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.
this seemed to be an appropriate place to link this because it talks about Hansen and Trenberth
http://www.foxnews.com/scitech/2012/08/07/climate-change-role-in-heat-waves-still-under-debate/?intcmp=features
Martin Lack: “… none of your alternative hypotheses can possibly explain the steady shift decade-after-decade”
There has been NO “steady shift decade-after-decade”, thus the point of your Alarmist comment is rejected.
Do yourself and the rest of the humanity a big favor, quit taking political activists hacks’ P.R. and Cohort Review Papers as fact. Do your own research, analyze the historical temperature data, think through the AGW claims, factor in the hypocrisy of claiming 0.01 degree precision based on data that is +/- 2.0 degrees accuracy (insert ‘2XFacePalm’ here) And for blanking sakes ask why have the proponents of AGW had to keep morphing their Alarmism.
Sam Yates says:
As for your concerns about the time period used, Hansen et al defend that choice in their paper:
Yes, indeed they do. Odd that such a choice would need to be “defended”.
“We choose 1951–1980 as the base period for most of our illustrations, for several reasons. First, it was a time of relatively stable global temperature, prior to rapid global warming in recent decades.”
i.e. – We chose the period to minimize the quantified variability, which will exaggerate the quantification of recent extremes.
Second, it is recent enough for older people, especially the “baby boom” generation, to remember.
WTF? What kind of scientific criterion is that? This paper was peer reviewed? If the inclusion of such nonsense in a ‘scientific’ paper doesn’t send chills down your spine …
Third, global temperature in 1951–1980 was within the Holocene range, and thus it is a climate that the natural world and civilization are adapted to.
i.e. – We assumed our conclusion. And look what we found! Surprise!
In contrast, global temperature in at least the past two decades is probably outside the Holocene range (7), as evidenced by the fact that the Greenland and Antarctic ice sheets are both losing mass rapidly
Sooooooooo … the Vikings didn’t live during the Holocene? Time to ‘adjust’ the history books.
(8, 9) and sea level has been rising at a rate [3 m∕millennium, (10); updates available at http://sealevel.colorado.edu/%5D well above the average rate during the past several thousand years.
WTF? Its on the same trend that started @ur momisugly 1900, according to their own data. Gratuitous.
Fourth, we have used this base period in scores of publications for both observational and model analyses, so it is the best period for comparisons with prior work.”
Yes Jimmy, when you hit upon a dodgy cherry pick, you are loyal to it.
Given the recent discovery of the PDO, which operates on @ur momisugly 60 year cycle and which is known to affect land surface temperatures dramaitically, the choice of a base period that is only 30 years long, and which (coincidence, I am sure) just happens to start at the bottom of a PDO cycle, and then is used to interpret the recent peak of same … well that choice is in need of some “defense”, now isn’t it?
Good thing that the memory span of a politically important demographic is such an important climatological factor, huh?
JJ says:
August 7, 2012 at 7:02 am
JJ – The overt political spin in Hansen’s current PNAS “scientific paper” is NOTHING compared to this:
<a href="http://pubs.giss.nasa.gov/abs/ha08510t.html" Scientific case for avoiding dangerous climate change to protect young people and nature. Proc. Natl. Acad. Sci., submitted.
I urge everyone here at WUWT to READ THIS. I really proves that mainstream CAGW climate “scientists” have gone over the edge and are now into full derangement mode…
Why do SOME sceptics believe NASA is lying when they say they landed a man on the moon?
Perhaps they should consider the long term effects of allowing a consumate lier within their ranks to be not be held accountable for his actions. If NASA wants people to continue to believe in them, they need to reign this in.
Is Curiosity real, or just a stage show being filmed in a large warehouse in Area 51? 😉
JJ
I was going to rip Sam Yates a new one for his defense of the indefensible, but you beat me to it. Well done.
The NEW Face of the United States Government: PHOTO and PHOTO and PHOTO
The reason why? The last fifteen years of GlowBull Warming GRAPH
Oh and while Hansen shrills on about Heat Waves. Anchorage, Alaska had an all-time record snowfall of 133.6 inches last winter – just over 11 feet… Department of Agriculture Snow Survey Supervisor Rick McClure… “Adding the record-shattering snowfall into the mix, it’s possible the melt of last year’s snow could overlap with new snow falls that can occur as early as September. When this happens, glaciers can form by compressing the old snow into ice”… Aug 6, 2012
It is not record colds that signal glaciation but record snows and mild summers where snow does not melt.
