Climate Change temperature chart

Published on October 31st, 2011 | by Zachary Shahan

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Curry Lost in Denial (& Global Warming Still = More Snow)

October 31st, 2011 by

I recently noticed an inane article in the Daily Mail trying to create another scandal out of climate skeptic Richard Muller’s recent finding that the climate scientists were right after all. Apparently, one of the co-authors, infamous (within climate science circles) Judith Curry was less than enthusiastic about the results.

When seeing the news (in the less-than-noteworthy Daily Mail), I thought, “oh boy, here we go again, another false b.s. scandal cooked up by deniers against someone who was once one of their own.” And, sure enough, that’s what it looks like it’s becoming. I now see on Google News that this ridiculous Daily Mail article is “Highly Cited” and see similar stories from FOX News, Investor’s Business Daily, and New York Daily News. (How I wish these news agencies would contact a legitimate climate scientist before running a story on a “climate science scam” that originated in the Daily Mail!)

Of course, this all comes at the perfect time for all the science failures who don’t seem to have learned that global warming = more moisture in the air, which equals more downpours when it’s warm and more snowstorms when it’s cold. We’re getting a record snowstorm in the Northeast right now, which comes as no surprise to anyone who follows climate science. However, for all those deniers out there, they think this is a sign that global warming is a sham. Oh, the irony….

Rather than waste my time responding to Curry’s confusion, the good folks at Climate Progress and Skeptical Science have already done so and I will repost their pieces below. First, though, rather than rehash the same responses to the “It’s snowing — there’s no such thing as global warming!!” fallacy, here’s a post that covers that:

7 Myths about Climate Change Science (#1 & 2)

And a video you may find useful:

Now, Skeptical Science’s reponse to the the Curry-BEST-Daily Mail debacle:

 

Baked Curry: The BEST Way to Hide the Incline

Sadly, the so-called climate “skeptics” continue to find new ways to spin the Berkeley Earth Surface Temperature (BEST) results.  First they came up with bogus excuses why the BEST results are not valid.  Then they tried to change the subject, doubling-down on other climate myths.  Now Judith Curry – a member of the BEST team no less (though her involvement in the project has been relatively minimal) – has claimed that the BEST team has tried to “hide the decline” in recent temperatures.

“This is “hide the decline” stuff. Our data show the pause, just as the other sets of data do. Muller is hiding the decline.”

Curry’s comments were in response to a BBC radio interview with the leader of the BEST team, Richard Muller, who said:

“We see no evidence of it [global warming] having slowed down”

So is Muller right that BEST shows no evidence of global warming slowing down, or is Curry correct in accusing her colleagues of hiding the decline in temperatures?

Misguided Curry

Firstly, it’s worth noting that the BEST team addressed the myth that global warming stopped in recent years in their FAQ:

“decadal fluctuations are too large to allow us to make decisive conclusions about long term trends based on close examination of periods as short as 13 to 15 years.”

In short, Curry’s comments are contradicted by actual statistical analysis done by other members of the BEST team.  As SkS has discussed at length with Dr. Pielke Sr., over short timeframes on the order of a decade, there is too much noise in the data to draw any definitive conclusions about changes in the long-term trend.

On his blog, tamino does the statistical analysis of the BEST data and finds that because the timeframe in question is so short, the uncertainty is too large to say for certain that the short-term trend in question is any different than the long-term trend.  Right off the bat, it’s clear that Dr. Muller was correct to say there is no definitive evidence that global warming has slowed down.

Hiding the Incline

The Daily Mail article containing the Curry interview includes a graph of BEST data originating from serial misinformation source GWPF, with a cherrypicked starting point of January 2001, through the final BEST data point in May 2010 (a period shy of a decade).  Figure 1 highlights the magnitude of the cherrypick by comparing the full BEST record to the fraction of the record included in the article.

BEST cherrypick

Figure 1: Entire BEST record vs. the data examined in the Judith Curry Daily Mail article

Eagle-eyed readers may notice a problem towards the end of the record, as tamino did: the April 2010 BEST anomaly is -1.04°C, which represents a sharp cooling of 1.9°C from the previous month, and is followed by a 2.1°C warming the following month (Figure 2).

