Polar Ice Extent

[jethro]

I can agree with a great deal of that, however I do think that the contributions from natural sources and the limitations of model projections are fully recognised, both in the scientific communities and by the main protagonists on these threads. Even as an amateur I can see the models have deficiencies, so I doubt the proponents of AGW theory within the climate scientific community are blind to them either. As for natural sources/cycles, as I have stated before, what we know about them has come to us from scientists in the various fields that have researched them or at least aspects of them. This is a group of people who despite their intimate knowledge of those natural sources/cycles still subscribe to AGW theory. For me that really is the killer argument, how is it possible that the bulk of that group of scientists can support AGW theory and ignore their own specialist knowledge of natural cycles. They patently believe that, yes natural cycles are real and have a massive role to play in the earths climate, but AGW is changing the nature of those cycles, presumably exaggerating upward trending temperatures and flattening out temperature drops. If that is not the case why are paleoclimatologists and related scientists not coming forward on mass and dismissing AGW theory as bunk.

It is perfectly possible that we have been going through a natural warming cycle with an AGW signal at the same time, even if we change to a cooling cycle that AGW signal will not go away, if (and that is the big if) great enough then it could override some of that cooling signal or even alter aspects of those natural cycles, in ways that we may not as yet perceive. That seems to me to be a logical conclusion from the support that the available evidence has as of this time.

There are some excellent points raised by sceptics on these pages, and points that should be raised. However in my eyes some of those points fall flat, because the authors all to often come across as holding the opinion that only they, and a few sceptic scientists whose papers they quote, understand the points raised and that the rest of the climate science community cannot grasp them or are just ignoring them, personally I find that highly unlikely. Often when pressed, the view is expressed that Scientists that support AGW theory only do so, so as their funding isn’t cut. I guess that’s better than suggesting that they are just to stupid to understand the counter theory’s.

I'm not suggesting the scientists are blind to them nor am I proposing that the evidence for natural cycles denotes AGW isn't real or debunks the theory.

My bone of contention (actually not a contention, more a consistent niggle) is that because we know so much about CO2 and so little about the oceans, clouds and atmosphere that CO2 is deemed to take precedent. To an extent that's inevitable, after all how can anyone discuss in detail something we do not have details for? But, and for me it's quite a big but, not knowing the details of something shouldn't denigrate it as an irrelevance as so often happens. Perhaps more importantly, exploring the contribution of natural climate phenomena shouldn't be taken as meaning "it's all natural".

Paleoclimatologists and related scientists are not coming forward on mass and dismissing AGW theory as bunk because they recognise the contribution of both, so do many sceptics, myself included.

[stewfox]

Page 92, post 1529.

I took it as humour, not sarcasm. Always glad to hear someone doesn't easily take offence

lol

[weather eater]

I'm not suggesting the scientists are blind to them nor am I proposing that the evidence for natural cycles denotes AGW isn't real or debunks the theory.

My bone of contention (actually not a contention, more a consistent niggle) is that because we know so much about CO2 and so little about the oceans, clouds and atmosphere that CO2 is deemed to take precedent. To an extent that's inevitable, after all how can anyone discuss in detail something we do not have details for? But, and for me it's quite a big but, not knowing the details of something shouldn't denigrate it as an irrelevance as so often happens. Perhaps more importantly, exploring the contribution of natural climate phenomena shouldn't be taken as meaning "it's all natural".

Paleoclimatologists and related scientists are not coming forward on mass and dismissing AGW theory as bunk because they recognise the contribution of both, so do many sceptics, myself included.

I wasn’t pointing at you, just that we have a few of that ilk on these threads. Personally I don’t think it matters what side of the fence anyone sits, or indeed if they sit slap bang in the middle as a don‘t know, however I feel that’s if points of view are going to be aired they should at least be logical. My own view is that AGW is real and it presents a real danger, and boy would I like to be wrong. However I'm not so certain that we are on the crux of an unstoppable tipping point as some would have it. Also it maybe that as we change to a cooler natural cycle we may hold, slow or maybe reverse some of the warming we have seen. the worry of course is that we are just delaying the problem and leading ourselves into a false dawn.

