Yorkshiresnows

And .... your ever increasingly upbeat and informative posts have nothing to do with it? How's the antarctic ice holding up this year !!! Also, its only your opinion that the Arctic situation is unprecedented. We do not have accurate records from satellites prior to the late 70's ... you seem to readily dismiss the notion that during such warm periods as the medieval warm period this could not have been the case ...... ! Puzzling. Y.S

I believe that The liitle ice age had a global effect. Why do you think that the Northern Ice cap expanded, the Vikings were forced to abandon their Greenland settlements and Northern Glaciers expanded into valley bottoms. Then their are the Farming records to consider. Their is a book called 'The little Ice Age' which charts agricultural changes as well as written records of the climate in an historical context from the end of the medieval warm period up until the 1850's. There are also several papers charting Pacific and Indian ocean proxy data (you'd have to google search as I cannot remember the titles) that also show reductions in temperature over this period. Y.S

Oh Crikey, Sorry Sunnyskies, I'm going to have to bow out of this one. Guess we will have to agree to disagree on the hockey stick graph ..... funny the IPCC have dropped it !!! Roy Spencer's work is published and peer reviewed. But, he is not the only one to have come to the same conclusions. But, all of this is getting tiresome, If you want to believe the AGW theory then that's your absolute right and I've no problem with it. If you have a little look around you will see a lot of support for the effect of clouds on the climate system. As stated hundreds of times previously the IPCC models rely on their SUPPOSED positive feedback (that is to amplify the warming) to get us to the amplification needed for their warming charts. Satellite data suggests they have a strong overall negative feedback (greater water low cloud density leading to reduced solar radiation absorption) ..... so something is not correct. I've read literally hundreds of papers and books on this subject and I've come round more and more to what I have previously stated. Untill a short while ago I was firmly in the AGW camp. The amount of CO2 we are emitting as I've shown previously really is quite small in the overall scheme of things ...... from 0.0003 to 0.0004 of a fraction of the atmoshpere from 1950's to 2010. If we can cut it, that's also fine with me as it is a greenhouse gas and I'd rather promote a greener way of life for many other reasons as well as that. Perhaps you could explain why the IPCC forecasts range from 1.5 degree C of warming to 6 degrees C of warming by the turmn of the century and also why we are currently so far off their predicted charts ..... I say again, no overall warming since 2000 !!!? PDO = negative // solar activity low = probable cooling for me !! Y.S

The mann Hockey stick has been successfully discredited (there were missing data points and also data points from tree ring proxy data that basically showed no medieval warm period or little ice-age). You can google search and get a ton of info on this (there's even a book written called the 'hockey-stick illusion .... or something like that. The IPCC don't even reference it anymore). I would suggest (from my review of a lot of data) that it is all to do with clouds, they are the key and principal mechanism of warming and cooling by either increased solar irradiation getting to the Earth's surface, or, a decrease (low level versus high level clouds). The IPCC computer models all work from assumed POSITIVE feedbacks of increased CO2 on cloud effects. Alternatively and this is where it gets controversial, you would only need a 1-2% change in low level cloud cover to have accounted for all of the 20th century warming. From the data I have read, I have come to the conclusion that natural oceanic cycles such as the PDO (and quite possibly solar effects) have impacted on the cloud effect and contributed the major component of global warming. Here's a link to some of the info: http://www.drroyspencer.com/research-articles/global-warming-as-a-natural-response/ http://www.drroyspencer.com/Spencer_07GRL.pdf The links and references to the above are all in my previous posts. I see that you have posted some information which I will look through and comment later. With direct reference to your cosmic ray query? There has been recent research (posted by others on this forum) showing that decreased solar activity does impact on Northern Hemisphere winters by impacting upon the jet stream (causing kinks and eddies in the flow), though I am not familiar with all of this data. There are also a host of papers that do show a link impacts upon pressure patterns (there is a big review on this in Peter Taylor's book). We also know that solar minimum occurred in all of the recent cool periods (wolf / Maunder / Dalton etc linked to the little ice age as well as maxima associated with warm periods e.g. Roman warm period / medieval and of course the 20th century which has seen a sustained period of solar activity ........ which has now dropped off. Figure 1: Annual global temperature change (thin light red) with 11 year moving average of temperature (thick dark red). Temperature from NASA GISS. Annual Total Solar Irradiance (thin light blue) with 11 year moving average of TSI (thick dark blue). TSI from 1880 to 1978 from Solanki. TSI from 1979 to 2009 from PMOD. There is a better graph linking sunspots and past minima / maxima that I cannot find at the minute. Anyway, you are of course entitled to whatever stance you wish to take, I am only highlighting that the case for human greenhouse gas emissions being the principal cause of the recent global warming is not proven and that other natural mechanisms / cycles can explain what has been observed. Y.S Hi V.P, Please reconsider, your inputs have been extremely important and relevant to the debates on here. Still going through the leaky integrator posts Y.S

