beng

Thanks David. I'll have a look through the el nino PFM data in the book tonight when I get home from work. Is it possible to print out the pages from the e-book? - I've not seen a print icon - it would make it a bit easier to read then (it's hard on the eyes staring at the e-book after a slog in the office).

Hi Iceberg, The one thing I'd add to that is that because only so much energy is released at these key wavelengths, there's a limit to how much can be blocked before the wavelength is essentially saturated and all outgoing radiation at that wavelength is blocked (don't ask me what that is though). To further complicate things there are probably other chemicals in the atmosphere also blocking at the same wavelengths. Another complication is the global spread of CO2 gases - a high percentage of outgoing radiation from the planet is obviously away from the equator and towards the poles, however if CO2 is not spread evenly across the planet, then that's going to complicate further the amount of radiation that it can absorb (either upwards or downwards). I think this is where we probably mostly agree ie C02 is a greenhouse gas, but we differ on how significant it is. Still haven't had a chance to get through all of David's book- although I have read some of it. I want to re-read the chapters relating to the lunar cycles and follow through on the references as it's not something I know too much about and it's obviously key to the whole theory. It does seem plausible though that large tidal swings could shift pressure builts slightly (eg by shifting warm water/cold water masses). A movement of the subtropical high in the South Pacific northwards would be consistent with an increased pressure gradient in the key cold enso forming areas and upwelling off the coast of Peru - I guess a question for David (or other qualified meteorologist/climate scientist) would be this - how big a movement of the subtropical high pressure northwards in the south pacific is required to create la nina conditions and how big a la nina (if at all) could we expect from a 1 degree latitudinal shift towards the equator? I think it's pretty obvious from the drop in global temps in the last year (and numerous other enso events) that enso can influence global climate - so a sustained run of more negative enso should have a cumulative effect on global climate due to the latent heat properties of the oceans.

Dev, I'll be sure to let people know what I think of the book when I've had a chance to read it and apologies for thinking you agreed with the fraud rumour. I'll also add (which you'll agree with I think) that I'm not sure we should be shouting fraud about Hansen anymore than anyone else (unless you've got cast iron evidence that would stand up in the law courts).

It's one thing saying a theory is a fraud (which actually I don't agree with either - in the case of AGW it's my believe that the theory is wrong in terms of the significance of the effect), however it's another making the accusation against a specific individual. So I take it from your response that you think it's okay for iceberg to have essentially smeared David as a fraud on a public site without even reading his book - or giving any evidence to back it up. Rubbish. Even when the enso factor is removed as per the recent 'real climate' graph the climate has been essentially flat for the last 10 years. LOL - you're applying that to CO2 then as well.

Well why haven't things warmed in the last 10 years? Warm PDO, warm AMO, very fast rising CO2 levels, low volcanic activity. The simple fact is that AGW theory cannot answer this question.

Do you want to backup this accusation with some hard evidence or is this just a smear tactic? It really annoys me when I see this kind of post in what's supposed to be a scientific forum. I have downloaded the book (but have not had a chance to read it in detail yet) - but I can assure you that it does actually exist and from that perspective it's no more a con than Al Gore's inconvient truth.

Are you implying that global temperatures in the last 2 years have been rising?! Global temperatures have dropped around 0.8c - according to satellite measurements. Temperatures have also dropped in the Hadley and GISS data series.

Globally temperatures have been pretty much flat for 10 years - so it's a warm global climate, but not warming - at least not for the last decade.

The GISS figure for June is out +0.26C Coldest June since 1996. Coldest first half of the year since 1996 too.

Seems a bit strange that doesn't it. Either a data error or maybe a chunk of ice has broken off?

CET: 15.5 Rainfall: 140% Generally rather cold and unsettled.

Sorry, no I can't accept that. :lol: The Atlantic is still in its warm phase. The PDO might have switched to its cold phase - but if this has happened, it was last summer after a 30 year spell in the warm phase (so you'd hardly expect much cooling or impact on the arctic in terms of cooling just yet). On top of that and if you believe in the solar connection, cycle 23 was still very active (although a bit less that 22) - only now are we in a minimum - which might well lead to a low couple of cycles. The natural factors do now possibly favour cooling, certainly from around 2010 or so when the AMO should go towards its cold phase again - but these factors are only just coming into play. If global temperatures don't respond to the natural forces over the next 5 years (assuming cycle 24 is weak) - then AGW is definitely a major factor - but short of invading China and India I don't think you're going to tackle it - we'll probably have to suffer the consequences and adapt. I think we may have some more immediate problems on our doorstep before then too http://www.dailymail.co.uk/news/article-10...city-years.html Imagine if those natural factors did kick in.

The PDO may have switched to the cold phase, but we certainly don't know that for sure as it only happened last year; it definitely has not had enough time to have much impact on 30 years of warming in the arctic (assuming it will). The Atlantic is still very much in its 'warm' phase and will be for at least another 5 years if previous patterns hold true. The Cold Phase if it has started, has only JUST started - which means if you believe there's a cold phase we're essentially at the pinnacle of the previous warm phase's warming.

http://icecap.us/images/uploads/MAY2008GLOBE.jpg Satellite observations show a 6 year cooling period now - still not long enough to confirm the end of AGW - and we need to see where we appear once enso recovers to neutral for a few months. :o

