Ice, again

By stoat on April 14, 2009.

But just for once not sea ice, at least not to start with.

RMG provides a nice link to some of the Wordie "collapse" stuff. Although I find that a touch confusing, as the Wordie had essentially gone by 1992 - see [[Wordie Ice Shelf]] for example. Reuters is also noting it as news. Odd. Perhaps they are confusing it with that other well-known ice shelf that begins with a W, the Wilkins. That hasn't collapsed (warning: link to BAS PR, and BAS has a terrible habit of re-writing its website and breaking all the old links. If it still works for you, be grateful). It has however lost a bit of pinning, making it moderately likely to fall to bits soonish (this subtle distinction appears to be lost on the desmoggers). Cue wild overexcitement from the Times. They win "null points" for The collapse of ice shelves does not raise sea level significantly, because the ice contracts as it melts (see RMG again for the complicated truth). The Times also gets no points for What is most alarming about the events in the Antarctic is their speed, which has taken scientists by surprise. These ice shelves are collapsing far more rapidly than most scientists had predicted only 15 years ago. As RMG points out, this was all predicted (see-also RC) - but in the usual way of things, without a timescale. When will the Wilkins collapse? We don't know; BAS at least is careful not to make any predictions, even now. Notice also that despite the careless talk of caused-by-GW, BAS is careful to say There is little doubt that these changes are the result of atmospheric warming on the Antarctic Peninsula, which has been the most rapid in the Southern Hemisphere. Can you spot the difference? RC has a discussion thread on that, but it has 500+ entries. If anyone said anything interesting there, do let me know :-).

Bottom line must be that ice shelves are falling apart, but we knew that, and it is hardly surprising as it has been getting warmer there recently. More exciting would be a clear link to SLR, but that is currently absent.

Meanwhile, up North, the current anomaly is fairly small but people detect hints of enhanced variability this year. The cryosphere today pics aren't that easy to track, so I like looking at IJIS. But it is clear from that, that the winter anomaly doesn't correlate too closely with the summer minimum (someone with time on their hands should scatter plot something like March anomaly against September anomaly). If you're feeling lucky, bets are still on.

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What about an update of the Corbyn forecasts?

[James A seems to be the Corbyn watcher of the moment, though (understandably) he grows bored of the game -W]

Is it your betting instinct that makes you thorough and sane, William? I am always impressed by the real thinking here at this site, and this post is a good example once you read through all the links.

So . . . back to phenology. I am an air quality scientist by day, and a field survey biologist by night/weekend (don't you hate it when people qualify their statements by such hogwash as resume citation on blogs? but I am not immune). I am sceptical of any attempt to quantify phenology in any real significant, meaningful way. The intentions are good of course, but here in Colorado (boulder) NCAR is into its 3rd year i believe of an ametuer phenology network for the US. Conclusions so far - first leaf or first bud of north american species ranges over 2-3 months (good luck with trends). Aha, biological diversity - much more robust, complex and diverse than any climate metric (ground based temperature readings and associated problems being a good example). Of course, this will produce a never-ending ensemble of off-the cuff news(unworthy) opportunities based on natural variability (vs. phenology) which is much more complex than the oft RealClimate rebuked internal weather variability (vs. Climate).

[Ah, you seem to have much the sameopinion of phenology as I have. It is less reliable than thermometers, but better attuned to producing news stories -W]

And now for the daily antecdotal weather/climate crap from me. 14-28" of snow in Denver over the next 48 hrs, there are lots of confused, fat, egg laying robins hopping around today. I do not recall major leaf-out of trees ever being this late in the season - still has not occured. And any trees that have been brave enough to make a leaf-out regime change over the last decade are about to be sexually unviable (bud death) and have their limbs broken off completely.

yours, thomas

By thomas hine (not verified) on 17 Apr 2009 #permalink

Hi William,

The Japanese record of Arctic Sea Ice is showing the greatest extent for this day of the year since their records began in 2002. See http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm

I guess my dream of winning £200 is just melting away :-(

[Or freezing over? -W]

Cheers, Alastair.

By Alastair McDonald (not verified) on 18 Apr 2009 #permalink

In my opinion the largest threat for California are cataclysms and ecological catastrophes. Not important is how many money we have because one tragedy can us take all.

>"But it is clear from that, that the winter anomaly doesn't correlate too closely with the summer minimum (someone with time on their hands should scatter plot something like March anomaly against September anomaly)."

Is the following visible? If so does it cast doubt on your 'clear it doesn't correlate too closely'?

http://www.climateprediction.net/board/download/file.php?id=24

[It is visible, but I think it is the wrong pic. I wanted to see a scatter plot of March extent against September extent -W]

This seems to me to indicate they are reasonably closely corelated in the sense that if you get a big freeze then it tends to be followed by a big melt. So last year Sept may well be a better guide than this year's Mar. Is this a bit different than you saying they are just not well correlated?

[For Mar/Sept, there looks to be little correlation. Which axis is which, BTW? For the melt-freeze (ditto) I'm not sure what you are plotting -W]

>"["The selected attachment does not exist anymore." -W]"

It would help if I posted rather than previewed hopefully they are there again now.

Just dumping the data in here probably isnt going to work so can I just email you the xls file?

Melt 79 is Mar 79 extent in million km^2 minus Sept 79 extent in million km^2.

Freeze 79 is Mar 80 minus Sept 79.

September anomaly is on the y axis and March anomaly on the x axis.

Freeze anomaly is on the x axis, Mely anomaly on the y axis.

1979
Mar16.44
Sept7.2
Melting9.24 (=16.44-7.2)
Freezing8.93 (=Mar 80 of 16.13- 7.2)
Straight line est of freezing8.317139785

FreezeAnomaly0.612860215
Straight line est of melting8.408516129

MeltAnomaly0.831483871
Straight line est of Mar16.19679435
Straight line est of Sept7.804537634
AnomalyMar0.243205645
AnomalySept-0.604537634

I tried to create a random system that simulates Mar extent as straight line plus noise and Sept also as straight line plus noise. The correlation between melting and freezing appeared higher than is usually generated by the random system but it isn't statistically significant - approx five sixths of time, correlation is less in the random system (5/6 is less than 95%).

The correlation between Mar anomaly and Sept anomaly is very low .047. 90% of the time the random system which shouldn't have any correlation generated a correlation coefficient that was further from 0.

In short, I didn't really find anything to distinguish reality from this random anomaly system.

I wonder whether to suspect there might be differences between the real system and the random anomaly system but I really have no evidence on which to base such suspicions. Therefore I should and do concede I was wrong - the graph I linked does not cast doubt on the point you made that the anomalies look pretty much random.