Hi, The abstract from the paper is re-printed below. No time ... on travels, but this includes the links to the raw data. The link to the paper is here: http://www.econ.ohio-state.edu/jhm/AGW/Loehle/SupplementaryInfo.pdf Tree-ring data has been shown to be flawed and hence non-tree ring proxy data is what is generally accepted as being the most reliable data in attempting to re-construct past temperatures. "Tree ring data have what is called a “divergence problem†in the late 20th Century where the tree ring data data suggests cooling, when in fact there has been warming. This, by itself, should cast serious doubt on whether tree ring reconstructions (such as Michael Mann’s famous “hockey stick†curve) can be used to estimate past global temperature variability. Supplementary information by J. Huston McCulloch for "Correction to: A 2000-Year Global Temperature Reconstruction Based on Non-Tree Ring Proxies," by Craig Loehle and J. Huston McCulloch Jan. 10, 2008 Loehle and McCulloch (LM, submitted to Energy and Environment as a correction to Loehle 2007) construct a Global Temperature Reconstruction for 16AD – 1935 AD based on 18 peer-reviewed published non-treering proxy series. These are the same 18 series used by Loehle (2007), with the dating of 4 of the series corrected by a 50-year shift. Each series was newly interpolated and smoothed with a 29 year moving average by CL over the period 1AD – 1980AD, to the extent available. Each series was converted to bimillennial anomalies by subtracting out its own mean. The global temperature reconstruction is the unweighed average of these anomalies. Because the number of available series drops abruptly from 11 to 8 in 1935, i.e. to less than half the maximum number of series, the reconstruction was terminated in 1935. The 18 smoothed series and their residuals about the global average are individually graphed at the end of this note. The smoothed series, as used in the reconstruction, are online via <http://www.econ.ohio-state.edu/jhm/agw/> . Links to the raw data have been compiled by Stephen McIntyre of climateaudit.org, at <http://www.climateaudit.org/?p=2393>. Hope this helps? Cheers Y.S

I know I shouldn't but couldn't help myself - just to back up my earlier post, before we all get too hung up about the Ice melt coming this year !! 2,000 Years of Global Temperatures This graph shows the average of 18 non-tree ring proxies of temperature from 12 locations around the Northern Hemisphere, published by Craig Loehle in 2007, and later revised in 2008. It clearly shows that natural climate variability happens, and these proxies coincide with known events in human history. Guess this more 'complacency' over humanities role .... or not ...... in polar ice retention. Y.S

It is really sad, when recognised scientists that have published and are still active in the field are dismissed as 'fringe' or fanatics or even heretics ....... and all because they do not support, or in both of the above cases have published data that question the role of greenhouse gases in global warming. What a world we live in. How does temperature of the oceans effect rates of CO2 absorption. Devonian, if you are going to make such bold comments, please back them up with some reason why you believe that this is not so. Around 50% of the Co2 that mankind churns out is absorbed back into the land/oceans One thing that can be measured and has been measured is the ability of the ocean to absorb CO2 from the atmosphere. How does this do this, well one of the main contributors is phytoplankton growth. During unusually warm years, the ocean gives up more CO2 than it absorbs. For instance, during a strong El Nino such as that of 1997/1998, more CO2 is released by the ocean than that taken out of the atmosphere by the ocean. Part of the explanation is the soda 'fizz' effect: warm water can hold less CO2 than cold water, with the main reason being that there is less plankton growth during El Nino's so there is less CO2 required for photosynthesis. During the strong El Nino of 1982-1983 changing ocean circulation patterns caused the deaths of trillions of marine organisms. In contrast, during cool La Nina conditions, the combination of cooler waters absorbing more Co2 and faster plankton growth leads to an anomalously large uptake of CO2 by the ocean. You can see these spikes in some of the CO2 charts: Y.S

