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Discussion in 'Environmental Discussion' started by Rybold, Nov 3, 2011.
APNewsbreak: Panel says wild weather worsens
Only the most reality challenged denier could possibly think otherwise!
(or current republican presidential candidates!)
There is a nice, clear discussion of the Russian heat wave analysis, by one of the authors of the paper, on Realclimate:
RealClimate: The Moscow Warming Hole
On one level, it's exactly what you'd think: Add a trend to natural variability and you set new records in the direction of the trend. The only thing that makes this confusing is that different trends apply to different parts of the world. And when you say "snow" people forget that means record precipitation, not record temperature.
They also did a nice explanation, some time back, of the simple statistics of record-setting events, for the simplest case (the assumption that whatever you are looking at is a stationary time series of random draws from a single underlying distribution).
RealClimate: On record-breaking events
...and the countdown starts... 3..2..1.. mojo?? AG?
who is gonna be first?
It seems like a hand waving explanation on why they rejected Dole, which is the current peer reviewed literature on the Russian heat wave.
At best we have two competing theories about the Russian heat wave. One seems to be born out of the IPCC mainly because it previously had stated more extreme weather, but has constantly failed to predict and define what this is. Without predictions any "bad" weather can be used. One fact agreed upon is more people are living where extreme weather is likely to occur and dollar losses will increase.
If the IPCC is to reject Dole, I would hope it would not be on political grounds, and it would find problems in the paper that have better explanations in this one. The we have a nobel prize excuse was used when arguing for much faster melting of glaciers based on other non-peer reviewed advocacy literature that turned out to be false.
There is a nice, clear discussion of the Russian heat wave analysis, by one of the authors of the paper, on Realclimate:
RealClimate: The Moscow Warming Hole
... explaining a fairly critical thing that Dole et al. did wrong, and why this more recent peer-reviewed publication is more likely to have gotten the (completely different) analysis right. Dole et al. found no association, in part because they found no summertime warming (hence "Warming Hole"), because they screwed up the urban heat island adjustment, applying the annual average adjustment to July data, thereby incorrectly finding no warming in July in Moscow. No hand waving needed.
And, of course, to state the obvious, it's not as if the entire conclusion of higher likelihood of more extreme events depends solely on analysis of one event in Russia. That would be like appealing to the peer-reviewed literature by focusing on just one paper.
That said, as an aside, for that one particular paper, it is worth noting that, despite their conclusion about this single event, Dole et al.'s analysis also concluded that the likelihood of such heat waves in that region will increase over the next century, as cited in the NOAA press release:
" Climate models evaluated for the new study show a rapidly increasing risk of such heat waves in western Russia, from less than one percent in 2010, to 10 percent or more by the end of this century."
So there appears to be no strong disagreement, based on that research, about global warming leading to increased likelihood of extreme heat events in that region. The disagreement appears to be limited to whether you need to use future tense (will) or current tense (has). Whether we have some evidence now, or merely expect it to happen later, based on the same models used to analyze the current event.
Nor is this even a novel thought, but instead, is one for which the evidence has been building steadily, and which the IPCC addressed in its last report, summary here:
I think I'm agreeing with Icarus on this one. At least in so far as a warmer earth bringing higher likelihood of more extreme high temperatures.
Huge hand waving being done here. We know that there is an urban heat island effect in Moscow. The authors state that it is overstated for July. Good enough, but then they don't try to make better adjustments, they change time periods and use other numbers that are equally if not more suspect. Finally they use the anomoly in their trend line. They do not explore at all the blocking event that Dole and his team attributed. They do not explain how none of the large number of IPCC climate models not only fail to predict this event, but do not have ghg causing a blocking event as happened. In order to do more than hand waving they need to explain how ghg caused this blocking or find a problem with the blocking explanation for the heat wave.
I was only criticising the part of the argument that I saw. The russian heat wave seemed the main focus of your real climate article.
Higher highs is an obvious prediction as well as more damage on low lying coasts. More extreme weather though is vague, and I would say I have not seen compelling evidence when it comes to hurricanes, tornadoes, or the Russian heat wave. In fact the evidence seems to point more forwards climate variability. OF course you agree with icarus
so you find this "hand waving"?
