Green Building Forum - Arctic sea ice

Arctic sea ice

tony — Thu, 16 Apr 2015 20:15:12 +0100

http://www.theguardian.com/environment/2014/oct/09/why-is-antarctic-sea-ice-at-record-levels-despite-global-warming

And why do we show the opposite in GB magazine?

Arctic sea ice

Ed Davies — Thu, 16 Apr 2015 21:18:51 +0100

You do know the difference between a polar bear and a penguin, don't you?

Has there been something in GB recently about this? I just read the Summer issue and don't remember seeing anything.

Arctic sea ice

tony — Thu, 16 Apr 2015 21:46:09 +0100

Yes about Arctic sea ice, I am all upside down at the moment.

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tony — Thu, 16 Apr 2015 21:48:56 +0100

Does this mean that the Southern Hemisphere are winning on reducing GHG emmissions?

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fostertom — Thu, 16 Apr 2015 22:38:51 +0100

Because the ice shelfs are breaking up into the sea at record levels?

Arctic sea ice

Ed Davies — Thu, 16 Apr 2015 22:44:02 +0100

Citation needed; which GB issue? Which article?

Bedtime reading: http://www.realclimate.org/index.php/archives/2014/12/clarity-on-antarctic-sea-ice/

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tony — Fri, 17 Apr 2015 08:01:36 +0100

new spring issue arctic sea ice decreasing, pic 2007 shows small

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SteamyTea — Fri, 17 Apr 2015 08:29:00 +0100

Is it about sea ice only?

If so, this changes size, shape and thickness on a regular basis and is not a great indicator of global temperatures.
Sea ice is not the same as land ice thickness and should not be treated as such.
You also have to remember in climate terms, we have very little data on sea ice and can only, at best, be used as supporting evidence and not as evidence in itself. Bit like a few sunny days in April in the UK, no one is claiming that our recent weather (what happened to the showers) is down to climate change, but if over the next few decades this pattern continues we may.

There is nothing wrong with being confused with the mixed messages that come from the mainstream media, they don't always see the whole picture. Read the academic articles if you want to understand what is going on.

Arctic sea ice

Ed Davies — Fri, 17 Apr 2015 09:58:49 +0100

Thanks tony, got it. Spring 2015, pg 6, â€œDoomsday Approachesâ€ by Chris Laughton.

Posted By: SteamyTeaIs it about sea ice only?

It's mostly about lots of things. The first paragraph is about global surface temperature anomalies (I assume, it just says â€œglobal climate anomaliesâ€). The first half of the second paragraph is about sea ice:

But the same data set produces interesting contradictions. Sure enough the Arctic polar ice cap was 4% less than the 1981-2010 average. One generally assumes the warmer it is, the less ice there will be and that this would suggest a rise in average sea level. But contrary to expectations, the larger Antarctic Sea ice was 10% above the same period's average.

There are pictures of the Arctic sea ice in 1979 and 2007 (though it doesn't say for what time of the year or even that they're for the same time of year though I'd assume they are). The remainder of the article is about ensuing politics rather than climate science as such.

I'm struggling to see anything surprising here. Still, a summary as I understand it:

1. Arctic sea ice extent has been steadily declining (with a bit of year-to-year variation) for the last couple of decades. The average thickness is declining as well so the volume is decreasing even quicker and a substantially ice-free Arctic at the end of the summer melt season looks likely in the next few decades (possibly even years though only a few people take that as very likely).

2. The Antarctic sea ice is increasing at the moment for reasons which are partially understood (as with many corner cases like this there are a number of plausible explanations but nobody's really sure which are the most significant) though that's consistent with model projections that eventually it'll decline a lot (see my RealClimate link further up this thread)

3. Continental land ice (glaciers, mostly) are declining. Not everywhere and not all the time but on average.

4. The Greenland and West Antarctic ice sheets appear to be declining faster than was initially thought likely given the mechanisms understood a few years ago.

5. The East Antarctic ice sheet was thought to be increasing a bit (warmer air being able to deposit more snow thereby upsetting the balance of deposition in the middle and melt round the edges) but there are recent worrying indications that big glaciers there are also speeding up and may speed up a lot.