You could make the effort and look at some data and then make a relevant comment ? Where's all the data that shows the Earth has been warming since 2000? Y.S

Hi V.P, Thanks for the link. Yes interesting. But, it is my belief that we will begin to see a drop off in world temps as the effects of the swing in PDO come into effect. Of course, time will tell. Please also note that I have never stated that CO2 is NOT a greenhouse gas, only that the effects we are seeing are predominantly of a natural cause. Y.S

Hi GW Global Dimming is another 'misconception' I'm afraid. I am assuming you are referring to the period of supposed reflection via supposed aerosal pollution that the modelling community wheel out to attempt to explian the 1945-1980 cooling period? If so, its a non-starter. The global dimming thesis has been often quoted in peer-reviewed literature, but with no reference to the data that would support the conclusion that global-scale industrial emissions had followed the necessary pattern. Scientific opinion on this area has in any case shifted. It is now clear that sulphate pollution from either industruial emissions or other sources such as volcanoes could not have been responsible for the 'dimming' because it was too localised. The most recent reviews of satellite data show that changes in natural aerosols and cloud patterns are implicated and that attributing the source of 'global dimming' to industrial aerosols was led by an artefact of measurement protocols that were biased to land and certain polluted regions of the northern hemisphere. When global data are analysed (quoting from Peter Taylor - Chill here), the effect is seen to occur in areas where anthropogenic pollution is not significant. Furthermore there are pubished indices of the 'dust veil' from volcanoes that do not provide any supporting evidence for any contribution to this dimming. This paper, the book by Peter Taylor and other references, come back to the same conclusion, that natural factors were at play, that relate to the transparency of the atmosphere to sunlight, ...... back to the question of clouds. One paper that deals with this is Wild et al (2005) "From Dimming to brightening: decadal changes in solar radiation at the earth's surface", Science, 308, 847-850. Y.S Hi, V.P Good answer, Its all too easy to 'try too hard' to get one's point across and I guess this can seem to be dogmatic. Think I'm falling into this camp !!! Time to ease off the throttle. Nothing is settled, that is the point I have been attempting to put across. Peace and calm now ! Y.S

Sorry, But you clearly do not understand science or you would not be posting such total rubbish. No, the CO2 feedback mechanisms are built on soley positive feedback mechanisms to do with water vapour and cloud cover changes. Please show me the analytical and actual measured data that goes into these ....... they are all assumptions for which the experts are split on. Assumptions that rely on computed modelling to generate the predicted temps. Currently we should be a lot warmer than we are (no overal warming since 2000 ..... thats around 10 years). CO2 has an association with temp change no problem with that. That it is a cause of rather than a result of is not proven one little bit. The period of the little ice age and medieval warm period showed this (remember the doctored hockey stick graph that conveniently got rid of these well documented periods). Here's another pinch from Accu-weather (Joe laminate floori blog) SOME PRETTY COMPELLING EVIDENCE ON WHAT IS DRIVING CO2 The table below shows c02 increases on Mt Loa since 1959. One can notice the spiking of co2 when el ninos occur, and how the co2 increases were higher when the PDO went warm. This further supports my idea that we are going to get our answer as to what is causing the warming. Cycles of c02 and the evidence that the co2 RESPONDS to warming not causes is pretty straightforward with co-ordinating the data. The real kick in the teeth of co2 being the driver is the big fall with the Pinitubo cooling! Anyway look for yourself check this out: COLD PDO YEARS year ppm/yr 1959 0.95 1960 0.51 1961 0.95 1962 0.69 1963 0.73 el nino starts 1964 0.29 el nino ends 1965 0.98el nino starts 1966 1.23el nino ends 1967 0.75 1968 1.02 el nino starts 1969 1.34 el nino 1970 1.02el nino ends 1971 0.82 1972 1.76 el nino starts 1973 1.18 el nino ends 1974 0.78 1975 1.10 1976 0.92 el nino starts WARM PDO STARTING: 1977 2.09 el nino ends, starts 1978 1.31 el nino ends 1979 1.68 1980 1.80 1981 1.43 1982 0.72 el nino starts 1983 2.16 el nino ends 1984 1.37 1985 1.24 1986 1.51 el nino starts 1987 2.33 el nino 1988 2.09 el nino ends 1989 1.27 1990 1.31 1991 1.02 el nino starts 1992 0.43 PINITUBO! EARTH COOLS!!!! el nino ends 1993 1.35 1994 1.90 el nino starts 1995 1.98 el nino ends 1996 1.19 1997 1.98 el nino starts 1998 2.93 super nino ends 1999 0.94 2000 1.74 2001 1.59 2002 2.56 nino starts 2003 2.29 nino ends 2004 1.55 el nino starts 2005 2.52 el nino ends 2006 1.70 el nino starts 2007 2.16 el nino ends 2008 1.66 Cold PDO starting 2009 2.02 nino starts 2010 ----- nino ends When you put it against the global temps, the co2 is plainly following the Pacific.. the new cold PDO should see a flattening out of the rate of rise. So lets see who is right. Her's another look at the PDO Chart from1900 to 2008: We have the warming period of the 20's, 30's and early 40's, a slight cooling from 1940's to the late 1970's and then a warming thereafter, all coincidentally falling to the pattern of global temp changes. Yes, could be just coincidence ..... maybe not. Y.S

