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dana1981 at 09:59 AM on 4 July 2011German Energy Priorities
It will be interesting to see how the Germans do. I really wish they would prioritize phasing-out coal first. If they can accomplish a phasing-out of both coal and nuclear at the same time, more power to them (no pun intended), but I'm skeptical (as is Chancellor Merkel). -
Chemware at 09:48 AM on 4 July 2011Great Barrier Reef Part 1: Current Conditions and Human Impacts
Back in 1967 my dad and I went for a drive from Cairns up to Port Douglas (which was then a run-down fishing village) along the coast. I remember seeing corals that came right up to the shore. However, when I repeated that trip in the mid 2000s there were no corals along the coast. -
Stevo at 09:43 AM on 4 July 2011Great Barrier Reef Part 1: Current Conditions and Human Impacts
Looking forward to the second part of this series. Agricultural runoff and overfishing have both done great damage - prawn trawling methods used on the central Queensland coast can be likened to clearfelling of the sea bed and harm biodiversity due to large amounts of bycatch. Add warming and acidification into the mix and I can't see a rosy future. -
kiwipoet at 09:41 AM on 4 July 2011Climate's changed before
Thanks Stephen Baines for your encouraging reply. I replied on this threat because that’s where E Sat’s post appeared. I will take the advice of the moderator, make some changes to the post, and place it on the infographic thread. Thanks moderator! A final thought, however, on the ‘climate’s changed before’ argument. By using the term ‘natural climate forcings’ for what we can observe in the past as opposed to ‘man-made’ global warming now, we reinforce the division between man and nature that has helped precipitate the crisis. (Anthropocentric is better word technically but doesn’t avoid the problem.) It seems important to stress that man’s activities are as much a natural force as any other. We are the volcanoes of the age. It is because we are an intrinsic part of nature that we can have such a profound impact on the planet. By accepting language that separates man from nature we are, conceptually, partly buying into the denier illusory worldview. -
BBD at 09:38 AM on 4 July 2011German Energy Priorities
JMurphy #5 A very broad statement. Which I very cautiously agree with. But we are a long way from talking about renewables displacing nuclear. And it's not something that will wait. -
BBD at 09:12 AM on 4 July 2011A Detailed Look at Renewable Baseload Energy
Moderator #122 Apologies for overstepping the mark. I took my measure of what is acceptable from this:I get enough irrationalism on this site from the deniers. I don't need another source as well.
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JMurphy at 09:11 AM on 4 July 2011German Energy Priorities
Nothing IS off the table, which is why nuclear must take its place as we move away from oil and coal. But nuclear is NOT the future, either : renewables are and will be. The sooner we can move to 100% renewables, the better. How we do that is an ongoing struggle. -
BBD at 08:52 AM on 4 July 2011German Energy Priorities
JMurphy We both want the same thing: rapid global decarbonisation. Let's debate the fundamentals reasonably. Nothing off the table. -
BBD at 08:26 AM on 4 July 2011German Energy Priorities
JMurphy Quoting Savacool #2Any rational investor, regulator, and citizen would choose instead to invest in the deployment of technologies that require little to no energy inputs so as to harness free and clean fuels widely throughout the world. Policy makers should peek beyond the smoke-and-mirrors Kabuki dance used to obscure the obvious advantages of renewable technologies and the obvious costs of nuclear systems. Any effective response to electricity demand in a world facing climate change involves enormous expansion in our use of renewable technologies and a steady abandonment of nuclear power.
This would be true if there was a convincing argument that renewables provide a more efficient path to rapid decarbonisation than does nuclear. -
JMurphy at 08:09 AM on 4 July 2011German Energy Priorities
Another, more up-to-date, article from B.K. Savacool makes interesting reading too : This article judges modern nuclear power and renewable electricity technologies according to six criteria: cost; fuel availability; land degradation; water use; climate change; and safety/security. It concludes that when these criteria are taken into consideration, renewable electricity technologies present policy makers with a superior alternative for minimising the risk of fuel interruptions and shortages, helping improve the fragile transmission network and reducing environmental harm. As does this article, from him too - The ªSelf-Limitingº Future of Nuclear Power" : Any rational investor, regulator, and citizen would choose instead to invest in the deployment of technologies that require little to no energy inputs so as to harness free and clean fuels widely throughout the world. Policy makers should peek beyond the smoke-and-mirrors Kabuki dance used to obscure the obvious advantages of renewable technologies and the obvious costs of nuclear systems. Any effective response to electricity demand in a world facing climate change involves enormous expansion in our use of renewable technologies and a steady abandonment of nuclear power. -
Dikran Marsupial at 07:27 AM on 4 July 20112010 - 2011: Earth's most extreme weather since 1816?
Norman, take a GCM, which embodies our knowledge of climate physics. Apply CO2 radiative forcing, and observe an increase in rainfall frequency and intensity. Does it then become science? The obvious google search gave this example. I suspect there are more. -
scaddenp at 07:21 AM on 4 July 2011Google It - Clean Energy is Good for the Economy
Well Camburn, the point of carbon tax is to change the economics of things like oil-central heating versus non-carbon alternatives. That is the crux of its effectiveness. Biofuel is the other alternative for long range transport. Beside small-scale stuff like sewage-farm "cogen", capturing CO2 from steel-making and pushing that into algal diesel is an interesting idea. 2nd gen crude oil from wood might be interesting too. While these arent economic against current oil price with carbon tax, I doubt carbon tax will be necessary within 10 years. Hydro is major component of our electricity industry (75% renewable and growing) but sadly I am not so sure about its viability in much of US. The crucial element of being able to create a high fall with high water flow seems missing for much of US topography but it would be great if I was wrong. -
BBD at 07:21 AM on 4 July 2011German Energy Priorities
This is well put:Thus from a logical and scientific standpoint, Germany should first phase-out the use of more dangerous and environmentally damaging fossil fuels before pursuing a phase-out of nuclear power. Unfortunately the German public has its priorities backwards, phasing-out the energy source which poses less of a threat to both public health and the global climate.