Arctic sea ice

Ed Davies — Fri, 17 Apr 2015 10:33:32 +0100

PS, just came across this:

http://www.sciencemag.org/content/348/6232/327.abstract
Volume loss from Antarctic ice shelves is accelerating

Fernando S. Paolo1,*,
Helen A. Fricker1,
Laurie Padman2

Unfortunately, the full article is pay-walled but the abstract says:

â€œThe floating ice shelves surrounding the Antarctic Ice Sheet restrain the grounded ice-sheet flow. Thinning of an ice shelf reduces this effect, leading to an increase in ice discharge to the ocean. Using 18 years of continuous satellite radar altimeter observations, we have computed decadal-scale changes in ice-shelf thickness around the Antarctic continent. Overall, average ice-shelf volume change accelerated from negligible loss at 25 Â± 64 cubic kilometers per year for 1994â€“2003 to rapid loss of 310 Â± 74 cubic kilometers per year for 2003â€“2012. West Antarctic losses increased by ~70% in the past decade, and earlier volume gain by East Antarctic ice shelves ceased. In the Amundsen and Bellingshausen regions, some ice shelves have lost up to 18% of their thickness in less than two decades.â€

Some terminology might avoid confusion here:

1) Sea ice: ice which has frozen on the sea (or comes from precipitation (snow mostly) which has fallen on the sea, I think).

2) Ice sheet: ice which has come from precipitation over the land.

3) Land (or grounded) ice: the part of the ice sheet which is supported by the ground (even if that ground is below sea level as it is in quite big bits of Antarctica).

4) Ice shelf: ice which was originally land ice but which has been pushed off into the sea (at the mouth of glaciers), so it's floating, but is still attached to the land ice. (When it breaks off it becomes ice bergs.)

Tony's original reference was to (1). This paper is about (3) and (4) which collectively form (2).

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SteamyTea — Fri, 17 Apr 2015 11:49:28 +0100

So no major changes from predictions then.

I tried to get a copy from the library portal but they don't subscribe to Science.

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Eddo — Sun, 19 Apr 2015 22:58:53 +0100

Climatologist friend says latest thoughts emerging are that the sun spot cycle is the key to it all. No one (until now) has considered the link between sun spots and global warming. Apparently,we are inside the Sun's atmosphere(!) and UV radiation from solar flares heats the Earth's atmosphere. The Sun has entered a (normal) phase of low sun spot activity for the next 10 years (if I remember right) and this shall/is leading to cooling of the atmosphere and triggering (apparently) a prolonged period of cooling. He says that climate change caused by fossil fuels etc., is noting compared to the heating effect of UV radiation in the atmosphere.
Give or take fluctuations in all this, his prediction is that global warming has ended and we are in for a mini ice-age, which will peak in 50 years and take another 200 years before temperatures return to where they are now. Mini ice-age means winters back to how they used to be in Granddad's time, when he were a lad.

Arctic sea ice

Paul in Montreal — Sun, 19 Apr 2015 23:34:31 +0100

Posted By: EddoNo one (until now) has considered the link between sun spots and global warming.

Sorry, that is absolutely incorrect:

http://www.scientificamerican.com/article/sun-spots-and-climate-change/

https://www.skepticalscience.com/solar-activity-sunspots-global-warming.htm

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/solact.html

http://desmogblog.com/global-warming-deniers-favorite-sunspot-theory-refuted-again

http://www.realclimate.org/index.php/archives/2005/07/the-lure-of-solar-forcing/

Al of the above refute your "climatologist" friend's claims.

Paul in Montreal.

Arctic sea ice

wookey — Mon, 20 Apr 2015 04:25:21 +0100

Artic ice is declining dramatically:
Animation of arctic sea ice volume summer minimums since 1979 (showing the 80% decline over that time, average (all year) decline is about 50%):
https://www.youtube.com/watch?v=9OBCXWAHo5I
Interactive graph: http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

Land ice is melting worldwide at hundreds of gigatonnes/yr: that's the Arctic (Greenland, 230GT), Antarctic (160 GT), and glaciers in between. Part of the West antarctic ice shelf has already become destabilised (lost its 'bung') and will drain out into the sea. That is now set in motion and there is nothing to be done about it. Resulting sea-level rise will be 3-4m, although the process will take a very long time).