Give up, Last one from me on this subject, you clearly are unable to grasp what I was inferring, but I suspect most of your posts are just wind-up efforts anyway as they are so silly to the point of being just plain stupid. The argument is that the PDO can affect global cloudiness (as well as predominance of El Nino / La Nina conditions). If it does have an impact on low cloud cover, then there will be a net reduction in global temperature due to a reduced rate of solar absorption at the Earth's surface. There are now several scientific papers (and blogs) you can visit that are suggesting just that .... one being Roy Spencer (go and have alook, huis blog contains a bevy of publications and you can see the peer reviewed literature for yourself !!). His model has actual satellite data (that's proven measurements) suggesting that such a link occurs and has produced a model that could (repeat could) explain most of the 20th century warming without relying on a greenhouse gas model (for which the methodology relies entirely on computed feedback mechanisms that are not proved). Y.S

Exactly. And, Devonian, the warming of a doubling of CO2 to around 540 ppm is accepted to result in a 1 degree C rise in the upper atmosphere. It is further accepted that at the ground this would relate to less than that (around 0.5 to 0.6 degrees C). So, it all comes round to the forcings and feedbacks. Is the climate system sensitive or resilient. What other factors could be responsible? The PDO is a fairly new concept ..... well, not new, but a greater understanding of its impacts are beginning to surface. Of course there are others such as solar, the AO, NAD and AMO. New science is emerging all the time. Just a few years ago most would not take the notion of a relationship between solar cycels and Northern hemisphere temperatures (probably global affects) that seriously. Its certainly under consideration now. Surely we can at least explore the possibility that the changes in states of these major oceanic / atmospheric players could impact global climate, is it that far-fetched when we know that El-nino and La Nina both warm and cool the climate almost immediately. If so, then why is the idea that longer term 30 year period or more changes in the PDO and other natural cycles could not impact on global temperatures ....... what effects do these have on global cloud cover for instance. A 1% or 2% change in cloud cover could have caused all of the climate change we saw during the 20th Century, and such a small change would have been impossible to detect. I've pinched the below from Mr Spencer's blog, but basically these show the pre-1940 warming coinciding with the positive phase of the PDO; then, a slight cooling until the late 1970s coincided with a negative phase of the PDO; and finally, the warming since the 1970s has once again coincided with the positive phase of the PDO. Mr Spencer then asked a simple question: What if this known mode of natural climate variability (the PDO) caused a small fluctuation in global-average cloud cover? Without regurgitating all of his work, I would recommend a visit to his blog and possible purchase of the paper back edition of 'The Great Global Warming Blunder' in which his work is discussed in simplistic detail (or even reference his publications). Even if you do not believe his views are correct, he has generated a simplistic model and used actual satellite measurements to almost exactly replicate the 20th century temperature changes !! Y.S