BEST with outliers

Figure 2: BEST record since January 2001, with the April 2010 anomaly highlighted in red

Was there really such a large temperature drop and rise between March and May 2010?  It doesn’t show up in any other surface temperature record.  When we examine the BEST data, the problem is immediately apparent.  The uncertainty levels in April and May 2010 are 2.8°C and 2.9°C, respectively.  Going back to January 2001, the next-largest uncertainty level is 0.21°C, and the average uncertainty is less than 0.1°C.  Tamino plots the monthly data hockey stick-like uncertainties (Figure 3).

BEST uncertainty

Figure 3: BEST monthly uncertainties since 2001, with a huge spike in April and May 2010

So what happened with the April and May 2010 data?  While the March 2010 anomaly was based on 14,488 stations, April and May were based on only 47 stations, all in the Antarctic (h/t Nick Stokes).  In other words, April and May 2010 should be excluded from BEST data analysis because they are incomplete, their uncertainties are just too large, and April 2010 is quite obviously an anomalous outlier.  Frankly they should not have been published in their current state.

Figure 4 shows how the short-term trend changes when we exclude those two unreliable data points.

hiding the incline

Figure 4: BEST data and linear trend since January 2001 including and excluding April and May 2010

The BEST linear trend increases from 0.03°C per decade when including the faulty data points, to 0.14°C per decade when they are excluded.  It’s also important to remember that according to NOAA, which is the dataset most similar to BEST, 2010 was the second-hottest year on record over land (behind 2007), and the hottest globally (effectively tied with 2005).  Ironically, the analysis the “skeptics” are using to argue that global warming has stopped ends in a record hot year for global surface temperatures.

In short, the problem is not that Muller is hiding the decline, the problem is that Curry is hiding the incline.

Enough Cherrypicking Already

As we have recently discussed, although we can’t say for certain statistically, it’s likely that the global surface temperature warming trend has slowed over the past decade, because virtually all short-term temperature impacts have been in the cooling direction over that timeframe.  Climate “skeptics” desperately want us to believe that the trend has slowed because global warming has magically disappeared, but that’s simply not the case.  In fact, as Santer et al. (2011) showed,

“Because of the pronounced effect of interannual noise on decadal trends, a multi-model ensemble of anthropogenically-forced simulations displays many 10-year periods with little warming. A single decade of observational TLT data is therefore inadequate for identifying a slowly evolving anthropogenic warming signal.  Our results show that temperature records of at least 17 years in length are required for identifying human effects on global-mean tropospheric temperature.”

Although the Santer et al. analysis applied to the temperature of the lower atmosphere, the same argument applies to surface temperatures.  Figure 5 shows the BEST trend from March 1993 to March 2010 (the most recent 17-year period available in the data, excluding the two final unreliable points).

BEST 17 year

Figure 5: BEST most recent 17 years of data with linear trend

Over the most recent 17-year period, the BEST trend is 0.36°C per decade*, clearly showing the anthropogenic warming trend over that period.

Examining the causes of decadal variability is both interesting as useful, but exploiting decadal variability to try and incorrectly argue that global warming has magically stopped is neither.  And of course those who argue that global warming has magically stopped conveniently ignore the continued increase in ocean heat content (Figure 6).

warming

Figure 6: Total Global Heat Content from Church et al. 2011

Note that Curry has agreed that tamino’s analysis (replicated in this post) is correct and useful, but

“my statement to Rose was about the plot with the 10 year running mean ending in 2006 being misleading. It is misleading.”

As it so happens, most of the BEST graphs include 12-month running means (i.e. see their research papers).  Moreover, how plotting a 10-year running mean is automatically “misleading” is a mystery (unexplained by Curry), and Curry’s accusations of deception remain unsupported, unwarranted, and unwise.

Accusing other scientists (especially one’s colleagues) of deceit for doing proper statistical analysis is simply unconscionable, and why Curry would accuse others of “hiding the decline” while herself hiding the incline is a mystery.  On  her blog, Curry complains that the article misrepresented her to some degree (while standing behind some of her worst comments, and acknowledging that the quotes attributed to her in the article are correct), but frankly when dealing with fake skeptics like those at The Daily Mail, most of us know that misrepresentation is the norm.