It's worth bearing in mind that Germany is already barely coping:The four German TSOs have indicated that the nuclear power moratorium is having a significant impact on the German electricity supply system. Sufficient security of energy supply may not be guaranteed in southern Germany on very cold winter days with concurrent low wind power generation. Section 11(1) of the German Energy Act (EnWG) obliges transmission system operators (TSOs) to operate a secure, reliable and capable energy transmissions system without discrimination. Furthermore, they are obliged to maintain the system, to optimize it in line with demand, to strengthen it and to expand it, to the extent this is commercially reasonable. However, as unbundled TSOs do not generate the electricity, and as recent shutdowns are limiting German generation capacity, the German TSOs are facing a challenge to comply with their obligations. As a result of the Fukushima moratorium and scheduled revisions, only 4 of the 17 German nuclear power plants are currently online. Favourable conditions (low network load, strong solar, but rather low wind power input) and system operator interventions have so far made it possible to maintain network stability, the TSOs pointed out. Assuming no unusual events, the situation shall presumably be manageable also for the summer period, the four TSOs (Amprion GmbH, 50Hertz Transmission GmbH, EnbW Transportnetze AG and Tennet TSO GmbH) said. However, stability will require using every possibility form of redispatch measures, interventions in the electricity markets, to postponing urgent grid maintenance and expansion projects as well as power plant revisions, they added. The TSOs also indicated that the free electricity market will be suspended for considerable periods of time. Still the risk of power failure has increased, the TSOs said. In case input capacity remained reduced by 8,000 MW after the end of the 3-month nuclear power extension moratorium (on 15 June 2011), TSOs foresee problems in particular for the coming winter months, as the possibilities for interventions were largely exhausted. In (industrial) southern Germany the electricity demand might not be satisfied on cold cloudy winter days with a low wind power input in northern Germany. 2,000 MW of secure generation capacity would be missing in southern Germany. Demand might also not be covered by electricity imports if other countries consume their electricity output themselves. As a consequence the risk for large power outages will increase, the TSOs warned.
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Dikran Marsupial at 07:18 AM on 4 July 20112010 - 2011: Earth's most extreme weather since 1816?
Norman@227 Yes, that is the point, it was you that was mistakenly talking about proof. In the case of linking mechansims, these are well known to hydrologists. Knowing the mechanisms however does not mean that you can accurately predict something. You can write down the physics of a double pendulum on a side of A4, but you can't predict it exact course. Does that mean we can only have opinions about double pendulums, but not science? Of course not. You appear to have a rather unusual definition of science. -
dream1958 at 07:18 AM on 4 July 20112nd law of thermodynamics contradicts greenhouse theory
Will someone debunk this argument please? http://wattsupwiththat.com/2011/02/17/regarding-thermodynamics-and-heat-transfer-why-al-gore’s-comments-to-bill-o’reilly-at-fox-news-are-wrong/#more-34175 -
Norman at 07:17 AM on 4 July 20112010 - 2011: Earth's most extreme weather since 1816?
Tom Curtis @ 219 Wow! You are definately a very intelligent person. I read through your post but will have to reread it a few times and think on it before composing a comment to what you have developed. I will try to make it satisfactory for your intellect. Thanks for taking the time to give such detailed and thoughtful responses. I know it took me awhile to find data to compose my post on Munich Re. -
Norman at 07:14 AM on 4 July 20112010 - 2011: Earth's most extreme weather since 1816?
Dirkan Marsupial @ 226 Sorry for the misunderstanding. You state "that a warmer atmosphere can contain more water vapour is not a hypothesis, or an educated guess, it is an observable fact." Yes it is, and that is not what I am calling a hypothesis. The hypothesis is that the current amount of moisture increase and temp increase will lead to more extreme weather events (at least to a noticeable degree). That is why I introduced the tall people analogy. I am not very good in statistics but I can understand the basics. I may be very wrong but the way to demonstrate your idea would be to make a precipitation graph with 4% more precipitation than another graph. Normal curve or flat tail whatever you want. You go out to the level of standard deviations you consider extreme and calculate how many more events occur with the 4% increase to see if it is noticeable enough at this time to attribute the recent floods to Global warming. -
jmsully at 07:04 AM on 4 July 2011Great Barrier Reef Part 1: Current Conditions and Human Impacts
Rob, Thanks for pointing me to that post. -
Norman at 07:01 AM on 4 July 20112010 - 2011: Earth's most extreme weather since 1816?
Dirkan Marsupial @ 213 "It isn't proof, it is corroborative evidence. In science you can't prove by observation, only disprove, and constant calls for proof of AGW (which is known to be impossible, even if the theory is correct) is a form of denial." Maybe you can't prove by observation but you can certainly develop linking mechanisms to explain what causes observed behavior and gives you the ultimate scienctific goal, predictability. When Chemists came up with the atomic theory it became a very valuable tool to predict future interactions among elements and molecules. Just stating the earth is warmer and there is more water in the air does not justify the conclusion that more extreme weather related events become noticeably more probable. Extreme weather events are well outside the normal and are caused by certain events that take place in the atmosphere. Some are known and some are not. This is from an abstract I quoted in post 192. "This suggests that natural variability of the climate system could be the cause of the recent increase, although anthropogenic forcing due to increasing greenhouse gas concentrations cannot be discounted as another cause. It is likely that anthropogenic forcing will eventually cause global increases in extreme precipitation, primarily because of probable increases in atmospheric water vapor content and destabilization of the atmosphere. However, the location, timing, and magnitude of local and regional changes remain unknown because of uncertainties about future changes in the frequency/intensity of meteorological systems that cause extreme precipitation." That is what is needed to become a science. You need mechanisms that explain past weather extremes (floods, hurricanes, droughts, tornadoes, heat waves, cold waves, snow). For instance, what were mechanisms that caused floods in Australia's past? Certain atmopheric and ocean conditions are set up that will lead to flooding. Once you get a good mechanism developed it will lead to future predicability and you will easily be able to see if global warming is increasing the return time of a given weather extreme because of how it effects the overall mechanism you found that produces flooding in Australia. Without offering a mechanism of how floods occur then you definately don't have a science. You have an opinion. Science is always going to the next level. -
Dikran Marsupial at 06:44 AM on 4 July 20112010 - 2011: Earth's most extreme weather since 1816?
Norman, that a warmer atmosphere can contain more water vapour is not a hypothesis, or an educated guess, it is an observable fact. That there is more evaporation in warmer conditions is similarly observable fact. Having more water in the atmosphere gives greater scope for heavy rainfall. You accept that it will increase normal rainfall, can you suggest a physical reason why it would increase normal rainfall but not extreme rainfall? Later on you write "No doubt if you keep increasing the moisture content you will reach a point where exterme events will be more likely (extreme based upon previous levels)." which suggests that you also accept that warmer conditions will lead to an increase in extreme events! I don't understand why you think there is some sort of threshold, it seems to me much more plausible that the probability of an extreme event (or equivalently its return period) is a continuous function of humidity (and a bunch of other variables). -
BBD at 06:39 AM on 4 July 2011A Detailed Look at Renewable Baseload Energy
dana1981However, a number of German studies found that they could at least reduce their use of coal even while phasing-out nuclear power, and may even be able to replace both with renewables simultaneously (though Merkel thinks some new fossil fuel plants will be necessary in order to meet the nuclear phase-out).
