From NASA: Research Links Extreme Summer Heat Events to Global Warming
A new statistical analysis by NASA scientists has found that Earth’s land areas have become much more likely to experience an extreme summer heat wave than they were in the middle of the 20th century. The research was published today in the journal Proceedings of the National Academy of Sciences.
Earth’s Northern Hemisphere over the past 30 years has seen more “hot” (orange), “very hot” (red) and “extremely hot” (brown) summers, compared to a base period defined in this study from 1951 to 1980. This visualization shows how the area experiencing “extremely hot” summers grows from nearly nonexistent during the base period to cover 12 percent of land in the Northern Hemisphere by 2011. Watch for the 2010 heat waves in Texas, Oklahoma and Mexico, or the 2011 heat waves the Middle East, Western Asia and Eastern Europe. Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio |
Anthony comments on the NASA animation by Dr. James Hansen of surface temperature trends from 1955-1999:
There are many issues with this presentation. It seems to be a big Cherry Picking exercise.
1. Note all of the missing southern hemisphere data. There are operating weather stations during his time, but they are excluded from the analysis. Why?
2. The period chosen, 1955-1999 (in the bell curve animation) leaves out the warmer 1930’s and the cooler 2000’s. Why?
3. The period from 2000-present has no statistically significant warming. Leaving that period out (of the bell curve animation) biases the presentation.
4. The period chosen exhibits significant postwar growth, urbanization is not considered.
5. As for severe weather, Hansen ignores the fact that neither tornadoes nor hurricanes have shown any increase recently. Only smaller tornadoes show an increase, due to reporting bias thanks to easily affordable and accessible technology. NOAA’s SPC reports that July 2012 seems to be at a record low for tornadoes.
6. My latest results in Watts et al 2012 suggest surface station data may be biased warmer over the last 30 years.
The statistics show that the recent bouts of extremely warm summers, including the intense heat wave afflicting the U.S. Midwest this year, very likely are the consequence of global warming, according to lead author James Hansen of NASA’s Goddard Institute for Space Studies (GISS) in New York.
“This summer people are seeing extreme heat and agricultural impacts,” Hansen says. “We’re asserting that this is causally connected to global warming, and in this paper we present the scientific evidence for that.”
Hansen and colleagues analyzed mean summer temperatures since 1951 and showed that the odds have increased in recent decades for what they define as “hot,” “very hot” and “extremely hot” summers.
The researchers detailed how “extremely hot” summers are becoming far more routine. “Extremely hot” is defined as a mean summer temperature experienced by less than one percent of Earth’s land area between 1951 and 1980, the base period for this study. But since 2006, about 10 percent of land area across the Northern Hemisphere has experienced these temperatures each summer.
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James Hansen and colleagues use the bell curve to show the growing frequency of extreme summer temperatures in the Northern Hemisphere, compared to the 1951 to 1980 base period. The mean temperature for the base period is centered at the top of the green curve, while hotter than normal temperatures (red) are plotted to theright and colder than normal (blue) to the left. By 1981, the curve begins to shift noticeably to the right, showing how hotter summers are the new normal. The curve also widens, due to more frequent hot events. Credit: NASA/Goddard Space Flight Center Scientific Visualization Studio |
Comments from Anthony:
This bell curve proves nothing, as it has the same problems with data as the surface temperature visualization above: cherry picking period, missing data, and contradictory severe weather statistics. This is nothing but a political ploy from a man who has abandoned any pretext of professionally done science in favor of activism. However, in spite of this, it will be used as “proof” by non-thinking individuals like Bill McKibben to promote a political end. Prepare for a barrage of such stories trying to link any observed weather aberration to climate. They’ll use the same level of fact checking like we saw with the melting street lamps last week.
In 1988, Hansen first asserted that global warming would reach a point in the coming decades when the connection to extreme events would become more apparent. While some warming should coincide with a noticeable boost in extreme events, the natural variability in climate and weather can be so large as to disguise the trend.
