Filski

Just for the record, I have been to the Maldives and I grew up on the Great Barrier Reef... well the main centre used by tourism for accessing it. :lol: Earthquakes are not likely to be a problem but subsidence during drought could possibly (though unlikely) cause some percieved rise/drop in sea levels by affecting the height of the islands themselves. This would be regional in scale. As for the high tide line, this depends firstly on the memory of the locals, which is subject to some drift and romanticism. Also which high tide? Spring tides? A moderate one? Remembering that tides vary thoughout the year it is difficult to say with any certainty that the tides reached a definitive height 5yrs ago, let alone 30. My home town would occasionally be inundated by spring tides but I could not put a level on it that had any less than a 0.2m margin of error - and that's in a built environment. Try doing better than that on a beach which is subject to movement. But back to the Maldives... I witnessed myself that erosion and encroachment by the sea on one side of our island was a definite issue and the tree line was receding as recently as 2001. On the other side the action of waves and wind had built up sand levels well above the level of the centre of the island. These are dynamic places. As for sources, look up PS Kench, PL Woodworth, CD Woodroffe for starters Another Comment on “Estimating future sea level change from past records” by Nils-Axel Mörner. (2007). R.S. Nerem a,b,⁎, A. Cazenave c, D.P. Chambers d, L.L. Fu e, E.W. Leuliette a, G.T. Mitchum. Global and Planetary Change 55 (2007) 358–360

The studies by Mörner have been disputed on at least 4 occasions. The main critique seems to be he does not understand sand island formation and evolution. Certainly there is no evidence that sea levels have dropped since 1970, nor is it conclusive that they have been higher than present during the last 5k years.

Nils-Axel Mörner.... Interesting.

Interesting info about the Maldives... I'd like to read more, do you have a link?

Precipitation is mentioned in the paper that you linked to. I forget exactly how much more heat water holds than air but consider the effect in the tropics of increased precipitation on temperature as a feedback. In more detail - As you say evaporation increases as temperature rises. Water vapour is a store of this energy and all that energy used to evaporate the ocean is then collected in larger and larger water droplets until eventually being precipitated out again - there is your negative feedback. It's a little bit of a loop, a natural buffer or coping mechanism that the planet has to mitigate the effects of rising temperatures. I don't think it's modelled well particularly because it is high resolution but as I said, perhaps it now will be included now that the effect has been looked at in detail.

It could be argued that with the proposed new PDO phase, La Nina, quiet solar period and supposed cool oceans that temps should be far cooler than they actually are. Something is keeping us warm...

Hang on, I'm not sure we can say that. There has been a degree of warming to be sure. We do not know exactly what is responsible and by how much. The IPCC are giving a fairly wide range between upper and lower estimates for projected future warming because of this uncertainty. I'll say it again - anybody who expects that we'll ever acheive 100% accuracy on hindsight modeling of observations and 100% accuracy of future projections is just setting themselves up for disappointment. It's just not acheiveable. http://www.realclimate.org/index.php/archi...y-say/#more-564

Sorry, I was perhaps a little too quick and flippant before. I'm a little familiar with this study. I'm not sure if you got to the conclusion where it states: There are some interesting points raised in the paper. I don't pretend to understand it all. What I do undertsand is that it will help to refine our understanding of climate science and be used to improve the models. Does the paper prove anything 'wrong' - nope.

Well there goes the sceptics argument that water vapour is the most important GHG :lol: Seriously though, it is an issue and one I'd like to see more information on. The fact is we have warming despite the weighting of various feedbacks and CO2. How is it happening if what everybody thought was the primary GHG - water vapour - is suddenly less important (relatively). The warming doesn't go away...

So what happened in the early 90's or around 2000? And why is there an extended positive phase at the start of the graph? http://jisao.washington.edu/pdo/img/pdo_latest.png NASA have said this could be a similar 'blip' or it could be the start of something much longer, we won't know for a little while.

