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stefaan at 18:14 PM on 28 June 2011Climate half-truths turn out to be whole lies
@Arka, don't forget that 1998 was a year with a very strong El Nino effect! Of course this has a strong effect on the temperature (thats why 2011 is up to today not an extremely hot year because we had still a moderate La Nina active untill may)... -
heystoopid at 18:10 PM on 28 June 2011Climate half-truths turn out to be whole lies
Excellent work, please don't forget to vote in the online poll too. -
Chemware at 18:09 PM on 28 June 2011Climate half-truths turn out to be whole lies
@1, Arkady: ... and while you are at it, do a line of best fit on the entire graph and tell us all the slope and intercept. For bonus points, include the standard deviation of the slope and intercept. -
Quartermain at 18:07 PM on 28 June 2011Climate half-truths turn out to be whole lies
Your article does not mention sunspots or other sun cycles. Sunspots have been at a record low. An interesting article would be on the effect of sun-related changes on the ionization of the upper atmosphere, and the resulting effect on global temperatures. After researching to write such an article, you may become sceptical too.Response: [JC] We've examined sunspots in much detail here at SkS. Eg - our page on solar activity and this recent post on low sunspots. -
Arkadiusz Semczyszak at 17:36 PM on 28 June 2011Climate half-truths turn out to be whole lies
"2005 and 2010 being the hottest years on record" - does not change the fact, that the differences between 1998, 2005, 2010 are very small - within the limits of "Standard of Deviations."Response:[DB] And yet they are STILL the hottest years on record, during a period in which the anthropogenic forcing have been the dominant attribution to the rise in global temperatures.
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Arkadiusz Semczyszak at 17:11 PM on 28 June 2011Uncertainty in Global Warming Science
I - like Cambrun - I agree that we now have a significant and rapid GW, that currently GW (and formerly) can not be explained by climate change without GHG's. Uncertainties the type "C", however, are very significant. These "uncertainties" in the "fitting curve" have the effect of significant errors in risk assessment and risk management. Camburn (synthesizing) mainly says: The main uncertainty concerns the natural influences on climate - especially the Sun. Practically same way - also - concludes NOAA:“ Our understanding of the indirect effects of changes in solar output and feedbacks in the climate system is minimal ” @KR If not Scafetta - may we quote - Beer et al., 2000., The role of the sun in climate forcing: “If one computes the global and annual mean of solar forcing caused by the 100 kyr period of eccentricity one gets an amplitude of in the spherical mean. This value is too small to be detected in climate records. But, despite the tiny global forcing value, we can observe the 100 kyr frequency during the last 800 kyr in most paleoclimatic records. The global mean temperature changes between glacial and interglacial periods are large: about 20C for polar (Johnsen et al., 1995) and 5 for tropical regions (Stute et al., 1995).” "0.12Wm ~ 2" - so would sometimes even multiply by 100 (!) - for the sum of direct and "indirect effects" influence of the Sun in palaeoclimate? Let us look at uncertainties based on an interesting example. The rotational motion of the earth. The authors of this figure: , on this basis - in this paper, write: “...the LOD [Length of Day] fluctuations are largely attributed to core-mantle interactions and that the SAT is strongly anticorrelated with the decadal LOD. It is shown here that 1) the correlation among these three quantities exists until 1930, at which time anthropogenic forcing becomes highly significant ...” All right ..., just that newer data (LOD) - from 198? year - are completely different from those shown on the aforementioned figure. If the author of the Wikipedia chart is right - that is, its graph - "curve" - is more "fit" - the true - is to "present day" - we have a (sometimes shifted in time - it's true) excellent correlation (ie anti-correlation ) - shorter day = higher temperature. What it can affect the climate? Earth rotating faster, the heat transport is closer to the poles (as in a glass - when we quickly mix tea ...), so the increase of CO2 added to the atmosphere with melted the "ancient" permafrost ... Kevin Trenberth ( More knowledge, less certainty, 2010.): „So here is my prediction: the uncertainty in AR5′s climate predictions and projections will be much greater than in previous IPCC reports ...” “But while our knowledge of certain factors does increase, so does our understanding of factors we previously did not account for or even recognize.” Sk.S. - skeptic, "denier", to the IPCC, and "mainstream" climate science? I think that - at least in some significant points type “C”- certainly yes. -
Dikran Marsupial at 17:00 PM on 28 June 2011Uncertainty in Global Warming Science
