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.
|
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.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
This was covered at length today in The (Glasgow) Herald.
I wonder if tomorrow they will cover the paper from Edinburgh about expensive wind energy.
I’m not holding my breath.
Yeah, not hard to find a change when you compare recent years to the three coldest decades on record! I wonder if the Doctor’s results would be the same, if he included the 30s, 40s, and 50s?!?
What was the source of Hansen’s temperature data?
I don’t see it mentioned anywhere.
GISS, fully adjusted (and readjusted, and readjusted)?
I notice he also conveniently left out South America and Australia, where they’ve been having record cold temperatures.
I used to like cherries.
Duncan B (UK)
You know, there have been a spate of papers to prove the warming alarm via statistics.
It’s time to use the same technique to show that GISS and CRU adjustments are also far from what can be expected by normal, random, unbiased forces and thus their warming signal is conclusively “man-made”.
If it doesn’t fit, you must omit…
apologies to Johnny Cochrane.
Waiting for James’ reply,……cue Jeopardy music. Great article Anthony. So sick of their “selective science”. How will Hansen be viewed by his peers in the future? Perhaps as one of the men who derailed science for political machinations (the cause).
“James E. Hansen: “When I testified before the Senate in the hot summer of 1988 , I warned of the kind of future that climate change would bring to us and our planet. I painted a grim picture of the consequences of steadily increasing temperatures, driven by mankind’s use of fossil fuels.”
If global temperatures are increasing over a time interval, it is out of the methods of science to predict global temperatures for the future without the knowledge of the physical mechanism of increasing or decreasing global temperatures. Each disregard of this limit of physics is not a method of science and/or a fallacious argument, which includes in the case of an authority the fallacy Argumentum ad verecundiam (Appeal to authority). ‘The Appeal to Authority uses admiration of a famous person to try and win support for an assertion.’.
Independent from this argument it needs not much logic to conclude that with increased global temperatures the processes driven by a higher heat must change in its effects. It seems to be intelligent to take the consequences in the adaptability as humans ever have done.
A further disregard of the methods of science is to take the old fashion dept phantom, people have controlled by kings, religions, and governments for many millennia, and mix it into a prediction of an authority, without any valid scientific argument.
http://www.volker-doormann.org/images/agw_poll.jpg
In a new analysis of the past six decades of global temperatures, which will be published Monday, my colleagues and I have revealed a stunning increase in the frequency of extremely hot summers, with deeply troubling ramifications for not only our future but also for our present.
To understand the nature of global temperatures it is necessary and possible to analyse the reconstructed and measured temperatures for the time interval of about 1 million years or for the time interval of about 10 ky to present. This is inalienable because a supposed linear increased temperature of 6 decades can be a phase of a oscillating function of centuries or millennia. From this it is not possible to extrapolate time interval of temperature into the future.
This is not a climate model or a prediction but actual observations of weather events and temperatures that have happened.
No Sir. You do say two times a word on prediction and future.
Our analysis shows that it is no longer enough to say that global warming will increase the likelihood of extreme weather and to repeat the caveat that no individual weather event can be directly linked to climate change.
No Sir. Your analysis shows simple that you think there is an connection between high global temperatures and effects from that level. But that is not a new recognition. That’s what wrong is, that your analyse shell show that ‘global warming will increase’ something, because this suggests a knowledge about the future, but this is not analysed.
our analysis shows that, for the extreme hot weather of the recent past, there is virtually no explanation other than climate change.
That is not the point in climate science. The point in climate science is to explain the cause for the analysable global temperature periods from many kiloyears to month. Periods which are well known since Bond have analysed the frequencies after Fourier’s method with an example of about 1 period per 1800 years. But it seems that there are 2 periods in 1800 years, and the temperature reconstruction from Zorita et al. fit with Bond’s data. There are 13 increasing temperature phases over 11.000 years but as you can see, there are also phases of decreasing temperatures after high global temperature levels
:
http://www.volker-doormann.org/images/bond_vs_zorita2.gif
This may show that an analysis of your chosen time interval of 6 decades with an increasing phase is not useful to make predictions to the future. You cannot rule out from the scientific point of view that the natural period of 1800 years, or better 900 years, occurs in a new decreasing phase of the global temperature.