To distinguish the trend from natural variability, Hansen and colleagues turned to statistics. In this study, the GISS team including Makiko Sato and Reto Ruedy did not focus on the causes of temperature change. Instead the researchers analyzed surface temperature data to establish the growing frequency of extreme heat events in the past 30 years, a period in which the temperature data show an overall warming trend.
NASA climatologists have long collected data on global temperature anomalies, which describe how much warming or cooling regions of the world have experienced when compared with the 1951 to 1980 base period. In this study, the researchers employ a bell curve to illustrate how those anomalies are changing.
A bell curve is a tool frequently used by statisticians and society. School teachers who grade “on the curve” use a bell curve to designate the mean score as a C, the top of the bell. The curve falls off equally to both sides, showing that fewer students receive B and D grades and even fewer receive A and F grades.
Hansen and colleagues found that a bell curve was a good fit to summertime temperature anomalies for the base period of relatively stable climate from 1951 to 1980. Mean temperature is centered at the top of the bell curve. Decreasing in frequency to the left of center are “cold,” “very cold” and “extremely cold” events. Decreasing in frequency to the right of center are “hot,” “very hot” and “extremely hot” events.
Plotting bell curves for the 1980s, 1990s, and 2000s, the team noticed the entire curve shifted to the right, meaning that more hot events are the new normal. The curve also flattened and widened, indicating a wider range of variability. Specifically, an average of 75 percent of land area across Earth experienced summers in the “hot” category during the past decade, compared to only 33 percent during the 1951 to 1980 base period. Widening of the curve also led to the designation of the new category of outlier events labeled “extremely hot,” which were almost nonexistent in the base period.
Hansen says this summer is shaping up to fall into the new extreme category. “Such anomalies were infrequent in the climate prior to the warming of the past 30 years, so statistics let us say with a high degree of confidence that we would not have had such an extreme anomaly this summer in the absence of global warming,” he says.
Other regions around the world also have felt the heat of global warming, according to the study. Global maps of temperature anomalies show that heat waves in Texas, Oklahoma and Mexico in 2011, and in the Middle East, Western Asia and Eastern Europe in 2010 fall into the new “extremely hot” category.
Sam Yates;
Until you do the same analysis on the data from the 30/40’s that Hansen did on the data he did use, that is just your perception.
Perhaps I might interest you in Figure 8 of this paper: http://www.metoffice.gov.uk/hadobs/hadex/HadEX_paper.pdf, which makes precisely the comparisons that you wanted to see.
Hottest summer I remember was in 1978. Forty plus days of 100+ temperature where I lived. Haven’t come close to that in 34 years here in Memphis, and I’ve lived here the whole time. This year is warm, but not as bad as that and we have temperatures in the sixties forecast for later this week.
But that is all just weather I suppose, not climate. But it does counteract Hansen’s claim that his base period was memorable as being cooler than currently. It all depends upon what temperature records you are looking at.
Sam Yates says:
August 7, 2012 at 9:56 pm
Perhaps I might interest you in Figure 8 of this paper: http://www.metoffice.gov.uk/hadobs/hadex/HadEX_paper.pdf, which makes precisely the comparisons that you wanted to see.
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I’ve no time to wade through another paper right now, perhaps next weekend. In the meantime, you may want to pay attention to the response from Dr Hoerling of NOAA:
“This isn’t a serious science paper,” Dr. Hoerling said. “It’s mainly about perception, as indicated by the paper’s title. Perception is not a science.”
http://wattsupwiththat.com/2012/08/07/editorial-hansen-is-simply-wrong-and-a-complete-and-abject-failure/
The paper you linked to may or may not show something. But that doesn’t change the fact that Hansen’s paper is not science, it is perception management.
Frank K. says:
August 7, 2012 at 10:55 am
Volker Doormann says:
August 7, 2012 at 10:26 am
Frank K. “I urge everyone here at WUWT to READ THIS.”
I think not.
Science is not to find errors in the minds of other people; science is to find real relations between structures in nature. War is easier but no valid method in science.