[sunny starry skies]

I think the problem comes from those who pretend that somehow we know less about the natural cycles than we do about current warming. A new paper (Ljunqvist 2010) has added yet another strand to the spaghetti of 1000+ year reconstructions, and once again finds the overall magnitude of natural cycles to be on the order of <0.5C globally from MWP to LIA, adding yet further support to the consensus that past historical climate changes are not of the same magnitude or rate as present ones (>1C LIA min-present). But once again, there is no pretence that the natural variations of the past didn't exist, fundamentally because in order to understand climate as forced by anthropogenic CO2 we have to understand climate as forced otherwise - that is the climate scientist's day job. You simply can't understand the anthropogenic without understanding the natural. Natural changes have not been so rapid since (at least) the catastrophic ice sheet retreats at the end of the Pleistocene, and the physics of the forcing works very well to explain both recent and palaeoclimatic changes. Natural variations, presumably the same variations that have operated over the past 1000+ years, have not achieved anything like this, and I find it hard to believe that natural variation would coincidentally go into overdrive at the same time we are releasing a known powerful greenhouse gas into the atmosphere at a rate neatly consistent with the observed change. I'll secong weather eater - boy would I love to be wrong on this, but there's as ever no coherent evidence for natural cycles playing a strong enough role to do more than slow our rate of warming.

BFTP - the exceptional late start to this year's melt still resulted in a near-tie or tie for 2nd place as the lowest sea ice extent on record (and was a clear 1st place just two months after the start of melt), why do you think the date of ice melt, or growth, start matters a jot if the overall ice extent continues to decline at an accelerating rate? 2010 finished almost exactly on the quadratic curve fit through the past 30 years of data.

I am happy to see the rapid extent increase of th last week or so, though I hope it's real area increase and not just spreading out of ice due to wind changes, as some have suggested. Another hypothesis, discussed over at Neven's blog, is that because we had a remarkably low concentration fragmented inner pack this year, the freeze-up of this inner region is accelerated by the seeding of <15% concentration areas by the fragmented ice debris already present. Previous years had little fragmentation in the inner pack, so growth had to be only around the edges. Another reason why 'extent' can be a misleading measure? Bring on Cryosat volume!

[4wd]

Surely the 'fragmented inner pack' was still counted in the extent figures?

I don't buy that explanation of the rapid refreeze.

The animated sequence linked previously shows spread in all directions which looks like freezing to me, not wind movement.

It seems like some are so determined to believe in death spirals they have trouble accepting reality.

Edited September 29, 2010 by 4wd

[Gray-Wolf]

Cor! busy little board!

What are the odds of your house burning down in any 1 year? or exploding? or collapsing? pretty darn slim eh? (notice I didn't use 'flooding' as those odds are shortening) but you still take out insurance don't you? It's all about loss management and if the losses are so huge (should the worse happen) then you insure yourself? How big are the 'losses' should the middle path of the IPCC models be correct? What madness to not prepare for such!

C'mon guys, as we found this year the measure is not how much ice forms but how much 'survives' melt season surely??? If we melt out any extra ice each spring/early summer (extra ice has to be around the edges doesn't it?) then where are we?

Cold summers with good ice retention (and high summer albedo) is the only way to 'rebuild a pack' is it not??? It's like filling a bath real fast knowing that once the plugs out all the water will drain.......where's the fun in that?

[stewfox]

I wasn’t pointing at you, just that we have a few of that ilk on these threads. Personally I don’t think it matters what side of the fence anyone sits, or indeed if they sit slap bang in the middle as a don‘t know, however I feel that’s if points of view are going to be aired they should at least be logical. My own view is that AGW is real and it presents a real danger, and boy would I like to be wrong. However I'm not so certain that we are on the crux of an unstoppable tipping point as some would have it. Also it maybe that as we change to a cooler natural cycle we may hold, slow or maybe reverse some of the warming we have seen. the worry of course is that we are just delaying the problem and leading ourselves into a false dawn.

Good post

Cor! busy little board!

What are the odds of your house burning down in any 1 year? or exploding? or collapsing? pretty darn slim eh? (notice I didn't use 'flooding' as those odds are shortening) but you still take out insurance don't you? It's all about loss management and if the losses are so huge (should the worse happen) then you insure yourself? How big are the 'losses' should the middle path of the IPCC models be correct? What madness to not prepare for such!

C'mon guys, as we found this year the measure is not how much ice forms but how much 'survives' melt season surely??? If we melt out any extra ice each spring/early summer (extra ice has to be around the edges doesn't it?) then where are we?

Cold summers with good ice retention (and high summer albedo) is the only way to 'rebuild a pack' is it not??? It's like filling a bath real fast knowing that once the plugs out all the water will drain.......where's the fun in that?