CB - no graphical slight of hand in my opinion. I've seen far more complex graphs with more natural and man-made forcings and it looks fairly similar in terms of -ve & +ve spread. I'm not sure if you've picked up the interesting bit about sulphates actually... man made, volcanic and the 60-70's. It explains a lot. Also what is the current trend of sulphate production? The last part of your post - if we were to remove GHG then there is a pretty big hole left. That is my point, what fills it? For mine, it is too big a coincidence to be able to produce a graph that relies on GHG to get that close to the temperature record. We would have to be way off base with all forcings and a liberal dose of chance for it to happen. I don't buy it, all evidence, all the papers I've read point to the contrary. It it takes a particularly stubborn sceptic not to agree. I can accept the models are not perfect but I can't accept we've got it all completely wrong. Snow-bear - I think it is incorrect to say "reduction of volcanic activity and sulphates" as the graph shows the influence of these increasing... You may want to check your figures, I get -ve forcings = -0.5, Solar and ozone combined 0.3. Still there is some error there. millenia - will have to come back to that.

CB, you are the first person in a year (since I became first aware and starting posting it) to pick this up. Well done. Of course Svensmarks work depends on sulphates as cloud condensing neucleii. A decrease in those means a decrease in cloud and we know how well those are understood. No wonder the models have a tough time. Still, the question is... if you take away GHG the models would be so far out it's not remotely funny. That indicates to me they have a reasonable handle on the situation, certainly getting it more right than wrong. Or are you saying that the result of the models is completely randomn? BFTP - you may be interested in this. http://julesandjames.blogspot.com/2008/04/...t=1209914040000 I for one expect at best a plateau for the next 5 or so years. I think NASA is being taken slightly out of context. For example we cannot predict if the downturn in the PDO is a temporary blip (eg 90's) or indeed the start of a long term trend. There are an awful lot of factors combining at the same time right now to produce the current temps and it's still pretty warm really. This current conjunction will not last long and temps will head up again soon. You can bet on it. B)

The models aren't perfect, nobody apart from sceptics claim they should be. The errors don't mean that the models are wrong outright, just that we don't have resolution in the models down to the degree that would remove more errors - a need for something like 1000x the computing power currently devoted to the task. Of course apart from resolution there is the level of understanding of the interactions between all of the forcing and there are far more than shown above. Our understanding of the forcings we know about is pretty good really, all things considered... For the sceptics to be correct about the role of CO2 means that our understanding must be so fundamentally flawed that modeling such a graph as above would be impossible. There is a group of scientists meeting in Reading this week to discuss the issue I beleive. It's not the scientists that are wrong, it's the media's reporting and the expectations of the sceptics that set themselves up for disapointment. http://environment.newscientist.com/channe...ate-debate.html Get this weeks New Scientist to read.

What I don't understand is why people ignore this simple illustration that the current rate of rise can only be explained with both natural and anthropogenic forcings. There are a number of different versions of this but they do stand up to scrutiny and I've yet to meet a sceptic willing to tackle this point. Of course modeling doesn't exactly match observations but the degree of error would be vastly larger if we did not include the effects of man-made GHG. Anyone?

GW - as a 13yr old in '83 I was laughed out at in my backwards northern australian country school because I raised in science class the prosepect of the effect of grazing animals on the climate. Together we may have the last, somewhat masochistic, laugh.

1998 was an anomaly. It has as much relevance to the heating/cooling debate as the reported 0.7 degree drop in the last 12 mths - absolutely zero. Blips will happen in the temperature record, large anomalies are common even. Using them to defend an argument such as no warming in the last 10yrs shows a lack of understanding (intentionally or not).

Well I've never owned a car. I own 2 bikes. In the past I've been a top level cyclist with a PB for the 40km time trial well under the hour so you could say I know a thing or 3 about going fast on bikes. However if you are not supposed to be driving fast in an area where people are likely to share the street environment (eg kids playing street cricket) then you probably shouldn't be tearing through on a bike either... Ride safely, ride sensibly. Last I saw 5yr olds with trainers wheels are cyclists too and not likely to get air save being pushed off a cliff.

