James Hansen on our Planetary Emergency

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Thanks for pointing to this.

I love the graphic he shows at the 8:40 mark. It shows both increasing summer temps and increase in extreme climate events in the same image.


The trouble with that graphic is that the individual sample periods were not detrended prior to calculating the temperature distribution.

Here's an example of how this can lead to misleading results. First fit a second order polynomial curve against one of the temperature indices, this curve will now become my index. Next fit linear regressions against the curve for different 11yr periods. For each of these lines calculate the distribution curve. The results I get are similar to Dr. Hansen's. The steeper the slope of a line, the greater its variance. Has he demonstrated that the increase in temperatures has accelerated? Yes. Has he demonstrated increased variability? No.

A better method would be to detrend the individual 11yr periods separately and then calculate the variance or standard deviation. I've done this for the USA48. The plot shows multidecadal variability, but no discernable trend.



Well, if you remove a trend from a line that trends upward, you will no longer have a trend to remove.

That you insist that there is a trend to remove and that trend is one to warming is indication THERE IS A WARMING TREND.

Nice try though.

Wow, Wow... I thought I dumbed down my argument enough. Looks like I'll have to try harder.

The point wasn't about the shifting of the mean, it was about the flattening and broadening of the distribution (i.e. the temperature variability). Hopefully you understand that linearly plotted points have a variance and that the steeper the slope the greater the variance. If you take a temperature index and calculate the linear trend for the 11yr periods starting 1950, 1960, ...2000, I suspect you'll find the trend of the trends increasing (i.e. accelerating). Using Dr. Hansen's method, this will result in the variance associated with the trend itself flattening and broadening the distribution over time. It's a flawed methodology.

In the method I've used, this effect has been removed from the USA48 data and I can't see a trend in temperature variability. What I do see is multi-decadal variability in the variability.

No, it was about removing the trend.

The trend is not the mean.

The mean and trend are different.

But you've been told what to say by McIntyre and Watts and they don't know statistics (or at least will rape it if it serves their purpose) and only know that if you remove the trend that this somehow proves no AGW exists.

If you remove the trend, that trend you removed was AGW.

And a trend, as anyone who's ever been to school for more than five years knows, is not the trend.

Nice try, but no biscuit.

wow and other agw church members

you don't need trends, fittings of curves, smoothing of curves, simulation programs etc. etc. and all other weird stuff from the postnormal pseudo-science "climatology" arsenal

just measure temperatures at the same places for a 100 years (please not at airports with hot air from jet engines, please), and then report the results. did you get that, stupid?

I'll pray for you, kai

Wow, Wow... In this case the data rapist is Tamino. I think you owe him an apology.

I just took his observations, applied my own methods, and plotted the calculated standard deviation for all 11yr moving periods.

I'll quote from his post:


"I think a better way to gauge the evolution of temperature variability (apart from average temperature, which we know has changed) would be to take each small-region record, and instead of just computing anomaly, actually de-trend the anomalies."

"There’s no visible sign of any change in the amount of temperature variability from one 11-year period to any other."

"... when it comes to increased variability in month-to-month average temperature for the USA48 area — I’m skeptical."

I happen to agree with Cliff Mass's view:


"But what they are not telling you is that the very warm anomalies we are seeing today would have been nearly as large if global warming had never occurred. ...heat waves of 10F might have been only 9F if global warming had not occurred. ...Those exaggerating the global warming signal imply that we are going from normal conditions to extremes due to global warming. In reality, we go from naturally induced extremes, to a bit stronger extremes due to global warming."

"Unfortunately, a very limited, but highly visible, group of scientists like Hansen are choosing to tell a story that is not supported by the facts, with a media that is happy to amplify such claims. Global warming due to greenhouse gas emissions of mankind is a very serious issue...one which our civilization is not dealing with in an effective way. But scientists must give society the straight facts and not shade or exaggerate the facts based on our personal views on what should be done."

No, I do believe the evidence is otherwise.

McIntyre will prostitute anything to get his oil paycheck. You DO know where he works, right?

"I just took his observations, applied my own methods"

Yeah, right.

You didn't apply any methods, you just repeated what McI said he'd done. This has happened before.

Scads of people talking about how they themselves personally used "pink noise data" and produced a hockey stick. Yet, when asked for their code and results, they pretended that these did not have to exist because "you can get them from Steve McIntyre".

Oddly enough, a complete absence of evidence they'd actually done anything themselves.

Anyhoo, what you've been told to do was to remove the trend then, now that this detrended data has the AGW trend removed, there is no trend (remember: detrended data) and this is then used to "prove" there is no AGW trend in this detrended data.

Circular logic is perfect for the closed intellects of the denialerati.

“There’s no visible sign of any change in the amount of temperature variability from one 11-year period to any other.”

Yup, remove the trend and there is no trend.

"heat waves of 10F might have been only 9F if global warming had not occurred."

Heat waves that may never have happened if global warming had not occurred.

One reason for a heat wave would be the PDO.