So we have studies in which Ch.Merkel has apparently limited confidence. Germany phases out nuclear, and in all probability is forced to install more conventional plant. Emissions will: - stay the same - rise - fall We shall see. What concerns me is things like this:The four German TSOs have indicated that the nuclear power moratorium is having a significant impact on the German electricity supply system. Sufficient security of energy supply may not be guaranteed in southern Germany on very cold winter days with concurrent low wind power generation. Section 11(1) of the German Energy Act (EnWG) obliges transmission system operators (TSOs) to operate a secure, reliable and capable energy transmissions system without discrimination. Furthermore, they are obliged to maintain the system, to optimize it in line with demand, to strengthen it and to expand it, to the extent this is commercially reasonable. However, as unbundled TSOs do not generate the electricity, and as recent shutdowns are limiting German generation capacity, the German TSOs are facing a challenge to comply with their obligations. As a result of the Fukushima moratorium and scheduled revisions, only 4 of the 17 German nuclear power plants are currently online. Favourable conditions (low network load, strong solar, but rather low wind power input) and system operator interventions have so far made it possible to maintain network stability, the TSOs pointed out. Assuming no unusual events, the situation shall presumably be manageable also for the summer period, the four TSOs (Amprion GmbH, 50Hertz Transmission GmbH, EnbW Transportnetze AG and Tennet TSO GmbH) said. However, stability will require using every possibility form of redispatch measures, interventions in the electricity markets, to postponing urgent grid maintenance and expansion projects as well as power plant revisions, they added. The TSOs also indicated that the free electricity market will be suspended for considerable periods of time. Still the risk of power failure has increased, the TSOs said. In case input capacity remained reduced by 8,000 MW after the end of the 3-month nuclear power extension moratorium (on 15 June 2011), TSOs foresee problems in particular for the coming winter months, as the possibilities for interventions were largely exhausted. In (industrial) southern Germany the electricity demand might not be satisfied on cold cloudy winter days with a low wind power input in northern Germany. 2,000 MW of secure generation capacity would be missing in southern Germany. Demand might also not be covered by electricity imports if other countries consume their electricity output themselves. As a consequence the risk for large power outages will increase, the TSOs warned.
Must read your post though. And thank you for staying with this thread. -
Norman at 06:24 AM on 4 July 20112010 - 2011: Earth's most extreme weather since 1816?
Dikran Marsupial @ 213 "A warmer world means that the atmosphere can hold more water vapour, and thus there will be a strengthening of the hydrological cycle. A consequence of that is likely to be an increase in extreme weather in some places. Thus an increase in weather extremes is what you would expect to see if AGW is ocurring, but it isn't poof. If you think that is not good science, then it is your understanding that is at fault." What you describe it the first stage of science. It is a hypothesis (educated guess). Inceasing the water vapour in the atmosphere should increase the normal rainfall amounts and you should see an upward rise for these measurements. I do not know how this would lead to a necessary increase in extreme weather in some places. I guess it comes down to how "extreme weather" is defined. There is a nice ongoing debate between you, Tom Curtis and Eric (skeptic) about what is an extreme weather or climate event. As of my post reading so far, it does not seem the issue is yet resolved. Here is an analogy to consider. On the Wikipedia explanation of Standard Deviation Standared Deviation. They give an example of Standard Deviation: "A slightly more complicated real life example, the average height for adult men in the United States is about 70", with a standard deviation of around 3". This means that most men (about 68%, assuming a normal distribution) have a height within 3" of the mean (67"–73") — one standard deviation — and almost all men (about 95%) have a height within 6" of the mean (64"–76") — two standard deviations. If the standard deviation were zero, then all men would be exactly 70" tall. If the standard deviation were 20", then men would have much more variable heights, with a typical range of about 50"–90". Three standard deviations account for 99.7% of the sample population being studied, assuming the distribution is normal (bell-shaped)." The first point is what is a good definition of extreme height for an American male? Two standard deviations above the normal is 6 feet 3 inches (sorry for English terms or 1.95 meters). This is not an extreme height in my opinion. Tall yes, but not extreme. So extreme is in the "eye of the beholder". I will think 6' 8" (2.03 meters) would be an extreme height (like the Moscow heatwave "Take for example the Moscow heat wave of 2010, with an expected return interval, which lay just above 4 standard deviations above the mean for July temperatures" From Tom Curtis at 214). That is the groundwork of this analogy. Now we have a population that wants to get taller so as a group they all begin to take a growth hormone which will raise the average height by 4% (the amount of water vapor that has increased in our atmosphere due to warming). 4% of 70 inches is 2.8 inches. Our entire population is 4% taller, some are more or less affected but the average increase is 4%. Will this 2.8" in average height now mean we have a noticeable increase in 7 foot tall men from this growth hormone? It may well do this. I would need some proof of it. No doubt if you keep increasing the moisture content you will reach a point where exterme events will be more likely (extreme based upon previous levels). I am not convinced, at this time, 4% is enough to push us to the new normal. The statistical experts that post on this thread (Tom Curtis or Berenyi Peter) may be able to demonstrate a 4% increase would make it noticeably more likely to effect the far ends of the normal curve. I am not sure. There would be calculations for this. -
Dikran Marsupial at 05:54 AM on 4 July 20112010 - 2011: Earth's most extreme weather since 1816?
Eric (223) I have pointed out to you more than once that return periods are conditioned on factors such as location. If you want the return period for a particular event at a particular station, that is one calculation. The return period for an extreme event occurring at one or more stations within a region is a different calculation. However, rather than rolling your own statistics, it would be better to first acquaint yourself with the standard solution developed by leading statisticians, namely extreme value theory. Extreme events generally ocurr to a coincidence of factors combining constructively. These same factors when they partially cancel out (which is what happens most of the time) is what generates the central parts of the distribution. However the factors are there for both the extremes and the day to day. The difference is in how they combine. Now if you can give an example where the physical mechanism of an extreme is different from the day to day, then give an example. Just asserting that they are different does not establish that they are. As it happens, modelling rainfall extremes in this way does actually work quite well (see e.g. this paper). -
BBD at 05:49 AM on 4 July 2011A Detailed Look at Renewable Baseload Energy
To be absolutely clear: I do not advocate nuclear because I think it is risk-free and wonderful. I do so because unlike some here, I can see no option. -
BBD at 05:47 AM on 4 July 2011A Detailed Look at Renewable Baseload Energy
JMurphy I do not excuse the insane siting of Fukushima 1. I do not excuse laxity in the inspection and maintenance regimes at the plant. But the damage to it was indisputably caused by the earthquake and tsunami. This is a matter of fact. You are going beyond matters of fact. See #101:Let's remember that Fukushima was a natural disaster that damaged a 40 year old plant which was both poorly designed and appallingly sited. The news about the cesium detected in child urine samples is extremely vague and inconclusive and more accurate information from a large sample is required. It is also essential to understand whether the contamination was from airborne or dietary pathways. It is a matter for serious concern. I don't think we should go any further yet. And I don't like the usual emoting and distorting that is coming from the anti-nuclear lobby either.