My apologies, but had to come back to one of your comments in your previous post. How much Co2 are we flooding into the atmosphere. Well, lets look at the facts: Looks pretty dire doesn't it. H'mmmm but then, although we are clearly increasing the amount of CO2 in the atmosphere (and yes, this will be expected to have some warming associated as it is a greenhouse gas), how does this scale relate to the total percentage of gases that make up the atmosphere. Well as of 2008, atmospheric CO2 was approaching 390 ppm by volume, or about 39 molecules of Co2 per 100,000 molecules of air and around 40% more than believed to be the case pre-industrialisation (270 ppm). Al Gore stated that you could average the amount of Co2 being pumped into the air every day would be in the region of 70 million tonnes ..... sounds brutal ...... but, If this statistic is correct it would take 5 years of these daily greenhouse gas emissions to add just one molecule of CO2 to every 100,000 molecules of air in the atmosphere. Thus, even though CO2 is a trace gas, it still takes a long time of our burning of fossil fuels to impact its atmospheric concentration substantially. As a fraction of the atmosphere and looking back from 1955 to 2010 we will have increased the overall atmospheric value from around 0.0003 to around 0.0004. (The graph I want to show is not behaving, so will pdf and input as picture later). So, either CO2 is capable of being a most potent greenhouse gas and regulates world temperatures, or, something else is at work. Y.S

What on Earth was the above post about. Absolute nonsence !!!! You have not understood, nor tried to, anything of what has been stated... nothing at all. Just so you know a little about Roy Spencer (as you have dished him): Roy Spencer is a principal research scientist at the University of Alabama. Formerly he was a senior scientist for climate research for climate studies at NASA, he currently leads the US science team for the advanced Microwave Scanning Radiometer for EOS (AMSRE) on NASA's aqua satellite. He is also co-developer of the original satellite method for precise monitoring of global temperatures from earth orbiting staellites and has provided congressional testimony on the subject of global warming. He is also the bestselling author of the book Climate confusion and has published extensively on the subect of weather, climate and global warming. You might want to take a look at this: Roy. W Spencer and William D. Braswell, "Potential Biases in cloud feedback diagnosis: A simple model demonstration", Journal of climate 21 (2008); 5624-5628 As for clouds / water vapour you need to understand the relationship between reflective low level cloud effects and refractive high level cloud effects. There is growing evidence that the change in PDO state leads to changes in the overall distribution and cloudiness (low level cover). This then leads to changes in the quantity of absorbed solar irradiation ..... water vapour has around 100 x the power to alter temperature as compared to CO2. Anyway, you can of course believe what you will. Y.S Hi TWS, Yes, accepted. I should have stated " It is becoming increasingly clear to me". Apologies Y.S

We only have accurate Ice measurement data from the last 30 years or so (satellite measurements) .... all in a period of positive PDO state. There is however, plenty of anectdotal evidence to suggest that there was indeed as much ice loss as now. Proxy data from the middle ages and prior to then (Roman times) have shown at least a possibility that there was low ice up North. Certainly that Northern hemisphere temperatures were consistently high. The Northwest passage was open in the early 40's and Vikings were for several centuries farming Greenland. These are all facts and you can look for them yourself, there have been links to books and publications made ... go and read them. (and GW ...... PLEASE don't give me any rubbish about how the Greenland colonists were 'clinging to existance' ..... even if they were, they survived farmed, fished and traded for many generations ...... where there is now ice sheets present.) Y.S

