fast and furiously.
You are right that the costs are higher than simple math shows. But it is still better for a European country needing new power plants to build solar + wind + storage instead of nuclear (expensive, too long to build, risky), coal (dirty), gas (has to be imported from Russia), even when carbon is mostly ignored.
And the assumption that because emissions need to be curtailed fast, that they will actually be curtailed fast, is wrong unfortunately imho. So the actual (too slow) rate of renewable deployment might leave enough time for adaptation to the intermittent nature of the beast and for building a smart grid.

29
So your forecast from last year proved correct. Another small chapter concluded on the GIS retreat story.
As to the shape of the new island, it seems to me that most of the triangle is old remains of the glacier? Just the left side is the actual island?

30
Arctic sea ice / Re: IJIS
« on: April 17, 2017, 03:36:39 PM »
The problem if I understand correctly is that the 2013 line and the 2000s average are not at 13.174 but much higher  :o
Must have been some kind of revision from then to now?

31
Arctic sea ice / Re: What is a model?
« on: April 17, 2017, 02:55:57 PM »
Well at least we can agree that extrapolations are indeed (very simple) models, which brings this thread to a kind of conclusion

32
Policy and solutions / Re: James Hansen loves nuclear power
« on: April 17, 2017, 11:23:46 AM »
Solar, wind and storage have only come down in price recently, and continue to do so. Real world examples could follow in 10 years, should a country mobilize itself the way France did with nuclear.

33
Arctic sea ice / Re: What is a model?
« on: April 16, 2017, 10:33:52 PM »
TBH, a linear trend-fitting forecast crosses zero too, not just the exponential one. Both are inherently limited by using only historical data.
A forecast based on historical curve-fitting is (indeed) a model, albeit a very simplistic one. Sometimes such empirical models have better predictive value than full physical simulations when the system is too complex and the data is not sufficient, although the physical models will provide more explanations and enable "what if" simulations.
And when using a very simplistic empirical model disconnected from the actual physical processes, it is best to stick to as few variables as possible unless the empirical evidence strongly says otherwise. Therefore Occam's Razor gets me to the "linear" "model" when looking at arctic sea ice.
(And yes I do expect a record low PIOMAS volume this year, but that's a different thread)

34
Consequences / Re: Sea Level Rise and Social Cost of Carbon
« on: April 16, 2017, 08:30:52 PM »
What is sea level going to do in the coming months and next several years?  Here is one possible look.....
Buddy I must say these blue and red straight "trend" lines sure look like cherry-picking. I too fear that there has been some acceleration in SLR in the last few years, but this chart does not show a doubling. The 2010 low was not representative of the previous trend, but its biggest negative anomaly instead. The data points since around 2014/2015 that are above the black trend line are interesting and disturbing but not long enough to form a certain signal.

35
Arctic sea ice / Re: What is a model?
« on: April 16, 2017, 05:06:19 PM »
It has to be said that increasing complexity and sophistication does not automatically produce a better result.
And indeed, the impetus behind this thread was the use of an exponential extrapolation to forecast Sept sea ice, while the use of the simpler linear function is more widely accepted for the job (and rightly so, imho).

36
Dr. Qinghua, seeing as you expect the arctic to go ice-free in 50-100 years based on your research and other knowledge. Should the arctic somehow go ice-free in 5-10 years, will that cause you to revise your estimates of the large role of natural variability?

37
Arctic sea ice / Re: The 2017 melting season
« on: April 15, 2017, 02:32:17 PM »
Looking at Hycom's Nowcast for the next few days, it seems openings are expected in Hudson and Kara.

38
Well said, AndrewB. I stand corrected.

39
Arctic sea ice / Re: The 2017 melting season
« on: April 15, 2017, 12:12:56 AM »
Thanks. Back of the envelope calculation: if the exported area (consisting mainly of older ice) was replaced by new ice somewhere in the CAB that is thinner by 2 meters, this is something like 300 km3 lost just by this mechanism in this vicinity, in addition to other export areas and of course the ice "lost" by lack of FDDs.

40
AndrewB, I too am not convinced by the Natural Variation attribution claim for several reasons. However, I think you have taken the criticism way too far, attacking Dr. Ding personally in some of your recent posts. I am sure Dr. ding is an honest researcher with good intentions in mind (even if the paper's method is not to my "liking"), and I am sure he would like to see AGW and CO2 emissions dealt with asap without having to prove himself to you or anyone else. As he is known to be reading this thread and even graciously responding, I am especially ashamed by these attacks and would ask you to avoid such.
In general, I believe your point has been well stated and then overstated, why not give it a rest for a while.

41
Hunter, thanks for the amazing images.

42
my pick was 2043
Well, the correct answer is of course, that the Arctic will experience ITS LAST year with September sea ice minimum extent ABOVE 1 million km2 the year BEFORE it experiences ITS FIRST year with September sea ice minimum extent BELOW 1 million km2, or do you expect September sea ice extent to keep BOUNCING BELOW AND ABOVE 1 million km2 for a few years?
'Cos I don't.  :)
This "bouncing" as you put it is quite probable.

