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Post by glc on Jan 14, 2010 10:43:05 GMT
Re: Statistically significant - or not since 1995.
All this is a bit misleading.
We have a statistically significant warming trend over the past 30 years. That is the fact of the matter.
Now then,
It is perfectly reasonable to test whether the last 15 years is a continuation of that trend. Here we would be testing the hypothesis that the Trend of 0.13 deg per decade was now no longer true. However, at the 90% or 95% levels of confidence we would have to reject the hypothesis, i.e. we would have to conclude that there is no evidence that the trend has changed 'significantly' from +0.13 deg per decade.
It is not reasonable to select a short term, cherry-picked period and decide that this (i.e. no warming ) is now the long term trend.
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Post by icefisher on Jan 14, 2010 12:05:26 GMT
Re: Statistically significant - or not since 1995. All this is a bit misleading. We have a statistically significant warming trend over the past 30 years. That is the fact of the matter. Now then, It is perfectly reasonable to test whether the last 15 years is a continuation of that trend. Here we would be testing the hypothesis that the Trend of 0.13 deg per decade was now no longer true. However, at the 90% or 95% levels of confidence we would have to reject the hypothesis, i.e. we would have to conclude that there is no evidence that the trend has changed 'significantly' from +0.13 deg per decade. It is not reasonable to select a short term, cherry-picked period and decide that this (i.e. no warming ) is now the long term trend. LOL! You guys crack me up! Gee, Ronald Reagan must be alive! After all we can demonstrate he lived at least for 93 years, the fact that there has been no sight of him now for 5 years is meaningless. Obviously RR being dead is a hypothesis we can reject with at least 97% certainty. . . .eyewitness accounts obviously can be discarded! ROTFLMAO!! I sense "science denier" has found fertile new ground.
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Post by steve on Jan 14, 2010 13:26:40 GMT
That was the other point I was going to make, but I've made it too many times before. When presenting the case for warming being due to CO2, the only unequivocal IPCC statement seems to be that the warming is happening. The attribution to human cause is given a probability of 9 in 10. Assuming the scientists have a valid reason for the 1 in 10 "get-out" clause, it is no surprise that statistics can be found that show the warming is either normal or stopped or reversing to some small level of confidence.
So the possibility that there is no warming trend (albeit in just one of the metrics used to assess AGW) does not disprove the central premise of AGW that warming from the CO2 rise is still due. If I throw 6 sixes in a row, that doesn't disprove the fact that the probability of a 6 is still 1/6.
Now if the sorts of proof that Lucia of rankexploits/blackboard is trying to present (that the warming trend is outside the model envelope) showed that there was indeed less warming over a statistically significant period (whatever that means), then that would be a potential disproof of the models' ability to project the rate of warming that would only be partially resolved if, for example, models initialised with the same starting conditions could demonstrate a similar (lack of) warming trend.
A lack of warming would also undermine the theory that temperatures need to rise 1.5-4.5C to balance a doubling of CO2. But note the rate of warming and the total amount of warming are two separate (though related) things.
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Post by aj1983 on Jan 14, 2010 14:47:10 GMT
Still discussing the temperature wiggles, using lies, damn lies and statistics... Anyway, I'd like to throw in another of my personal opinions, of which I have little proof. One of the reasons why the IPCC temperature curves have a rather homogeneous temperature trend is that they might underestimate external forcing mechanisms ("space weather" e.g. solar activity, cosmic ray fluctuations, etc.). I don't believe the hockey stick is a representable temperature record for the last thousand years, because it is probably based on the smoothed average of many temperature proxies (one shows a positive anomaly and another a negative anomaly etc) which have rather large uncertainty. Individual proxies show much more variability, but that can also be explained by the large uncertainties and local effects of course. For me it's hard to believe that the global temperature has been SO constant before the last century, but that's completely intuitive. Possible underestimation of external forcing mechanisms (space weather on climate) is understandable, because recent climate science has been focussing on the internal atmospheric mechanisms, and less on the external ones (i.e. from space). That's not surprizing, because it needs both a detailed understanding of the internal and external variables and the interactions. External variation ("space weather") is better understood by astrophysicists, but they generally have a lack of understanding of the internal climate dynamics, and the interactions between both. Now that a lot of research has been done on internal climate