I offered the article as a nice, accessible illustration. Which it is. I don't think I said that was the only or even the most important aspect of this.
The Realclimate article is about the author of a new study explaining what he did, in his new study. It is not a post dedicated to taking apart and re-assembling the Dole study. Instead, the author of this new study, in the course of explaining what he did in this new study, was merely burdened to point out this new study disagrees with the Dole et al study. That is, he is properly paying attention to prior published work. He is not trying to replicate what Dole et al. did.
Just read what he writes.
"The main argument why Dole et al. conclude that climatic warming played no role in the Moscow heat record is because they found that there is no warming trend in July in Moscow. They speak of a “warming hole” in that region, and show this in Fig. 1 of their paper. Indeed, the linear July trend since 1880 in the Moscow area in their Figure is even slightly negative. In contrast, we find a strong warming trend. How come?"
He then goes on to show that, while there is an urban heat island effect in Moscow, it is confined almost entirely to the winter months. So that taking the winter urban heat effect, and subtracting it from summer temperatures, gives you the wrong adjusted trend. Just-plain-wrong.
It's really not rocket science. And that explanation seems to hold water to me. If Dole et. al found no warming, it would seem fairly difficult to demonstrate that warming added to the likelihood of the heat wave. Perhaps they have a point regarding blocking, whatever that is. But for sure, if you estimate no warming, it would be hard to attribute an increased likelihood of heat waves to warming.
If you somehow know this is wrong, then point me your source of information. Otherwise, my option is to take the author of this new study at his word, that he is correctly characterizing the research. The other authors of the Dole paper are already posting their re-analyses, as here. I have no clue whether this addresses the basic point about the adjustment that Rahmstorf raised on Realclimate.
Did he then go on to replicate the Dole piece? No, of course not. The point of this post is to explain his own research. Replicating Dole would be an entirely new piece of research. Dole made numerous runs of general circulation models to get his result, so replicating Dole would be a non-trivial task. The proper person to modify and replicate Dole's analysis would be Dole.
And, I guess I'll say it again: There appears to be no fundamental disagreement about the trajectory, only whether it is already happening or merely is likely to happen in the future.
I'm perplexed that this thread has been up nearly twelve hours without a single unsubstantiated knee-jerk "nu-uh" post.
My criticism is that this is not the Dole team's only or even main argument. The previous research looked at CO2, climate models, sea ice, etc as well as past anomalies. In order to characterize these extreme weather events as mainly caused by ghg, climate variability needs to be taken into account. The previous paper did not rule out any contribution of ghg warming, but concluded it was small compared to the effects of blocking, and that current models do not show ghg causing the blocking.
This seems like an interesting avenue to do better adjustments for urban heat island effect and use some of roy specer's satellite work to check the work. I would not say using GISS data is just-plain-wrong though. If you read the conclusions of the link you provided bellow, you will see in the same long time period western russia and moscow have not been appreciably warming.
The dole team did account for warming, sea ice, and ghg. They simply used the giss figures though. I would be interested to see if adjustments to these figures are made whehter the origingal team would change their conclusions.
I think peer review is the key here. I would wait for this pnas piece to be reviewed. It definitely does not overwelm the prevous research. There may very well be disagreements, but the russian heat wave seemed to be much hotter and longer than simple ghg warming would account for. I do not want you to reject the pnas reasearch out of hand, it may be interesting. I just am very sceptical of this one piece of using monte carlo simulation to attribute causation but not looking at blocking patterns. I hope that models will be able to incoroporate ghg and ENSO, PDO, and blocking patterns. Until then I will stick to the idea that individual non predictable events are not proof of or against warming caused extreme climate change.
Well yes, I would think he would give his criticism to dole and see if it affects the results. He did ask dole if he used adjustments for urban heat island. If you are going to use pure statistics to generate the probability of a past event and ignore other explanations of that event, it does not pass my test for scientific evidence. Once the statements have had a chance to be reviewed I'll withdraw or strengthen my criticism.
Ive lost a lot of respect for the Nobel Prize lately.
My view hasnt changed since the last weird weather discussion.
