Friday, December 12, 2014

Plenty of Trend at the Bottom

With all the talk about the pause, the plateau, new record surface temperatures and more, Eli was looking at something from his friend Rob Honeycutt which explained the world according to Judith Curry


when the Bunny noticed an interesting thing


Lots of trend at the bottom, and maybe even something to think about.

30 comments:

Victor Venema said...

If you were a trader, one would call this technical analysis. Don't bet your pensions this way.

Unknown said...

Victor beat me to it...

This looks like an ascending triangle which is a bullish continuation pattern. Trend is intact and it looks poised for a breakout.

Never understood how people could post denialist rants on financial sites which did TA when from a TA perspective the chart of global temperatures is still in an uptrend. But TA is kind of tealeaf reading garbage and never underestimate the power of people to suppress cognitive dissonance.

EliRabett said...

Hey, Eli is but an innocent quant.

Rob said...

I was, frankly, amazed when Curry made the statement that 1998, 2005, 2010, 2014 looked like a plateau to her.

Unknown said...

Also the way I'd draw the upper channel line would be to throw out 1998 and connect all the peaks between 2003 and 2010, and not connect it up to 2014, which would roughly parallel the lower red channel line that Eli drew. That fits both by eyeball and has the advantage that I can explain that as 1998 being an outlier El Nino, and this last year was pretty ENSO-neutral so it makes sense it'd be in the middle of the channel near the green line. Not only does technical analysis suggest that is correct channel line to draw (lol) but it has the advantage that I can actually explain it via a physical process.

Think Eli has a future in finance. Watch out Wall Street...

sylas said...

I am looking forward to sometime around 2016/2017, when the warmest months will be cooler than the coldest months.

Brandon R. Gates said...

Careful sylas, some simple literal-minded soul out there might take you seriously.

sylas said...

Oh, I do hope so! (And make that about 2020; didn't look carefully enough at the scale)

Lars Karlsson said...

When did Curry say this?

EliRabett said...

While spinning

"Well, ranking 1998, 2005, 2010 and 2014 as the ‘warmest years’ seems very consistent with a plateau in surface temperatures since 1998. Even if 2014 maintains its status among the top 4, how does this impact the ‘pause’ narrative"

Russell Seitz said...

Minimum temperatures tend to be at night, when innocent quants are asleep in their beds, with sugarplum futiures adance in their heads.

EliRabett said...

Well actually they tend to be in the winter when all the bunnies have fled south, which is what Eli thinks is going on here.

FWIW Eli, being not so innocent has a full time, live in compliance principal, Ms Rabett, to keep him on the straight and not so amusing.

James Cliborn said...

I would love to leave some cogent, intelligent comment, but I'm laughing too hard!!! Good catch!!

BBD said...

Eli sez

Well actually they tend to be in the winter when all the bunnies have fled south, which is what Eli thinks is going on here.

And Eli may well be correct, at least according to Cohen et al. (2012) and most recently Robeson et al. (2014).

Both studies identified cold mid-latitude NH winters since ~1998 as a contributory factor to the slowdown in the rate of surface warming.

Both studies found an ongoing increase in warm anomalies in spring, summer and autumn over the same period.

Victor Venema said...

She really wrote that. I had to click on the link to believe that. She really wrote that. A trained natural scientist.

"Well, ranking 1998, 2005, 2010 and 2014 as the ‘warmest years’ seems very consistent with a plateau in surface temperatures since 1998. Even if 2014 maintains its status among the top 4, how does this impact the ‘pause’ narrative"

adelady said...

Yup, Victor.

Speaking as one who has the dread task of occasionally marking yr 9 maths/science work, this is one of those that would have earned one of those "schoolby howlers" entries in earlier days. Nowadays, it earns a bit of red ink and a reminder to self to revise basic concepts - again.

How an adult, let alone a scientist, could write stuff like this is beyond me.

MinniesMum

Shelama said...

So how long now, Judith, before those trend lines cross and the temps at the bottom exceed those at the top?

Lars Karlsson said...

adelady:
"How an adult, let alone a scientist, could write stuff like this is beyond me."

