The pitfalls of prediction

This is the last post on pseudo-skeptics for a while, I promise. I have written four in two melting seasons, out of approximately 250 posts.

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The Arctic sea ice, it can burn.

We all remember how Anthony Watts and Steven Goddard were a bit overconfident last year and predicted a nice recovery ('you bet ya'). Their prediction turned out to be just 1 million square km too high. Of course, it didn't matter much for their reputation.

Nevertheless, this year the bravado has magically disappeared and thus they didn't do any predictions, although Goddard still likes to imply that we are witnessing a recovery at every opportunity he gets (for example writing multiple posts at the start of the melting season about how well 2011 is tracking 2006).

Their colleague Joe Bastardi did much better, taking a conservative view and predicting that 2010 would go relatively low. As it did. This success instantly made him last man standing on the pseudo-skeptic side of the debate. Or at least with regards to the Arctic sea ice.

So what did he predict for the 2011 melting season?

 

One down, zero to go. Extent didn't set a new record low, but the credibility of pseudo-skeptics did. Bastardi was at least as wrong as Watts and Goddard (who got off lucky) last year.

Of course, this could happen to anyone (happens to me quite regularly). But most rational and honest people own up to their mistakes and learn from them. Or did I miss Bastardi's explanation for his miserably failed prediction?

Comments

[Rich and Mike Island]

I never thought that 2013 would be the year arctic sea ice melts away completely. But the trend is down, and I think it is more likely than not that we will see a new record low in 2012 or 2013. And before 2030 I think we will see minima below 2.5 million sq. km.

As far as good ole Joe goes, I'll reserve my thoughts ;)

[Noel Ward]

Gee, I wonder what he has to say now about 2011.

Of course, he gets paid to say what he does, so as long as he has a good imagination, he can keep on going!

[Jeffrey Davis]

Why peg your reputation on something as goofy as the extent metric? 2007 was dramatic in that regard, but it was right in line with the trend line in terms of volume. 2008's extent rose back toward trend, but its volume fell dramatically (around 1 std dev) from 2007 and there has been far less seasonal ice in the Arctic since 2007. When you follow extent (as Bastardi does) you're going to get stung every time the winds shift. Is it just a case of any rhetorical port in the storm?

[Kevin McKinney]

When selling FUD, rhetoric is about all you need.

Or can afford, for that matter.

[Chris Reynolds]

Neven,

You said I should post here if I had anything interesting. Well I've got a humdinger I recommend to you, and your esteemed peanut gallery. ;)

While looking for a reason for the recent (post 2007)cool wet summers we've had in the UK I've stumbled upon something very interesting indeed. Link.

[Neven]

Cool, Chris. Thanks a lot.

[Noel Ward]

Chris R. Interesting work! Have you also looked at winter changes? NH winter weather also seems to be shifting in recent years with more cold and snow.

[Ned Ward]

The pitfalls of prediction

Hey, way back on July 15 I predicted (on this very site!) that the IJIS daily minimum would be 4.47 million km2. That was only 1.2% off from the actual minimum (4.527).

Of course, this was mostly just good luck, but my plan now is to refrain from making any further predictions, thus allowing me to retire with an enviable success rate.

Disclaimer: Despite the similarity in names, I am not related to the author of the previous comment (Noel Ward). Or not to my knowledge anyway!

[Chris Reynolds]

Noel Ward,

I've been meaning to post about the issue of winter cold snaps. But it's very involved and things keep cropping up.

Here's the quick version:

There are 3 theories.

1. Late season open water in the Arctic impacts the atmosphere, these impacts last for at least 3 months and could cause colder winters.

2. Reduced UV radiation from the Sun causes stratospheric cooling which cause an easterly shift in European blocking highs - causing cold winters for Western Europe. This seems likely to have caused the 'Little Ice Age'. May also be wider effects than just Western Europe.

2. Siberian snowfall causes low level regional cooling, this sets up a high pressure anomaly which impacts the jetstream and causes cold winters in the Northern Hemisphere.

Note that these 3 are not mutually exclusive, the combination of all of them seems to suggest more cold winters to come. However there is research that shows that in 2009/2010 the conditions causing the cold winter originated with snowfall in Siberia.

The deadline for posting all this is late October. If Judah Cohen is correct (and I think he is) using Siberian snowfall anomalies in October/November and NCEP/NCAR reanalysis it should be possible to give a prediction about this winter.

Whether I can do that is another question. ;)

[Glacierchange.wordpress.com]

Note in the video Joe B. says he was presenting a paper soon in Bastrop Texas. He was one year early to view the fire impacts. That is ironic, he was quite wrong on sea ice, and did not see the drought coming either.