WRT the INES 7 classification of Fukushima - you still haven't read the facts about Chernobyl, I see.(Sorry to have gone one but I always argue against blind faith)
And your views on the potential for renewables to displace coal and nuclear are based on what, exactly? -
dana1981 at 05:29 AM on 4 July 2011A Detailed Look at Renewable Baseload Energy
I think Germany is a good example here (see the German Energy Priorities post I just published). They've decided that phasing out nuclear power is their top priority, whereas I agree with Tom that we should maintain what nuclear power we currently have and phase-out fossil fuels first. However, a number of German studies found that they could at least reduce their use of coal even while phasing-out nuclear power, and may even be able to replace both with renewables simultaneously (though Merkel thinks some new fossil fuel plants will be necessary in order to meet the nuclear phase-out). So it will be interesting to see if Germany can do what BBD seems to think can't be done. They seem confident that they can. -
JMurphy at 05:09 AM on 4 July 2011A Detailed Look at Renewable Baseload Energy
OK, a final highlight of pro-nuclearitis : BBD : "You close with this: 'The fact that you try to lessen the seriousness, speaks volumes.' This is incorrect and strategically dishonest, which is in line with much else you say here." Really ? Compare and contrast : BBD : "It is a grotesque misrepresentation. There have been no fatalities and none are currently expected. In other words, such contamination as may have occurred is likely to be minor and transient." BBD : "After all, Fukushima has caused no fatalities, and resulted in no life-threatening exposure to radiation. Odd, isn't it?" Odd indeed...if you want to believe in fortune-telling, rely on wishful-thinking and wear rose-tinted glasses : Results of ACRO's monitoring in Japan (30th june 2011 update) Overall, the situation at the Fukushima Daiichi nuclear power plant remains very serious. Perhaps you should put the IAEA straight and tell everyone in the vicinity that they are currently not expected to die or be affected by radiation in any shape or form, now or in the future ? I'm sure they'll respect your opinion. BBD : "You seem to have forgotten that the Chernobyl and Fukushima events were caused by abysmally poor design and afflicted plant many decades old." BBD : "Some of what you say confuses me, but Fukushima 1 was 40 years old and badly designed. And it still worked fine until hit by a massive earthquake and inundated by the consequent tsunami." Old, badly-designed...and, perhaps, affected by falsified safety records for more than 10 years; a failure to inspect 33 pieces of equipment; a long-term, incestuous relationships between government regulatory bodies and this particular private industry (the cosying up which you seem to support, at least in the UK); and the ignoring of concerns about potential earthquake damage. Yes, that sure is 'working fine' - in a broken, corrupt kind of way. BBD : "However, the INES 7 ratings for Chernobyl and Fukushima are puzzling" BBD : "When you do get a minute to review the evidence, you can see for yourself that the INES 7 rating for Fukushima may have been an over-reaction." Perhaps you had better seek and dole-out more enlightenment : IAEA - Level 7 : "An event resulting in an environmental release corresponding to a quantity of radioactivity radiologically equivalent to a release to the atmosphere of more than several tens of thousands of terabecquerels of [iodine-131]" This corresponds to a large fraction of the core inventory of a power reactor, typically involving a mixture of short and long lived radionuclides. With such a release, stochastic health effects over a wide area, perhaps involving more than one country, are expected, and there is a possibility of deterministic health effects. Long-term environmental consequences are also likely, and it is very likely that protective action such as sheltering and evacuation will be judged necessary to prevent or limit health effects on members of the public. JAIF - Many areas still showing 'High' and 'Severe (Need immediate action)' Significance, and many Countermeasures that are still 'Under construction' or 'To be done (including studying and manufacturing)'. Maybe you should tell them where they are going wrong and that they are indulging in "over-reaction". Finally, as I have already said here (and elsewhere) : I believe it is an old, dirty and dangerous way of producing energy and that we should move as quickly as possible to renewable sources, but that doesn't mean that I don't think it shouldn't be used now, where there are no other options. It should only be a last resort, though, and only as a temporary stop-gap before renewables take over. It is just your evangelism for nuclear that makes you see anti-nuclear 'enemies' everywhere - perhaps even under your bed. (Sorry to have gone one but I always argue against blind faith) Fin -
Rob Painting at 05:05 AM on 4 July 2011Great Barrier Reef Part 1: Current Conditions and Human Impacts
jmsully - You might want to ask John Bruno as well, given that he provided comment on the Osborne 2011 paper. The SkS link in the blog post above - that's to John Bruno's discussion about the AIMS survey. -
Eric (skeptic) at 04:42 AM on 4 July 20112010 - 2011: Earth's most extreme weather since 1816?
Dikran, the events are not a dime a dozen, but the locations for potential extreme events are. So we have a situation of numerous independent tests of an event with a very low probability (by the recurrence measurement). By multiplying the probabilities of nonoccurence at each location we can determine the probability that the event will not occur at any location, then invert that to obtain the probability of occurrence. For example an event that has 0.1% probability in one location will have 1 - (0.001 ^ 100) or 9.5% probability in any one of 100 locations. The caveat is that the weather event occurrences are not necessarily independent tests. The other problem with the binomial approach is that it that the extreme event has to be defined a priori. As an extreme example I could define "extreme" as 1.00 inches, no more and no less. Or 0.99 inches. The more of these events that I invent, the greater the probability that an event will occur. Those are analogous to the head post stating: "The formation of Tomas so far south and east so late in the season (October 29) was unprecedented in the historical record; no named storm had ever been present east of the Lesser Antilles (61.5°W) and south of 12°N latitude so late in the year" (from the head post). I could easily pick some year in the 1950's or other early year and pick out a hurricane that formed so early so far west or north or late and farther north or any of dozens of potential combinations. Then I can point to the lack of a trend since the 1950's since I invented all those extremes for that decade. Tom, I think we are differing on the definition of extreme event. I find it critical to define that up front, then look for trends, then attribute to AGW and natural causes. The fact that Toowoomba's flash flood event has gone from 1 in 100 to 1 in 20 may be a suitable topic to study attribution, but not attribution of extreme events. The Toowoomba event was one location but the probability of an occurrence of such an event must be calculated across all potential flash flood locations. In that context the Toowoomba event is not extreme because if it didn't happen there, it could happen somewhere else. Dikran (222) I don't think you can equate the physical processes of the extreme and day-to-day events nor use the statistics of the day-to-day events to say anything about the probability of extreme events. -
BBD at 04:26 AM on 4 July 2011A Detailed Look at Renewable Baseload Energy
Mark Harrigan 123Still - I like this debate. At least it focuses on what the options are to move forwards and Mark's contribution is certainly a positive one
Not if it's wrong, and being used to push energy policy in the wrong direction. Tom Curtis asks me above (114): Why the bitter and unenlightening attack on renewables? I think this is unreasonably harsh, but then I would. However, if TC had read my original comments when I joined the thread, he would understand why I have a problem with renewables advocacy. It is fantastically dangerous to energy policy (see #69 and above, where Hansen's warning to President Obama is discussed), and it is going to cause an energy policy disaster in the UK (see #72). It will cause an energy policy disaster everywhere in due course, if not stopped, but I happen to be in the UK where I can see what is going on (eg #98; #99). What such activism is not going to do is displace coal significantly from the global energy mix. Which means it is as dangerous from a climate perspective as scepticism. We need to get past the all-consuming anti-nuclear bias and accept the unpalatable facts as they stand. Then formulate energy policy that makes sense. -
jmsully at 04:22 AM on 4 July 2011Great Barrier Reef Part 1: Current Conditions and Human Impacts
Dr. Hoegh-Guldberg, I was wondering what you thought of this article: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3053361/ recently published in PLoS One which analyzes the AMIS data to come to the conclusion that there is no widespread decline in coral coverage. My initial thought was that it focused on too narrow a question, but otherwise seemed OK. Of course this is being used by denialists to claim that "coral reefs are OK! Nothing to worry about!", but I'd be interested in your take. -
BBD at 04:12 AM on 4 July 2011A Detailed Look at Renewable Baseload Energy
dana1981 See SPM p19:More than half of the scenarios show a contribution from RE in excess of a 17% share of primary energy supply in 2030 rising to more than 27% in 2050. The scenarios with the highest RE shares reach approximately 43% in 2030 and 77% in 2050.