dynamics, and a lot of skeptics are attacking AGW using arguments which focus on the link between space weather and climate, we are already seeing a slow shift towards more interdisciplinary research. A lot of research for example is currently been done on the dynamics of the stratosphere, and troposphere-stratosphere interactions. The stratosphere (and layers above) seems to be much more directly influenced by space weather than the troposphere. It is likely that they will find more space weather - climate relations and that a better estimate can be made of the influence of space weather on the earth's climate. Currently (possibly due to a lack of understanding) the influence is estimated to be very small for known variations. Meanwhile I hope that astrophysicists will improve space weather "forecasts", so that they can be included into a much more complete model of climate. My forecast is that I think the IPCC will generally be downgrading both the uncertainty and the magnitude of CO2 induced warming somewhat, and that it will start upgrading the variation induced by spaceweather, and maybe also slightly by natural internal variability. A completely different discussion, also often found on this forum and at many other places is if we should do something about the warming. This kind of risk assesment is quite beyond my expertise, but nevertheless interesting. AGW is not completely certain, nor are the results of warming on mankind. Also, the warming, for a large part, can not be stopped anymore. A complete focus on absolute CO2 reduction at all costs (without other pollution reduction, which has a much more direct beneficial effect on both us and the environment) might be less beneficial than trying to increase the ability of man kind to cope with all kinds of climate variations. It would be especially nasty if nature decided that after AGW it is time for an ice age .
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Post by icefisher on Jan 14, 2010 17:56:02 GMT
That was the other point I was going to make, but I've made it too many times before. When presenting the case for warming being due to CO2, the only unequivocal IPCC statement seems to be that the warming is happening. The attribution to human cause is given a probability of 9 in 10. Assuming the scientists have a valid reason for the 1 in 10 "get-out" clause, it is no surprise that statistics can be found that show the warming is either normal or stopped or reversing to some small level of confidence. Small level of confidence? Its damn stopped Steve. Look outside, read the thermometers! So the possibility that there is no warming trend (albeit in just one of the metrics used to assess AGW) does not disprove the central premise of AGW that warming from the CO2 rise is still due. If I throw 6 sixes in a row, that doesn't disprove the fact that the probability of a 6 is still 1/6. In this context its known as a "Resurrection". Its not like dice because we can look at the die and see a 6 printed on one of six sides. We can't see any warming, its gone and we know not where. Nor can we empirically establish that the warming of the past, a few decades ago, or a few centuries ago was not due to natural global variation. Now if the sorts of proof that Lucia of rankexploits/blackboard is trying to present (that the warming trend is outside the model envelope) showed that there was indeed less warming over a statistically significant period (whatever that means), then that would be a potential disproof of the models' ability to project the rate of warming that would only be partially resolved if, for example, models initialised with the same starting conditions could demonstrate a similar (lack of) warming trend. The warming is outside of the model envelope. Look at the AR3 projections for warming. They shoot straight out of the previous 20 years of temperatures in essence claiming all the warming in the 1980's and 1990's was caused by CO2. If they had been aware of natural variation and drew a centerline like Akasofu did through a lot of natural oscillations then to arrive at their predictions they would need a hinge point or include a stronger acceleration curve to get from the lower slope to the prediction points. This would be in violation of physical laws Steve!!! That is the very same unchanged physical laws allegedly encoded in the models! Of course the physical laws encoded in the models could be wrong! In fact, that at this point in time is the only possible conclusion that at least some physical laws have been wrongly encoded. . . .thus the models are already falsified. Now I am not arguing that everything in the models is worthless but the IPCC in 2001 included a grey shadow for the entire run of all 35 models and 2009 actual temperatures is well outside of that shadow. Now none of that says that if the models are in part recoded they could be predictive of the future. However, nobody can explain how they should be recoded. Currently it appears the science community is shifting towards recognition of the lower underlying warming slope as the warming of the 80's and 90's becomes better understood. wattsupwiththat.com/2010/01/11/ipcc-scientist-global-cooling-headed-our-way-for-the-next-30-years/#more-15116The question that remains of course is what other wonders are we going to learn about as time and research goes on.