She has an audience that want to read stuff like this.

Dano said...

IF you look at the La Nina and neutral years, you'll see upward trends too. IMHO the only reason why "the pause" is pounded so hard over and over and over is because it is the only thing they can come up with: cherry-picking. They do it with Arctic ice (remember John Daly and his Nenana Ice Festival comedy?), with Great Lakes ice, etc.

Best,

D

Simplicius Simplicissimus said...

There are lots of non-denialists who see a plateau. I see two: one from 1981 to 1997 and another from 1998 to 2014.

gistemp

UAH

Fernando Leanme said...

It also depends on the data set one uses. HADCRUT4 shows a flat trend in the 21st century. UAH and others show the same effect.

I've seen too many arguments over plot trendology over the years (debates over the hyperbolic decline parameters of fracked wells can get emotional when a property is being sold). I would focus more on the overall trend. And that trend definetly has a kink in the 21st century. I'd say it looks like stair steps. The models don't model stairsteps, and therein lies the cause of your tribulations.

I noticed Morocco is getting a lot of rain, they are starting to export a lot of tomatoes. This is worrying spanish farmers. Here in eastern spain we are also getting a lot more rain. This is seen as a very positive development. We didn't have a drought like California, but the water was too hard. Now it's tasting much better.

BBD said...

The troposphere is not the climate system.

OHC 0 - 2000m

There is no 'pause' in global warming. It's not worth talking about.

Sure, variability in ocean heat uptake (England et al. 2014) modulates the rate of surface warming. Nobody every said it wouldn't, just as nobody ever said warming would be monotonic.

Short-term variability in the rate of surface warming tells us nothing about climate sensitivity. Those claiming or insinuating otherwise are mistaken at best.

BBD said...

The models don't model stairsteps, and therein lies the cause of your tribulations.

Wrong, as usual.

Simplicius Simplicissimus said...

BBD: I am quite sure you do not understand my point.I have no "tribulations" and I am certainly not "wrong" , nor do I know what you are referring to by "as usual". I've not posted on this site in maybe 5 years. There is a flat trend in the data sets I posted from 1981 through 1997. It is similar to the trend line for the next 17 years. The HADCrut sets tend to show a bigger difference for the two trends while GIStemp and UAH both show very similar trend lines for the two periods. Those are all facts. What you choose to make of those facts is up to you. Lindzen and Christy and Curry conclude that the 1998-present trend line is exceedingly rare. I conclude that it is rare to find your missing keys if you don't look for them. The authors of the papers below all seem to think that the trend over the past decade and a half needs explanation but they don't seem to think that the previous similar trend line needs explanation. I don't understand why.

I think the term "pause" is a red herring. In any event all who are cock sure that there is nothing worth thinking about would probably do well to at least read the abstracts of these papers:

http://www.nature.com/ngeo/journal/v7/n3/full/ngeo2105.html (Reconciling warming trends Gavin A. Schmidt et al) who write:
Climate models projected stronger warming over the past 15 years than has been seen in observations.


http://www.sciencemag.org/content/333/6044/866.short (The Persistently Variable “Background” Stratospheric Aerosol Layer and Global Climate Change, Solomon et al) ... independent data sets show that stratospheric aerosols have increased in abundance since 2000. ... Climate model projections neglecting these changes would continue to overestimate the radiative forcing and global warming in coming decades if these aerosols remain present at current values or increase.

and another:

http://onlinelibrary.wiley.com/doi/10.1002/grl.50156/abstract (Surface response to stratospheric aerosol changes in a coupled atmosphere–ocean model J. C. Fyfe) [1] Previous work with a simple climate model has suggested a global cooling impact of increasing stratospheric aerosol.

and another:

http://www.nature.com/ngeo/journal/v7/n3/full/ngeo2098.html (Volcanic contribution to decadal changes in tropospheric temperature Santer et al) Despite continued growth in atmospheric levels of greenhouse gases, global mean surface and tropospheric temperatures have shown slower warming since 1998 than previously

My question is: Given that the 1981-1997 trend is similar to that of 1998-2014 trend why are there no attribution studies for the earlier period? I presume that at least some of the stratospheric aerosols are due to Chinese power plants. Although these authors don't seem to mention them (in their abstracts which is all I read.)