Would you pay £9,000 every year to ensure your house or wait till you see 3 housing burning down the road (it would cost you more then).

I’m afraid most will wait and see.

The longevity of any melt season of course would have an impact from Arctic Wildlife to Shipping.

Perhaps my degree in Economics did me some good, people seem to think you can spend your way out of something that may happen?

Edited September 29, 2010 by stewfox

[BornFromTheVoid]

Surely the 'fragmented inner pack' was still counted in the extent figures?

I don't buy that explanation of the rapid refreeze.

The animated sequence linked previously shows spread in all directions which looks like freezing to me, not wind movement.

It seems like some are so determined to believe in death spirals they have trouble accepting reality.

No it doesn't. It shows ice from "our" side of the Arctic pushing towards the NP, while sea ice at the other side begins expanding away from the NP, which tied in nicely the recent wind direction. The has been some new ice growth, which has probably now exceeded the growth from wind induced spread. If wind was able to drive the ice compaction, why does believing it helped with the recent accelerated growth mean belief in the "death spiral"?

Anyway, another big jump today by nearly 70,000km2. I'm happy to see this growth, even if it doesn't mean as much as if were occurring on top of a healthy pack, you gotta start somewhere!

[Methuselah]

I did, and the arctic will get a big ice increase this winter compared to recent bad years as the cold ocean phases take hold and a late melt start next year.

BFTP

Is that a prediction, Fred?

[Gray-Wolf]

I thought we had a 'record' late start to the melt season just ending??? Did we not still end up with 3rd lowest 'extent' and lowest 'volume' recorded?

Were this the 1970's with an intact inner core of mighty 'old perennial' then I'd have to agree but when we have no more 'old perennial' in the basin and ice thickness impacted by a more dynamic Arctic (A.A. and increased occurance of storm tracks into the Basin with 'increased precipitation events).

[ghrud]

Cor! busy little board!

What are the odds of your house burning down in any 1 year? or exploding? or collapsing? pretty darn slim eh? (notice I didn't use 'flooding' as those odds are shortening) but you still take out insurance don't you? It's all about loss management and if the losses are so huge (should the worse happen) then you insure yourself? How big are the 'losses' should the middle path of the IPCC models be correct? What madness to not prepare for such!

C'mon guys, as we found this year the measure is not how much ice forms but how much 'survives' melt season surely??? If we melt out any extra ice each spring/early summer (extra ice has to be around the edges doesn't it?) then where are we?

Cold summers with good ice retention (and high summer albedo) is the only way to 'rebuild a pack' is it not??? It's like filling a bath real fast knowing that once the plugs out all the water will drain.......where's the fun in that?

We're probably facing the same odds of the next ice-age starting sometime soon as the IPCC being right with their predictions... shouldn't we also be preparing for the possibility of this event too? Even a minor shift in climate either way could be a disaster for mankind!

[picog]

Still a great view from the webcam that was placed at the pole

http://www.arctic.noaa.gov/latest/noaa2.jpg

[MR EXTREMES]

We're probably facing the same odds of the next ice-age starting sometime soon as the IPCC being right with their predictions... shouldn't we also be preparing for the possibility of this event too? Even a minor shift in climate either way could be a disaster for mankind!

cant agree more and like ive said many times before why focus on something that could well flip the oposite way.

[stewfox]

No it doesn't. It shows ice from "our" side of the Arctic pushing towards the NP, while sea ice at the other side begins expanding away from the NP, which tied in nicely the recent wind direction. The has been some new ice growth, which has probably now exceeded the growth from wind induced spread. If wind was able to drive the ice compaction, why does believing it helped with the recent accelerated growth mean belief in the "death spiral"?

Anyway, another big jump today by nearly 70,000km2. I'm happy to see this growth, even if it doesn't mean as much as if were occurring on top of a healthy pack, you gotta start somewhere!

Wind induce spread which I assume has happen since the year dot.

In the summer its not wind induced reduction of course , its all the ice going out of the Fram straight that’s causing the decline

I assume its bit of both for the winter and summer .

Will we hit near another 100,000 today after corrections ?

At the current rate of increase we should hit all things being equal 20million at the end of March

Edited September 29, 2010 by stewfox

[Gray-Wolf]

Wind induce spread which I assume has happen since the year dot.

In the summer its not wind induced reduction of course , its all the ice going out of the Fram straight that’s causing the decline

I assume its bit of both for the winter and summer .