[Remko Kampen]

Nice job Chris.
A remark: please look around the hemisphere. Last winters share a charateristic of high anomalies over (sub-)tropics and very high latitudes, the cold being concentrated around 45-60° N (thus affecting Europe, Russia, United States). Is a pattern. Example: January 1985, http://data.giss.nasa.gov/cgi-bin/gistemp/do_nmap.py?year_last=2011&month_last=08&sat=4&sst=1&type=anoms&mean_gen=01&year1=1985&year2=1985&base1=1951&base2=1980&radius=1200&pol=reg .

[Noel Ward]

Chris R,
Yes, those are the 3 factors I'm thinking about.

The Siberian one doesn't have enough data yet (at least as I understand it) but there at least seems to be some influence beyond regional cooling.

The other factors do seem to be having pretty far reaching effects. The high pressure that hovered over the Arctic last winter did push cold air south, and I'd guess most of us are waiting to see what happens this year. (On the upside, it brings more snow and the skiing is great!). The downside is not so good.

And Ned Ward, no we're not related. But enjoy your "retirement" and the accolades of your prediction. I was predicting about 4.85 but did not go public!

[Peter Ellis]

Ned / Noel: As a molecular biologist, I can assure you that you are most certainly related, the only question is how closely. Mind you, I'd say the same about a banana :-)

[Free Tip: when you go to get a marriage license, and the registrar officially asks if you know any reason why you can't legally marry your intended, "for example, if you're related to one another" - keep your mouth SHUT. Do not open it and start "Well, technically...". That leads to elbows in uncomfortable places.]

[Janne Tuukkanen]

I really hope there's no lasting change to harsh winters in Europe. I hate cold! Ok, where I live, it's -40C Jan-Feb anyway, only difference last two years was increased snow fall. But that kind of temperatures and precipitation in Helsinki or Stockholm, let alone in Denmark or even souther, are very real pain for people and infrastructure.

Interesting thing is temp anomaly in Antarctic during this SH winter. What difference does it mean on the huge ice cap if the surface temperature is -60 or -40 centigrades?

[Kevin O'Neill]

A new paper is out regarding *scientific* prediction of arctic sea ice - Influence of Initial Conditions and Climate Forcing on Predicting Arctic Sea Ice. Authors are Blanchard-Wrigglesworth, Bitz, and Holland. (GEOPHYSICAL RESEARCH LETTERS, VOL. 38, L18503, 5 PP., 2011)

The paper explores the predictive ability of sea ice area, thickness, and volume in Global Circulation Models using the Community Climate System Model version 4. From 'Discussion and Conclusions'

In the model there are times when no significant area predictability exists from either initial conditions or climate forcing, whereas for volume, significant predictability is present almost continuously. We find that beyond the spring, model predictions are equally good whether initialized in September or January, implying that in practice forecasts of the summer sea ice may be made as early as the fall.

Some interesting research on the persistence of volume and area as predictors. And likewise on the time it takes each to reach a new mean:

It takes only about 4 years for the volume to reach a new mean state (when the secular change exceeds -1 standard deviation), whereas for area it takes about 6 years.

And the beat goes on.

[Chris Reynolds]

Remko Kampen,

Thanks I'm aware of the pattern, it's the classic low index AO pattern, although it doesn't always manifest as cleanly as in 2009/10 2010/11 or the graphic you link to (Jan 1985). Actually 2010/11 wasn't that unusual, with a low index AO in December of only 2.631, as against January 2010's record low of 4.266, the lowest since 1960.

Noel Ward,

I think Cohen has done pretty good job of demonstrating that the start of Winter 2009/10 was from the surface, not the stratosphere, and was probably from Siberia, with an anomalous snowfall. However what is less clear is how much reduced UV irradiance and reduced geopotential height thickness (due to low levels of Arctic sea ice in early freeze season), biassed the system towards the ensuing record winter. I need to have more 'fallow' time to let my subconscious work on what I've learned.

Janne Tuukanen,

I agree. 2009/2010 and December 2010 were very expensive for me in terms of heating, and were a nightmare to get around. It wasn't so much the snowfall; here in the UK we get snow and normally it's melted after a few days. In those instances the snow fell, froze, got compacted and froze more. The end result was that the pavements were an ice-rink, only main roads were snow free. Not having a car (by choice) it was a nightmare getting to work.

Thanks Kevin, I'll read that shortly.

[Jeffrey Davis]

Bastardi mentioned his studies. Did he ever divulge what those involved? One could imagine him studying, say, Page 3 and then coming up with predictions.

[Chris Reynolds]

Jeffrey Davis'
"Bastardi mentioned his studies. Did he ever divulge what those involved? One could imagine him studying, say, Page 3 and then coming up with predictions"

I think he just clicked his heels together and wished, vewy vewy hard!

[Espen]

What happened to this Bastard(i) ? And where is he now?