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Post by icefisher on Jan 14, 2010 18:40:33 GMT
Still discussing the temperature wiggles, using lies, damn lies and statistics... Anyway, I'd like to throw in another of my personal opinions, of which I have little proof. One of the reasons why the IPCC temperature curves have a rather homogeneous temperature trend is that they might underestimate external forcing mechanisms ("space weather" e.g. solar activity, cosmic ray fluctuations, etc.). I don't believe the hockey stick is a representable temperature record for the last thousand years, because it is probably based on the smoothed average of many temperature proxies (one shows a positive anomaly and another a negative anomaly etc) which have rather large uncertainty. Individual proxies show much more variability, but that can also be explained by the large uncertainties and local effects of course. For me it's hard to believe that the global temperature has been SO constant before the last century, but that's completely intuitive. Possible underestimation of external forcing mechanisms (space weather on climate) is understandable, because recent climate science has been focussing on the internal atmospheric mechanisms, and less on the external ones (i.e. from space). That's not surprizing, because it needs both a detailed understanding of the internal and external variables and the interactions. External variation ("space weather") is better understood by astrophysicists, but they generally have a lack of understanding of the internal climate dynamics, and the interactions between both. Now that a lot of research has been done on internal climate dynamics, and a lot of skeptics are attacking AGW using arguments which focus on the link between space weather and climate, we are already seeing a slow shift towards more interdisciplinary research. A lot of research for example is currently been done on the dynamics of the stratosphere, and troposphere-stratosphere interactions. The stratosphere (and layers above) seems to be much more directly influenced by space weather than the troposphere. It is likely that they will find more space weather - climate relations and that a better estimate can be made of the influence of space weather on the earth's climate. Currently (possibly due to a lack of understanding) the influence is estimated to be very small for known variations. Meanwhile I hope that astrophysicists will improve space weather "forecasts", so that they can be included into a much more complete model of climate. My forecast is that I think the IPCC will generally be downgrading both the uncertainty and the magnitude of CO2 induced warming somewhat, and that it will start upgrading the variation induced by spaceweather, and maybe also slightly by natural internal variability. A completely different discussion, also often found on this forum and at many other places is if we should do something about the warming. This kind of risk assesment is quite beyond my expertise, but nevertheless interesting. AGW is not completely certain, nor are the results of warming on mankind. Also, the warming, for a large part, can not be stopped anymore. A complete focus on absolute CO2 reduction at all costs (without other pollution reduction, which has a much more direct beneficial effect on both us and the environment) might be less beneficial than trying to increase the ability of man kind to cope with all kinds of climate variations. It would be especially nasty if nature decided that after AGW it is time for an ice age . Nice post AJ. You are sounding like Dr. Revell. I agree with your post except that I think the IPCC should be mothballed. Its only function is political science. The objective of concensus whether the decisions are authoritative or democratic it isn't science at all. Its a big waste of money that could better be put to more useful pursuits. In fact, if Dr Latif is right, and in 2013 when the next assessment is due and warming is still in suspended; all it will serve is to provide is a vehicle for attacks against it. It will appear to be a fool's errand and make it more difficult in the future to act on AGW should it return in 10 to 20 years. I agree the money will be better served in the area of space science. Disbanding the IPCC politically isn't an option. Starving it is though. We need to understand better why our atmosphere acts the way it does. And in that regard, reading tea leaves (tree rings et al.) to drive concensus and silence skepticism isn't likely to provide the solid information we need. Nature has spoken and demands a fair hearing. Moving beyond all that potentially relieves the expense of auditing historic ground temperature records, which day by day become more clear they are highly subjective and not likely to return reliable climate information for the purposes at hand. Funding programs to improve climate monitoring and design better systems for actually being able to track heat on our planet will be an important element of "space weather" research and better understanding about climate impacts no matter the source.
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Post by glc on Jan 14, 2010 19:04:44 GMT
LOL! You guys crack me up!
Gee, Ronald Reagan must be alive! After all we can demonstrate he lived at least for 93 years, the fact that there has been no sight of him now for 5 years is meaningless. Obviously RR being dead is a hypothesis we can reject with at least 97% certainty. . . .eyewitness accounts obviously can be discarded! ROTFLMAO!!
I sense "science denier" has found fertile new ground.
Your understanding of statistics is clearly limited. Let's take a simple example. Let's say that the average height of the US male is assumed to be 5ft 9in. Now let's say we have a random sample of 50 US males and the average height of the sample is 5ft 10in. Does that change the previous assumption that the average height is 5 ft 9in, i.e. is this a statistically significant result.