Hi, Nope, I stand by all of the above. What is preposterous is your narrow minded and quite dissmissive posts without looking into what is being stated. You need to go and look at the wider scientific picture. I have. For your information, previously I was a AWG beleiver and believed as you do that global warming was caused by man's misuse of the environment and output of green-house gases. What I have read and looked at (some of which I have referenced - its not my fault if you cannot be bothered to look at recent literature) has moved me away from these earlief views. The green house gas theory has some big flaws which have not been adequatly explained or investigated. I have never ever said that we have not warmed, also I have never said that Co2 is having no effect. Clearly we have warmed, it is the main cause of the warming that I question. Fact 1: A doubling of CO2 from pre-industrial levels to around 500-550ppm is widely accepted to only itself be able to force a warming of around 1 degree C. This is atmospheric warming which would result in approx 0.5 to 0.6 degree C on the ground). Everybody seems happy with this. Fact 2: The IPCC forecasts which vary from a warming of 1.5 (minimum) to over 6.0 degrees C is based on the presumption (for which there is absolutely no concrete evidence) that the climate system is very sensitive and all feedbacks will be positive. They believe that cloud cover changes as a result of warming will amplify the warming. What has never been made clear is that there is a lot of controversy as to whether cloud pattern changes are a result of any warming, or actually cause a forcing themselves, How this actuall would occur and the distribution of any change and effect. Fact 3: There is satellite data available from the last 10-20 years that at the very least suggest that forcing and feebacks from cloud cover changes occur throughout each and every year, that is, clouds are the key and can have dramatic effects on the amount of solar radiation absorbed by the Earth. The PDO cycles are associated with warming and cooling phases of the climate. Our most accurate satellite data from 2000 through 2008, show that the PDO impacts on the Earth's energy balance. Over the 9-year satellite period of record, the radiative imbalance varies over a range of 2.5 watts per metre square. Although this natural source of radiative forcing is only 1 percent of the average flows of sunlight into and infrared radiation out of the system, Roy Spencer has shown , via a simple computer model run on a home computer that this is itself sufficient to explain over 75% of the warming experienced during the 20th century. Thus, the PDO itself can potentially explain most of what we popularly call global warming. And, whilst the anthropogenic explanation for global warming involves a forcing mechanism that can only be computed theoretically, the PDO forcing mechanism (a natural player) is actually observed by satellites. A recent publication has also made the connection between the PDO and climate change (D.H Douglass and R.S.Knox "Ocean heat content and Earth's radiation imbalance". Physics letters A, 373 (2009): 3296-3300) I enjoy this forum immensly and have learned and continue to learn a great deal from it, I am also aware of certain posters views and beliefs ..... all valid and I have no problem with any of them posting. But, I do take offence at some of the recent posts aimed at ridiculing some of the information I have offered, clearly without bothering to check up on what has been said. I have now read 8 books and countless scientific papers and what myself and others are pointing too is that perhaps (not saying for absolute certainty ... though I am getting closer day by day) is that there is more uncertainty around AGW than some think and contrary to the IPCC consensus, there are natural cyclical explanations for the late 20th century warming that has liitle to nothing to do with greenhouse gas emissions by the human population. I would also state that personally I am happy to curb greenhouse gas emissions and transfer the world economy to a greener footing, this would be brilliant ..... I am just discussing and looking at what has caused the recent warming. I do have graphs and charts that I should post, but these will have to wait for another time (I travel a lot and do not have access to my home files). Y.S

Please, please can you address why the 1930's and early to mid 1940's saw sea surface temperatures monitored around the polar region as registering as as warm if not warmer than now ..... you can google search the newletter items of the day (there have been recent posts on this site staing the same) as the 'unprecedented reductions' in polar ice were being reported. Then there came the turn around ... peeking in the late 1970's, then another turnaround ........ as so on and so on ..... Blah balah blah !! .... coincidence this all occurred with the turn in PDO from -ve to positive) Y.S

Sorry TWS but it is my belief that you are mistaken here. There is now a lot of evidence that the warming (that has undoubtably occurred) can be explained by natural cycles and changes in global cloud cover (associated with the coupled oceanic / atmposheric cycles). As such it is becoming increasingly clear,that although CO2 is a greenhouse gas, and yes is contributing to the global warming scene, ... it is a minor and not a major player. Furthermore, it is the misguided notion that the climate system is predominatly sensitive (via positive feedback mechanisms) rather than tolerant (via feedback and forcing mecahnisms combined) that is skewing the IPCC global forecast models 'predictions' for the future. Clearly new satellite data and recent publications on the solar cycles and perhaps most importantly PDO cycles cast huge doubt on the singular anthropgenic greenhous gas theory. Y.S

Hi Blast, Just been perusing Roy Spencer's site and almost finished his book ...... personally I'm now more than 90% certain that man made global warming is a very minor component to what we have experienced. The change over in the global ocean temoperatures is quite amazing. There really is only one way this can go now ...... thats to a cooler regime in my opinion. The PDO and low cloud cover are key elements that with solar activity provide a compelling argument for a major major role of natural cycles in the late 20th century warming and which point to a general cooling trend over the coming 20-30 years. Satellite data have shown that radiative forcing as well as feedback need to be factored into the IPCC models for climate change, that they do not ... and only deal with feedback is the achilles heel of climate modalling. It will be intersting to see, even this year how the predicted to actual temperature plots go. Also, just seen Joe laminate floori's call for a cold European winter, ..... nice early call ....!!! Y.S