BBD said...

Simplicius

BBD: I am quite sure you do not understand my point.I have no "tribulations" and I am certainly not "wrong"

Confusion, I fear. I was responding to Fernando, whose words I quoted.

To the points you raise:

Climate models projected stronger warming over the past 15 years than has been seen in observations.

The Schmidt et al. (2014) paper shows that when the CMIP5 model forcings are updated to reflect real-world conditions (solar, volcanism, ENSO) then they come into much better agreement with observations. This suggests that the slowdown in the rate of surface warming is multifactoral - variability in ocean heat uptake, cold mid-latitude NH winters, increased volcanic aerosol negative forcing, quiet solar cycle 24.

Your other references support this view and I certainly agree with it.

My point is that none of this influences climate sensitivity but lots of contrarians claim that "the pause" (which barely exists if you look at OHC 0 - 2000m layer and remember that the climate system is mostly ocean) somehow "proves" that "the IPCC is alarmist" etc.

Are we in violent agreement by any chance?

Simplicius Simplicissimus said...

oops. Yes. Violent agreement! But why is the trend line from 1981-1997 uninteresting while that for 1998-present needs explanation?

If people had tried to account for the previous 1.5 decades and concluded that it was intrinsic variability then they'd have a hard time arguing that the 1998-present trend COULD NOT be accounted for by the same. The papers above all seem to be in agreement that something happened during the last ~15 years that needs explaining. Did the climate models not overestimate the warming from 1981-1997? Do the models show a flat trend for that period?

BBD said...

Simplicius

Did the climate models not overestimate the warming from 1981-1997? Do the models show a flat trend for that period?

As I understand it, the models are designed to investigate the long term behaviour of the forced climate system. They aren't designed to predict the real world climate exactly, decade for decade. This being so, they cannot be held up against observations and deemed to be lacking in skill if they don't match exactly for short periods.

BBD said...

Simplicius

My question is: Given that the 1981-1997 trend is similar to that of 1998-2014 trend why are there no attribution studies for the earlier period?

This might be of interest: Jones et al. (2013) Attribution of observed historical near‒surface temperature variations to anthropogenic and natural causes using CMIP5 simulations:

We have carried out an investigation into the causes of changes in near‒surface temperatures from 1860 to 2010. We analyze the HadCRUT4 observational data set which has the most comprehensive set of adjustments available to date for systematic biases in sea surface temperatures and the CMIP5 ensemble of coupled models which represents the most sophisticated multi‒model climate modeling exercise yet carried out. Simulations that incorporate both anthropogenic and natural factors span changes in observed temperatures between 1860 and 2010, while simulations of natural factors do not warm as much as observed. As a result of sampling a much wider range of structural modeling uncertainty, we find a wider spread of historic temperature changes in CMIP5 than was simulated by the previous multi‒model ensemble, CMIP3. However, calculations of attributable temperature trends based on optimal detection support previous conclusions that human‒induced greenhouse gases dominate observed global warming since the mid‒20th century. With a much wider exploration of model uncertainty than previously carried out, we find that individually the models give a wide range of possible counteracting cooling from the direct and indirect effects of aerosols and other non‒greenhouse gas anthropogenic forcings. Analyzing the multi‒model mean over 1951–2010 (focusing on the most robust result), we estimate a range of possible contributions to the observed warming of approximately 0.6 K from greenhouse gases of between 0.6 and 1.2 K, balanced by a counteracting cooling from other anthropogenic forcings of between 0 and −0.5 K.

Hank Roberts said...

> ascending triangle which is a
> bullish continuation pattern....
> poised for a breakout.

Paging Tamino, cross-reference for
http://tamino.wordpress.com/2014/12/09/is-earths-temperature-about-to-soar/

John Brookes said...

Maybe that temperature was just bumping up against the glass ceiling...