Teske is the outlier. The report points to ca 30% RE by 2050. I don't want to argue about this sort of thing; it's pointless. The press release grossly misrepresented the actual report. Which was both exceptionally stupid of the IPCC, and unforgivable. -
dana1981 at 03:52 AM on 4 July 2011A Detailed Look at Renewable Baseload Energy
BBD - not sure what you mean about SRREN. It examined 164 different scenarios, up to 77% renewable production by 2050. Mark - in response to your #1, I don't think there's enough wind turbines installed in any single country to test that load management. Regarding #2, it would depend on how much the gas turbines were fueled by natural gas vs. biofuel, for one thing. How many gas turbines would be necessary would depend on the breakdown of the rest of the power grid mix. But remember that even natural gas has significantly lower CO2 emissions than coal, and these gas turbines are proposed to operate as peak load power, only used when there is insufficient wind and solar energy to meet demand. Solar PV costs have been declining quite rapidly, as well. They're expected to become as cheap as coal power (without subsidies, and excluding coal external costs) within the next decade. -
BBD at 03:50 AM on 4 July 2011A Detailed Look at Renewable Baseload Energy
Mark Harrigan #123 Good to see some critical thinking ;-)1) Have there been any actually implementations of this sort of load management model implemented on any serious commercial scale (as opposed to modelling)? [No] 2) Just how much "peak load" gas type generation will be needed in a given annual scenario and how much CO2 might they produce (for example as a % of today's Australian emissions assuming the same generation requirements as today). In other words if we could wave a magic wand and switch on Mark's proposal tomorrow what would that do to emissions?
Perhaps an even earlier question to ask than your (2) is: what kind of gas turbine can be brought up from cold shutdown to full operating capacity fast enough to respond to peaking demand? And why, in countries such as the UK, can't we have some? Instead, we are obliged to compensate for wind intermittency with gas turbines permanently running because they cannot otherwise respond quickly enough to allow grid balancing? Needless to say, this cancels out any emissions saving from UK wind. And it might do worse. Consider this statement by someone who knows what they are talking about:One of Britain's leading energy providers warned yesterday that Britain will need substantial fossil fuel generation to back up the renewable energy it needs to meet European Union targets. The UK has to meet a target of 15% of energy from renewables by 2020. E.ON said that it could take 50 gigawatts of renewable electricity generation to meet the EU target. But it would require up to 90% of this amount as backup from coal and gas plants to ensure supply when intermittent renewable supplies were not available. That would push Britain's installed power base from the existing 76 gigawatts to 120 gigawatts. Paul Golby, E.ON UK's chief executive, declined to be drawn on how much the expansion would cost, beyond saying it would be "significant". Industry sources estimate the bill for additional generation could be well in excess of £50bn.
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Patrick 027 at 03:42 AM on 4 July 2011The Planetary Greenhouse Engine Revisited
(PS of course liquid water coexists with vapor over a range of temperatures, but the vapor phase is in a mixture in such familiar conditions. If the vapor phase were chemically pure, then the vapor pressure would be the pressure that the liquid is at as well.) -
Patrick 027 at 03:38 AM on 4 July 2011The Planetary Greenhouse Engine Revisited
Re Michele - The cooling effect occurs within the isothermal sinks because the conversion heat->EM radiation, in effect, is a phase transition... That last term - maybe part of the problem? Granted, energy is changing forms and so that could be considered a phase transition, but when I here 'phase transition', I generally think of a substance or mixture changing from a solid to a liquid and/or to a gas, etc., or various changes between different crystal structures. Sometimes I think this may also involve changes in chemical equilibria (I think in some cases a liquid may react with a solid to form a different solid during a phase transition in which each solid is a different substance (though with dissolved impurities); it certainly can involve solid vs liquid vs gas solubility. For a pure substance, generally (so far as I know) such physical phase transitions occur isothermally (if provided they are also isobaric) - meaning that the two or more phases only coexist in equilibrium at a single temperature (for a particular pressure). And any latent heat involved must be given off or taken up at that point. However, in mixtures, it can often be the case that a phase transition occurs gradually. This may be punctuated by some isothermal (if isobaric) phase transitions (for example, if I remember correctly, the point at which the remaining liquid freezes into two different solids in a eutectic phase transition (this can happen because two substances may be miscible as liquids but only have limited solubility in each other as solids)), but in between there are spans of temperature in which different phases coexist, with proportions varying gradually - the phases will generally have different compositions that vary with temperature and the composition of the whole is maintained by changing the mix of phases. This is commonly the case between a liquid and solid phase. In a phase diagram, this is illustrated with lines/curves, I think they're called the solidus and the liquidus. Other interesting terms - peritectic, syntectic, etc. And of course, chemical equilibrium varies gradually (although maybe sometimes quickly) over a span of temperature. Anyway, none of this really is quite the same as changing the form of energy from a difference in vibration/rotation mode to a photon. Each type of transition behaves according to the relavent physics. Photons don't 'boil off' a material like steam from liquid water at a single set temperature. -
Mark Harrigan at 03:07 AM on 4 July 2011A Detailed Look at Renewable Baseload Energy