It might be but probably isn't - it depends on factors such as the standard deviation. In other words this new subset of data doesn't change the previous hypothesis (mean=5ft 9in).
The "lack of statistical warming" since 1995 doesn't mean there is no warming (there is) it just means that the 95% Confidence Interval includes the zero trend.
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Post by socold on Jan 14, 2010 19:36:44 GMT
From a paper by a famous scientist. Finds that after removal of internal variation (ie ocean cycles, etc), the global temperature record is very similar to an exponential curve over the 20th century:
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Post by icefisher on Jan 14, 2010 19:40:50 GMT
The "lack of statistical warming" since 1995 doesn't mean there is no warming (there is) it just means that the 95% Confidence Interval includes the zero trend. "(there is)" You mean "(there was)". You are confusing statistics with the real world. Got news for ya! Drawing linear trend lines does not turn a period of relative flat or cooling into a period of warming. You are talking statistical jargon and you are not accurately describing what the real world is doing right now.
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Post by hairball on Jan 14, 2010 19:40:59 GMT
I hope that graph is from Hansen, 'cos if that's the raw data it'll go up like a rocket once he gets his hands on it.
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Post by icefisher on Jan 14, 2010 20:15:05 GMT
From a paper by a famous scientist. Finds that after removal of internal variation (ie ocean cycles, etc), the global temperature record is very similar to an exponential curve over the 20th century: Thats fine Socold but solar activity has shown an exponential curve over the 20th century as well. Thats especially true if you eliminate the last solar cycle that appears to have resulted in a flattening of both solar activity and temperature. I notice that about 13 years of data is missing from your graph also. One can also clean the sunspot record of the 11 year cycles as they might only be a solar unique manifestation of the space weather that might affect earth's climate perhaps not unlike the ocean oscillations. I didn't do that but it would drive the curve closer to the exponential fit as is done in your figure. So the fact that temperature has increased exponentially does not prove anything of importance, unless of course one potential driver continues to show an exponential increase and the other does not. As I see it after a grand solar maximum the best experimental plan might be to do nothing but encourage independence from foreign energy sources for the next decade. A grand experiment may be underway if the majority of predictions for the coming solar cycle pans out. It might be a bad move to eliminate the exponential increase in emissions at the very point it appears the exponential growth in temperature may be faltering. It might be a good thing that European cap and trade fell flat on its face.
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Post by AstroMet on Jan 14, 2010 21:30:51 GMT
Still discussing the temperature wiggles, using lies, damn lies and statistics... Anyway, I'd like to throw in another of my personal opinions, of which I have little proof. One of the reasons why the IPCC temperature curves have a rather homogeneous temperature trend is that they might underestimate external forcing mechanisms ("space weather" e.g. solar activity, cosmic ray fluctuations, etc.). I don't believe the hockey stick is a representable temperature record for the last thousand years, because it is probably based on the smoothed average of many temperature proxies (one shows a positive anomaly and another a negative anomaly etc) which have rather large uncertainty. Individual proxies show much more variability, but that can also be explained by the large uncertainties and local effects of course. For me it's hard to believe that the global temperature has been SO constant before the last century, but that's completely intuitive. Possible underestimation of external forcing mechanisms (space weather on climate) is understandable, because recent climate science has been focussing on the internal atmospheric mechanisms, and less on the external ones (i.e. from space). That's not surprizing, because it needs both a detailed understanding of the internal and external variables and the interactions. External variation ("space weather") is better understood by astrophysicists, but they generally have a lack of understanding of the internal climate dynamics, and the interactions between both. Now that a lot of research has been done on internal climate dynamics, and a lot of skeptics are attacking AGW using arguments which focus on the link between space weather and climate, we are already seeing a slow shift towards more interdisciplinary research. A lot of research for example is currently been done on the dynamics of the stratosphere, and troposphere-stratosphere interactions. The stratosphere (and layers above) seems to be much more directly influenced by space weather than the troposphere. It is likely that they will find more space weather - climate relations and that a better estimate can be made of the influence of space weather on the earth's climate. Currently (possibly due to a lack of understanding) the influence is estimated to be very small for known variations. Meanwhile I hope that astrophysicists will improve space weather "forecasts", so that they can be included into a much more complete model of climate. My forecast is that I think the IPCC will generally be downgrading both the uncertainty and the magnitude of CO2 induced warming somewhat, and that