'Chasing Ice' provides a graphic illustration of the glacier melting rates:
https://www.youtube.com/watch?v=s0p29akJym0

The increase in Antarctic sea-ice extent in the last few years is a small fraction of the lost volume of Antarctic ice, and is due to the increase in melting fresh water flowing into the sea (details of the mechanism are under investigation).

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SteamyTea — Mon, 20 Apr 2015 06:08:18 +0100

Posted By: Paul in MontrealSorry, that is absolutely incorrect:

Thanks Paul, saved me bothering

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Eddo — Mon, 20 Apr 2015 11:57:31 +0100

Thanks for the links, Paul in Montreal, I had a look at them. I would say they "disagree","question" or "strongly dispute" rather than "refute" my friend's allegations. since refute means to prove wrong, and it is really only through hindsight that a theory may be refuted. Nevertheless, I shall put your info (along with the other contributions) back to the professors at my local University (The Royal Oak), and we shall see whether the consensus shall change from last week's!
So what is this talk about a "pause" in global warming?
http://www.economist.com/news/science-and-technology/21598610-slowdown-rising-temperatures-over-past-15-years-goes-being
Is it just all about computer models and who forgot to include which variable into the simulation? In which case, no-one really knows what is going on!

Arctic sea ice

wookey — Mon, 20 Apr 2015 12:23:12 +0100

There is no pause:
https://tamino.wordpress.com/2015/01/20/its-the-trend-stupid-3/

Or more accurately: there is no statistically significant evidence of a change in the rate of warming since the 1970s

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bot de paille — Mon, 20 Apr 2015 12:27:05 +0100

And the emperor is wearing all his clothes

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fostertom — Mon, 20 Apr 2015 12:56:31 +0100

I understood that the 'pause' (as experienced on the surface) says nothing about the continued rise of deep-water temperatures.

If it looks like not much additional heat is being stored in the atmosphere, that's because vast amounts of heat is being stored in deep water, undetected by everyday folks on the surface.

What happens when deep cold water gets warmer? Stratified stability breaks down, convection/mixing increases. In other words, huge bubbles of deep water rising to the surface, bringing their stored heat with them.

Quite suddenly no doubt - weather and sea-current effects, anyone? That's when the doubters my get convinced - too late.

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Ed Davies — Mon, 20 Apr 2015 13:06:13 +0100

Posted By: EddoThanks for the links, Paul in Montreal, I had a look at them. I would say they "disagree","question" or "strongly dispute" rather than "refute" my friend's allegations. since refute means to prove wrong, and it is really only through hindsight that a theory may be refuted.

Paul's links absolutely refute your suggestion that no-one has until now looked at the connection between sunspots and global warming. It's well known to anybody who pays any attention to the matter at all that the connection between sunspots and climate has been considered for a long time.

I'd strongly recommend you have a good read round the subject before making such a complete fool of yourself.

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Seret — Mon, 20 Apr 2015 13:14:49 +0100

Posted By: Ed Davies
I'd strongly recommend you have a good read round the subject before making such a complete fool of yourself.

Now, now. Being wrong about something (especially a somewhat esoteric subject) doesn't make one a fool. Eddo has clearly been told a bunch of nonsense by a friend who he thought was more expert than him/herself.

Arctic sea ice

Paul in Montreal — Mon, 20 Apr 2015 14:22:56 +0100

Posted By: EddoThanks for the links, Paul in Montreal, I had a look at them. I would say they "disagree","question" or "strongly dispute"

Posted By: EddoNo one (until now) has considered the link between sun spots and global warming.

I absolutely refuted your assertion above. Many people have looked at this, as my links attest. It's not a case of disagreeing (which they do anyway).