Let me add my voice to those who find the NASA news release pretty much incoherent. I certainly hope that Hansen and his coathors had nothing to do with the stuff that is posted at the NASA web site. The full article http://www.pnas.org/content/early/2012/07/30/1205276109.full.pdf looks much better (how could it be worse?). I generally don’t do temperature discussions. It’s a food fight and not much fun. But I would like to see some temperature people comment on the PNAS paper. My take is that Hansen et al might have a point, although I don’t think I’d present it the way they do. Why are they using the mean and sigma for a different time interval that they are looking at? Is that legitimate? Is there some reason not to simply compute sigma for each year and show that it is increasing?
@ur momisugly JesusWept, next time I see a landslide I’ll know the dust is what moves the rocks… /sarc
Frank K. says:August 7, 2012 at 7:34 am
The overt political spin in Hansen’s current PNAS “scientific paper” is NOTHING compared to this:
http://pubs.giss.nasa.gov/abs/ha08510t.html
Hansen, J., P. Kharecha, Mki. Sato, F. Ackerman, P.J. Hearty, O. Hoegh-Guldberg, S.-L. Hsu, F. Krueger, C. Parmesan, S. Rahmstorf, J. Rockstrom, E.J. Rohling, J. Sachs, P. Smith, K. Steffen, L. Van Susteren, K. von Schuckmann, and J.C. Zachos, (2012) maintain:
„Global warming due to human-made gases, mainly CO2, is already 0.8°C and deleterious climate impacts are growing worldwide.”
s. a. pdf: http://pubs.giss.nasa.gov/docs/notyet/submitted_Hansen_etal.pdf
They all show a graph as Fig. 2. (B), using reconstructed temperatures of the past 800,000 years (32). The amplitude pp is about 7 to 8 K.
A fast Fourier analysis shows that connected mode resonances of saw tooth oscillations in the range of 10ky ^-1 to 400 ky^-1 exhibit the terrestrial spectrum. From this it is easy to simulate spectrum with Ehrlich modes:
http://www.volker-doormann.org/images/bentic_f_graph.gif
It seems to me that an oscillator with a fundamental frequency of ~190 ky^-1 and a lot of higher modes loading ~8K more heat to the earth over many ky (20+ ky), needs an oven.
It is the Sun?
Hansen and they all show a graph as Fig. 1. using hadcrut3 temperatures of the past 132 years.
Again an analysis of the temperature frequencies of the past 10 ky, especially of the past 50 years show that solar tide functions, fitted in the strength of the tide pairs respectively, match with the global temperatures. Lower frequency simulations need 6 planets and higher temperature frequencies need 11 planets.
http://www.volker-doormann.org/images/temperatures_1880_ff.gif
To explain terrestrial global temperatures of the past centuries and decades and years with solar tide functions and the terrestrial global temperatures of the past 1 million years with Ehrlich modes suggests that processes in the solar system caused the climate of the Earth, and there is no place for an idea that little changes of CO2 in the atmosphere is relevant for the dynamics in climate.
I urge everyone here at WUWT to READ THIS.
I think not.
http://www.volker-doormann.org/images/agw_poll.jpg
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.
V.
Droughts are caused by atmospheric pressure systems preventing precipitation from occuring to the extent that drought conditions exist. When pressure systems no longer block precipitation from forming drought conditions end. In order to prove causality, Hansen needs to 1. connect anthropogenic CO2 with atmospheric high pressure system changes and that during these pressure system changes, high temperatures were higher than under similarly strong drought inducing pressure systems of the past. 2. He needs to connect anthropogenic CO2 with preventing the jet stream from clearing out blocking high pressure systems thus extending drought periods beyond the range seen in the past. Otherwise, long periods of extensive persistent high pressure systems that induce drought must be considered to be caused by natural events. In a word, mechanism. Not on temperature itself, but mechanism on atmospheric pressure systems that produce long lived and more frequent blocking highs.
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…
My guess about high temperature record rates: They are set frequently with new stations as well as old ones that have deteriorated. Record rates set by old, well placed (representative of each and all climate zones and across all long term oscillations), and well maintained sensors need to be compared as the control to current record rates. It is plausible that the recent record rate of high temperature records being set is an artifact. At the very least, these sensor artifacts should be ruled out before touting that an increase in record setting rates is correlated to CO2 only.
Frank K. says:
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,
It will happen with or without CAGW. All that’s happening here is the selection of the form of the Destructor.
November…
Won’t make much difference either way, IMO.
Frank K says:
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,
I’m with Frank on this one. The ‘alarmists’ have consistently exhorted us to ‘think of the cheeldren!’