Ken Lambert Jut out of curiosity, is the "constant energy difference" idea based on the idea that you can regress global temperatures reasonably well as a function of integrated TSI? If so, it is well worth asking what is the physical mechanism that would mean that TSI affects the climate by long term integrated, rather than direct forcing? It is straightforward to construct accurate regression models by casting around to find variables that look correlated (or to manipulate them by e.g. integrating to make them look correlated). However this ends up over-fitting (you have as many degrees of freedom as the number of variables or manipulations of variables that you consider), which generally means the model has poor predictive value. As (effectively) a statistician, I can tell you there is no reason to be impressed by the fit of such models, unless physics suggests that form of model is justfiable. -
Dikran Marsupial at 16:48 PM on 28 June 2011Uncertainty in Global Warming Science
Ken Lambert It is fine to talk about the "radiative forcing side of the ledger" (except that CO2 also gives rise to radiative forcing), however if you only look at one forcing in isolation and ignore the feedback from that change in forcing (that would restore radiative equilibrium), then it is hard to see how any conclusion you might draw has any useful bearing on the discussion (as it would only apply to a planet with physics very different from that which applies on ours). "My point is that the TSI contribution is really unknown unless you know the 'equilibrium' TSI which will produce neither warming not cooling in the absence of all the other AG forcings." This point is incorrect as forcings are defined as a change from pre-industial levels. Satelite data gives higher precision estimates of TSI, that doesn't mean we don't know anything abou TSI prior to the satelite record. -
KR at 13:56 PM on 28 June 2011Uncertainty in Global Warming Science
Ken Lambert - I have responded on the far more appropriate It's the sun thread. Now, can we get back to the uncertainty discussion? -
KR at 13:54 PM on 28 June 2011It's the sun
Ken Lambert - If you are talking about forcing imbalances, then statements such as "If TSI is above an 'equilibrium' value and stays constant -there is a constant imbalance in forcing which translates to a linearly increasing gain in energy..." are completely unwarranted, as you should well understand. The climate will respond by warming due to increased energy in the system, and reduce the imbalance due to increased TOA radiation. The "constant imbalance" phrase is one you have repeated several times in this context - it's been wrong every time before, and it is wrong now, as it implies a constantly increasing TSI - which is not the case. "My point is that the TSI contribution is really unknown unless you know the 'equilibrium' TSI which will produce neither warming not cooling in the absence of all the other AG forcings." There is no such thing as an "absence of all other AG forcings". The climate is the sum result of all the forcings and feedbacks. Climate change is the result of changes in one or more forcings. TSI has changed very little over the past century, where we've seen the most warming, and the 'equilibrium TSI' would have been long since reached at some equilibrium in the absence of other changes. In particular, there has been essentially no change in TSI since 1980. "E pur si muove" - and yet it moves! Essentially, you seem to be looking for a unique equilibrium, when any fixed forcing will reach an equilibrium tied to that forcing. Climate changes from that point are due to changes in forcing, and we have an excellent track of what the TSI changes are - negligible. The observed climate change is therefore primarily due to the greater than exponential increase in CO2, hence a greater than linear forcing change. -
Bob Lacatena at 13:52 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
71, Camburn, I fear that I agree that the effectiveness of the dams may be lost... around the world. Very many dams were built with an entirely different climate in mind, and will be overwhelmed. Maybe not today or tomorrow with any regularity, but it's inevitable, and sad. But for some people, until we can statistically prove that 95% of all pre-2000 dams are now worthless, they won't admit that climate change is a problem. -
Camburn at 13:51 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Must have done something wrong. Here is the link about the Missouri River http://www.capjournal.com/articles/2011/06/27/opinions/columnist/doc4e07cf2e2ec3a824492051.txt -
Camburn at 13:46 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Actually thoughtful: I spose I could dig up all the pertinent information with links etc but that is a huge task. I do know that in April and early to mid may, the discharge from Garrison was less than minor flood stage in Bismarck. I do know that NOAA has long range forcasts that showed above average precip. I do know the state has been asking the corp to release more water from Garrison for over 6 months so that the flow could be better regulated when the snow pack started melting. This article sums up the Missouri River flood. I fear that the effectiveness of the dams may be lost. Current state of Missouri -
Tom Curtis at 13:37 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Two comments on Norman's list: First, the author of the website made his list for the 19th century and earlier by taking a list of events made from examining logs of ships in ENSO effected areas around the globe, and then adding in other events as derived from other proxies. The risk of double counting with such a procedure is large. Second, the websites claims about 20th century El Ninos should be checked against the ENSO Southern Oscillation Index:
Clearly the website he is relying on has very dubious information.