Paul in Montreal.

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Ed Davies — Mon, 20 Apr 2015 14:31:28 +0100

Seret, yes, I was pretty direct there. But it's not an esoteric subject - it's something which is widely discussed with major implications for the future of our society and there are multiple sources of information. If you're mislead by one person when it's well known that many hundreds or thousands of people who've studied the subject a lot have come to a different conclusion by multiple chains of evidence, and it's been reviewed internationally over a period of decades probably more thoroughly than any other scientific theory, then I'm sorry but you really do risk making a fool of yourself.

Arctic sea ice

Ed Davies — Mon, 20 Apr 2015 14:42:05 +0100

Posted By: Eddo: â€œSo what is this talk about a "pause" in global warming? â€¦

Is it just all about computer models and who forgot to include which variable into the simulation? In which case, no-one really knows what is going on!â€

Oh, no, the old â€œwe don't know everything so we know nothingâ€ argument. Yes, the pause (which, if it's even really there at all is a lot less significant than many make out) was not exactly predicted by the computer models. Never-the-less, the models do produce similar results with enough runs so it's not that surprising.

It's as if you ran a weather model now for the UK for the whole of this summer. You really wouldn't expect it to be able to predict whether it's going to rain on August the 1st but you would expect it to get a plausible amount of rainfall for the whole of August. Obviously in real life it's very variable and you'd hope to see something of that variability in multiple runs of the model though, since measuring variability is the purpose of the models, you wouldn't be too worried if the variability was off a bit.

Whatever, even if some details were badly off (which I don't think they are) it doesn't follow that the overall effects are false.

http://www.nature.com/nclimate/journal/v4/n9/full/nclimate2310.html

Arctic sea ice

skyewright — Mon, 20 Apr 2015 15:00:41 +0100

Posted By: EddoClimatologist friend says

See other responses for refutation of your friends comments.

Posted By: Eddo his prediction is that global warming has ended and we are in for a mini ice-age

Which if true would still make "insulate, insulate, insulate", increased use of renewables, reduced use of fossils fuels, etc., all good ideas so that the FF take longer to run out. The motivation would be different, but it would still make sense, and in the meantime the nay sayers would be helping to ameliorate the real causes.

Arctic sea ice

marktime — Mon, 20 Apr 2015 15:12:19 +0100

Eddo has some remarkable friends.

"Okay, as for the question: why the paranoia? Okay, go on laugh at me, but a friend who is reliably psychic (here we go) has warned about the grid coming down for longish periods, in the future. Another friend says the Earth's crust is going to rebound near the poles because of the reduced weight on it from the melting ice. This means earthquakes and volcanoes. Now, IF they are both right, oil supplies may become disrupted, therefore power cuts (like back in the 70's) or no power for days, possibly. So, what's wrong (I ask myself) in being prepared, just in case?
I bought a 5 kg sack of rice the other day, just in case. Or should I get new friends?

I wonder how confused he really is. I smell a rat.

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Ed Davies — Mon, 20 Apr 2015 16:13:36 +0100

Poe?

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SteamyTea — Mon, 20 Apr 2015 16:39:17 +0100

Posted By: marktimelike back in the 70's

That was industrial dispute rather than technical issues. Good job I know you better.

Right, off to get my future diving rods to sort this out once and for all.

Ed, it will rain on 1st August down here, school holidays have started

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Ed Davies — Mon, 20 Apr 2015 16:52:23 +0100

Posted By: SteamyTea: â€œThat was industrial dispute rather than technical issues. Good job I know you better.â€

Marktime was quoting Eddo from another thread: http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=13219

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fostertom — Mon, 20 Apr 2015 16:55:55 +0100

There's the practical need to be as sure as possible, to guide policy and action (we should be so lucky).

Then there's the psychological need to be absolutely certain, to make the capricious world seem a bit less frightening. God help anyone who threatens or challenges those cosy certainties, which by a lifetime of religious or scientific fundamentalism, have been precariouly established. The venom by which those beliefs are defended are about as unscientific as anything could be - pure infant survival-terror.