Most of it's being lost through Fram and if you look at how the Beaufort Gyre/Trans Arctic drift operates (and view the time lapse of ice loss over the past 10yrs) you'll see that the very ice we need to hold onto is the majority casualty from this drift.

When we had the 'old perennial' floes were large enough to effectively 'block'/'stem' the flow out of the Basin but not for the past 4 winters, even the ice arches that used to block Nares (narrow channel) have failed to stop winter ice loss of late.

Re. North pole cam: I wonder how heavy all that snow is pressing down on the ice below? There must be a good couple of ft of snow now ( the buoy is actually well away from the 'pole' now http://psc.apl.washington.edu/northpole/DriftTrackMap.html) and heading into warmer waters in the mouth of Fram.

[Guest mycroft]

I think the problem comes from those who pretend that somehow we know less about the natural cycles than we do about current warming. A new paper (Ljunqvist 2010) has added yet another strand to the spaghetti of 1000+ year reconstructions, and once again finds the overall magnitude of natural cycles to be on the order of <0.5C globally from MWP to LIA, adding yet further support to the consensus that past historical climate changes are not of the same magnitude or rate as present ones (>1C LIA min-present). But once again, there is no pretence that the natural variations of the past didn't exist, fundamentally because in order to understand climate as forced by anthropogenic CO2 we have to understand climate as forced otherwise - that is the climate scientist's day job. You simply can't understand the anthropogenic without understanding the natural. Natural changes have not been so rapid since (at least) the catastrophic ice sheet retreats at the end of the Pleistocene, and the physics of the forcing works very well to explain both recent and palaeoclimatic changes. Natural variations, presumably the same variations that have operated over the past 1000+ years, have not achieved anything like this, and I find it hard to believe that natural variation would coincidentally go into overdrive at the same time we are releasing a known powerful greenhouse gas into the atmosphere at a rate neatly consistent with the observed change. I'll secong weather eater - boy would I love to be wrong on this, but there's as ever no coherent evidence for natural cycles playing a strong enough role to do more than slow our rate of warming.

BFTP - the exceptional late start to this year's melt still resulted in a near-tie or tie for 2nd place as the lowest sea ice extent on record (and was a clear 1st place just two months after the start of melt), why do you think the date of ice melt, or growth, start matters a jot if the overall ice extent continues to decline at an accelerating rate? 2010 finished almost exactly on the quadratic curve fit through the past 30 years of data.

I am happy to see the rapid extent increase of th last week or so, though I hope it's real area increase and not just spreading out of ice due to wind changes, as some have suggested. Another hypothesis, discussed over at Neven's blog, is that because we had a remarkably low concentration fragmented inner pack this year, the freeze-up of this inner region is accelerated by the seeding of <15% concentration areas by the fragmented ice debris already present. Previous years had little fragmentation in the inner pack, so growth had to be only around the edges. Another reason why 'extent' can be a misleading measure? Bring on Cryosat volume!

Thats not quite how it comes across in the paper,

A new temperature reconstruction with decadal resolution, covering the last two millennia, is presented for the extratropical Northern Hemisphere (90–30°N), utilizing many palaeotemperature proxy records never previously included in any largescale temperature reconstruction. The amplitude of the reconstructed temperature variability on centennial time-scales exceeds 0.6°C. This reconstruction is the first to show a distinct Roman Warm Period c. AD 1–300, reaching up to the 1961–1990 mean temperature level, followed by the Dark Age Cold Period c. AD 300–800. The Medieval Warm Period is seen c. AD 800–1300 and the Little Ice Age is clearly visible c. AD 1300–1900, followed by a rapid temperature increase in the twentieth century. The highest average temperatures in the reconstruction are encountered in the mid to late tenth century and the lowest in the late seventeenth century. Decadal mean temperatures seem to have reached or exceeded the 1961–1990 mean temperature level during substantial parts of the Roman Warm Period and the Medieval Warm Period. The temperature of the last two decades, however, is possibly higher than during any previous time in the past two millennia, although this is only seen in the instrumental temperature data and not in the multi-proxy reconstruction itself. Our temperature reconstruction agrees well with the reconstructions by Moberg et al. (2005) and Mann et al. (2008) with regard to the amplitude of the variability as well as the timing of warm and cold periods, except for the period c. AD 300–800, despite significant differences in both data coverage and methodology.

