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Post by steve on Oct 17, 2012 5:51:01 GMT
Steve: "I do not rule out apparently random change caused by undetectable or hard to detect 'natural variation'". It is not that hard to detect. First, the fish detected it. Then the fishermen detected that the fish had detected it and moved. So did the fishermen. Then scientists noticed that the fish and fishermen had detected a natural variation in temperature, indexed by the PDO. This expanded to studies of the ENSO "Oscillation" (actually, Cycle), then to other cycles such as AO, NAO, Indian Ocean. These appear to be teleconnected. Here is a start: wattsupwiththat.com/2012/10/03/bob-tisdales-dirty-weather-control-video-rated-rr/You can use these to make forecasts about weather and temperatures over months and seasons, but even then, the forecasts are often not very good. Over the long term, there is no hypothesis with a good physical explanation that links these things to the longer term warming trend.
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Post by steve on Oct 17, 2012 6:08:38 GMT
Steve: Here is a demonstration that global warming has not stopped in the last 16 years. The trend from 1965 to 1998 (when global warming stopped) is *less* than the trend from 1965 to now. That graph is totally misleading. After observing the Greenland debackle of last year, the Iceland debackle of this year, it is very very important to include error bars in any temp trend. Wood for trees doesn't include the error bars in its temp graphs. That is something that should be included. When you plot a graph, using the error bars which can't be observed on your graph, the trend can be almost flat with a 95% confidence level. You can also plot a graph 1998-2010 that shows a very pronounced downturn in temps. Once again, using the error bars to the 95% confidence level. sigurdur, You are a bit confused. The two lines are comparing like with like. The trend shows warming at well over 95% for both the periods I showed even if you include the error bars. The claim put by the Daily Fail is that the trend stopped in 1997. Comparing like with like, the lines show that the trend *increased* after 1997. As I know farmers, I understand your pessimism. Suppose your hens lay 100 eggs in year 1, then 105,110,115,120 in subsequent 4 years. Then in year 6 they manage a startling 150 eggs. But in year 7 they only manage 149 eggs. You'd then be moaning at them for being lazy even though they are well ahead of their 5 egg per year trend. So don't get all holier than thou with me when you've said "As far as the Daily Mail, part of what they wrote is true. The 16 year trend is flat. That much I will give them. " for a graph where they've not included the error bars and where even after cherry-picking their end-points they still had to *fake* some of the data at the start and end to disguise the small rising (central) trend that still remains: www.woodfortrees.org/plot/hadcrut4gl/from:1960/plot/hadcrut4gl/from:1997/trend/plot/hadcrut4gl/from:1965/trend
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Post by Andrew on Oct 17, 2012 7:41:29 GMT
Steve Are you saying it is now acceptable science to say that humans are responsible for the ending of the little ice age? That's a bit of a "When did you stop beating your wife?" question because the concept of the LIA means different things to different people, and there is no consensus as to its cause or causes. I read quite a long time ago a study (possibly on realclimate or similar) that suggested that without man's CO2 emissions the (paraphrasing what they said) steady cooling that had occurred over the last millennium or so would have continued into the 20th Century. You are the one who is definately saying that the current warming is caused by humans where anybody who disagrees is barking mad. Where is your AGW warming if the little ice age existed?? To cap it all, other civilisations enjoyed much warmer weather than we have today. You guys seem to have totally lost the plot.
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Post by steve on Oct 17, 2012 12:11:47 GMT
Radiant,
You have shown yourself quite capable of parsing sentences, so I conclude the distortion of what I said is deliberate.
Someone who discusses barking mad theories is not necessarily themselves barking mad. They may be deluded or they may have ulterior motives. And all I've definitely said is that current warming is at the very least strongly influenced by human activities.
So with a couple of slight changes I'll just repeat myself:
Here are some black and white views: If you think that the forcing calculation for CO2 is seriously wrong then you <i>may be</i> a dragon slayer* If you think that the increase in CO2 over the last 100 years or so is not mainly down to additional CO2 emitted by man's activities then you are a dragon slayer. If you think that CO2 is not a *plausible* explanation for much of the warming over the last 50 years then you are a dragon slayer.
If you think that CO2 is not sufficiently *proven* to have caused much of the last 50 years' warming, then you are perhaps an optimist or perhaps recognise that taking action now to protect your descendents is something you are seeking to avoid doing.
*dragon slayer - term used regularly on Judith Curry's blog and by Judith herself to define someone who discusses barking mad alternative physical realities in which it is impossible for increased CO2 to cause warming.