We conclude by offering Dr. Curry the same advice we recently offered Dr. Pielke: DNFTD (Do Not Feed The Delayers).  In short, if an interviewer tries to “tease out” from you a quote about “hiding the decline,” or some other denialist myth, don’t let them.

===================

* There is probably a small contribution to this trend from the 1991 Mount Pinatubo eruption. The 15-year trend is 0.30°C per decade, 16-year is 0.28°C per decade, and 18-year is 0.41°C per decade.

 

And Climate Progress’ piece on the Curry-BEST-Daily Mail debacle:

 

Koch-Funded Study Finds Recent Warming “On the High End” and Speeding Up, as Curry Frags Muller Herself

We have learned two important things from the Berkeley Earth Surface Temperature Study (BEST):

  1. Denier claims that prior scientific analysis of the key land surface temperature data OVER-estimated the warming trend were not merely wrong, but the reverse was true.  Warming has been high and accelerating.
  2. The Deniers and Confusionists and their media allies can never be convinced by the facts and will twist themselves into pretzels to keep spreading disinformation.

We also learned that BEST’s Judith Curry still would rather be a confusionist than a scientist  — but that ain’t news (see “Judith Curry abandons science“).

average temperature chart

The decadal land-surface average temperature using a 10-year moving average of surface temperatures over land. Anomalies are relative to the Jan 1950 – December 1979 mean. The grey band indicates 95% statistical and spatial uncertainty interval.

Recall the foundation of the phony Climategate charge.  Somehow the climate scientists at the Climatic Research Unit (CRU) at the University of East Anglia, led by Phil Jones, were manipulating the data and the peer review process as part of a grand conspiracy to convince the public the earth has been warming faster than it really is.  A key point is that “the CRU compiles the land component of the record and the Hadley Centre provides the marine component.”

The BEST team vindicated climate science — see Koch-Funded Berkeley Temperature Study Does “Confirm the Reality of Global Warming.” Equally important, if you read the key paper, they found:

we find that the global land mean temperature has increased by 0.911 ± 0.042 C since the 1950s….  our analysis suggests a degree of global land-surface warming during the anthropogenic era that is consistent with prior work (e.g. NOAA) but on the high end of the existing range of reconstruction.

D’oh!  The BEST data shows considerably higher warming in recent years than HadCRU (the red line above).

Of course, this isn’t news to anybody who actually follows this issue.  Two years ago, the Met Office released an analysis concluding that “The global temperature rise calculated by the Met Office’s HadCRUT record is at the lower end of likely warming.”

As an aside, Muller, in a March 2010 talk (near the end) clearly states that if warming is on the high range, then humanity should be more concerned because we have “less time to react.”

What’s even more worrisome is that the study clearly shows that the warming trend is accelerating.  First, “Our analysis technique suggests that temperatures during the 19th century were approximately constant (trend 0.20 ± 0.25 C/century).”  No big surprise there.

But then as human emissions kick into overdrive, things heat up:

The trend line for the 20th century is calculated to be 0.733 ± 0.096 C/century,well below the 2.76 ± 0.16 C/century rate of global land-surface warming that we observe during the interval Jan 1970 to Aug 2011.

That is, in the past 40 years, the land has warmed nearly 4 times faster than it did in the last century.  This really kills the denier meme that the observed data suggests we will see only a small amount of warming this century.

In fact, even the high and accelerating warming of the past 4 decades was reduced by human and volcanic aerosol emissions and the general lags between emissions and warming.  Thus, it is now patently obvious that if we stay on our current emissions path, the acceleration of warming will continue as greenhouse gas concentrations continue rising.  That’s without even considering the amplifying carbon-cycle feedbacks.

Another mini-bombshell in the paper, which has led co-author Curry to (try to) frag team leader Muller, is this conclusion:

Though it is sometimes argued that global warming has abated since the 1998 El Nino event (e.g. Easterling and Wehner 2009, Meehl et al. 2011), we find no evidence of this in the GHCN land data.  Applying our analysis over the interval 1998 to 2010, we find the land temperature trend to be 2.84 ± 0.73 C / century, consistent with prior decades.

Still warming, after all these years.

Now even though Curry signed her name to this submitted journal article, she apparently doesn’t believe it’s true.

The pseudo-journalist David Rose of the UK’S Telegraph got a bunch of quotes from her in a piece headlined, “Scientist who said climate change sceptics had been proved wrong [aka Muller] accused of hiding truth by colleague” [aka Curry].

