Future temperatures

Anybody else up on Antarctic grounded ice? I'm nearly sure we talked about Velicogna et al 2014 before. I wonder if it has been updated.

But man o man when you look at Antarctic sea ice, there is a month-old trend that our cheerers for short trends forgot to see:

Sea Ice Index
Sea ice in Arctic and Antarctic at record lows - CNN.com

Other than that bottom-falling-out thing, the earlier upward trend is small +/- larger. If it were a temperature graph we can be sure mojo would say not significant! and that would be correct.

The century scale for Antarctic sea is flat. It was about a month ago we talked about that. Gosh you forget bad news quickly.

 

fuzzy1 I missed your post on that weeks ago. Amazing how an election can distract folks from other important things.

I needed mojo's wakeup call. For which I am grateful as always. Personally I doubt this Antarctic sea ice low spike can last. It is just too cold of a place, with eay-to-freeze freshwater arriving from the continent. It'll be back up to its 10 to 100 year flatness soon I expect.

The Velicogna I mentioned:
Velicogna, I., T. C. Sutterley, and M. R. van den Broeke (2014), Regional acceleration in ice mass loss from Greenland and Antarctica using GRACE time-variable gravity data, J. Geophys. Res. Space Physics, 119, doi:10.1002/2014GL061052.

Could use an update but Figure 1 shows the main features for both Antarctic continent and Greenland. Areas of rapid loss and larger areas of slow increase. As I've said, something for everybody.



Antarctic continent overall net loss 70 gigatons per year, by another paper that is very heavily cited, but deserves a refresh. By the way this is a downward revision of earlier GRACE loss estimates by one half to one third.

Matt A. King, Rory J. Bingham, Phil Moore, Pippa L. Whitehouse, Michael J. Bentley & Glenn A. Milne (2012). Lower satellite-gravimetry estimates of Antarctic sea-level contribution. Nature 491, 586-589. doi:10.1038/nature11621

+++
And next time mojo forgets and asks again I suppose we'll have to tell him again. Sigh

 

By the way that Figure above is not a map in the strict sense, lacking scale bars. Cartographers are very picky about that. But recent few posts suggest that Greenland overall is losing faster than Antarctica overall. Somehow I would not have expected that? But, we are stuck with quantitative data and analysis.

Maybe should have expected. Southern half of Greenland is much closer to equator than even the Antarctic Peninsula

 

First ref is to

H. Jay ZWALLY, Jun LI, John W. ROBBINS, Jack L. SABA, Donghui YI, Anita C. BRENNER. (2015). Mass gains of the Antarctic ice sheet exceed losses. Journal of Glaciology, 61(230), 101-1036. doi: 10.3189/2015JoG15J071

Which is free to download. I would appreciate it as always if others would look at this and compare to other conclusions that appear to disagree. Or, if someone can find indications of discussions between Zwally and Velicogna? Those are the folks who know. There should be no need to rely on affinity websites here.

The two graphs come from
Greenland Ice Sheet Surface Mass Budget: DMI
(actually this web link is more recent than what mojo posted)

Where one can also read:
"Over the year, it snows more than it melts, but calving of icebergs also adds to the total mass budget of the ice sheet. Satellite observations over the last decade show that the ice sheet is not in balance. The calving loss is greater than the gain from surface mass balance, and Greenland is losing mass at about 200 Gt/yr."

If I read that correctly, DMI SMB does not include calving ice loss. So one would have to take care to not misinterpret DMI.

 

Oh dang, mojo, you deleted the DMI SMB graphs@30. Any reason you'd care to disclose?

 

Zwally et al. 2015 compare two periods: 1992 to 2001 and 2003 to 2008. This is not a 'criticism' it means we'd want to understand why only those, how data sources differed in those two periods, and (ideally) what happened during other periods.

Zwally et al. 2015 appear to use 10,000-yr scale-changes in ice-core densities as part of their analysis. Velicogna et al. 2014 (and other studies AFAIK) only use 'current' data. My impression is that disparity in results may arise in this way. It would be very useful if someone can locate a discussion among people who publish in this field addressing this disparity. And what additional data or analyses might lead towards concordance.

There are more 'ice satellites' planned for future launch, and our need for them appears large. I have to hope that funding for Earth System Science does not diminish.

 

OK then, you posted an outdated page, I posted the current one, where we read that Greenland is -200 gigatons per year. I wish I could say that settles things, but this ain't my first mojo-rodeo.

Ice calving. It just falls off the edge of grounded ice everywhere. So we could say that calving is caused by gravity. True, but incomplete. How did that ice get to that edge?