Haven't read all the posts here but would like to ask when Mark Diesendorf says "There are a number of renewable energy technologies which can supply baseload power. The intermittency of other sources such as wind and solar photovoltaic can be addressed by interconnecting power plants which are widely geographically distributed, and by coupling them with peak-load plants such as gas turbines fueled by biofuels or natural gas which can quickly be switched on to fill in gaps of low wind or solar production." 1) Have there been any actually implementations of this sort of load management model implemented on any serious commercial scale (as opposed to modelling)? 2) Just how much "peak load" gas type generation will be needed in a given annual scenario and how much CO2 might they produce (for example as a % of today's Australian emissions assuming the same generation requirements as today). In other words if we could wave a magic wand and switch on Mark's proposal tomorrow what would that do to emissions? Despite the proselytising of Wind, data I have seen suggests it's load factor is about 1/3 of gas or coal. I have even heard it alleged that sometimes lots of Wind can lead to increased emissions because it can displace other forms of renewables and the need for the back up generators can cause problems - but I confess I don't know how reliable that allegation might be. So how many wind plants would be needed and how widely distributed would they need to be on a well connected grid to achieve the model parameters Mark sets out? Is this practical in Australia? The problem with Solar Thermal, as I see it and by Mark's own admission, is that it is simply not a commercially viable technology yet. A 20 Megawatt plant that can only operate less than 3/4 of the year is hardly inspiring. Solar PV remains grossly expensive in terms of the cost per tonne of carbon offset and I'm yet to hear of any Solar PV plants in commercial operation producing more than 100MW. Given that Australia currently has well over 50GigaWatt generating capacity it's hard for me to see how we can replace that so easily with the alternatives on offer - at least not very quickly within our financial means and not with the relatively poor grid interconnection available today. I have to confess, as much as I might find it appealing, I am sceptical about Mark Diesendorf's approach as being practical or affordable in the near to medium term. Still - I like this debate. At least it focuses on what the options are to move forwards and Mark's contribution is certainly a positive one -
BBD at 02:50 AM on 4 July 2011A Detailed Look at Renewable Baseload Energy
Tom Curtis Your points 1 - 4 are entirely reasonable. Your apparent belief in the ability of renewables to displace coal significantly by 2050 is not. You have not justified your position, so you have effectively lost this debate. Your misreading of Hansen's letter is obtuse. End of. WRT nuclear safety, I find your position untenable, and your reasoning misleading. You obviously don't take well to criticism:Anyway, this will be my last post responding to you. You have demonstrated a complete unwillingness to enter into rational debate, to the extent that you have several times completely ignored my clear statements and tried to set me up as as strawman. You have also repeatedly repudiated the burden of justifying your claims when challenged. I get enough irrationalism on this site from the deniers. I don't need another source as well.
Oho. I see. Fine, off you go then. ( -Snip- ).Moderator Response: (DB) Inflammatory snipped. -
Tom Curtis at 02:00 AM on 4 July 2011A Detailed Look at Renewable Baseload Energy
BBD @114, I repeat:"I still think the letter contains good sense - all of it. But I have to wonder, seeing you have introduced Hansen as an authority why you are ignoring those sections that I have highlighted? Why the bitter and unenlightening attack on renewables?"
(emphasis added) So, as explicitly stated, I introduced highlighting not to "reveal the true meaning" of Hansen's quote, but simply to emphasise those parts of it which obviously you find uncomfortable, and which contradict the line you are pushing. Further, no body can ever reveal the "true meaning" of a quote by adding emphasis. Adding emphasis changes emphasis, and by doing so changes the meaning. That is why people who are concerned about accuracy of quotation always note when they add emphasis, and your failure to do so shows that accuracy in conveying Hansen's meaning is not a concern of yours. In fact, you clearly attempt to distort his meaning when you say "... when renewables fail to deliver on the hype (as Hansen clearly believes is likely)...". Indeed, Hansen's "carefully worded" message states that "Energy efficiency, renewable energies, and an improved grid deserve priority ..." (my emphasis). When you remove your heavy handed emphasis it is clear that as much generation of electricity that can be done by renewables should be done by renewables. However, he clearly thinks that nuclear is better than coal and that we should not put all our eggs in one basket. And let me emphasise again, and for the third time, I think Hansen's advise is good. All of it, or at least all of it that letter, except for the discussion of the Carbon Tax where I am indifferent between broad means of pricing carbon (but not about implementation). My preferred policy is: 1) Place a price on carbon that increases incrementally on an annual basis (whether by tax or emissions trading I do not care); 2) Remove broad prohibitions on nuclear power except for occupational health and safety, and security regulations; 3) Implement regulations guaranteeing that waste disposal does not place any additional risk on later generations; and 4) Let the market sort it out. Apparently that is too anti-nuclear a position for you. Anyway, this will be my last post responding to you. You have demonstrated a complete unwillingness to enter into rational debate, to the extent that you have several times completely ignored my clear statements and tried to set me up as as strawman. You have also repeatedly repudiated the burden of justifying your claims when challenged. I get enough irrationalism on this site from the deniers. I don't need another source as well. -
BBD at 01:50 AM on 4 July 2011A Detailed Look at Renewable Baseload Energy
dana1981 Careless writing; apologies. J&D do indeed claim that renewables can replace nuclear as well as fossil fuels. And their treatment of nuclear is egregious. Not something I'd focus on, if I were you ;-) But to your point: what difference does it really make? All high-renewables energy scenarios claim the same thing. All fail to make a convincing case. Interestingly, I wonder why the main conclusion of the SRREN report - ca 30% renewables by 2050 - is so far at odds with J&D? Had meant to ask earlier but it slipped my mind. -
Mark Harrigan at 01:33 AM on 4 July 2011It hasn't warmed since 1998
Thanks Dikram for those points. I think your point about 1970 onwards is the most compelling since this is indeed the relevant AGW period. As for your comment about "honesty" - I agree the paper shows no dishonesty. But I don't think it is "naive". If you had been following Mr Cox's tactics on the ABC and other blogs you might question whether he is always entirely forthright in his approach. He is actually a lawyer - not a trained scientist. He wrote an article once on Drum (http://www.abc.net.au/unleashed/44734.html) about how there had been a challenge to the Australia/New Zealand tempetarure data, implying some sort of conspiracy on the part of BOM people in New Zealand. He made it out as if this was independent challenge from credible sources. What he failed to disclose directly in the article was that he was actually one of the prime architects of the challenge (in his capacity as secretary of the Climate Sceptics)- which didn't come from reputable client scientists at all. He also published the link to his "paper" on Drum in response to a challenge to submit a piece of peer reviewed science that invalidated AGW. Somehow he conveniently neglected to mention that it hadn't actually been published. In other words he has an avowed political agenda - it not simply a naive approach or lack of self-scepticism -
Dikran Marsupial at 01:30 AM on 4 July 20112010 - 2011: Earth's most extreme weather since 1816?
