trevw

I still don't see why cooling/lack of warming caused by diminished solar radiation/internal climate variation disproves the theory that additional CO2 will result in a forcing of the climate, it may of course delay/negate any effects for a time and may also help us pin down how much of the recent warming was natural and how much anthropogenic? That aside. For whatever reason the trend has (temporarily?) plateaued I would hope the opportunity is being taken by those who write the (Daft?) climate models to try and nail down the forcings and internal climate variations that are the cause. This will hopefully result in even more accurate models being available in n months/years time.. Will be interesting to see what if anything is said about this kind of thing from the major modeling groups. Trev

Definitely taken as a question - and to be fair before I could answer I had to look up supposition to be sure I new exactly what it meant - instead of just assuming I did glad my reply made some sense at least! True, that would be bad though I would guess as it would mean we had lost more of the older ice at the expense of some more easily lost 2 year ice for next year? I would agree, I don't expect it to get that low either.. however I wouldn't be that suprised to see the melt last a tad longer or go a bit quicker in these later stages than last year simply due to (back to my musings/theory) more 'easy to get' thin/thinner ice possibly at lower latitudes than at the same time last year.. Of course the closer we get to last years ice levels the less this would be the case.

Daft Models? Somewhat dismissive? I'm fairly sure quite a bit of hard work goes into making them not tooo daft.. Political Interferance.. I'd be interested in evidence that there is more of this from the pro AGW side than from the against.. Pretty sure there is funding available for climate researchers from organisations and governments who don't really want AGW to exist as well.. A hundred years is a very short timescale as far as the climate is concerned.. I thought that was the reason for the concern, unless we are unlucky I don't expect AGW to be a huge issue in my lifetime, I think that is why the press struggle - they want to make the consequences or lack thereof of immediate interest rather than 50/100 years down the line. For myself I am as yet unconvinced what the CO2/natural variation split was/is for the current warming trend, I believe CO2 was at least a significant contributor because I find the basic science convincing but the climate sensitivity calculations not so (perhaps due to lack of understanding on my part). I am concerned though that people can seem to equate the world cooling due to a lull in solar output (if this happens) with proof of CO2 not having affected our climate.. I just don't see how one logically follows the other. Trev

But although global temps can be said to have plateaued or even dropped slightly if you take your start point as 1998 they are still relatively high as far as recent history is concerned (and this is taking AGW opponents data sources) so I'm not sure I understand what localized low temp records are supposed to prove to me other than interesting synoptics have occurred in those areas? Maybe they could have been caused by the atmospheric changes resulting from large amounts of open water at the pole as we headed into winter?

I think supposition (as in assumption) is possibly a bit harsh I would say more of a logical derivation from various sources..which could of course be based on incorrect assumptions (I did say 'I would have thought' in there somewhere to indicate it was speculative..) Thought processes being: 1) Last year the remaining area was far smaller than ever before.. this would suggest that a lot of the remaining ice was there probably at least the previous year - this ignores ice pack mobility which is where this might fall on its face. 2) This winter we had a large refreeze, everything above last years minimum area (or outside the area of minimum extent) is obviously single year ice. 3) This year we are behind last years melt and so in all likelyhood have not melted all of the single year ice. simplistic I know and I would not suggest any figures be calculated on this basis due to differences in melt patterns, movement of the ice etc. but surely the basic premise holds? What do you reckon? Trev

Doesn't new ice melt quicker in part because it is more saline? Older ice somehow purges itself of salt slowly becoming fresher and thus having a higher melting temp? Or is that wrong..

Definitely some interesting information linked to in the article.. If true in the short term we could be glad of our CO2 :-) probably don't want to have twice as much kicking around when things warm up again though... It is a shame though (and both 'sides' of the argument are guilty of this I'm sure) that they feel the need to try and give the impression this completely debunks the entirety of existing science on AGW, largely by misrepresenting the science and then 'blowing it away' with their new info. No scientist I am aware of has suggested that variations in CO2 have a greater effect than variations in the Suns output. What I believe they have said was that over a certain period the known variations in natural forcings (including the sun) cannot by themselves have produced the warming we have seen, add increase in CO2 to the picture and you can explain the warming. Also a few places on the globe having one off cold winters or poor summers are surely down to synoptics rather than sudden plunges in global temperature? Some of the linked to articles even trot out the ol' "CO2 change lags temperature -just look at the ice cores" line. That said, I would definitely be interested to read what follow up research is being done. Also where and how the drop in temps of 2degC was arrived at from the Amargh measurements.. Trev

on the other hand, by this time last year there was little to no thin first year ice left I would have thought? Therefore large amounts of melting were required to continue to reduce areas/extents.. Whereas this year there is still a bit of the thin stuff to go so even conditions condusive to mild levels of melting can have an effect on area/extent until later in the season?