I do, and my greatest fear for future generations is that under the guise of ‘saving the planet’ they will be duped and subsumed into a Serfdom from which they will never be able to escape.
Frankly, Frank, I agree with you.
It’s sinister and we have to react. Thank God for WUWT, Jo Nova, CA, Donna and all the rest I say.
Duncan B (UK)
JJ:
“’We choose 1951–1980 as the base period for most of our illustrations, for several reasons. First, it was a time of relatively stable global temperature, prior to rapid global warming in recent decades.’
i.e. – We chose the period to minimize the quantified variability, which will exaggerate the quantification of recent extremes.”
Not at all; in the paper they also show the effects of using 1981-2010 as their base period, and although the widening of the bell curve is not quite as visible, the shifting of its midpoint (and the increased incidence of extremes of temperature) is still clearly apparent.
“‘Second, it is recent enough for older people, especially the “baby boom” generation, to remember.’
WTF? What kind of scientific criterion is that? This paper was peer reviewed? If the inclusion of such nonsense in a ‘scientific’ paper doesn’t send chills down your spine …”
The focus of the paper is whether or not people nowadays should be able to recognize climate change based solely on their own observations, and the paper is entitled “Perception of Climate Change.” The use of a recent base period is extremely relevant.
“‘Third, global temperature in 1951–1980 was within the Holocene range, and thus it is a climate that the natural world and civilization are adapted to.
i.e. – We assumed our conclusion. And look what we found! Surprise!”
…I’m afraid I don’t quite follow. What conclusion are they assuming? He’s quite correct to note that the temperatures during the period from 1951-1980 are within the Holocene range; surely that’s not controversial. And that climate IS what we’re adapted for, since it’s the only one that humanity has experienced. Would you mind elaborating on this a bit?
“‘In contrast, global temperature in at least the past two decades is probably outside the Holocene range (7), as evidenced by the fact that the Greenland and Antarctic ice sheets are both losing mass rapidly’
Sooooooooo … the Vikings didn’t live during the Holocene? Time to ‘adjust’ the history books.”
Where Vikings did or did not live in the past is utterly irrelevant. Greenland covers approximately 0.4% of Earth’s surface, which is easily small enough for it to have been, in the past, as warm or even warmer than now without having any real effect on global temperatures. The modern period is unique due to the global nature of the current rapid temperature change, in contrast to the rapid regional and glacially (if you’ll excuse the adverb) slow global changes that occurred in the past.
“‘(8, 9) and sea level has been rising at a rate [3 m∕millennium, (10); updates available at http://sealevel.colorado.edu/%5D well above the average rate during the past several thousand years.’
WTF? Its on the same trend that started @ur momisugly 1900, according to their own data. Gratuitous.”
Um…No it isn’t: http://www.cmar.csiro.au/sealevel/sl_hist_few_hundred.html
“‘Fourth, we have used this base period in scores of publications for both observational and model analyses, so it is the best period for comparisons with prior work.’
Yes Jimmy, when you hit upon a dodgy cherry pick, you are loyal to it.”
You have yet to demonstrate that it IS an example of cherry picking. He has a point that using the same reference period makes comparisons easier, and as he showed in the paper itself, using a different, more variable period (1981-2010) does not dramatically affect the results. The rightward shift of the gaussian is still very much in evidence.
“Given the recent discovery of the PDO, which operates on @ur momisugly 60 year cycle and which is known to affect land surface temperatures dramaitically, the choice of a base period that is only 30 years long, and which (coincidence, I am sure) just happens to start at the bottom of a PDO cycle, and then is used to interpret the recent peak of same … well that choice is in need of some “defense”, now isn’t it?”
http://www.ncdc.noaa.gov/paleo/pubs/biondi2001/biondi2001.html There you go, a reconstruction of the PDO from the mid-1660s to 1991. And here’s another one, for a shorter period of time: http://jisao.washington.edu/pdo/ Note how the current state of the oscillation is not terribly unusual, climatologically speaking, while global temperatures…are. Note, also, that according to the PDO index we should have been cooling since ~1985, which fairly obviously is not what has actually happened.
Perhaps nobody noticed that it was all about the Northern hemisphere, as it is precisely stated in the first line… Or do the usual posters of WUWT never read any further than the headline? Talk about cherry picking…
Sam Yates;
Upon review, you are correct! The paper is actually called “Perception of Climate Change”!
And a fine example of perception management it is!