Tom Curtis Counting events is not the only way in which you could determine whether the return period has changed. For instance, you could model the distribution of observed rainfall at a particular location as a function of time, using perhaps the methods set out in the paper by Williams I discussed in an earlier post. You can then see the trend in the return period by plotting say the 99th centile of the daily distributions. This would be a reasonable form of analysis provided the extreme events are generated by the same basic physical mechanisms as the day-to-day rainfall (just with "outlier" magnitudes), rather than being cause by a fundamentally different process. Alternatively extreme value regression methods might be used. -
Tom Curtis at 01:19 AM on 4 July 20112010 - 2011: Earth's most extreme weather since 1816?
Eric (skeptic) @218, you seem determined to exclude yourself from the discussion as completely irrelevant. To see what I mean, consider this definition of a severe thunderstorm:"In Australia, for a thunderstorm to be classifi ed as severe by the Bureau of Meteorology, it needs to produce any of the following: • Hailstones with a diameter of 2 cm or more at the ground • Wind gusts of 90 km/h or greater at 10 m above the ground • Flash flooding • A tornado.
That come from the joint CSIRO BoM 2007 report on Climate Change,which then goes on to make predictions about cool season tornadoes and the number of hail days expected per annum. I have seen other prediction in Australia for AEP rainfall events of 1 in 20 for various periods. From memory it was an expected 30% increase for the top 5% of one hour events, and a 5% increase for the top 5% of one day rainfall events by 2030. The twenty year return peak rainfall for one hour at one Toowoomba station (Middle Ridge) is about 60 mm, with about 80 mm, ie 25% higher. For another (USQ) they are about 55 mm and 75 mm respectively, ie, 36% higher. So in terms of rainfall intensity, and the fact that it involved a flash flood, Toowoomba was exactly the sort of event about which predictions where made. Now, the question is, was Toowoomba's flash flood a 1 in 100 event, or has it now become a 1 in 20 year event (as is predicted for around 20 years from today). The only way you can find out is by counting the number of relevant events. You, however, have carefully contrived your definition of "extreme event" so that it does not count exactly the sort of events we need to track to see how the AGW prediction is bearing out. In doing so,of course, you have contrived your definition to include events about which there is no explicit AGW prediction in the near term (or in many cases the long term), and which occur far to rarely for any sort of statistical analysis. What that amounts to is an attempt to remove your beliefs from empirical challenge. It also means your discussion on this thread is irrelevant because you have carefully chosen to avoid discussing the type of events about which AGW has made its predictions. -
dana1981 at 01:09 AM on 4 July 2011A Detailed Look at Renewable Baseload Energy
BBD - J&D is essential to a claim that wind, water, and solar alone can displace 100% of fossil fuels and nuclear. It's not essential to claims that renewables can significantly displace coal. I haven't had a chance to read the links about that paper, but this is an important distinction to make. -
dana1981 at 01:05 AM on 4 July 2011Glickstein and WUWT's Confusion about Reasoned Skepticism
andreas - I would agree with you, except Glickstein didn't propose a carbon tax for the economic benefits. He proposed it purely as a capitulation because he felt the 'warmists' have succeeded in convincing the public and policymakers that some action is necessary, and he would prefer a tax to cap and trade. It's not that he thinks a carbon tax would be beneficial, he just thinks it's not as bad as cap and trade. So I think the description in the post is valid. -
Dikran Marsupial at 00:44 AM on 4 July 20112010 - 2011: Earth's most extreme weather since 1816?
Eric, would you say that an event that is sufficiently dramatic that it only happens once in a thousand year is an extreme event? The return period is a measure of the "extremeness" of an event; the threshold return period that demarcates extreme from non-extremes depends on the nature of the application. The same is true of statistical significance tests. The 95% threshold is often used to indicate an event sufficiently extreme that it is difficult to explain by random chance. However what people often forget is that Fisher himself said that the threshold depends on the nature and intent of the analysis. Expecting a single threshold that is right for every aplication is unreasonable in both cases. As to the additional effects such as area, event duration etc. These are conditioning variables on which the return period depends. They are already taken into account in the analysis. For instance, what is the return period for 12" of rain falling in some particular catchment in Cumbria in August. If the events you are discussing are "dime a dozen" then by definition they have a low return period, and hence would not be considered extreme according to their return period. That is the point, the return period is self-calibrating to the distribution of events at the location in question. -
Tom Curtis at 00:38 AM on 4 July 20112010 - 2011: Earth's most extreme weather since 1816?
Norman @200:"On both links you posted, the 1 and 2 levels on the charts are not considered disasters. Loew & Wirtz call the first two "small and moderate loss events" the next four levels are various degrees of disaters. Munich Re lists the higher levels as catastrophes and not disasters but the meaning would be the same."
I wondered about that from the slides to which you linked, so I looked a bit further for clarification and found Löw and Wertz, who say:"The Munich Re global loss database NatCatSERVICE divides natural disasters into six damage categories based on their financial and human impact, from a natural event with very little economic impact to a great natural disaster (see Figures 3). The combination of the number of fatalities and/or the overall loss impact ensures that each event can be categorised with one or two of these criteria. The limits of overall losses are adjusted to take account of inflation, so it is possible to go back into the past if new sources are available."
(My emphasis) That wording strongly suggests that category 1 and 2 events are included in the database as natural disasters. That the events are described in a continuum of increasing severity reinforces that interpretation, with 1 (small scale loss event) and 2 (moderate loss event) being followed by 3 (severe disaster). If level 1 and 2 events are not included, we have to wonder why no minor or moderate disasters ever occur in the world. You also have to wonder why an event with 9 fatalities (level 2) is not worth calling a disaster. I know insurance agents are widely considered to be heartless, but that is going to far. If you disagree with that assessment, may I suggest you contact either Munich Re Geo or the NatCatService for clarification.