—
With all due respect, Volker, people here should read the cited PNAS paper because we need to know what these people are thinking, and how it will affect EVERYONE in the years to come. If the CAGW activists are not countered, we will end up with an oppressive government that controls every aspect of our lives – what we can eat, what we can drive, our jobs, our houses, our land, how many children we can have. And it’s already starting – look at the coal industry! Soon there will be a huge glut of lawsuits, and like-minded liberal judges will start the process of outlawing products and services not deemed “environmentally friendly”. This will all come to pass…unless we act,
November…
Hi Frank K.,
I give my greatest respect to people, who are realizing freedom to fight as worrier of truth. History is full of stories (and movies) about brave people all over the world, but also in the U.S.A. Regarding the change in the spirit of the time one can see that the old fashion structures like finance, governments, authorities, parliaments, curt’s of justice, universities, or armies, but also religions and climate science are breaking in piece, because they have failed to respect the dignity of each human essence. You and me and most of all brave simple people of the folk of all countries take the freedom of speech to reinstall the balance of justice in the public affairs.
There is no doubt that therefore is a recognition necessary about what is wrong in reference to that what is right, but the very point is that to know what is wrong one must know what is right. All old fashion breaking structures take all their magic power to hypnotise people in WUWT, peer reviewed fantasy papers or sponsored catastrophic TV channels and blogs and sorry, WUWT is part of this if only the output of people are trumped who are trying to save their chairs, and comments are trumped back noisy.
The simple point is that all presumptive ‘wrong’ depositions must be found by strong arguments, because in the case of an absence of strong arguments there would be no difference between the depositions of authorities like Hansen et al. and your deposition that everyone should read that presumptive wrong depositions.
If everyone is reading all presumed junk science stuff, it leads not autmatically to the truth. OK, WUWT is not a science blog, it is a blog on global warming and climate change with the aim to discuss and trump errors in the thinking of the established Earth climate science community.
My way and my postings include strong arguments in this discussion regarding the claims of Hansen et al. as shown in two graph links above, but you haven’t a word on it and nobody else. Ok its science, but the rules in in the science of philosophy concern also the science of logic and argumentation, depositions like ‘The dog is red’ are no arguments.
However, thank you for your brave words.
V.
davidmhoffer said :
IOW, I have no time to look at the science, but I DO have time to parrot what Anthony found outside scientific literature.
Volker,
I’m sorry that none of the scientists, nor any of the bloggers that you approached felt any need to respond to your assertions regarding the synodic tide aspect of Pluto and Quaoar in relation to terrestrial climate.
I hope that some day someone of authority will recognize your genius and pay proper respect to your findings..
DavidMHoffer: And from the same article there’s a comment by Andrew Weaver, a climate scientist at the University of Victoria, stating that he finds the results compelling. One comment from this or that researcher is not enough to confirm or invalidate a paper, you know.
Rob Dekker, Sam Yates;
Your defense of the indefensible does not speak well of you. Quoting Weaver in support of Hansen is like quoting a parrot. As for not reading the science, as I said in my comment, if the paper linked to has merit, it doesn’t change one by one iota that Hansen’s paper has none. Ignoring decades of data and then trumpeting conclusions about “perception” and offering them up as indicators of anything at all isn’t science, particularly in a field like climate where change takes place over many decades and centuries and separating fact from perception requires looking at all the data at hand precisely to remove perception from the equation.
Hey now, I did just what you asked of me; with that link, I attempted to show that taking the 1930s and 1940s into account does not materially change Hansen’s conclusions, and that therefore his decision not to consider that period of time did not invalidate his results. I agree, it’d be nice to have a longer span of time for the comparison. I disagree, though, that Hansen’s basic point–a slight increase in temperature yields a dramatic increase in temperature extremes–is invalidated. To back up this position, after you stated “Until you do the same analysis on the data from the 30/40′s that Hansen did on the data he did use, that is just your perception,” I gave you an example of prior work that makes a similar comparison between data that encompasses the 1930s-1940s with modern temperatures and late mid century temperatures, showing both a similar rapid warming today and a similar dramatic increase in temperature extremes relative to the past century.