Existence or otherwise of the little ice age doesn't change the fundamentals of radiation physics.
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Post by Andrew on Oct 17, 2012 16:56:30 GMT
Steve
You are testing my patience.
>>You have shown yourself quite capable of parsing sentences, so I conclude the distortion of what I said is deliberate.
I wonder if you would actually dare to say that to my face?
You are the one who has apparently told me dragon slayer is a person who thinks it is impossible for C02 to cause warming
Maybe you need to clarify what you mean by the term please
Do you mean in that way?
Or do you mean something different?
What do you mean by "*plausible*" do you mean theoretically possible? or do you mean most likely or what?
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Post by steve on Oct 17, 2012 19:42:50 GMT
Radiant, I sometimes type too quick and often say ambiguous things. You often spot these ambiguous things and assume the worst interpretation. I accept that because it is my fault for not being clear. In the above case, I was clear. Nobody is "barking mad". Some people do however profess barking mad theories such as AGW being banned by 2nd law of thermodynamics. However, being of the opinion that CO2 is not a threat does not put one into that category. The term "dragon slayer" is used on Judith Curry's blog. It relates to the following book which professes barking mad theories as to why CO2 cannot cause warming. "Slaying the Sky Dragon - Death of the Greenhouse Gas Theory" John O'Sullivan et al www.amazon.com/Slaying-Sky-Dragon-Greenhouse-ebook/dp/B004DNWJN6Judith Curry hosted guest posts by some of the authors of this book. She thought that by exposing their ideas to comments on her blog that she could educate her readers and undermine these views. Recently (a couple of months ago) she has stated that she has stopped engaging with dragon slayers. Plausible means it is a potential explanation that is physically reasonable given what we know. But it could be wrong if *reasonable* assumptions turn out to have been wrong. Eg. climate sensitivity may be at the low end of estimates, and natural variability has contributed to recent warming more than is thought. The IPCC give a 5% chance in their collective judgement for natural variability to be a bigger influence than CO2 for the warming over the last 50 years.
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Post by sigurdur on Oct 17, 2012 21:41:01 GMT
Steve: Here is a demonstration that global warming has not stopped in the last 16 years. The trend from 1965 to 1998 (when global warming stopped) is *less* than the trend from 1965 to now. That graph is totally misleading. After observing the Greenland debackle of last year, the Iceland debackle of this year, it is very very important to include error bars in any temp trend. Wood for trees doesn't include the error bars in its temp graphs. That is something that should be included. When you plot a graph, using the error bars which can't be observed on your graph, the trend can be almost flat with a 95% confidence level. You can also plot a graph 1998-2010 that shows a very pronounced downturn in temps. Once again, using the error bars to the 95% confidence level. sigurdur, You are a bit confused. The two lines are comparing like with like. The trend shows warming at well over 95% for both the periods I showed even if you include the error bars. The claim put by the Daily Fail is that the trend stopped in 1997. Comparing like with like, the lines show that the trend *increased* after 1997. As I know farmers, I understand your pessimism. Suppose your hens lay 100 eggs in year 1, then 105,110,115,120 in subsequent 4 years. Then in year 6 they manage a startling 150 eggs. But in year 7 they only manage 149 eggs. You'd then be moaning at them for being lazy even though they are well ahead of their 5 egg per year trend. So don't get all holier than thou with me when you've said "As far as the Daily Mail, part of what they wrote is true. The 16 year trend is flat. That much I will give them. " for a graph where they've not included the error bars and where even after cherry-picking their end-points they still had to *fake* some of the data at the start and end to disguise the small rising (central) trend that still remains: www.woodfortrees.org/plot/hadcrut4gl/from:1960/plot/hadcrut4gl/from:1997/trend/plot/hadcrut4gl/from:1965/trendSteve: I think you missed my point. You know how error bars work. A line within the error bars is as significant as a line at the center mean of the error bars. The line concerning temps could show an increase in warming since 1997, or a line since 1997 could show an increase in the rate of cooling. That is why it is considered statistically a flat period since 1997 as reference to warming. Both of the above statements are correct, so one takes the middle ground.