Hi GW, But the point is ..... you do not know for fact ... as we do not have detailed ice-measurements that go back beyond a few decades. We do however know that the Vikings colonised, farmed and hunted the Western coasts and southern shores of Greenland ... and that they were there and prospering for several hundreds of years. I would suggest to you that that could mean a lot warmer conditions were prevalent during this period over the Northern hemisphere ..... further backed up by various farming records (I reference the book ' The Little Ice age' here) - showing stable crop harvests and plentiful food over the medieval warm period for Britain and Europe. Perhaps the Arctic was magically spared this warm period ....... perhaps not. Y.S There is also plenty of data aailable to at least suggest that such a situation was alos

Agree entirely. Not suprising that we have seen a warm start to the year, coming off the back of a strong El-nino. Given where we are world wide temp wise (that is at a high following the warm up from 1979 to 2000), a spike is quite expected. But, PDO is negative and El-Nino collapsing, only one way to go and that's down !! Jo laminate floori is so far pretty spot on with his forecasts for the year ..... time will tell ! Y.S

I'm not to sure about the above TWS. The sun's ability to heat ocean water in the arctic is pretty poor (due to the angle of the suns rays, only really impacting for two to three months at most). There is then also the added complication of heat loss to the atmosphere (this is in fact part of the global thermocirculatory system ... heat gained in the tropics is circulated via ocean currents to Northern areas of permament heat loss. Temperatures in the arctic over winter months will always fall very low due to the permanent night, and ice will always form in the winter months........ unless global warming really sky-rockets. I'm also not so sure about the arctic's perceived global refrigeration role ....... it has been ice free (summer months) in the past (at least there is very good anecdotal evidence) and yet this has not led to runaway warming. I suspect that as you say, it is more to do with ocean currents and cyclic changes that dictates the amount of summer ice retention. The PDO has been in a positive phase since 1979 and ice in the arctic has been on a more or less downward spiral since then. The last negative phase was from around the late 40's when ice extent increased (30's and early 40's were also bad for arctic ice cover). PDO is now mooted to have moved into its negative phase, so I guess we will need to wait and see what happens next ? Y.S

Nice one. Mind you, probably would have been the same reaction if they had read the 'Global Warming Blunder' by Roy Spencer (this is a guy who collects the data from the NASA Aqua satellite for global temperature measurements) - he has also published various papers and claims to have concrete evidence (based on the satellite data), that climate forcing via C02 feedbacks are grossly exaggerated and that the late 20th century warming can be attributed to natural factors. Half way through myself and its very interesting - another scientist who believes that Cloud cover is the key element and that the global climate modals which assume that the climate system is very sensitive to Co2 are incorrect. These modals assume massive positive feedback effects when there is growing evidence of a far more robust climate system with strong negative feedback effects (through low level cloud cover) coupled to the Oceanic cycles. He presents evidence from his own peer reviewed data to back this up. I'll pop a few of his diagrams in here on later posts to illustrate his reasoning - but there are more and more scientists now seriously questioning the IPCC forecast modal. Quite a few wobbly wheels ...... but time will tell !! Y.S

You might like to explain why the Northwest passage was navigable without ice-breakers between 1940 and 1942. Pretty low ice late 30's early 40's. The sudden cliamtic shift of 1979 coincinding with the switch in PDO to positive is presumably no more than coincidence in regards to the warming observed during the 80's and 90's. We have not warmed since 1998 (will give you 2000 since the El-Nino spike is clearly there) and signs are that the PDO has shifted to negative. Coupled with low solar activity, it will be interesting to see what gives over the next few years Have we been as warm as now in relatively recent history. You bet - medieval warm period, non tree-ring proxy data confirm this. Greenland colonisation also clearly shows this. But, CO2 is a greenhouse gas, and will have some effect. In my opinion, this is small in comparison to the forcing by natural cycles. Another read for you GW is the book: The Great Global Warming Blunder by Roy Space (just realeased). Provides some very interesting data. Y.S