43
Arctic sea ice / Re: The 2017 melting season
« on: April 14, 2017, 10:39:47 PM »
Great animation Andreas. Any idea of the total distance moved? Is this something like 1000 km?

44
Antarctica / Re: Rift in Larsen C
« on: April 14, 2017, 07:42:48 PM »
The Making of an Iceberg
April 14, 2017
In 2014, a crack began opening in the Larsen C Ice Shelf—a huge slab of floating ice along the Antarctic Peninsula. By April 2017, only 16 kilometers (10 miles) of ice separated the tip of that crack from the open sea.
Predicting when the cracking shelf will set loose an iceberg is a challenge because ice fracturing depends on several factors, some of which are poorly understood. The iceberg, which is likely to be the size of Rhode Island, could break off any time from days to years from now, according to scientists from Project MIDAS, a United Kingdom-based group that is monitoring the event.

I am surprised it's still attached...

45
Arctic sea ice / Re: Latest PIOMAS update (April)
« on: April 14, 2017, 07:33:47 PM »
Just a quick one. 2017 has build a big lead over 2012 in the race for the lowest annual minimum (Arctic Sea Ice) volume.

The graph shows that most of the lead was gained in the freezing season: end-October/begin-November, followed by a smaller spurt in December. The bump in February, followed by the slow decrease in March may or may not be regarded as "noise". No regression toward the mean indeed.
I too think this chart is very disturbing. The low autumn volume should have caused the ice to thicken more later, but it didn't. And the continued strong export of old ice into the Atlantic gives good cause to believe that end-April PIOMAS numbers will be as bad.
My only (slim) hope at this stage is that PIOMAS somehow made a mistake in concentrating all the volume in that moving "blob" further to the north of Greenland, while past years, and other models such as Hycom, put it closer to Greenland in the protected Lincoln Sea. In which case more volume might actually emerge out of the winter than the number claimed by PIOMAS.
btw the FDD anomaly shows a similar trend, most of it happened in the autumn and only a little was added over the winter - but there was no mean reversion.

46
Arctic sea ice / Re: What the Buoys are telling
« on: April 14, 2017, 07:39:00 AM »
I don't think there is anything inherently different. Luck I guess.

47
Policy and solutions / Re: James Hansen loves nuclear power
« on: April 14, 2017, 07:30:04 AM »
Ontario's nuclear fleet is wonderfully low carbon but has been an extremely expensive burden.


So you would prefer a intermittent renewable system like Germany, very expensive with CO2 emissions 10 times higher than France?

https://www.cleanenergywire.org/dossiers/eeg-20-new-legal-framework-german-energy-transition-0

http://www.environmentalprogress.org/big-news/2017/2/11/german-electricity-was-nearly-10-times-dirtier-than-frances-in-2016

I thought the objective was to reduce CO2 emissions.

tombond, sometimes you sound like an advertisement for nuclear, with the talking points stacked in one direction. Germany and France are in different positions, but the real question should be where to invest going forward. Yes the objective is to reduce CO2 emissions. Should a country trying to reduce its emissions build lots of new nuclear plants, or lots of solar and wind with overcapacity and storage? For many countries (if not all) I believe the answer is the latter, because of economic, risk-management and deployment-speed reasons.

48
Arctic sea ice / Re: Operation IceBridge - Arctic Spring 2017
« on: April 13, 2017, 07:12:55 AM »
Does anyone know if they posted a photo of the Nares "Arch" in the Lincoln Sea? I am very curious to see what it looks like up close.

49

If you can show me an ensemble mean ( more than 10 to 20+ realizations) of multiple models forced by anthropogenic forcing ( whatever you like to add in the models, Co2, aerosol, land surface use and ozone etc ) that can well capture the observed circulation change in the past 40 years. I think this would be a good evidence that my argument is wrong. If not, we have to say that a portion of observed circulation change is due to a natural source and this part of natural source can melt sea ice through a dynamical impact rather than the greenhouse effect.
 
Please read our papers in 2014 (fig. 4) and 2017(fig.4) . We checked all available models to do this analysis and we couldn't find a similarity.

(I added emphasis to quotation)

As far as I can understand should the statement be:

The circulation change is due to an unknown cause.  Modelling cannot find a link between Co2 and this circulation change, which is evidence that it is not Co2.  But until this circulation change is better understood it is not really known whether it is purely random natural variation, an alternative external forcing such as aerosols etc, or whether there is an important influence of Co2 on the climate that models cannot yet capture.
Thanks Michael, good summary of my thinking in better terms than I could articulate.

50
Policy and solutions / Re: James Hansen loves nuclear power
« on: April 12, 2017, 11:39:52 AM »
My main problem with nuclear reactors is not their risk profile under regular operation, but their risk profile under the beginning of civilizational collapse. Think of the Mosul Dam, or the Tabka Dam, both in countries under collapse. They weren't very risky to begin with, but both are now at highly increased risk averted through the intervention of foreign powers. All the fine engineering won't help much when maintenance stops or guerillas take over the plant.

Pages: [1] 2 3 ... 22