The map you looked at only shows the United States as having more than 650 natural disasters in the period 1980-2004. Chile is shown as having from 51 to 150, the second lowest category. The reason different countries have different numbers of natural disasters varies. The US has a large number in part because of Tornado Alley. Australia, in contrast, has relatively few (351 to 650) partly because it is so sparsely populated. In contrast, it is almost certain that Africa shows very few catastrophes (outside of South Africa) because of poor reporting. UN agencies, aid agencies and other NGO's only become involved in and report large natural disasters. Many African governments are dysfunctional, and western media ignore all but the largest catastrophes in Africa, and often ignore those as well. Wether they like it or not, this inevitably introduces a bias into Munich Re's figures for Africa and (probably) South America and former Soviet Block nations. Because of that bias, although I quote the headline trends for simplicity, I only employ trends that are reflected in North American and/or European figures where these selection biases do not apply. Indeed, because reporting from Africa and South America is so low, any distortion they introduce to the overall figures is slight. Consequently this bias is unlikely to distort trend data very much, but it does make international comparisons of limited value, and mean the total figures understate the true number of natural disasters significantly. Of more concern are China, SE Asia and former Soviet Block nations where there may be a significant trend in increased reporting over time. Again the figures are not large relative to the total trend, and none of these regions show an unusual trend when compared to Europe or North America, but it is something to be aware of. The important point,however, is that global trends are reflected in European and North American trends where these reporting issues are not a significant factor."I looked back at your post 116 on the thread "Linking Extreme Weather and Global Warming" where you posted the Munich Re Graph. I guess the graph shows about a 55%increase in 25 years in number of disasters (about 400 in 1980 to 900 in 2005, and annual rate of 2.2%) Here is a link on the yearly rise in home prices. National average was 2.3% but some areas were at 3% and more. A yearly rise of 2.3 in a home's value (not to mention the items in the house) will get you a 57.5% increase in value in 25 years. The value of property rose at a faster rate than the disaster rate. But the biggest thing is there incremental choices they picked for determining a disaster. From 1980 it was $25 million. In 1990 it was $40 million. In 2005 it was $50 million. The overall rate of determining a disater rose 50% in 25 year or at a rate of 2% a year. From 1990 to 2005 the rate of increase would only be 1.3% a year. The criteria to become a disaster was rising at a much slower rate than property values."
First, it is important to note that the categories are inflation adjusted. That is, the threshold levels are stated in inflation adjusted figures. The changing threshold is therefore only introduced to adjust for increased wealth in society. Second, adjustment is carried out be two methods, by fixed stepwise adjustment as reported by Löw and Wertz, or by linear interpolation as reported by Neumayer and Barthel. In the stepwise approach, the levels for a Major Catastrophe are $85 million from 1980-1989, $160 million form 1990-1999, and $200 million from 2000 to 2009. For linear interpolation the figures are linearly interpolated between $85 million in 1980 and $200 million in 2009. In the graphs contrasting all disasters with major disasters, it is the Neumayer and Barthel method that is used. The Munich Re graphs either show all disasters (category 1 to 6) of Devastating and Great Natural Catastrophes (category 5 and 6), or Great Natural Catastrophes (category 6). Both of the later have to few events for effective statistical analysis of any trend due to global warming. Using property prices as an index of overall wealth is probably as good as you'll get for a simple comparison. So, to see how the Neumayer and Barthel adjustment fared, I compared their interpolated threshold to an index based on an exponential 2.3% (average value) and 3% (high value). Of immediate interest is that 85*1.03^29 is 200, give or take, so the endpoints preserve there values to within 0.15%. This means the middle values would overstate the relevant threshold by up to 9.5% using the 3% inflator, thus understating the number of natural catastrophes. But, the average price rise was 2.3%, not 3%. Using the average price rise as the inflator, the 2009 threshold should be 165 million dollars, and the 2010 threshold should be 168 million. That is, using the average increase in US property prices, the Munich Re threshold overstate the threshold in later years by as much as 21.5%. The effect of this is that Munich Re would be understating the number of disasters in 2009 and 2010 relative to 1985. The rarety of these events, and the large variability of damage done means the understatement of the number of major disasters will not be anywhere near 20%, but it is an understatement, not an overstatement as you conjectured. -
Dikran Marsupial at 00:31 AM on 4 July 2011It hasn't warmed since 1998
Mark, note that some arguments are stronger than others, for instance the test used to detect the step change may still be reasonable, even if the noise is non-Gaussian, but in such circumstances it is up to the authors to convincingly demonstrate that it is O.K. (for instance by testing it using synthetic data where the noise is statistically similar to the real data). They would have to do more than just remove ENSO, even after that is done, a linear trend model over a complete century still isn't a reasonable model, given what we know about climate of the 20th century, so it would still be a straw man. If they wanted to demonstrate that there really was a step change in 1997 that was evidence against AGW, they would have to limit the analysis to the period where mainstream science actually says CO2 radiative forcing was dominant (e.g. approximately 1970 onwards). For any test, the null hypothesis ought not to be known to be false apriori. If they wanted to show it wasn't just ENSO they would also have to use data that had been adjusted for ENSO. As it is well known that ENSO affecte climate (especially Australian climate), showing ENSO is responsible is nothing new. If the want to say it is PDO, this is more of an oscillation that modulates ENSO, so a step change model isn't really appropriate anyway. I don't think there is evidence that the analysis isn't honest, just naive (from the climatology perspective) and lacking in self-skepticism. -
BBD at 00:23 AM on 4 July 2011A Detailed Look at Renewable Baseload Energy
Tom Curtis Just a general reflection: it would be constructive if you actually read my original posts here in full rather than creating an artificially distracting fuss about a couple of paragraphs. We could start with the various critiques of Jacobson & Delucchi's contentious claim that we can transition globally to 100% renewables. Funny how the critical response to J&D was greeted by absolute silence here. Especially since it is absolutely essential to any claim that renewables can significantly displace coal. -
Eric (skeptic) at 00:20 AM on 4 July 20112010 - 2011: Earth's most extreme weather since 1816?
Hi Dikran, the wikipedia article on return period does not offer any criteria on what is extreme. In fact it assumes that "extreme" or other threshold event has already been defined, then simply offers an estimation of likelihood in any year or years. One cannot assume the event is extreme just because the likelihood is low using that formula. There are a lot of factors that need to be considered, some of which I mentioned above, such as the event duration and areal extent. For example flash floods are much more common than river basin floods because the areal extent is smaller along with the event duration. My own location in Virginia is hilly enough to have flash floods mainly from training thunderstorms. The probability for any single location is low but much higher considering the large number of potential flash flood locations. Truly a dime a dozen. Meanwhile the major river that I live on shows no trend in extreme floods (1942 is the flood of record, see http://www.erh.noaa.gov/er/lwx/Historic_Events/va-floods.html) Tom, on your point 1, the fact that Munich Re defines tornado events in some arbitrary way does not invalidate my point about areal extent and event duration. On your point 2, the Moscow heat wave qualifies as extreme by my criteria and not just barely. However the blocking pattern that enabled the heat wave is a natural phenomenon and makes the probability of the extreme event higher. The mean and standard deviations of heat waves are higher in blocking patterns which makes extreme heat waves more likely. Independent of that, AGW makes extreme heat waves more likely. The Towoomba flash flood was indeed not extreme. The Brisbane flood had 1 in 2000 rainfall over a very small areal extent, not uncommon and not extreme. The more widespread rain was borderline extreme as you point out and fell on saturated ground. There were complications of measurement of river levels with damming in place. That damming may mask an extreme event by lowering levels downstream. Urban hydrology may exacerbate an event causing it to have river level extremes which would not have otherwise existed. Damages and economic losses were exacerbated by poor zoning. IMO the Brisbane flood was a somewhat borderline extreme weather event creating an extreme flood due to a variety of factors.
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