If you are looking for people stupid enough to accept this as a reasonable explanation for excluding decades of data, and for trumpeting unfounded conclusions to the media, I am certain that you will find them in droves.
But not here. And you reveal yourself for what you are by attempting to do so.
I’m just not seeing how any of these statistical analyses have any ability to express anything except how the entire series differs from a subset of the series. If I take the entire 359-year dataset from HadCrut of the Central England temperature and plot it over time, it has a trend of 0.03C per decade. If I plot the anomalies from the mean of that entire time, there is a bunching up of positive anomalies from 1980 on, but nothing any higher than ever occurred before — just not as many negative anomalies. I think that’s something to be happy about.
I have zero doubt that if Hansen had picked seven different 30-year spans for his baseline he’d have had seven different curves, with the peaks sliding one way or the other.
And the biggest fraud is that NONE of that analysis ties CO2 to the rise in temperatures. It’s a “hide the pea” routine, with the “CO2 caused this rise in temps” hypothesis hidden under the cups of constantly moving statistics. If anything, these analytical exercises should be ignored and the focus returned to “How does this prove that CO2 has anything to do with it?”
We KNOW it’s gotten warmer. We’re NOT SURE how much warmer, because of the poor siting issues. But nothing about getting warmer by itself is evidence that CO2 is causing it. This argument is just another one stolen from the creationists: CO2 is the “God of the gaps.”
DavidMHoffer:
Hm. I think we may need to backpedal a bit; we’re obviously just talking past each other at this point. If you don’t mind my asking, what would you expect to see in the chart if a longer interval had been used for the baseline comparison? What would you expect to see if a different interval of the same duration had been used? And why so? I want to establish (appropriately enough) a baseline, so that I know where you’re coming from here.
…And on a completely unrelated note, may I ask how quotes and/or italics are managed on this site? My last post was nigh-unreadable thanks to formatting issues, and I’d rather not subject y’all to that again.
francois: “Perhaps nobody noticed that it was all about the Northern hemisphere, … … posters of WUWT never read any further than the headline?”
All this time we thought ‘it’ was about G-L-O-B-A-L Warming. More specifically, the claim that Carbon from industrialized human’s activities were the sole cause of claimed increase in G-L-O-B-A-L temperatures. To our great relief, we now know ‘it’ was about “Northern hemisphere”, not about Southern hemisphere, not about human activities, and not about Carbon. 😉
Could someone please pass this Epiphany on ‘it’, to the E.P.A. and White House; so we can quit needless closing coal fired power plants and quit wasting billions of Tax dollars on Solyndras? 🙂
Sam Yates;
Sam Yates says:
August 7, 2012 at 7:05 pm
DavidMHoffer:
Hm. I think we may need to backpedal a bit; we’re obviously just talking past each other at this point. If you don’t mind my asking, what would you expect to see in the chart if a longer interval had been used for the baseline comparison?
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
1. PERCEPTION of warming is about as scientific as…. well, to be frank, it is the antithesis of science. Science is about separating fact from perception. Sometimes the two coincide, but until you have the facts, you don’t know that, and frequently perception is wrong.
2. As to what I would EXPECT, I don’t have a clue. Expectation is the root of confirmation bias. Iif the hypothesis is that there are more extreme events due to global warming, then the frequency and intensity of such events in the cooler past would either falsify or support that hypothesis. From the late 20’s to the early 40’s we have anecdotal evidence from all over the world that periods of intense drought and heat waves scorched various parts of the globe. My PERCEPTION based on my reading of the historical record and my PERCEPTION from stories told by elderly relatives of that period of time suggests that these were MUCH worse than what we are experiencing in recent years. But my PERCEPTION is not science. Examining the DATA from that time period is SCIENCE. If in fact my PERCEPTION is correct (as borne out by the data), and that time period was cooler than current times (which according to Hansen it was) then the hypothesis is falsified. If the data doesn’t support my perception, then so be it. But by excluding that important period of time, and focusing on perception of the data rather than the data available, Hansen as left science behind and entered the realm of perception management.
dmh
Sam Yates: “What would you expect to see if a different interval of the same duration had been used?”
Alarmist claims of 70’s as in another Ice Age.
DavidMHoffer: Well said. I agree wholeheartedly with everything you wrote except, perhaps, the last sentence, which I would quibble with for reasons I’ve mentioned earlier (no indication of 1930s/40s being exceptional in the global record, no great alteration in the appearance of a shift in temperatures when a different baseline is used, etc.)
Download a “high-res” visualization? There were computers 25~30 years ago capable of better graphics than that. How many miles/kilometers does each block cover?