Note he says it is possible that temps are higher BUT is only seen in the instrumental data not multi proxy data

Edited September 29, 2010 by mycroft

[Gray-Wolf]

My my My! that was a quick digest of the paper? Recent warming does not have the same precipitation CO2 profile of the 'natural' periods and so you could not expect to see the same 'growth patterns' in either vegetation or critters. Once enough time has elapsed for nature to catch up (and step change) into the new temp regimes then I would imagine we will be able to draw direct comparisons with past growth/blight patterns/proxies.

[NorthNorfolkWeather]

My my My! that was a quick digest of the paper? Recent warming does not have the same precipitation CO2 profile of the 'natural' periods and so you could not expect to see the same 'growth patterns' in either vegetation or critters. Once enough time has elapsed for nature to catch up (and step change) into the new temp regimes then I would imagine we will be able to draw direct comparisons with past growth/blight patterns/proxies.

Sorry, but I would call foul on that comment. Proxy records are only OK when they show you what you want? that's how that comment comes across, I'll disregard everything else.....

[Gray-Wolf]

Sorry, but I would call foul on that comment. Proxy records are only OK when they show you what you want? that's how that comment comes across, I'll disregard everything else.....

Sorry if you understand it as such it was certainly not meant to voice that?

As I've maintained all along 'man made' warming differs from 'natural warming' by the fact that it is 'man made' and not 'Natural' and so , to me, you expect to see 'difference' from past warmings??

[Guest mycroft]

My my My! that was a quick digest of the paper? Recent warming does not have the same precipitation CO2 profile of the 'natural' periods and so you could not expect to see the same 'growth patterns' in either vegetation or critters. Once enough time has elapsed for nature to catch up (and step change) into the new temp regimes then I would imagine we will be able to draw direct comparisons with past growth/blight patterns/proxies.

No as you are probably aware the extract i posted was copy & pasted from WUWT

So 30 years is not enough time to conclude whether its natural or AGW then?

Edited September 29, 2010 by mycroft

[BornFromTheVoid]

IJIS has updated to a gain of 105,000km2. That makes it the only year on the IJIS record to have more than 1 daily gain of over 100k in September.

Another 2 days of these gains and we will have over taken both 2009 and 2005. If we can continue these (at least by recent standards) record gains past the other years then it is a very good sign. If we simply nestle in to the middle recent years figures after these large increases, then it will, IMO, reduce their value to just the result of a typical refreeze being augmented by the extra open water available after such a low minimum extent.

[MR EXTREMES]

IJIS has updated to a gain of 105,000km2. That makes it the only year on the IJIS record to have more than 1 daily gain of over 100k in September.

Another 2 days of these gains and we will have over taken both 2009 and 2005. If we can continue these (at least by recent standards) record gains past the other years then it is a very good sign. If we simply nestle in to the middle recent years figures after these large increases, then it will, IMO, reduce their value to just the result of a typical refreeze being augmented by the extra open water available after such a low minimum extent.

certainly looking very promising late start to the melt season and late start to the freeze up but just goes to show how robust the arctic is lets hope it continues imagine 100k per day though winter awsome lol.

that would certainly put a spanner in the works lol.

[Devonian]

certainly looking very promising late start to the melt season and late start to the freeze up but just goes to show how robust the arctic is lets hope it continues imagine 100k per day though winter awsome lol.

that would certainly put a spanner in the works lol.

But highly unlikely, indeed probably impossible.

Reading posts elsewhere I think the explanation that the easy bits are freezing up atm (melts pools, leads, bays, inlets and the pack that has lasted the year simply consolidating) and that, if you look at the graphs, the rate of increase slows in November when open seas start to freeze.

[The PIT]

Blimey amazing climb back up. http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm back too 2009 and 2005 levels.

Just need the East Siberian Sea to wake up and then we would be rocking http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/recent365.anom.region.9.html

No as you are probably aware the extract i posted was copy & pasted from WUWT

So 30 years is not enough time to conclude whether its natural or AGW then?

Nope it isn't. A mere billionth of a second in the life time of the planet.

Edited September 29, 2010 by The PIT

[Devonian]

Nope it isn't. A mere billionth of a second in the life time of the planet.

But why is this an argument? Does it mean it's not happening? If someone robbs me of a sum can the robber dismiss it by saying it's nothing compared to my total lifetime earnings so far (even if they don't, sadly, run to billions )? How does he know when I'll earn again and how much?

Edited September 29, 2010 by Devonian