I blogged earlier today at work about the latest ENSO assessment from the Climate Prediction Center, and said this:
We’re at the point in the year where forecasting is hard, so the computer models used to try to get a handle on where this is headed are all over the map.
It’s the conventional wisdom the ENSO forecast community has been giving me for years, a sort of “pivot point” around this time of year when their forecast skill is weakest.
Then comes this draft paper from Jim Hansen and others:
We suggest that an El Nino is likely to originate in 2006 and that there is a good chance it will be a “super El Nino”, rivaling the 1983 and 1997-1998 El Ninos, which were successively labeled the “El Nino of the century” as they were of unprecedented strength in the previous 100 years.
(hat tip RP for the link to the Hansen piece)
Hansen goes on to “argue further that global warming has increased the likelihood of super El Ninos.'”
As it happens, I’ve been poking at this question as well because of the important relationship between ENSO and the climate here in the southwest. More/bigger (less/smaller) El Ninos means less (more) drought where I live. As Eric Guilyardi recently put it, “Predicting El Nino occurrence and amplitude… is a key societal need.”
The problem, as Hansen acknowledges, is that the global climate models are all over the map on this one.
Haiyan Teng and colleagues at NCAR just published a model intercomparison in GRL that looked, among other things, at the way a suite of global climate models handled ENSO under CO2 held constant at 2000 values.
In the present set of models, 9 out of 16 models show a committed El Nino-like response, while the rest have either a La Nina-like response or more uniform committed warming across the tropical Pacific. The reasons for these differing responses require further investigation.
That’s the paper that got me curious, which led me to Guilyardi’s paper in Climate Dynamics which also did a big model comparison. Again, the results tilted toward increased El Nino amplitude in a warmer climate, “though there is a considerable spread of El Nino behaviour among the models.”
I’m not a scientist, so I won’t try to evaluate Hansen’s claims, but were I a journalist trying to write about this and looking for the sweet spot where the bulk of the science lies, I’d have to explain to readers that Hansen is well to one side of it on both the question of what can be said now about what will happen in the coming year, and of what effect greenhouse warming might have on ENSO.
I don’t know enough about the theory or the models to say for sure, but it looks as if Hansen is proposing a new physical mechanism for incorporation into both. Given his prominence and track record, maybe it would be better to say the field is to one side of Hansen?
Also, note that RP Jr. transformed Hansen’s statement of a “likely” El Nino for this year with a “good chance” of a really strong one into Hansen having staked his reputation on it actually happening. It’s this sort of stretch that gives RP Jr. the reputation he has (that and deeming “brilliant” utter cr*p like the “Nightmare Science” opinion piece he posted Wednesday). But I’m sure I’m mischaracterizing his views once again.
But I’m much more interested in the overall context for this piece (noting that it covered two topics besides ENSO-GW) and in particular the implications of the latter topic that a) we are now definitely warmer than at any time during the Holocene, b) “business as usual” will by 2100 put us at the warmest temp for at least the last million years and, most important of all, c) proposes a working definition for dangerous climate change (relating it back to the UNFCCC, which is the law of the land here and in most countries) coupled with a projection that “business as usual” will cross the threshold into dangerous climate change in approximately ten years.
Hansen has been hinting around at this for the last year or so, but this seems to be the first statement of it in a form that can (and I suspect will) be used in the AR4.
a) In checking the graphs at the bottom it’s apparent that in most of the world the Holocene has been just as warm – not even considering the overriding effects of precipitation, nor the uncertainty of the observations. Hardly alarming …
b) Here’s what the IPCC said about their projections, and there’s no indication they’ve included the missing influences to any competent degree since:
“Feedbacks between atmospheric chemistry, climate, and the biosphere were not developed to the stage that they could be included in the projected numbers here. Failure to include such coupling is likely to lead to systematic errors and may substantially alter the projected increases in the major greenhouse gases.”
c. Yep, ten years (two hands worth of fingers) seems to be a pretty standard alarmist time frame:
Steve H. –
Are you just trolling with this global cooling meme that you’ve been splatting all over the Internets in the last 24 hours, or do you take it seriously?
John, of course Steve is repeating that stuff even though he has long since seen the information refuting it, but just to make absolutely certain (and for anyone else reading this who wants to know the details of the “global cooling” myth): http://www.realclimate.org/index.php?p=94.
Steve H. answered any remaining questions about his own credibility a couple of weeks ago when he resorted to an article by Lyndon Larouche to support some point he was making.
Ah, Steve B. – back to throwing out ad hominems I see. Congratulations though, you resisted for a week… Of course, you said nothing of value during that week either that I saw. I guess this is all you have.
However, your Realclimate link says this:
“By the end of the 1970’s, though, it had become clear that CO2 warming would probably be dominant; that conclusion has subsequently strengthened.”
I wonder what references “in the scientific press” they have saying that back in the 1970’s? Of course by your statement you believe it to be so. Got any backup? I didn’t think so.
John – One point is the “10 year thing” – Two hands of 5 fingers. The equivalent of “50/50” – frequently an indication somebody really has no clue… But mostly showing how “science” has flipped itself from one projected disaster to the opposite in the last 30 years. Of course maybe I’m wrong and Steve B is right. Maybe he will actually come up with a reference backing the statement up. I’m not holding my breath though…
I’m not sure what meme you’re talking about though – Certainly not the “Global Warming Will Be Catastrophic” one. That’s the one over on the “Realclimate” site.
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hi, you know that hansen’s paper was just a draft. can’t understand the stuff above. i sent my comments to hansen to fix his draft and question reasons for the el nino forecast. anyone could (and some did) jump on a bandwagon to that was still parked in the barn.
i thought you were a bit above it. mickey
You may be right Mickey. It’s a close call, given the draft nature of the thing. But on balance, I think these discussions are interesting, and therefore worth airing in public when we can. It’s the journalist in me.
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Steve H., I don’t know why I bother, but this is probably a good place for you to start: http://www.aip.org/history/climate/GCM.htm#L_M013 . As you can see the late ’70s were a key period in the development of the science, culminating in the 1979 Charney report.
Thanks, Steve B. Looks like a lot of good reading.
hi john, thanks for your comments on my comments. i should send you if you want to see them what i wrote to hansen about his longshot forecast of a super el nino this year (2006). there is a lot more of a downside to his being wrong than there is an upside if he is right.
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A super El Nino isn’t possible because of electrics.
During the peak of the interglacial El Nino occurred every 15-20 years. It’s only the past 5,000 years that with general cooling that El Nino has occurred every 2-7 years. A strong El Nino causes such lightning in South America as to change regional East Pacific sub surface charge and induction conditions and makes it more difficult for the cloud altering electrics to re occur. Here is a good strike link to follow for this winters weak El Nino, highly inconsistant with Jim Hansen’s call and GHG theory in general:
Notice how the greatest anomalies are in the location of South America where ENSO is most impacted by thunderstorms.
Here are the podcasts on topic:
I am on 20 minutes into the show.
I am on 20 minutes into the show.
I am on 25 minutes into the show.
On the Nov 2 TT I am on 20 minutes into the show.
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