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Post by icefisher on Oct 17, 2012 21:44:24 GMT
You can use these to make forecasts about weather and temperatures over months and seasons, but even then, the forecasts are often not very good. Over the long term, there is no hypothesis with a good physical explanation that links these things to the longer term warming trend. Well the fact is Steve when the weatherman says 60% chance of rain tomorrow that means there is 40% chance of no rain. As we have seen in these 60 year oscillations there is also an overlying ENSO oscillation that screws any forecast one can make about the 60 year direction in less than about a 5 year window. The fact is uncertainty is more rampant in climate science than in the weather. People would like to believe they know how it all works but only a few folks are having much success. If you look at ENSO prediction records its in fact Hansen who is doing the worse. The guy that is doing the best is using a models developed by a skeptic. That doesn't mean he is correct about being a skeptic what it means is being a skeptic is apparently having less effect on his ability to predict some of this finer climate phenomena. However, Dr Akasofu is correct that one cannot derive an anthropogenic signal from the noise brought by all the other stuff that effects climate.
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Post by magellan on Oct 17, 2012 22:55:14 GMT
Radiant, You have shown yourself quite capable of parsing sentences, so I conclude the distortion of what I said is deliberate. Someone who discusses barking mad theories is not necessarily themselves barking mad. They may be deluded or they may have ulterior motives. And all I've definitely said is that current warming is at the very least strongly influenced by human activities. So with a couple of slight changes I'll just repeat myself: Here are some black and white views: If you think that the forcing calculation for CO2 is seriously wrong then you <i>may be</i> a dragon slayer* If you think that the increase in CO2 over the last 100 years or so is not mainly down to additional CO2 emitted by man's activities then you are a dragon slayer. If you think that CO2 is not a *plausible* explanation for much of the warming over the last 50 years then you are a dragon slayer. If you think that CO2 is not sufficiently *proven* to have caused much of the last 50 years' warming, then you are perhaps an optimist or perhaps recognise that taking action now to protect your descendents is something you are seeking to avoid doing. *dragon slayer - term used regularly on Judith Curry's blog and by Judith herself to define someone who discusses barking mad alternative physical realities in which it is impossible for increased CO2 to cause warming. Existence or otherwise of the little ice age doesn't change the fundamentals of radiation physics. Fine steve, then explain the MWP and RWP via radiation physics. The hockey stick was specifically for the purpose of eliminating those periods of history. It has been 100% debunked, and in many's view (including mine), fraudulent. You come here every so often, throw a few firebombs, then disappear for a time and spew the same discredited crap. Also steve, I'm still waiting for your monumental knowledge of physics to cite the experimental data which tests the hypothesis that CO2 can warm the ocean mass to any measurable degree. I contend only shortwave solar radiation can account for warming of the oceans.
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Post by Andrew on Oct 18, 2012 2:09:08 GMT
Radiant, I sometimes type too quick and often say ambiguous things. You often spot these ambiguous things and assume the worst interpretation. I accept that because it is my fault for not being clear. In the above case, I was clear. Nobody is "barking mad". Some people do however profess barking mad theories such as AGW being banned by 2nd law of thermodynamics. However, being of the opinion that CO2 is not a threat does not put one into that category. The term "dragon slayer" is used on Judith Curry's blog. It relates to the following book which professes barking mad theories as to why CO2 cannot cause warming. "Slaying the Sky Dragon - Death of the Greenhouse Gas Theory" John O'Sullivan et al www.amazon.com/Slaying-Sky-Dragon-Greenhouse-ebook/dp/B004DNWJN6Judith Curry hosted guest posts by some of the authors of this book. She thought that by exposing their ideas to comments on her blog that she could educate her readers and undermine these views. Recently (a couple of months ago) she has stated that she has stopped engaging with dragon slayers. Plausible means it is a potential explanation that is physically reasonable given what we know. But it could be wrong if *reasonable* assumptions turn out to have been wrong. Eg. climate sensitivity may be at the low end of estimates, and natural variability has contributed to recent warming more than is thought. The IPCC give a 5% chance in their collective judgement for natural variability to be a bigger influence than CO2 for the warming over the last 50 years. Steve Since we are both understanding the same explanation of Dragon Slayer............ Therefore, when we have no idea why the World began cooling to create the little ice age and presumably we have no idea why it began to end, and the temperatures now are very similar to what prevailed before the little ice age, why is is plausible to say the world is now a similar temperature as before the little ice age because AGW is the most likely cause of most of the return to the same warmth?
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Post by icefisher on Oct 18, 2012 2:47:06 GMT
Since we are both understanding the same explanation of Dragon Slayer............Therefore, when we have no idea why the World began cooling to create the little ice age and presumably we have no idea why it began to end, and the temperatures now are very similar to what prevailed before the little ice age, why is is plausible to say the world is now a similar temperature as before the little ice age because AGW is the most likely cause of most of the return to the same warmth?