[SNIP: Please check site policy here. And you don’t get to decide what is illogical and then present it here to disparage commenters. The antics of Anderegg and Doran are not welcome here. Whining about “cenbsorship” won’t do you any good either. -REP]
Sam Yates says:
August 8, 2012 at 8:49 am
Hey now, I did just what you asked of me; with that link, I attempted to show that taking the 1930s and 1940s into account does not materially change Hansen’s conclusions
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I did a skim of your prescious paper. It is focused on daily indices and the trends of these as an indicator to warming. So what? We’ve been warming since the LIA, and there is nothing in this paper to show that the last century is any different than the previous three. As for your figure 8, you might want to note that the cold nights/ warm nights is done with just 202 weather stations and the cold days/warm days just 169. Further, the plots are of ” the percentage of time during the year when the indicators were below the 10th percentile or above the
90th percentile.” and at a PEAK of 0.10% hardly justify any conclusions regarding anything but a minor change, which, as I already pointed out, is commensurate with the warming we’ve seen for the last several centuries.
This paper has NOTHING to do with the claims being made in Hansen’s paper. That you point me to it suggests that either you don’t understand the content of either, or you were bluffing in the first place, hoping that I would either not read it or not understand it.
Go away, or at the very least, stop wasting my time.
Second attempt at comment (first having mysteriously failed to appear).
[Moderator’s Note: You keep complaining about this. Your posts are not being “disappeared”. Maybe you need to check your connection. -REP]
With the greatest of respect, Anthony, Hansen has cherry-picked nothing. Excluding Antarctica, what percentage of the Earth’s land surface is in the southern hemisphere; and how does this compare to the 2% of the contiguous USA (or the global % of sites in urban locations)…?
As for the word “perception” in the title of Hansen et al (2012), this is used in place of “attribution”. The paper was not about psychology; it was about statistics – the statistical analysis of historical facts. Similar, in fact, to James McCarthy’s comprehensive rebuttal of everything John Christy said in the E&PW Senate Committee Hearing last Wednesday.
Opening statements of Sen. Boxer and Sen. Inhoffe and written testimony of all Witnesses:
http://epw.senate.gov/public/index.cfm?FuseAction=Hearings.Hearing&Hearing_id=c0293eca-802a-23ad-4706-02abdbf7f7c3
Rob Dekker says:
August 8, 2012 at 3:33 am
Volker,
My way and my postings include strong arguments in this discussion regarding the claims of Hansen et al. as shown in two graph links above, but you haven’t a word on it and nobody else.
–
I’m sorry that none of the scientists, nor any of the bloggers that you approached felt any need to respond to your assertions regarding the synodic tide aspect of Pluto and Quaoar in relation to terrestrial climate.
I hope that some day someone of authority will recognize your genius and pay proper respect to your findings..
Hi Rob,
Thank you for your kind words to my findings. As my (above links to the) graphs show, there is an (astronomical) method available that is able to simulate the terrestrial climate temperatures in general and good fidelity. Although the physical mechanism is unknown, the comparison’s to hadcrut3 or other (UAH) temperatures shows, because of the heliocentric synodic tide functions that the global Earth temperature anomalies cannot have a terrestrial cause.
This point refutes the claim of Hansen & Co: „Global warming due to human-made gases, mainly CO2 , is already 0.8°C and deleterious climate impacts are growing worldwide.”
Maybe it takes some years for the authorities to accept new insights. Today in 2012 there is another prove of communication with Mars. “In 1893 the Royal Academy of Sciences were convinced by Ball that communication with Mars was a physical impossibility, … ‘no electrical signalling to Mars appears to me to be possible, for the simple reason that the apparatus would have to be sixteen million times more efficient as that which would suffice to do for wireless telegraphy’ …”
V.
There are several issues which have not been raised here.
The first is a the choice of names for the “warming” categories. From Figure 5:
It needs to be stressed that in the paper, these categories are actually defined as the difference of the observation from the mean temperature for that local region during the 1951 to 1980 time period and not relative to an absolute measure. A region that was very cold will contribute “extremely hot” anomalies as the temperature warms even slightly despite that the fact that the actual warmer than usual temperatures could not reasonably be described as “hot” in any fashion.