doesn't the NSIDC image show extent of ice with greater than 15% concentration? This means that areas of 15% concentration sea ice are shown as solid white tending to make the coverage seem greater than it is.. I remember there was a discussion earlier about the leading edge of the nsidc timeseries graph.. over the last few days it has been waggling up and down like a dogs tail! it's down again today. I know that there is a correction done after the data is first added or something.. What suprises me is the length of the section that 'waggles' is this down to them using a running mean? If so the discrepancy between added results and corrected must be quite large to have that much affect..? Trev

We've got one of those roads where you have road then curb then grass then pavement if you know what I mean. Unfortunately unlike a road a few across they have not planted trees in the grassy bits.. I've been wondering for some time whether to sneak out and plant a tree there when no one is looking (perhaps in the dead of night ) Wasn't sure if I could get in trouble for it mind.. ? I'm sure if I applied to the coucil they would decline to allow it on the basis of possible future damage to road and pavement.. but still, it would be green and would look nice!

yes, sorry, I think it was. Sometimes forget which thread I'm reading.

must admit I've noticed all summer that the curve always looked like it was turning upwards at the 'end' but come back a week later and it had been straightened up at the point of the previous upturn but had a new upturn at the new 'end'. It got to the point where I wondered if it was a statistical issue to do with their calculation of rolling means they use. Of course if the same is holding true now then the fact that the end is straightish means that the 'upturn artifact' is hiding a downturn :lol:

Presumeably the only reason melt stopped so abruptly last year is that due to the phenominal melt rate over the summer all the 'easy to get' ice had melted and all that was left was thick multi year ice? Not sure how to bring up the weather at the arctic for mid august to late sept of last year. If that was the reason for the halt (rather than a sudden change in weather) then I vaguely remember melt continuing one prior year into the 3rd week of september which would give a whole extra months melt? Allbeit at a steadily reducing rate.. With a lot of 'easy to get' ice left it will be interesting to see where things end up.. Think we'd have to be unlucky with the synoptics to match last year but I have a feeling we could get close enough to quieten those who are talking of a major recovery? Trev

hope there was no permanent damage! GWO - my comment was more in relation to the question of when the A was going to be removed from AGW. I've dug around this thread a bit but unfortunately was not reading from the start.. I have to admit to being initially skeptical of the mechansim you propose as being responsible for the current climate variations. Have you done any quantitative calulations of the gravitational effects to try and prove the possibility or is your theory mainly based on statistical correlation at this time? One can use the flat earth thing both ways, you could say that AGW is like the 'round earth' theory, now mostly proven beyond doubt with a few die hard detractors determined to try and prove otherwise. To me the truth is that the comparison doesn't hold, the physical shape of the earth (flat or round) is an extremely simple thing to test once at a certain technological level with no uncertainty left once tested, nor is there any possibility of it being a bit flat but mostly round or vice versa.. I guess the issue is what you try and encompass within a theory.. I would say that lumping everything under the heading AGW and calling it a theory makes it difficult to prove or falsify (without just watining to see) due to the complexity of the system and disagreement over what level of AGW is expected from one proponent to the next, however the building blocks used for coming to the conclusion that AGW is occuring are testable/falsifiable. E.g 1) absorbtion of short wave em radiation & emission of longer wave em by CO2/methane etc, what frequencies they absorb, how this overlaps with water vapour absorbtion, at what point saturation does or doesn't occur. 2) Increase in atmospheric CO2 (and its cause - proven beyond any reasonable/possible doubt to be us) etc.. The problem then being (as I see it) that we know beyond any doubt that we are responsible for changes that would tend to force warming. However the climate system is complex with many feedbacks and knowing how it will react to this forcing is impossible to calculate directly. Therefore we move to models to try and demonstrate how the planet will react to the drivers that we _know_ exist.. I believe it is at this point that a level of doubt starts to creep in and debate can be interesting. Is tuning the models using historical data always valid, are other types of pollution/changes going to alter the climates response to temperature change e.g. change the level of increase of water vapour resulting from the Co2 equivalent forcing etc. apologies for rambling on, should really get back to work Trev