Nice question.
Lets see what does the litchur say about that:
Corinthians 15:4 - And he was buried, and he arose on the third day, according to what is written.
Mr. Hockey Stick must have nine lives.
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Post by Andrew on Oct 18, 2012 4:08:51 GMT
Also steve, I'm still waiting for your monumental knowledge of physics to cite the experimental data which tests the hypothesis that CO2 can warm the ocean mass to any measurable degree. I contend only shortwave solar radiation can account for warming of the oceans. Magellan it sounds to me like you are still stuck on the 'basic science' of the influence of C02 dispite all of my previous efforts. C02 obviously cannot warm anything. C02 causes the sea to be warmer because C02 behaves similarly to an insulator while the Earth is heated by the sun. I showed the beginnings of an experimental proof for the theory by showing a hot brick cools slower when near a cold brick and the surface of a hot brick becomes warmer when near a cold brick Are you also saying, like Icefisher, that even H20 cannot enable the Earth to be warmer because even H20 cannot act like an insulator? Surely you cannot be saying this?
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Post by steve on Oct 18, 2012 5:57:38 GMT
sigurdur
No, this is not the way that error bars work.
When fitting a line to points with error bars, usually the central line is most likely the right answer of all possibilities, and as you move away from the central line, the probability reduces.
The probability of the answer being within the so-called 1 sigma range is around 66%. The probability of being within 2 sigma is around 95%.
But even that is really only part of the answer because assuming a linear trend over a limited period is only a first order guess as to what is going on. If you know there are short term ups and downs in data, then looking at the short term trends will often be misleading if it misses a lower frequency longer term trend.
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Post by steve on Oct 18, 2012 6:13:00 GMT
magellan,
A nice easy one, thanks. Variations in earth's orbit and tilt meant that 1000+ years ago the Northern hemisphere was receiving a lot more sunshine during the summer months. The hockey stick was a first guess (using a new technique) as to the temperature variations back to 1000 years (so has nothing to do with the Roman period). If it's been debunked I obviously missed the paper.
Fire bombs!? I keep my eye out for thought provoking posts. A lot of stuff here has been too US-centric so being British I didn't have much to input. Perhaps if you locked yourself into a room with no computer you'd have no trouble with pesky people pointing out your misconceptions.
You are still waiting...so you do want me around to bless you with my knowledge. Thank you.
The answer to your query is that you are misposing the question by focussing it on co2's ability to warm the ocean. The ocean is warmed by the sun, sure (you should go to Judith Curry's site and tell the commenter called "myrrh" who is convinced that shortwave radiation cannot warm the ocean). However, the ocean is cooled by a number of processes including radiation, evaporation and so forth. It is obvious that the rate of cooling by these processes will depend in some way on the temperature of the atmosphere relative to the temperature of the surface of the ocean. The former is impacted by CO2 the latter is impacted by the processes that mix heat into the deeper ocean.
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Post by steve on Oct 18, 2012 6:27:19 GMT
Radiant First there is a difference of opinion as to the depth of the LIA. Looking at the central england temperature, for example, the difference is maybe half a degree cooler than the 1940-1970 period. www.changecollege.org.uk/img/HadCET_1772_to_2009.gifHaving looked in detail once, it's clear to me that the 1962-1963 UK winter would have been cold enough to freeze the Thames had old London Bridge still been present. Second, while we don't really know for sure, it seems that the sun was part of the cause and that higher rates of volcanoes was another part. These two influences do not seem to be involved in the current rate of warming. Third, basic physics tells us that CO2 will have a warming effect which can be estimated quite well. Those who think CO2 is of most importance in recent time believe that the science tells us that the effect from variations in volcanic pollution and/or solar over the last 60 years are small compared with CO2. Fourth, records prior to the LIA period are sketchy and Northern Hemisphere focussed. As I said to Magellan above, there are good reasons as to why NH summers might have been warmer, and this also might have impacted climate in other ways. But if you look at detailed records of local areas you don't see quite so much of a global and continuous warming. For example, in the period 1000-1100, Iceland suffered three periods of severe cold (as established from proxy data from clam shells which align with famines). These cold periods are not aligned with volcanoes. This period was the period when Vikings were going to Greenland. Perhaps wind patterns were sending the warmth to Greenland and leaving Iceland in the cold???
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