The use of “extremely hot” however serves the propaganda purpose very well when the authors mention the relatively fewer localities where extra warming could be a problem. By mixing all of the locations together, they create a false view of exactly how prevalent the existence of genuinely extremely hot conditions might be.
The second is a more technical question. If one were examining extremes, why would you choose to use the mean rather than the more informative maximum temperature?
The mean temperature is affected by the possible changes in both the maximum AND the minimum temperatures. If the maximum were to stay the same and the minimum increase, the average would also increase. To describe this as a “more extreme” situation would be a misnomer.
The maximum temperature would be more variable than the mean so that using the Hansen metric would very likely not produce as dramatic effect. However, one would expect that such a consideration would not prevent its use in a scientific paper. Interestingly, I could not locate any data of max and mins on the GISS web site.
Just for fun, I went to the Climate Explorer website and had the site calculate the mean difference between the CRU 3.10 summer max and min temperature anomalies relative to 1951 to 1980 for the northern hemisphere. The result is interesting:
(In case the image does not show: http://statpad.files.wordpress.com/2012/08/summer_diurnal_1901_2009.jpeg )
The difference max – min is relatively constant from 1901 to the late 1970s at which point to drops dramatically. The change basically stabilizes at a new level from that time point. The effect of this was to add a substantial contribution from the minimum temps to the overall increase of “extreme temps”. I wonder if Mr. Hansen et al were aware of this…
Dear Moderators: Point noted (although I would dispute your assertion that I keep doing this). Please feel free to delete the first sentence of my previous comment, your response, and this (none of which need appear). Thanks in anticipation of your co-operation, Martin.
[REPLY: Martin, sorry, I didn’t mean to be abrupt or accusatory. You are not the only one recently reporting comments disappearing. The other commenter I’m thinking of is posting from half a world away from you so it can’t be easily written off as an ISP issue. If anyone else finds themselves having to repost a comment, please make a notation at the bottom of the comment, but please give it enough time to be retrieved from the spam folder if that is indeed where it went. I’m not sure there is anything we can do, but I’ll try and check out similar complaints and see if there is some kind of pattern. Please be assured that we will tell you if a comment over-steps bounds. It is only in cases where someone starts thread-bombing and ignores cease-and-desist requests that we just trash comments. So, if anyone else is experiencing difficulty, just make a note in your comment, I’ll check it out, and if there is some kind of pattern I’ll notify Anthony. Fair? -REP]
DavidMHoffer: I think you skimmed a bit too quickly. Those are probability distribution graphs, and hence the TOTAL incidence of all temperatures is normalized to 1; consequently, the y-axis values are not percentage values. 0.1 on the y-axis does not represent 0.1%, it represents 10%. It’s the x-axis that’s percentage, and the bell curve in those graphs show that very few of the temperatures fall EXACTLY at the average value, most are a bit higher or lower, and a very few are FAR higher and FAR lower–precisely as you would expect, considering how much temperatures fluctuate on the short term. The location of the peaks, furthermore, is not really the main point of interest; all that that shows is that average temperatures have been sidling slightly upwards. The reason I brought the graphs to your attention is that you can see clearly that as average temperatures increase slightly, due to the shape of the bell curve extreme temperatures (that is, temperatures that were rare to nonexistent in the previous timespans) increase dramatically–and you can also see that the addition of the period 1900-1950 does not render the last thirty years any less remarkable.
I acknowledge that it would be nice if more stations were used, but then more stations are always to be wished for, and considering that the stations in question are globally distributed, and thus wouldn’t share the same micro or meso-climate, there’s no obvious reason why they would be untrustworthy.
I’m sorry that you think our conversation has been a waste of time, by the by; I’ve enjoyed it, myself, and come across some information that I otherwise wouldn’t have stumbled across. If it’s so very noisome to you, though, I’m willing to let the matter rest–although, of course, I’d prefer to keep it up, because as I said I’ve been enjoying this so far.
Martin Lack;
There are a lot of key words that send your comment to the spam folder. 95% of the time that is the issue. When the comment just “disappears” after you click “post comment” that is invariablity where it went. My practice is to just post another comment that says “mods ~ one down the hidey hole, please rescue?” or something like that. Either the post shows up in short order or you get a note from the mods (rarely) that they cannot find it.