proof? <_<

Just posted this in the summer discussion arctic ice reports thread as that is what I was reading when I came across the nsidc update - thought I'd chuck it in here as well: Interestingly it has been said a lot that the ice is much thinner this year - I have said it myself and read it all over the web, however looking at the latest nsidc update it seems that the situation is less cut and dried than that - definitely less perenial ice but the single year ice is thicker than one would intuit: Looking at the satellite images thickness is definitely worse than last year, just not as much as one would expect? Trev

Interestingly this has been said a lot - I have said it myself and read it all over the web, however looking at the latest nsidc update it seems that the situation is less cut and dried than that - definitely less perenial ice but the single year ice is thicker than one would intuit: Looking at the satellite images thickness is definitely worse than last year, just not as much as one would expect? Trev

interesting times.. I am not yet convinced it is 'impossible' for us to equal or beat last years record losses however to do so the melt rate would obviously either have to accelerate to an unprecidented level or continue to a later date than ever before.. From what I can tell the reduced ice thickness means that a radical end to the season is 'possible' but whether it makes it 'likely' or not is I have to admit beyond me and will presumeably depend on weather and sea currents/temps? Am finding it almost as interesting to speculate and read the opinion of others on here on this subject as I do during the annual mania surrounding prediction of snow (although it is obviously a far more serious subject) (It seems to me that over the last few days CTs graph has started to catch up on last year a bit - no similar indication on the nsidc but then they use a 5 day running mean so it wouldn't necessarily show up as quickly) Trev

Hadn't considered that effect, thanks. I also realized that I was (rather naively) thinking of the arctic ice 'perched' on top of the sea and so was expecting to see huge holes once the bottom melted out. After a couple of seconds of actual thought (which I find painful these days) I realise that the 'distance' between sea level and ice surface will be related to the ratio of the densities of the ice and water. I think about 80-90% should be below the level of the water so you would only expect 20-40cm of drop?

Must admit I feel the images are definitely interesting, if not necessarily indicative of the state of the entire arctic, they do give an interesting insight to the conditions. Is it just the light or has there been abit of snowfall in the second pic? I was also wondering if there were other mechansims that could drop the water level... All the pools seem to have dropped by the same amount - which is I expect not as much as the level would drop if the pools went all the way down to see level, this seems to imply that either the solid surface has been raised generally (snow fall?) or perhaps evaporation has outpaced melt for a period? My reasoning for this is that I would expect the deeper pools to melt through first and once they did for them to empty very quickly..

I read an article that claimed that the entire 'ice age is coming' thing in the 70s was due to the press (shock horror) misquoting a science paper. It basically went along the lines of changing 'An ice age is due soon - probably some time in the next 20/30 thousand years' to 'Scientists say an ice age is coming soon' I imagine this was probably a headline around the time off a heavy (inch or two) snow fall in london or something Of course you wouldn't catch our press doing something like that now! I can't remember the source or its level of legitimacy (could have been new scientist but I'm not sure). However it wouldn't suprise me in the slightest.. Trev

just to pick out a quite interesting image from the nsidc monthly report that GW has already posted about for those who won't read it.. this illustrates the difference in melt onset dates - quite a stark difference this year, doesn't prove anything about where we will end up but of interest none the less?

looking at the x axis it doesn't go beyond 1970 ish? also worth noting its Northern Hemisphere only so while obviously relevant to global temperatures it is incomplete on its own..

absolutely, more ice extent in april 08. since when the curves have converged as the rate of extent loss has been greater this year than last since mid april.. if this trend is continued then some time before the end of June you would expect the curves to cross and for us to be ahead of last years ice loss.. will be interesting.

but the rate of decline is currently steeper than last years both on CT and nsidc..