Hansen Profile in the Latest Issue of Seed

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According to Roger PIleke, Jr. Hansen went Out on a Limb with a Super El Niño Prediction

"a strong El Niño event is typically inconsistent with a very active hurricane season, so if Dr. Hansen is proven right, then a bunch of other folks will likely be wrong (including Bill Gray, NOAA, and others who are anticipating another active hurricane season). Time, and not much of it, will tell." -- Roger Pielke

Well, time has told and once again, Hansen has been proven correct and "a bunch of other folks" wrong.

Apparently the scientific "limb" he was on was quite strong -- or perhaps he just knows something the rest do not and was actually sitting safely in the main crotch of the tree and it was others who were out on the spindly limb (and did not realize it).

Looks like his credibility is now headed beyond the stratosphere.

Tim Flannery's recent book, The Weather Makers, also has something to say about El Nino events. Is he out on a limb or in the crotch of the tree? I'm inclined to think he's not too far out on a limb if at all.

Here's an excerpt from my review ( http://www.scienceshelf.com/WeatherMakers_FieldNotes.htm )

Of particular note is his discussion of "Time's Gateways," which mark abrupt, irreversible transitions in global or regional climate. He makes a plausible case that a "magic gate" opened in the western tropical Pacific Ocean in 1976. Before that year, the region's surface temperature frequently dropped below 67 degrees Fahrenheit. Since then, it has rarely been below 77. Another gateway came in 1998, which seems to mark a dramatic change in the El Nino-La Nina cycle. Both of these changes have resulted in dramatic shifts in rainfall patterns, including extended droughts in the African Sahel, Australia, and southeast Asia.

Arguably, those events may be no more than transitory fluctuations. But they may instead be harbingers of more serious transitions to come as the world's climate passes through other gateways later in this century. If they are the latter, the contrarian strategy of waiting for more data before acting is risky business indeed.

To me, the scariest part of this enterprise, which I've been following for 20 years and writing reviews about for seven, is that once extreme scenarios are becoming plausible. The term "magic gate" is hardly scientific, but it may be useful for conveying something to the general public about the difference between weather and climate and the possibility of crossing a threshold into a new climate regime.

Folks...2006-2007 did not see a Super El Nino. A moderate one, yes, but hardly like 1997.

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Chris--I would say that the school's not yet out on the ENSO intensity or duration for 2006-7. There is uncertainty as to whether conditions favoring a fifth kelvin wave are developing or not. As to Hansen, the bite to his prediction is for having an ENSO prediction, not a La Nina, last spring.

Mike

ok fair enough....is it safe to say that 2006 did not see a super el nino, although it remains to be seen what develops in 2007?

For those interested in more detail, here's a quote from the latest El Nino forecast issued today by the Climate Prediction Center:

Most of the statistical and coupled models, including the NCEP Climate Forecast System (CFS), indicate that SST anomalies are near their peak and that decreasing anomalies are likely during February-May 2007 (Fig. 5). Recent observed trends in the upper ocean tend to support those forecasts. Decreasing upper-ocean heat content in the central equatorial Pacific has been progressing east in association with the upwelling portion of the most recent Kelvin wave. In the absence of any further Kelvin wave activity, the upper-ocean heat content should return to near average in a few months. However, there is considerable uncertainty in this outlook, given the resurgence of MJO activity in late December 2006. It is possible that the enhanced precipitation phase of the MJO, which is currently entering the western tropical Pacific, might trigger a more persistent pattern of cloudiness and precipitation over the anomalously warm waters of the central equatorial Pacific during the next several weeks. If that occurs, then the equatorial easterlies over the central Pacific will likely weaken possibly leading to the initiation of a fifth Kelvin wave.

Chris,

I suggest you put your question:

[ok fair enough....is it safe to say that 2006 did not see a super el nino, although it remains to be seen what develops in 2007?]

to farmers and cattle ranchers in southern Australia. El Nino has impacts at both ends.

Jeff Masters also sees El Nino fading, which, he notes, could be bad news for the 2007 Atlantic hurricane season.

Hi Chris:

I had to confirm what I understood as the appropriate terminology regarding ENSO, particularly what is meant by a strong El-Nino vs. weak El Nino (event verses episode I assume). I am not at all sure what is a super-El Nino (a twelve month in duration episode?).

The reason I took you to task is that an El Nino event usually evolves in Autumn, but can resolve itself into an El Nino episode by January. You seem to be implying that we have an event, when what we have is an episode, the strength of which is unclear as to whether the episode will continue to late Spring/early Summer, or late Summer depending on how long the elevated SSTs persist. The weather impact of ENSO will not be fully understood until late Winter and Spring of this year.

Mike

Mike,
Fair enough. I've been reporting on this stuff for almost a year now yet the distinction between "event" and "episode" never came to the foreground until now, for some reason.

At least I think we are agreed that if the current El Nino conditions--whether representing an "event" or an "episode"--are indeed in decline and go away by hurricane season, then we will not have had a "Super El Nino"....

I am not at all sure what is a super-El Nino (a twelve month in duration episode?)

From what I've read, 1997-1998, 1982-1983, and sometimes 1972-1973 are typically considered 'super' El-ninos.
Some peak values from various indices (data from ESRL (CDC) plot page):

1972-3: SOI: -3.40 (May 72) ONI: 2.1 (Dec 72) MEI: 1.776 (Jan 73)
1982-3: SOI: -7.60 (Feb 83) ONI: 2.3 (Dec 82) MEI: 3.149 (Mar 83)
1997-8: SOI: -5.70 (Mar 98) ONI: 2.5 (Nov 97) MEI: 2.72 (Mar 98)

The 1991-1993 El Nino is notable for its unusual length, and on some indices (like MEI) it peaked higher than the 1972-1973 .

Unfortunately I'm unclear on how the different indices define whether an El Nino is weak/moderate/strong. I believe that for both ONI and MEI, 0.5 - 0.9 is weak, 1.0 - 2.0 is moderate or strong.

Plots:
SOI
ONI
MEI

Descriptions:
SOI
ONI
MEI

List of ESRL time series can be found at the ESRL / CDC Climate Indices: Monthly Atmospheric and Ocean Time Series web page.