it will start upgrading the variation induced by spaceweather, and maybe also slightly by natural internal variability. A completely different discussion, also often found on this forum and at many other places is if we should do something about the warming. This kind of risk assesment is quite beyond my expertise, but nevertheless interesting. AGW is not completely certain, nor are the results of warming on mankind. Also, the warming, for a large part, can not be stopped anymore. A complete focus on absolute CO2 reduction at all costs (without other pollution reduction, which has a much more direct beneficial effect on both us and the environment) might be less beneficial than trying to increase the ability of man kind to cope with all kinds of climate variations. It would be especially nasty if nature decided that after AGW it is time for an ice age . Perhaps, but I do not see the IPCC lasting much longer, in fact, there is talk about dismantling it altogether - which I wholly support because the IPPC and its companion scientists (most if not all who are involved in Climategate) haven't done much to promote climatology - but rather, made things worse than they were since the 1980s. The dynamics of nature, and this includes spaceweather, have not been included in conventional climatology as it has been practiced since 1981, when Hansen and his inner circle started the whole AGW mess. They know that the Sun plays the major role, but, they tied their wagons to the AGW horse and saw their own personal interests, i.e, career advancement, grant monies, fame, etc. Now that that horse is being seen for the mouse that it really is, they are jumping ship. Already, today, a climate scientist who was a proponent of AGW emailed me and asked me how I was so accurate in my ENSO forecast from 2006. I told him that it was astrometeorology, and he said he would be willing to learn. The media is also following suit as more and more CRU emails are read and organized to show what some of us already knew - that man-made global warming was a lie to begin with. Now the rest of the world is discovering that they have indeed been bamboozled, and many are not happy about it, nor should be. I also expect that this spring, when temperatures in May are above average, and summer-like in the northern hemisphere, that we will once again hear that man is responsible for global warming. Once again, we will see that the last vestiges of AGW alarmists clamoring for attention despite the fact that humanity has no control over their climate in the first place. The problems of getting accurate model data has been greatly tainted by those making these "products" which have become quite pricey over the last decade. That market, for these computer models, is really what AGW has been about along with the companies created by the interested parties to charge carbon credits among the nations and make billions for themselves. Now, that game is up and they are running for cover. These kind of people never belonged in science to start with and I am glad to see that this year will be their last - including the IPCC - which will try to stay "important" but which will, in the end, be dismantled by the United Nations. Good riddance I say. So, I expect to see more emails from climatologists in the coming months as more and more of them abandon Mann's "hockey stick" graphic and AGW overall so they can actually get back to work on forecasting the climate and weather in the real world.
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Post by socold on Jan 15, 2010 4:16:27 GMT
Well here's my prediction. Climategate has not affected AGW whatsoever. That's because emails have no bearing on the strong scientific evidence for it. The twitterings of the blogs likewise have no impact. Therefore I expect there will be a next IPCC report, that AGW will remain the dominant theory in the field, barring some future scientific breakthrough.
I expect the "skeptic" blogs will keep posting the same old rubbish. WUWT's take on the NASA emails is ridiculous. Surely you can read those emails and realize now that the error and correction was blown out of all proportion by "skeptics" simply to smear manmade global warming, the theory that is dominant today in the field of climate and the theory which "skeptics" are politically opposed to.
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Post by socold on Jan 15, 2010 4:18:54 GMT
From a paper by a famous scientist. Finds that after removal of internal variation (ie ocean cycles, etc), the global temperature record is very similar to an exponential curve over the 20th century: Thats fine Socold but solar activity has shown an exponential curve over the 20th century as well. No it hasn't. www.woodfortrees.org/plot/sidc-ssn/from:1900/plot/sidc-ssn/from:1900/mean:132
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Post by spaceman on Jan 15, 2010 4:52:07 GMT
I think that the IPCC has done a good job of proving that AGW has very little to do with climate at all. The entire point of their cause was the geometric rise in temps. Incremental changes aren't the same. The function of temp in relation to time. As long as the prediction matches the temps the derivative doesn't move, it stays at 0 because that was expected. If it is greater than what was expected then it becomes positive. If it is less than what was expected it is negative. The negative proves that there is no connection between man made co2 and climate. It has been negative for awhile. An increase in temps below the geometric is still a negative. The further out in time we go, the less correlation there is. (if there ever was) The hockey stick is geometric, hence the circus in Denmark.
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