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actually thoughtful at 13:36 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
windbarb - thank you for clarifying some of the jargon. I see that the Lorenz of ensemble results is the same Lorenz of butterfly chaos theory (indeed that the latter suggests/requires the former) - that just makes me happy. Maybe the default of La Nina conditions is why CFS went with La Nina in the fall, even though most models disagree? -
actually thoughtful at 13:31 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Camburn - do you have facts (not anctedotes) to back up your claim that the Mississippi flooding is manmade? This has been a slow moving tragedy - it is hard to imagine those dams haven't been wide open for quite some time. Can you show reservoir levels for each year in April, for example, and show that they have been filling for 19 years (1992 Clinton was a new President - long time ago). Can you show that dam managers didn't follow best practices to manage/mitigate the flood situation? It really is a strong charge that these floods were manmade - other than in the broad sense that dams exist (or if you want to pin it on AGW) - but even that you would have to show it would have been better with no dams - which is not an obvious outcome. Or that the probability of this event WITHOUT AGW is less than 20% (a standard I just made up...). On a broader scale I think that is the problem. Dr. Masters has pointed out that all the things we are seeing are precisely what climate scientists are predicting, but to claim that it is caused by AGW (in a chaotic weather system (paging Dr. Lorenz)) you would need to establish a statistical likelihood without AGW, and then see a trend (more than one year) that demonstrated you were seeing those weather events well beyond the statistical likelihood. I think Dr. Masters did it for one year - but too soon to be able to scientifically make that claim (I think). I do think 2010 was a watershed year (pun intended) wherein we went from "we should see x because of AGW" to "we are seeing x because of AGW" - I personally have a lot less patience for those who claim it isn't happening, given the overwhelming evidence even the common person can observe. -
Rob Painting at 13:27 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Windbarb @ 65 - Yeah, I think the impact of the change in the background state is completely overlooked by many bloggers. As you point out that in itself will have a noticeable impact, particularly its effect on drought in the Amazon-should an El Nino-like state emerge. -
actually thoughtful at 13:20 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Norman, You ignore the 50% increase in the current decade. That could be an artifact, or it could be that some tipping point has been exceeded, thus switching us to a busier ENSO cycle. Also, I find your counting of cycles to be fairly unsatisfying. Even myself, not trained in this area, am asking basic questions you apparently have not thought about: 1) How long was each event in each decade? 2) How strong was each event in each decade? You might be exactly right, or you might be confusing number of events with duration and intensity - the point is your analysis leaves us with more questions than answers. I can't imagine drawing any conclusions from the sparse data you have presented (and as I recall, when I last checked your data I found it was off by at least 50%). I haven't checked your data yet as you are missing so much at the logical level it doesn't seem warranted yet. -
windbarb at 13:17 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Rob @60, yes, thank you for catching me there. Future ENSO events will occur on top of a background state that may look more like a modern El Nino or La Nina. The resulting impact to weather patterns around the globe, though, is likely to reflect the tendencies of whichever background state the SSTs do approach... thus impacting extreme weather events. In other words, if the future background state looks similar to current La Nina SST patterns, the impact on the storm track is likely to be similar, meaning that areas favored for (say) higher than usual tornado activity during/following a La Nina might trend in that direction in a climate changed world, too. -
Ken Lambert at 13:14 PM on 28 June 2011Uncertainty in Global Warming Science
Sphaerica, KR, DM I was only discussing the radiative forcing side of the ledger, and from TSI only. For sure S-B and other feedbacks (WV & Ice Albedo) will increase the outgoing 'climate response' side of the ledger to bring about a new equilibrium at a higher temperature. I have mentioned this elsewhere many times. For sure you cannot measure individually the radiative forcings in the climate system as listed in Fig 2.4 of AR4. They are modelled and theoretical individual warming and cooling forcings which add up to a total of about +1.6W/sq.m. My point is that the TSI contribution is really unknown unless you know the 'equilibrium' TSI which will produce neither warming not cooling in the absence of all the other AG forcings. Looking at the 'differences' in TSI which can be done with 'high precision' satellite measurement is only relevant if you know the 'equilibrium TSI'. -