Sam Yates
I suggest you check the update from Michaels in the more current thread on this issue.
Martin Lack:
I second the information and advice to you from davidmhoffer. His experience which he reports is the same as my own.
I write to add to points.
I have found moderator REP to be very fair. He was always right on the occasions when he has ‘snipped’ me. And I know of no occasion when any of the WUWT moderators has ‘disappeared’ my posts, but several of the moderators have ‘found’ posts of mine which had vanished into the ‘bin’
Especially problematic words which cause posts to vanish in the ‘bin’ are (trying to nos-spell but leave intelligible for obvious reason)
fr@ud
denyar
natsi
Hittller
a wide range of obscenities many of which are very mild.
I hope that helps.
Richard
DavidMHoffer: I’ve seen it, but I’m puzzled as to why it only dealt with the US; that’s less than 2% of the Earth’s surface, after all, and when the entire globe is examined, a somewhat different picture emerges. I’d particularly direct your attention to figures 6 and 7: http://journals.ametsoc.org/doi/pdf/10.1175/jhm-386.1
Clearly, the US is not the best test case when it comes to figuring out what the globe is doing, drought-wise. I don’t know how important this is or if there are other effects, of course, but I would guess that part of the reason that the US doesn’t show the same relationship between the two that the world does is because drought in the US is often associated with La Nina years, which tend to starve the Midwest of water while still being fairly cool. I would guess that, in the US at least, unusually warm years are associated with drought due to the increased evaporation from the soil, while La Nina years (which are also going to be unusually cold) are associated with drought due to the air and water circulation patterns in our neck of the woods. I do NOT insist on that, mind; it’s just speculation on my part, and there might be a completely different reason why the US shows no correlation between temperature and PDSI, while the globe does.
Sam Yates says:
August 8, 2012 at 3:07 pm
DavidMHoffer: I’ve seen it, but I’m puzzled as to why it only dealt with the US; that’s less than 2% of the Earth’s surface, after all
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chortle. lol. snicker.
So… you’re complaining that it only dealt with 2% of the earth surface? What % of the earth’s surface do the approximately 200 weather stations in the paper you cited represent? You can’t have it both ways!
2% all crammed together, and therefore under similar climatic effects, overall. The stations from the paper I mentioned earlier are scattered all over the globe, and consequently are not exposed to the same climatic effects and can be expected to more accurately represent global trends. If you want to figure out the average temperature of an object, you don’t cram a few hundred thermometers in one part of it and assume that the rest follows that behavior (unless you have an excellent reason for believing that that one section is representative of the rest); you take measurements from all over, so that any local variations are averaged out.
Sam Yates,
Sorry, but you are just rationalizing. Several commenters have responded with similar analysis from the CET and other temperature records from all over the world. Further to your point, the broader the sample the better, and that goes for spatial distribution as well as temporal. There is no excuse for a study of this sort excluding decades of data on a flimsy excuse, nor can you cite papers that are on a superficial level similar to fill in the gap. Either Hansen applies his methgodology to all the data at hand, or he must provide a credible reason not to, and he hasn’t.
Hm. When you say I’m rationalizing, are you disagreeing with my statement that a global record is more useful for determining global drought trends and correlations than a local (US) record, or are you just referring to my views on the validity of Handen’s paper? If the latter, again, his stated reasons are related to the ability of people nowadays to perceive the effects of climate change. His purpose is not to show that the temperatures today are hotter than they’ve been for a thousand years, or two thousand years, or however many millenia you might wish; they’re to show a perceptible increase in temperature relative to what people can remember, and to demonstrate that the dramatic temperature excursions like the 2003 heat wave in Europe, Australia’s millenial drought, etc. can be credibly linked to the slight increase in average temperatures that has occurred over the Earth’s surface. It seems to me, and I grant I could be wrong, that you’re blaming him for failing at a task he never attempted.
As to the CET record–well, it’s valuable, no doubt about that, but it’s LOCAL. Just as the US is local. It, by itself, says effectively nothing about global climate and the occurrence of extremes.