The PDO is where the temperature difference between upper and lower ocean layers (separated by the thermocline) is enough to cause overturning (much like summer storms caused by the overturning of two conditionally stable airmasses overlaying each other) to cause the colder deeper water to rise to the surface and the warmer upper water to be mixed down and warm the lower ocean layers.

If the warming of the ocean water increases, you will get more overturning.

Which would cause more drying PDO cycles in an area than would have existed without the warming trend on the ocean upper layers.

A heatwave that would not have existed if it were not for AGW.

Why do you go to mental midgets to get your ideas from, AJ?

They may appear genius to your intellect, but you're a mote being loomed over by midgets.

AJ: "I’ll quote from his post"

But not quote this?

"Note that the most recent 11-year period shows much greater spread than earliest ones. The “conclusions” section specifically mentions (my emphasis):"

And neglect this?

"I used the temperature data from climate divisions of the U.S. mainland (USA48)"

Well, the variation in the mean increases as you reduce the sample.

Since the USA is 2% of the earth's surface, deviations increase by the square root of 50: 7x.

And missing out this:

"That doesn’t mean there’s no change at all in the variability of temperature for this area (USA48). In fact I think there are much better ways to search for variability change in these data, than just estimating the probability functions for visual graphical comparison. Also, the graphs from Hansen et al. are for individual seasons whereas my graph is for all months of the year (seasonal patterns are a subject I have yet to investigate)"

Wow, AJ, though Hansen talks (a bit loosely) about "variability", he is talking about the shift in mean, not a change in the variance. He mentions "the movement of the Bell Curves to the right".

He normalised the data for last 3 11-yr periods using the mean and stdev from 1950-1980. He shows that, while the data fitted between -3 and +3 for 1950-80, it now fits between roughly -2 and +7.

Detrending the data will not show the shift in mean unless you remove from all the data the 1950-80 trend (which is just about 0, anyway).

toby... You might be correct, but his results will have to be replicated with the correct method first before that determination can be made. For the USA48, there is no trend in variability.

Seeing that nobody else has performed this task, I'll put it on my todo list for this winter.

There is a trend in the climate.


toby... Hansen's distribution curves can be described with two terms; mean and standard deviation. We see the movement in the mean simply by plotting the temperature record. As for the s.d., instead of showing 6 11yr periods, I think it's better to use 11yr moving periods. Better still, remove the "acceleration" effect in the s.d.

BTW.. my comments weren't prompted by Hansen's video. I haven't even watched it. I find he's too passionate for a discipline that requires a dispassionate analysis of the data. My comments were in response to Andre's comment.

AJ you cant win any arguments here because in the end, anyone who isn't sure or doesn't understand will just ask the simple question: do i believe the expert nasa scientists, or some random internet commenter?
i dont have to be a genius to answer that one.

By solarspace (not verified) on 11 Nov 2012 #permalink

"I haven’t even watched it."

Summing up the denialist mindset admirably.

Doesn't know and proud of it, but knows that everyone has it wrong who says there's AGW...


So true. I'm just so happy that Dr. Hansen isn't designing rockets :)

Because you're incompetent at recognising competence?

i have listened to hansen's speech in the video above and i feel sorry for him as he looks and talks in such a depressive way. it appears that the feels strongy the quickly nearing total defeat of his alarmistic movement and has obviously given up to fight any longer vigorously. it's entirely clear that he is totally wrong about human global warming, but it's just sad to see a failing and falling old man at the end of his professional wrong way. i wish him all the best for his life after his retirement

I see kai tried to post his usual vacuous bullshit at Tamino's place with predictable result: he found out that Tamino does not suffer fools. At all.

Oh, kai, did you know that California's cap-and-trade system starts taking bids tomorrow?

wow, exusian and other co2 hysterics:

1. the climate always changes. this is called natural variability

2. there is no global warming at the moment because the calculation of a mean global temperature is based on faked thermometer data by noaa in the ghcn database

3. there is no influence of mankind on earth air temperatures

Kai, are you telling us Christy and Spencer are making up their satellite data, too?

Why, yes, you are!

I think we found one of those who filled out Lewandowsky's survey and checked all conspiracy theories...

He got an adult to help.

1. Correct. However, this statement utterly fails as a logical argument that human activity can not also change climate.

2. The assertion of a delusional paranoid in complete denial of physical reality.

3. Not even the urban heat island effect? Not even the waste heat effect? Oh, dear, even Willard Watts would have problems with this kai.


2. Not even Watts published paper insists that the NOAA data is incorrect to the extent of erasing the warming trend.

Even WallyWatts disagrees with kai.

I need to correct my post up thread: it was Eli, not Tamino. (Too many open windows.)

That's unnusual as Eli allows people to say pretty much anything in a comment. Kai must have written something really stupid for Eli to delete it.

Is this the same James Hansen whose 1988 predictions missed the mark by a whopping 150%? This "scientist" has been discredited so many times it's hilarious that anyone takes him seriously any more...