To whom it may concern, analysed solar tides can be simulated from 3000 BC until 3000 CE. The pattern of some solar tide functions indicate, it fits with Bond et al. and Zorita et al. and lower temperatures in the next decades to 2040 CE..
http://www.volker-doormann.org/images/bond_vs_zorita3.gif
V.
I’m a bit jealous of you over in North America with your excellent summer, over here in Scandinavia it’s the coldest and wettest summer in many many years. There is also a very interesting phenomenon occurring this year in that the northern parts of Scandinavia and areas 1000m above sea level will miss this summer completely, in meteorological terms that is (temperatures of more than 10 degrees C for more then five days).
[joke]I have an idea for where all this excess heat is coming from. It comes from Trofim Lysenko spinning in his grave at 3600 RPM at an abuse of science that makes his life’s work look trivial by comparison.[/joke]
As anyone examined the barometric pressure record over the same time period?
This huge shift in temperature, if true, must also include an air pressure component.
[Snip. Read the site Policy. ~dbs, mod.]
Jim Hansen is assuming that 1951-1980 defines the full range of natural climate variability. That’s the same mistaken assumption he used in 1988 to assert his 99% certainty that human-caused global warming was already apparent.
Statistics can only tell one whether one set of numbers is like another, or not. It can’t say anything about whether some weather vagaries during historical period are within natural climate variability or not. That distinction takes a viable physical theory of climate. That theory does not exist.
Jim Hansen’s analysis and conclusion are entirely pseudoscience. I’m not surprised it was published in Ralph Ciccerone’s PNAS.
I suppose one of his great many cherry picks must be the largest. That’s like trying to pick out the largest elephant in Africa though. There’s a lot of them and they’re all big.
“It’s “science” Jim. but not as we know it”
For this kind of exercise to make sense either 1) The set of stations whose data they are looking at needs to be constant throughout the entire analysis period; or 2) The set of observations in each years needs to be an independent random sample out of all possible locations. I am pretty sure (1) is not true. I am also pretty sure (2) CANNOT be true (see )
As such, this pretty animation cannot show anything other than the fact that the distribution of temperatures at the stations whose data continue to make it into the data set shifted right.
Guess I got you the story too late? I thought I’d finally scooped you on something 🙁
Jim @10.27 am. Hansen did include the 1950s from 1955 on
This ‘statistical analysis’ reminds me of a Nicholson scene in ‘The Witches of Eastwick’…
The period chosen, 1955-1999 leaves out the warmer 1930’s and the cooler 2000’s. Why?
The period from 2000-present has no statistically significant warming. Leaving that period out biases the presentation.
Well, it might help if you actually watched the animation. It shows 1955, 1965, 1975 and then 1985-2011. The 1930s were warmer in the US, not the whole NH, and the 2000’s were by no stretch of the imagination ‘cooler’.
4. The period chosen exhibits significant postwar growth, urbanization is not considered.
No factors are ‘considered’ this is just a map of recorded temperatures. However according to Richard Muller “I think the conclusion that urban heat islands contribute essentially zero to the warming we see is on very solid ground.”
http://www.guardian.co.uk/environment/blog/2012/aug/03/scepticism-climate-study-richard-muller
Logically there would be a similar reduction in extremely cold winters. Is there any mention of this in Hansen’s paper?
Or is that a silly question?
JohnnyBoy says:
August 6, 2012 at 10:55 am
Typical warmist. Complete opposite of the truth. I have seen only exponential growth in skeptic numbers. The delusion of the warmists is what is growing.
Hi Anthony. It is clear to me that your up-coming paper has been increasing the angst among the despairing CAGW moven mavens.
http://www.urbandictionary.com/define.php?term=moven
JohnnyBoy says:
“Anthony seems to react without thinking, no substance at all in his complaints. The “global warming denial church” is falling apart and the debate will soon be over.”
You forgot the sarc tag…