100/100 will never be acheived. It is not possible and should not be desired since it assumes a complete knowledge of how climate systems behave. This is impossible since no matter how fine the gridded data there will always a finer level of detail missed. It is unreasonable to request a perfect model and even states this in the paper (pg 4). Detractors of the AGW theory always state that we cannot know everything and then complain when the models are not 100% accurate. They set themselves up for disappointment.

paper http://www.inscc.utah.edu/~reichler/public...7_BAMS_CMIP.pdf Comments?

I've been having a more or less identical discussion on another forum about temperatures since 1998. I agree with Magpie as to the correct way to view temperatures. 1998 was as much of an anomaly as the drop Jan07-08. Running means are the best way to test if indeed temperatures have indeed dropped since 1998 (and they have ever so slightly) Geographical and seasonal variability should also be considered. This was the graph posted to illustrate that temperatures have not risen and to show the extreme drop Jan 07-08 This shows that it is not a unique occurence and that a recovery usually follows Solar cycles -black for troughs and green for peaks. The current trough is not shown for obvious reasons. ENSO Cycles - down is El Nino, up is La Nina Finally shifiting the reference by just one month to Dec 06-07 halves the temperature difference. I challenge anybody to demonstrate that there is a continuing natural cycle in all the above that proves we are about to enter a continued cooling phase. Even now with a convergence of natural cycles (solar and ENSO) - the 'perfect storm' - at their minimums we are still pretty warm. With a forecast global anomaly of +0.4'C nothing like a reversal is beginning. If natural cycles were soley to blame then we have a problem, because we have not identified a natural input to our climate that exceeds the sun and ENSO combined.

Without wanting to cloud the issue but I suspect the straw that broke the camels back comprises 2 parts. 1. Cross section of the polar vortex. I have been looking into the polar votex and AAO for a little while to see if there is a predictive element for the aussie snow season. A weaker vortex (shown by negative values or the red patch) will influence the SLP and ultimately the sea level in that area. Differences of only a little would be enough to cause stress in the ice shelf. 2. I've read reports of severe storms and wave heights of several tens of metres in the southern ocean around that period. I can't be stuffed looking for the relevant charts but I'm willing to bet that this at least in part was caused by wave action from storm activity and worsened by a weakened structure due to melting broguht about by GW. I am not in anyway suggesting that this is or is not a GW related event. It is a very complex issue and it is worth following up every avenue. The storms are 'weather' but the AAO is certainly climate.

Thanks for the update Carinthian. I am somewhat optimistic that a delay to the melt will be seen this year and a shortened summer (based on little more than dubious signals from down south and some hopecasting). This may allow the recovery of some multi-year ice, though not as much was lost last year. Let's see shall we. Things are not good but Mother Nature has a habit of ironing out the spikes (being 2007). Gray Wolf is correct to worry. The longer trend, even if we do get a couple of cool years now is one of warming and reduction of ice. Sceptics should not take signals of a superficial recovery as justification for their position.

Eddie - you are getting a little silly now. Nobody is suggesting that all roads will be turned over to this speed limit. What next? Motorways, rail? I haven't seen the proposal's details yet but I'd expect that only new roads will have the new speed limit and even some of those will not. No inconvenience will be caused to existing developments or businesses for example, not unless a nationwide rollout of the speed limits is imposed. Even then there will be strict rules about how it would be applied. We are not going to throw out decades of sound road design proposals just to discourage people from using cars. Where the changes are useful is where you have a high density of different users. Take a look around any european city and a great deal many british ones too - the principles are there. Shared surface design in high streets where cars don't have a clear carriageway and, although technically the speed limit is higher, only a low speed can be maintained because people are crossing all the time, bikes are all over the place, etc. To drive faster would be negligent. This is what is seen in Denmark, the Netherlands, etc.

TWS - we are not talking about warehouse and articulated lorry deliveries here. At most it'll be high street type areas which can only benefit from a slower speed environment. Even that will be limited since the vast majority of that which will be affected is residential. I'm not going to get into a lowest denominator argument, because I see the great equaliser as a child riding a bike. Can you suggest how to bring that up to the level of a car?

It's a reference to the problem drivers in the post above. It's not aimed at anyone here.