It is exceedingly difficult to know what Curry is saying because

  1. It is always difficult to know what Curry is saying (see Hockey Stick fight at the RC Corral).
  2. Rose generally isn’t reliable (see “David Rose destroys his credibility and the Daily Mail’s with error-riddled climate science reporting” and links therein).
  3. Curry has already walked back some of her comment’s (see here post here, but put a head vise on first, please).

But, she does say on her blog, “In David Rose’s article, the direct quotes attributed to me are correct.”

Still, neither she nor Rose appear to know what they are talking about.  Nor does Curry appear to have read the paper she put her name on.

Tamino has sorted out the statistics in his post, “Judith Curry Opens Mouth, Inserts Foot.”  He notes at the end:

Judith Curry protests that she was misrepresented by the article in the Daily Mail, and several readers have mentioned that David Rose, the author of the article, is just the man to do such a thing. It’s easy to believe that she was indeed the victim of his malfeasance.

But even after reading this post, she still hasn’t disavowed the statement “There is no scientific basis for saying that warming hasn’t stopped.” In fact she commented on her own blog saying, “There has been a lag/slowdown/whatever you want to call it in the rate of temperature increase since 1998.” Question for Curry: What’s your scientific basis for this claim?

In his post, Tamino shows there is no scientific basis for the Curry’s claim at all:

Judith Curry’s statement is exactly the kind of ill-thought-out or not-at-all-thought-out rambling which is an embarrassment to her, and an embarrassment to science itself. To spew this kind of absolute nonsense is shameful. Judith Curry, you should be ashamed of yourself.

If I may offer an imperfect analogy, suppose your kid averages 70 in his ten math tests in 7th grade, and then averages 80 in ten tests in 8th grade and then averages 90 in ten tests in 9th grade.  Is your kid getting better in math?  What if your kid got the same exact yearly averages but had one 100 toward the end of 8th grade and one 100 toward the end of 9th grade.  Does that suddenly mean your kid didn’t get better in math in 9th grade?

The deniers and confusionists would have you believe so.  In fact, Tamino shows that the warming trend is real in the Berkeley data even if you start the trendline fairly recently.  You’ll have to read his post for details, since it’s hard to summarize his analysis.

Bottom Line:  Curry tried to frag Muller, but dropped the grenade on herself.

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About the Author

is the director of CleanTechnica, the most popular cleantech-focused website in the world, and Planetsave, a world-leading green and science news site. He has been covering green news of various sorts since 2008, and he has been especially focused on solar energy, electric vehicles, and wind energy since 2009. Aside from his work on CleanTechnica and Planetsave, he's the founder and director of Solar Love, EV Obsession, and Bikocity. To connect with Zach on some of your favorite social networks, go to ZacharyShahan.com and click on the relevant buttons.



  • hardyharzen

    Hello there Zachary,

    I just wanted to reply to your comments pertaining to mine on cleantechnica, however, all “skeptical” comments there are now “under review”, not visible, and their posters banned from commenting further. Way to have a scientific debate!

    Anyway, I want to say one thing in response to your argument, which boils down to “ignoring the April outlier there appears a warming trend”: This trend, in the greater scheme of things, is basically meaningless. To illustrate my point, please take a look at these diagrams:

    What these show is that there never was a time when the climate was stable; furthermore, much stronger fluctuations have happened entirely without human influence. Finally, as the last diagram impressively demonstrates, we’re in much more danger of hitting the next ice age soon rather than being endangered by slight warming. The holocene optimum was generally beneficial for agriculture — ice ages certainly are NOT.

    Take care.

  • Heather

    This article is a little odd. It seems to suggest that the duration of time they looked at was not sufficient to support a deiners claims, but is enough to prove global climate change is occuring, to support people who promote global warming theory…..

    This seems a little odd to me! How can it be insufficent to prove global warming is not occuring, but sufficient to prove it is?

    • http://importantmedia.org/members/zshahan/ Zachary Shahan

      I think you’ve misread it. Curry is focusing on a 10-year period. The study as a whole was focused on a much longer period of time. Note the dynamically changing graph that shows the time period Curry was focused on versus the time period the study was focused on.

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