Camburn at 13:13 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Tom: Look a little closer please. Right now, the discharge rate from Garrison is 150,000CFS+. The inflow is less. The reason for the 150,000CFS+ is that there was danger of going over the emergency spillway and potentially dam failure. With the increased flow, the positive is that the river is cleaning itself back to historical depths. I am not slandering anyone. There has been a fight for years on the level of Garrison. -
Camburn at 13:06 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Tom@57....thanks. -
Tom Curtis at 13:06 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Camburn @53, the same accusations were falsely made regarding the Brisbane flood. Unless the discharge from the dams exceeded the inflow for significant periods, then it is certain that the floods would have been worse without the dams. That does not mean the floods could not have been mitigated better, but that is quite different from saying they are man made. I have looked at the dam levels for the relevant dams and they are quite constant over the period making it very unlikely that they have discharged more than their inflows. Therefore, in the absence of significant evidence, you should probably stop your slanders. -
Camburn at 13:03 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
adelady@54: This year we have a La Nina, which as a rule increases our snow/rain. The previous 8 years have not been as wet as this year. It took 6 years to refill the dams. This year we are wet because we went into last fall saturated.....La Nina again. That link I posted from NOAA shows the area of the USA that gets above normal precip. A large part of that area is the Missouri River Basin. Anyways, it was a fight between the corp and the fish and wildlife folks. Not a happy ending. -
Rob Painting at 13:02 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Windbarb - "Some GCMs indicate that in a warmer climate, ENSO could look more "La Nina-like", while others look more "El Nino-like" This misconception continues to pop up, I notice in the scientific literature even climate scientists get confused on the topic. The 'El Nino- like' or 'La Nina-like' simply describes a change to the background state. That is: either the Central and Eastern tropical Pacific warm more the the Western Pacific (El Nino-like), or the Eastern and Central tropical Pacific are cooler than the Western tropical Pacific (La Nina-like). It is a separate issue (but of course related) to the evolution of ENSO events. -
Tom Curtis at 13:01 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Bern @49, to make matters worse, the "unaltered river basins" include among their number that pristine environment, the Thames river valley. By unaltered, they mean un-dammed, and the study takes no account of, and makes no adjustment for any loss of water for irrigation, or urban and/or industrial use. -
Norman at 12:52 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
actually thoughtful @50 I did break down the 20th Century to see if there was a signal from warming. From the Jeff Masters article above he states that the Earth has warmed 0.5 C since the 1970's. With this in mind I will break up the 20th century data. Same link as earlier for reference. El Nino events in 20th Century broken down by decade. 1900-1910 2 1911-1920 3 1921-1930 3 1931-1940 2 1941-1950 1 1951-1960 3 1961-1970 2 1971-1980 2 1981-1990 2 1991-2000 3 From this breakdown it is hard to see how the 0.5C increase in Global Temps since the 1970's is causing a noticeable increase in the frequency of El Nino events. -
Tom Curtis at 12:52 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Camburn @42, here Norman @46, I cited five peer reviewed papers, but you dispute that because you can cite a web page? Seriously? -
actually thoughtful at 12:48 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Based on Bern #49 - advice for all my Canadian friends DO NOT buy a mobile home! These things are proven to attract tornadoes. Indeed there is strong evidence that the extreme tornado season has more to do with the sale of mobile homes in the Southern USA than ANYTHING to do with AGW http://www.drroyspencer.com/category/blogarticle/page/2/ Heh - probably the only time I will be referencing Dr. Roy Spencer - unless to question his results.... -
Tom Curtis at 12:40 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Norman @39, from Neumayer and Barthel, 2011:
Note, a Major disaster is a disaster in which 100 or more people died, or in which there was a certain, time adjusted value of damage done.
So Norman, is that the information you wanted me to get from that paper? Or did you just want me to cherry pick the data on their normalized damages (which is down by their method of normalizing, but up by the more standard measure)?
In the paper Neumayer and Barthel address the key issue of whether the decline in normalized losses (by their method) is due to a decrease in damaging potential of disasters, or to improved methods of mitigating:
"One of the problems with normalizing damage from natural disasters, independently of the method chosen, is our inability to take into account defensive mitigating measures, which rational individuals would undertake in response to an increasing frequency and/or intensity of natural hazards. An increase in such measures could prevent an increasing trend in natural disaster loss that would otherwise occur in the absence of such measures and could thus prevent detection of a potential climate change signal in the data. For example, flood defence measures in Western Europe have dramatically reduced the risk of flood damages from winter storms (e.g., Lavery and Donovan (2005) on the River Thames tidal defences or Ronde et al. (2003) on flood defence development in the Netherlands), while stricter building codes introduced in parts of coastal Florida from the mid-1990s onwards have significantly reduced hurricane damage from Hurricane Charley in 2004 (Institute for Business and Home Safety 2008). Our findings of a downward trend in natural disaster loss with the alternative method for all natural disasters and for all non-geophysical disasters at the global level could be driven by such measures. Splitting up the sample into developed versus developing countries, we find a strong and more clearly statistically significant downward trend for developed countries, but no trend whatsoever for developing countries. This would also be consistent with increased defensive mitigating measures since developed countries are much better able to fund such measures than developing countries. To be sure, increased mitigating measures are only one possible explanation for the findings, but not the only one."
(My emphasis) They discuss this issue at length, and show (charts given above) that geophysical disasters have increased slightly over a thirty year period, but that weather related disasters have increased substantially. They then discuss the possibility that this is just due to increased reporting. They show that the significantly greater increase of weather related disasters persists if you only look at major disasters, that would not be under reported in the past. They also point out that even in densely inhabited nations like Germany, where no previously uninhabited areas have become inhabited over the past thirty years, the same pattern exists. They conclude:"Independently of the reason behind the strong increase in the frequency count of weather-related disasters over our period of analysis, how can this be reconciled with our finding of no upward trend in normalized damage from natural disasters? There are three possibilities. First, there could be an opposite reporting bias in terms of damage caused such that economic loss is over-estimated in the early years of our study period and under-estimated in the later years. Second, weather-related natural disasters could have become less intensive over time. Third, weather-related natural disasters have not become less intensive, but defensive mitigating measures have prevented increasingly frequent weather-related natural disasters from causing an upward trend in normalized natural disaster loss. Since there is little reason to presume that loss has been systematically over-estimated in the past or that weather related natural disasters have become less intensive, the third explanation presents a distinct possibility."
I consider the last sentence a significant under statement. There is a significant irony in your pointing to this paper. You have argued that Munich Re data should be ignored because it measures disasters (damaging events) rather than hazards (potentially damaging events). Now you look at a paper and cherry pick the damage done as being significant, while ignoring the clear evidence on the number of events, and that the increase in damaging events is correlated with an increase in hazards. And you now accept a study financed by, and using data from Munich Re because you think it supports your case. Your selective standards could not be more openly displayed. -
adelady at 12:32 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
camburn "There is a natural wet dry cycle in this part of North America. We are now in the wet cycle, and have been since approx 1992. ... During the dry cycle the dams were low on water and the Fish and Wildlife were screaming ... and the dams were refilled with no room for flood mitigation. All last winter and spring the dams have been releasing minimal amounts of water. ...this spring the dams were full." Since 1992? How come the flooding wasn't so extensive during the previous 8 years of the 'wet cycle'? -
Camburn at 12:25 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
adelady@46: I am not familiar with all the dynamics of Aussie flooding, so can't comment on them. AS far as USA flooding: 1. The flood on the Mississippi this spring did not exceed the flood of 1927, if memory serves me. 2. The flood on the Missouri River basin has two causes: a. There is a natural wet dry cycle in this part of North America. We are now in the wet cycle, and have been since approx 1992. b. Extremely poor management of the Missouri River dams. During the dry cycle the dams were low on water and the Fish and Wildlife were screaming to decrease the discharge rates. Well, they got their way and the damn were refilled with no room for flood mitigation. All last winter and spring the dams have been releasing minimal amounts of water. So when the rain, enhanced by La Nina in this area, came this spring the dams were full. When the snow pack started melting, the discharge rate had to be increased to a very high level. Without the damn, the flooding would have been minimal. The same applies to the Mouse River. The floods on the Missouri and Mouse are man made. -
windbarb at 12:23 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Eric @ 37 and 47, The answer is both. Some of the SST forecasts are produced by GCMs and others are shorter-range dynamical models (or statistical models, which don't replicate the atmosphere like a GCM does). GCMs are still not handling ENSO well, and that includes both amplitude and phase. Some GCMs indicate that in a warmer climate, ENSO could look more "La Nina-like", while others look more "El Nino-like". I don't have a specific reference handy, unfortunately, but I did listen to a lecture by Michael Mann just this spring, and he was inclined to think the La Nina-like solutions might be more favored. Until the models get better at resolving ENSO events in climate simulations, though, much of this is scientific speculation and very early hypothesis generation! Regarding model resolution of the steepness of the curve in early vs later runs, I actually don't have a good answer for you, but that is a very good question. Again, hope this has helped! -
windbarb at 12:16 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
actually thoughtful @ 22, A deterministic solution is one answer to a question, even though producing one answer might not be the best science. A good example is a forecast of temperature for 7 days from now. I can tell you that our forecast is 90F, which is a deterministic forecast. A deterministic model produces one solution. An ensemble produces multiple solutions by varying one of two things, either the initial conditions or the model physics. It allows a forecaster (weather or climate) to quantify the uncertainty in the forecast by looking at the range of solutions created by very small changes. Ed Lorenz is the grandfather of the ensemble idea courtesy of his "Deterministic Nonperiodic Flow" paper (http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469%281963%29020%3C0130%3ADNF%3E2.0.CO%3B2). CPC relies on not just their own CFS model, but the whole suite of model solutions seen in the IRI chart. By that chart, the majority of models indicate a neutral phase, with a few outliers (CFS included) in either direction. Their weekly and monthly summaries do follow a template, but I agree that they don't discuss the envelope of solutions as thoroughly as they could. -
actually thoughtful at 12:15 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Norman without looking at your source for veracity - 4 so far this century, extrapolated, would be 36 this century - or a 50% increase over last century. So even your own data support Tom Curtis's point. I can't speak as to whether your data is accurate or not, just that it supports the point that more heat will lead to more frequent El Ninos and La Ninas. -
Bern at 12:14 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Norman, to take the key sentence from Pielke Jr's response, he looks at "tornadoes, large-scale river floods (in unaltered river basins), and landfalling hurricanes" to make his assertion. That seems to be a nicely cherry-picked selection of criteria. Let me offer my opinions: Tornadogenesis is a very difficult question at the best of times. But it seems obvious from my reading on the subject that it requires severe thunderstorms in combination with strong wind-shear aloft to induce rotation, forming supercells. Well, the Gulf of Mexico had abnormally high sea surface temperatures this northern Spring. Combine that with higher moisture content due to a warmer atmosphere, and you've got the ingredients you need for a lot of very strong thunderstorms. So there may be a link (though tenuous, yet) between global warming and tornados. I understand the jet-stream (which causes the high altitude wind-shear) is predicted to move further north as the planet warms further, so perhaps we might see a long-term downward trend in tornados, despite the increased thunderstorms. Then again, maybe they'll just move further north, and the Canadians will get hammered instead of folks in the US central plains. Secondly, 'unaltered river basins' would restrict you to a very small subset of the world's major rivers... and that qualification seems designed to exclude pretty much every major river basin in the US, as they've all been altered. A convenient way to 'exclude' the record flooding in the Tennessee, Ohio, Mississippi, and Missouri basins over the past 12 months or so. Also the Indus river in Pakistan (which displaced 20 million people when it flooded last year), and the major flooding experienced here in Australia over last summer. And restricting hurricanes to land-falling only allows him to discount the 2010 Atlantic hurricane season, which was the second most active on record, despite almost no storms affecting the US. A pretty bunch of cherries, indeed... -
adelady at 12:11 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
norman - first things first. That 4% increase is averaged over the whole atmosphere. The average automatically requires that in some places at some times, there will be much more than 4% increase and in others a decrease. Once we take that into account, it's much easier to see why there are more floods caused by unusually intense deluges - Pakistan, Colombia and Toowoomba being the classic examples, and others in the USA. The increased average moisture just means that the expected drought/flood variations around the world become more exaggerated. Australia and the USA provide the obvious examples of extensive flooding in some regions matched by equally intense drought and wildfire in others. Queensland and Victoria flooding while Perth is on fire, Missouri and Mississipi rivers flooding huge areas while parched Texas and Arizona burn. -
Eric (skeptic) at 12:11 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
windbarb, if you have a chance, I would like add ENSO frequency to my question. I noticed that the ensemble members that are steepest are usually labeled "latest" forecast members and the less steep ones are labeled "earliest" (at least that is the case now during a forecasted transition back to La Nina). But in earlier forecasts this year the blue and red members were more evenly distributed (+/-), was that just because it was early season forecast (and less reliable)? Is there some indication from these models that inflection points are more closely spaced and/or slopes are steeper? -
Norman at 12:06 PM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Tom Curtis @40 "You have been presented evidence that warm conditions result in more frequent El Nino or La Nina states (ie, fewer years of neutral ENSO states), and in more intense El Nino and La Nina's, both of which would result in more and more intense weather extremes." You have presented this but at the same time I find information that does not support this. El Nino events: 16th Century: 17 17th Century: 21 18th Century: 28 19th Century: 30 20th Century: 24 21th Century: 4 so far Link to source of information Historical El Nino's. -
actually thoughtful at 11:46 AM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Camburn read the ENSO report you linked earlier in this thread. It answers your question in 42 -
Norman at 11:45 AM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
adelady @ 38 Why would a 4% increase in atmospheric moisture lead to several % increase in precipitation (that is why I ask for mechanisms). Extreme weather events seem to be caused by storms stalling or tracking over the same area. And it seems it has happened forever. Drought and flood cycle is a yearly event somewhere. Some places get much below their normal moisture and others get much above. What is global warming doing to the forces that cause drought and flood to increase? Here is a link from climate scientists who were asked the very same question being discussed here. Climate scientists debate the issue. If you read Roger A. Pielke Jr's response to the question you will see what my current position is and why I am questioning Skeptical Scientists posts on the issue. -
actually thoughtful at 11:42 AM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Camburn your link at 35 demonstrates the what - El Nino an a negative NAO. You would do well to think about the "why" of those two events. There isn't any claim that weird weather hasn't happened in the past. The claim is that there is more weird weather now, and it is intensifying. It is an interesting link, but I left it feeling very unsatisfied that they didn't dig into the why. -
Camburn at 11:42 AM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Tom: What evidence do you have that Enso has increased numerically? -
Camburn at 11:38 AM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
adelady: Please cite literature for that 4% increase in moisture. -
Tom Curtis at 11:37 AM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Norman @34, your original statement was:" Basically the Munch Re report can not be used to determine the frequency of extreme weather events (hazards). An EF5 tornado is only a hazard in a field with no people present. It is recorded as a disaster when it strikes a populated area. Disasters are increasing but not enough data is available to determine if hazards are increasing."
