Arctic sea ice set to hit record low

mojo@19 most 10,000 years warmer. Yes this is as you have said before, and it is not the interpretation of the people who have cored the ice or analyzed the isotopic temperature proxies. It would be great to go further than that, but what stikes my simple mind as a useful test does not seem to have been done: collect some newly fallen snow in the vicinity of the corings, and measure the stable isotopes of that.

We can certainly address the second point about (paleo) arctic sea ice extent.
Kinnard et al. 2011 in Nature “Reconstructed changes in Arctic sea ice over the past 1,450 years”

doi:10.1038/nature10581

is the shortest paleo study that pops up, but they include a graphic that I excerpt here

This is only panel a, sea-ice extent, see the original for the other panels.That is years across the top, numbered from AD 800 to 2000, area extent in millions of Km^2, and the lighter orange band is the uncertainty in their proxies.The dotted orange line at the recent end is direct observations. Looks clear enough to me, and it even mirrors the MWP and LIA at the right time.

We can also relate this to the NSIDC seasonal ice extents that have been widely posted, as they use the same units. For example the NSIDC 2012 max was 16 million Km^2 and it has now fallen to 4 million.

For a longer look,
Antoniades et al 2011 PNAS “Holocene dynamics of the Arctic’s largest ice shelf”
www.pnas.org/cgi/doi/10.1073/pnas.1106378108

or Funder et al 2011 Science “A 10,000-Year Record of Arctic Ocean Sea-Ice Variability--View from the beach”
DOI: 10.1126/science.1202760

Both cover about 10k years, but based on local measurements not basin wide. Neither offers what looks like a money shot to me, and they are not easy to read, but here are excerpts:

From the former “Our results show that the ice shelf was absent during the early Holocene and formed 4,000 years ago in response to climate cooling.”

From the latter “Multiyear sea ice reached a minimum between ~8500 and 6000 years ago, when the limit of year-round sea ice at the coast of Greenland was located ~1000 kilometers to the north of its present position. The subsequent increase in multiyear sea ice culminated during the past 2500 years…”
They report intervals of less ice cover at different times. But they look in different areas, so it is not necessarily a contradiction. My summary is that from 10k to about 2k years ago, arctic sea ice was highly variable, and the current stand is not exceptional. Over the last 1000 years, it is.

I will also suggest reading
http://www.nytimes.com/2009/03/29/magazine/29Dyson-t.html?pagewanted=all
because it offers many insights. The link to this discussion is near the bottom
“Most of the time in history the Arctic has been free of ice,” Dyson said

I wouldn’t judge the man, but the literature above helps us to assess the idea.

 

So 'sea rise' is a monolithic thing, not a lot of possible variations? That seems massively unlikely.

 

I have no idea what that means.

Sea level rise is a single measure. We do have a great deal of proxies that show how high the sea levels rose in the last couple of interglacials, which were higher. We also have some evidence from the little ice age that the sea levels fell during this march higher. Is that what you mean as variation?

 

If you dont believe it ,then email Alley.
But its pretty much plain to see here.
Antarctica will show the same.
http://wattsupwiththat.files.wordpress.com/2010/12/easterbrook_fig5.png

 

Heres proxy studies from all over the planet that say the Earth was warmer for much of ,and most of the past 10,000 years.
CO2 Science

 

You will note that that information is for greenland only. Greenland is cooler than many years in the last 10 millenium, but that does not mean global temperatures have been cooler. Proxies in most of the rest of the world show the earth has been getting warmer. The earth does not warm evenly. The temperature record is very good for the last 400 years, as we start going back farther we have less and less places measured with proxies, and these proxies become less and less accurate.

 

Easterbrook figure unavailable to me (wordpress often blocked). Sorry. Maybe it's the same one that you posted a few months ago, that said it was from Alley and it wasn't?

I have to say, that Idso (CO2 science) page is much better assembled than anything I have seen them present about CO2 fertilization. It would be relatively painless to read most of the listed references and see if that actually say what Idso says they say. This is what would happen if it were sent for journal review. I did some like that above, so if you feel that it's your turn now, hop in.

++

When AustinG said stopping Co2 increase now won't stop sea level rise, he may have meant:
1. New heat already in the ocean has not yet equilibrated with surface ice.
2. CO2 already added to the atmosphere will continue to affect energy balance until it is removed from circulation by deep-ocean sinking.
3. Deceased surface albedo in newly ice-free areas (land and sea) will boost local energy balances, assisting in the melting of local ice.

These are what most people mean when they say things like that. Of course he might have meant something else entirely But those ideas track back to particular sets of published studies. A type of shorthand; perhaps ill advised.

Once again, this whole system is complicated. It does not lend itself to simplification. Doing so for individual factors must be approached cautiously, as I tried with the arctic sea ice message above. Not to over interpret.

Do keep the notion of (over) simplification in mind, on your next visits to WUWT or CO2science of Easterbrook's or iceagenow. Or heck, many others, I don't even know 'em all.

Keep the same notion in mind at skepticalscience or realclimate, etc.

Whoever announces 'look how simple this is!', or contends that 'the latest thing' is a gotcha that overturns much research, or focuses on the messenger not the message... Well, there's the sign. There's BobW's 'tell'. What you do next, after noticing that, it up to you.