PIERS CORBYN accurately predicted the Halloween snow one month in advance.
Anyone predicting heavy snow in Oct must either be nuts or must truly understand the mechanism that causes weather and climate.
Its not CO2 or global warming,its the Sun and moons influence on the Earths magnetic field.
Piers Corbyn also predicted hurricane Irene 85 days in advance .He also predicted the plethora of volcanic and seismic activity last month between Oct 15-28 .
Piers Corbyns science is validated by observation,
AGW theory is never validated because its never correct.
Yes. See my reply above. It is addressed by the link chogan2 included
Scientific Assessment of 2010 Western Russian Heatwave - Additional Information
Most of the preliminary report seems reasonable, in fact more reasonable that previous assertions by the IPCC. I liked these parts
Didn't take long for t he Corbyn reference,,,
Could you please provide data to support you comment? Perhaps a statistical representation and histogram of goofball comments versus serious comments versus technical comments during the first twelve hours of a post, throughout the history of PriusChat, since it's origins. Please include a trend line and standard deviations, and submit your data on this thread for peer review.
Otherwise, I see no basis for you being perplexed.
I wouldnt have bothered if he hadnt made some recent phenomenal predictions.
Well, this is getting kind of over-the-top. Sometimes a picture is worth 1000 words.
See how the curve turns up at the end? The essence of Rahmstorf's analsysis is that, absent that upturn, you were far less likely to see a new all-time-high temperature. It's not really hard. The hard part was quantifying that in some accurate fashion. By contrast, if you fit a linear trend for the entire period, you'd be blind to the 1930s and 2000's upturns. The red dots are new highs, the blue dot are new lows. It may also be worth saying that, in so far as the abstract goes, the Rahmstorf paper says nothing about the causes of the warming. On the face of it, it is merely making the point that, if there is a warming trend, then new highs become more likely. That's why I think I agree with the original "duh" comment. All the science was in quantifying how much more likely, given the actual temperature timeseries.
There are 3 related essays just published that relate to this subject, and they are open access
The human cause of climate change: Where does the burden of proof lie?
Click after the doi's at the bottom.
We can at least know better what some practioners think about attribution. Of course the matter is under discussion at RealClimate and Climate etc. (just to name two)
FWIW, given Corbyn's successes (announced here) it seems surprising that he is not mentioned at Climate Etc., even among the audience comments. They don't know his work? The soup is too thin? Of course there are other hypotheses. Never a shortage of those.
IMHO if you have the null hypothesis that anything bad is caused by warming then you will have that duh moment. I would prefer using scientific evidence, and have a rather higher bar than most here, but that is fine.
I have not read the pnas paper, and do not feel qualified to fully evaluate it even if I had. I'll leave you with these comments about the graph
1) When doing proper data analysis of a predictive region, that region should not be used. The graph line is obviously using the 2010 data to evaluate the causation of the 2010 data. I am unsure how much the analysis will change when this is removed.
2) From your other link of the NOAA preliminary 2010 ongoing assessment of the russian heat wave it appears that there is less or no statistically significant warming if the region instead of just moscow is used. The data in the pnas graph gets rid of adjustments for heat island effect and ignores data in the region other than Moscow. The authors mention that these other stations were looked at, but they do not include them in the graph. They also note that the heat island effect was over estimated in July, but give no reason to not adjust for what they consider the effect to be instead of 0.
3) The NOAA preliminary ongoing assessment states that the data is sensitive to time period and the modeling technique will change this sensitivity. The pnas authors need to explain what model they used and why this is the appropriate one. Would they have chosen the same model if they did not know before choice that the heat wave occurred? Both seem to be in agreement that if you change the model for trend line it will change the results.
4) Why do they ignore the possibility of blocking in the model when deciding the probability of temperature gain in Moscow being a causative factor. This seems a major omission in the modeling that would severely change the predictive nature of the analysis. The previous NOAA analysis included many IPCC models that failed to predict this from ghg or warming.
The pnas authors may overcome all of these objections. I have low confidence that the 80% figure will stand after they remove the heat wave from the data in trend line analysis.
I believe it is due in no small measure because of his reluctance to have his "work" peer reviewed?