(My emphasis) Despite your obvious awareness of the distinction between "hazards" and "disasters", in 23 above you dispute Master's observations about the number of hazards solely on the basis of evidence relating to, not even the number, but just the scale of the disasters. So strong do you believe this evidence of the scale of disasters in the United States over part of the period of discussion, you consider it not only grounds to dismiss Master's observations about the number of hazards globally over a longer period, but sufficient grounds for accusations of fraud and dishonesty. In other words, what counts as a reason to believe something completely reverses for you, depending on what it will require you to believe. This has been evident before. Shen presented with evidence showing the danger of AGW you strain at gnats in your critical analysis, going so far as to quote the sexual scandal in a subsidiary of Munich Re as a reason to believe Munich Re's reported statistics on natural disasters are falsified. In contrast, when presented with evidence purporting to show the opposite, even evidence which has been refuted, you show no critical analysis. Instead you just thank the denier for the information, or just accept it as something that needs to be disproved. Your pose is well and truly exposed by your hypocritical response to Master's post. Finally, a denier is somebody who refuses to accept evidence that AGW is real and/or sufficiently dangerous to warrant taking effective action against it. You have been presented evidence that the number of weather related disasters is increasing faster than can be accounted for without reference to global warming. You have been presented evidence that warm conditions result in more frequent El Nino or La Nina states (ie, fewer years of neutral ENSO states), and in more intense El Nino and La Nina's, both of which would result in more and more intense weather extremes. You have been presented evidence of increased strengths of convective events, of increase water in the hydrological cycle due to the straightforward correlation between increased surface temperatures and increased evaporation. None of this is enough for you. Given the fact that evidence of a low number of disasters over 2% of the Earth's surface over twelve months is sufficient evidence for you to suggest fraud in somebody claiming a high frequency of hazards over the entire globe over eighteen months, clearly your failure to be convinced is not due to your high evidentiary standards. -
Norman at 11:31 AM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
This report is for you Tom Curtis. Global Environmental Change. -
adelady at 11:17 AM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Norman "It will cause some warming of the Globe. ... as well as wanting some mechanisms to explain why warming is causing the extremes." Just checking before going further with this. When you accept the science of 'warming', do you accept that a warmer atmosphere holds more moisture? Given that, do you accept the commonly cited figure of 4% more moisture related to the measured warming so far? More moisture requires more precipitation - sometime, somewhere. Would taking that into account go any distance as an explanation of 'warming causing the extremes' for you? -
Eric (skeptic) at 11:14 AM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
windbarb, thanks for the answers. I have a more general question, are these ENSO prediction models similar to or different from the GCMs for long term climate prediction? It seems to me that the main difference is the availability of detailed initial conditions for ENSO prediction. We had a discussion on another thread on whether ENSO was becoming more extreme (in amplitude). Do the models yield any insight on possible trends? -
Camburn at 11:13 AM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
Ooops......2009-2010 snows etc. -
Camburn at 11:09 AM on 28 June 20112010 - 2011: Earth's most extreme weather since 1816?
The snows, temp etc of the 2010-2011 winter in the US were not a result of AGW. This is what NOAA has found: NOAA climate slueths
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