 

Heres the same information of Alley graph Greenland from Noaa website.Cant be much clearer.

 

See study link in post #24.Even gives info from IPCC.

 

Yes, that is mostly what I meant. The heat and co2 in the system will take a long time to melt ice. That doesn't mean we are not speeding it up, but if man disappeared the ice would still be melting.

You must mean a different post. That one is simply the gisp2 reconstruction of temperature in greenland.

 

@28 Ah so. This is as I recall the one you brought up before. The trouble was (and still is) that the cited paper discusses the time period from 16,000 to 10,000 years ago. Before 1950 to be more precise, and the significance of that you'll see in a moment. The paper is

Alley 2000 PNAS “Ice-core evidence of abrupt climate changes”

PNAS 97(4): 1331–1334

(they weren’t using DOI way back then)

and I could have nothing to gain from attempting to mislead anyone about the contents. Youse could just go look for yourselves. Indeed I hope for that.

So the graph presented again @28 is miss-cited and I can't fix that.

Actually, I had poked around a bit and found something else pretty similar. Battling powerpoints on line. Red meat! First Pasto's

http://files.meetup.com/1436270/AGW_Hoax_Scientific_1.pdf
with particular attention to page 22. Then Mandia's

http://www2.sunysuffolk.edu/mandias/global_warming/climate_change_man_or_myth.pdf
which shows Pasto's on page 50, and then goes on to clarify.

I use the word clarify quite intentionally, because there does seem to be a bit of dissimulation floating about. For example, whether the year 1855 is correctly called "present".

But now you've both ppts, which are each in their own ways making points enthusiastically. Enjoy them if it suits your tastes, or just read the literature if you'd rather be an old fuddy duddy like me. In that sense at least, the choice indeed could not be clearer.

 

#25 then.
Studies from different world locations ,all showing the Earth was warmer for the past 10000 years. [quote="austingreen, post: 1629179, member: 5850]



You must mean a different post. That one is simply the gisp2 reconstruction of temperature in greenland.[/quote]

 

I would take that co2 science piece with an air of skepticism. The latest paper in their link appears to be 1995. There has been a great deal of proxy research since then, that has changed reconstructions. Still there are large potential errors at attempts to go back that far.

 

Antarctica shows the same .Past 10000 years warmer than today.

 

Even with the 1.44 degree added much of the past 10,000 years was still warmer than today(14 peaks still were warmer). No way can the blue crosses be of any relevance unless you intend to add 3.5 C to the 1850 temp.That is only an absurd calibration error.Adding 1.44 degrees to 1850 is already probably a 2x exaggeration.


"It’s also clear that there is a mismatch between the temperature reconstructions and the ice core record. The two blue crosses on the chart show the GISP site temperatures (adjusted from GRIP data) for 1855 and 2009. It’s clear there is a calibration issue between the long term proxy (based on ∂18O measurement) and recent direct measurement of temperatures on the Greenland ice sheet. How that might be resolved is an interesting question,"

 

THE HOCKEY SCHTICK: New paper shows surface temperature of Arctic icecap was warmer during most of past 11,000 years

"Tuesday, April 10, 2012

New paper shows surface temperature of Arctic icecap was warmer during most of past 11,000 years


A paper published today in the Journal of Geophysical Research shows that a large ice cap in the Canadian Arctic had surface temperatures higher than the present for the vast majority of the past 11,000 years"

 

Heres a more recent study then.60 proxies from around the globe North and South.
THE HOCKEY SCHTICK: New paper shows Earth was significantly hotter during past several thousand years

 

Very useful stuff. Hockeytschtick being a blogspot, I can't go there so the best would be to just list the journal references themselves. The ice guys ought to be refining their work, if they were not we should be upset. Whatever emerges from the reviewed studies ought to be summarized (upcoming) in IPCC AR5, if they were not we should be upset.

I'm not really backing a particular horse here. I'm backing the (metaphorical) horse-race process. High Holocene temperatures actually point to ocean-circulation processes being more important than people currently think. That would reduce confidence in climate models cause they don't 'do ocean' well.

Anyway, studies like this should certainly tell us what T does during times when CO2 does not vary much. That is critical to know!

AG@37 scepticism misses my point. Idso has laid out the points, one by one and attributed them to literature sources. He has made the checking very easy to do, and that's what the enterprising student of paleoT ought to do. If a manuscript attributes something to a publication that it din't say, Journal Reviewers get peeved. I've been there! at the knife-handle not at the knife poiint

 

I'm skeptical not because that wasn't peer reviewed, but because it is in disagreement with newer temperature reconstructions. The last reference seemed to be to 1995, and I hope that the science has progressed since then.

I can also be skeptical of peer reviewed publications People often get science wrong. If we actually were certain about the last 10,000 years of temperature records we would have to have great models to take a few points of the earth to global temperatures. I don't think we are there yet. When people attempt to do a reconstruction from 5000 years ago, but only have a small number of locations, and proxies have blended hundreds of years of data together, my eyes gloss over.

Back to the topic. Does the melting sea ice mean that sea levels will soon rise tens of meters?

For every problem, these is a solution that is simple, obvious, and wrong. - Einstein