Hello Grey Wolf, Have a look at the link below and tell me again that the ice extent at the S pole was below the 79 baseline. http://arctic.atmos.uiuc.edu/cryosphere/IM....area.south.jpg Ice extent minima last S Hemisphere summer looks on a par with 79 to me. Last winter it was the greatest in the satellite records and this winter there could be another record. My understanding is that BAS have reported ice loss from the peninsula which is only one small part of the continent. The interior of the continent has cooled slightly in recent years (which is more consistent with the svensmark cosmic ray theory than current climate models - ie clearer skies due to reduced cloud cover over the interior of the antarctic offsetting some of the warming over the rest of the planet). Arctic ice extent while worrying for the reasons you've given - but I still think it may well be part of a cycle as we know it was reduced in the 1930s too. It will become clear either way in the next 5 years as we're at the point where if it relates to the PDO and AMO cycles, then it should be close to increasing again - if it doesn't then we could be in trouble. Ben

Let's put this in perspective for a minute - yes there's some gaps developing in the arctic ice cap now - this is normal in June - even back in 1980 you will see this happen. The question is how big will the ice loss be by August (I've said August because I expect an earlier refreeze this year). http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh - yes we had a record min (from the data back to 79) last summer - all during the warm phase of the PDO. It's simply too early IMO to conclude that last year's minimum will be beaten this year - for several reasons. Last year there was a change in the circulation patterns in the Pacific with the switch in the PDO and change from el nino to la nina - all that excess heat had to go somewhere and the most likely answer was that it was radiated into space via the North Pole - hence much larger than normal ice loss there. This year the PDO is cold and enso is slightly negative so there will be much less heat to transfer from the tropics to the Pole this summer. Additionally we see from the data coming out for May that the tropics are much colder than normal - it's quite likely that the winter freeze in the arctic will start earlier this year which may put a cap on how great the minimum will be. Against all that of course we have the reduced multi-year ice up there at the moment - which will favour reduced ice extent this summer - but I think it's too early and to assume the loss this summer will surpass last year. Sea Ice extent last winter (S Hemisphere) around antarctica was the greatest on records back to 79 - so I'd say it's just as interesting as the small summer extent further north.

CET 14.1c Rainfall: 150% A very wet month across England and Wales - Scotland may fair the best (away from North Sea Coasts - sorry Michael). Sea temperatures favour blocking to our NE - and a slightly displaced (westwards) azores high - which will allow for low pressure around the UK. The only saving grace is that the jet is less strong than last summer - so perhaps some drier spells between the rain - and always the possibility of warm spells into the SE from the continent.

Just to be pedantic - the PDO did switch negative briefly around 2000, but since then it was mainly positive up until last year http://atmoz.org/img/nao-pdo-amo-timeseries.png

http://icecap.us/images/uploads/TRENDAPRIL.jpg Yes it doesn't prove anything yet - since it's only a 5 year timeframe - but it is interesting given the lack of volcanic acivity, enso conditions averaging slightly positive since 2002 , and with both the PDO and AMO positive for most of the period (until the PDO switched last year) you might be forgiven for expecting the 5 year trend to have shown warming (I also think you could knock out the recent la nina from the graph and you still wouldn't have a warming trend). The only obvious factor that would have favoured no warming is the current solar cycle.

Some of the heat may initially be subducted to the deeper ocean, however it cannot remain there and will ultimately make its way back to the surface (warmer water is less dense). As others have said, records to quite a depth show some cooling - so to me the most plausible solution is that much of the energy has been radiated back into space at the poles (presumably mainly the arctic (as the antarctic is so isolated by the strong currents surrounding it) which would be consistent with the warming there as energy has been transported from the tropics). I may be wrong of course as perhaps the massive, oceanic currents are able to lock away the energy for a long time - as you say we can't know for sure. This doesn't mean AGW is disproved or (has stopped in the longer term), but I do think it's representative of what's been happening for the last 5-10 years.

Please can you provide some evidence - eg temperature recordings to support this statement that the global temperature has increased in the last 10 years? Everything I have seen says that it's been stable - with even a drop in the last 5 years.

You can always manipulate these short-term graphs by playing with start and end points - however it's s pretty accurate assessment based on Hadley surface data and satellite data to say that for whatever reason, there's been no real warming so far this century - or indeed for the last 10 years in fact. Temperatures are currently plateaued at around the same level that they reached in the late 90s. From here we could go up or down.

I suspect they are partly discussing the findings from Sloan and Wolfendale in respect of Forbush Decreases - their conclusions are disputed by Shaviv here - in fact there's a discussion between Sloan and Shaviv at the bottom too http://www.sciencebits.com/SloanAndWolfendale Incidentally as to the conclusion that a negative AO has no overall global impact on temperatures - I find that surprising. If anyone has the time to correlate winter polar ice extent and N Hemispheric temperatures with the AO I'd be interested to know what they show and whether they support that conclusion.

Well in a way we probably agree then Devonian in that I don't think the PDO is the real climate driver, but I do think it can lower or raise global temperatures through enso during the course of its warm/cold cycles - in other words it can have the impact of enhancing or reducing the overall climate trend. I think we disagree on what causes the long term climate trend though.

So why not discuss the science? I rarely see much hard science discussed on this - all we ever see are floating polar beers. Have a look at what wavelengths of infra red radiation CO2 can actually absorb? Then have a think about the fact that there's only 380 parts of CO2 in the atmosphere to evey million. Consider further that the atmosphere is not infinitely thick and that might sway your oppinion on how much energy additional human released CO2 can actually absorb. You should also bear in mind that we need CO2 to survive, if the atmospheric content drops below around 200 parts/million then it's possible plant life will die back enough to trigger extinctions. During the little ice age it's believed that CO2 levels got quite close to that level (although how accurate those measurements are I'm not sure). CO2 is a small greenhouse gas, and the scary scenarios are all as a result of possible positive feedback from things such as water vapour among other things. If you're not convinced by the water vapour feedback idea (which i'm not - and apparently neither is Nasa's AQUA satellite - and nor is the historic temperature records - or we'd see feedback in them - rather than abrupt cooling on several occasions) then CO2 ceases to be very scary since the maximum warming then is reduced drastically. :lol: