Hansen's latest on El Niño

[Robert Chris]

In Hansen's latest commentary he makes the following observation about El Niño predictions:

There are inherent limitations on predictability caused by chaotic aspects of atmosphere and ocean dynamics, but that cannot account for the huge range among models. It is common to look at the range of model results and treat this as if it were a probability distribution for the real world. It is not. It is simply the fog of results from all models – the good, the bad, and the ugly – and a rather fruitless comparison.

This is an important observation that applies more widely.   The IPCC routinely makes this mathematical error.  Model results are not a probability distribution and in the absence of specific reasons to the contrary (which rarely exist), any model result should be considered as likely as any other.

Regards

RobertC

[Tom Goreau]

AI is trained to find the average, worthless though they may be, and ignore outliers……….

 

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[Robert Chris]

Tom, this is what Perplexity says about that:

Use the ensemble mean as a reference point, but rely at least as much on the spread, tails, and model agreement. For risk-sensitive decisions, the question is usually not “what is the mean?” but “what range of outcomes remains plausible, and how much risk sits in the extremes?”

Regards

Robert

[Tom Goreau]

Well, yes, but that’s not what governments do. IPCC reviewers read Hansen’s papers more than 5 years old, and lump them with the rest, even though almost all are of inferior quality. IPCC Government “reviewers” (censors) are sure to reject outliers whose quality differences they don’t understand.

[Jan Umsonst]

Hi all all this Super El Nino prediction non-sense made we write a post some days ago - happy that Hansen sees it similar.

This non-sense made me write this post citing a study on which models to use for "long term" prediction of El Nino upstream of the spring time prediction barrier for El Ninos. Important that from a subsurface perspective we are not in super El Nino territory which can change the next months but far from clear...

Here my short post on the matter:

A short on all this super El Nino forecast nonsense that fills now the ether...

First there exists a spring prediction barrier with forecasts being highly unreliable before July.

Secondly, subsurface temperature anomalies are not integrated in most forecast models which show at the moment no Super El Nino as warm water anomalies in the western Pacific and temperature anomalies are too low currently.

Added two graphs showing the recent trends. Not too much but an El Nino certainly being possible.

But this does not mean that we will not get a strong El Nino in terms of temperature rise as no strong El Nino is needed as 2023/24 had shown so strikingly.

But another temperature jump of such a magnitude seems highly unlikely. But if it would happen, as this system surprises us now all the time the extinction level event triggered by a warming rate dependent feedback cascade would happen fast...

One more jump and this system goes off chart in terms of extremes and feedbacks...

Here what they write:

Furthermore, once an ENSO event has been sufficiently stimulated in July, it usually persists until the following February, with high predictability. However, the prediction skill made before July is much lower for all forecasting models (Barnston et al., 2012), which is termed as the spring predictability barrier (SPB) (Clarke, 2014).      

Despite decades of research on forecasting the El Niño–Southern Oscillation (ENSO) in the past decades, skillfully predicting the ENSO across the spring predictability barrier remains challenging. In this study, we utilize the ensemble of four model products to identify a new subsurface precursor consisting of the anomalous equatorial zonal velocity over 180°–150°W and 140–180 m and potential temperature in the western Pacific (over 120°–140°E and 120–160 m), which could predict the ENSO before spring by applying regression analysis. Such a precursor can predict the Niño 3.4 index in December at a lead time of 13 months with a regressed correlation of 0.79. The anomalous subsurface zonal velocity in the central Pacific favors the eastward migration of the warm water during the development of El Niño. Further validations with diverse training and application periods indicate that for initialization in November, this new precursor shows high skills in predicting the Niño 3.4 index at a lead time of 6–18 months over 1993–2016, outperforming counterparts for the other traditional precursors. Our study can help highlight the importance of subsurface processes in the ENSO development, improving our general ability to predict the ENSO, and enabling better preparedness for the implications of its occurrence. 

"A new subsurface precursor across the spring predictability barrier for the ENSO prediction"; https://lnkd.in/dJiFAumF

https://www.linkedin.com/posts/jan-umsonst-92ba859a_a-short-on-all-this-super-el-nino-forecast-activity-7448350455992045568-SOuE?utm_source=share&utm_medium=member_desktop&rcm=ACoAABUpBvMBMxadQJFFBo2hbi8x-qMaoOk0TU0

Here the two graphs with the heat accumulation in the western Pacific and temperature anomalies:

The last one had been updated and reached now these levels - these graphs of subsurface heat are a good approximation of what will be possible as in the past they correlated with El Nino strength:

Here the source: https://www.pmel.noaa.gov/elnino/upper-ocean-heat-content-and-enso

All the best

Jan

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[Tom Goreau]

I’ve been tracking global SST anomalies and coral bleaching since the satellites to measure SST went up in 1982. None of the models have proved very accurate. Wait and see what the data says!

 

This El Niño event started when the southern hemisphere was warming up. Severe high temperature coral bleaching took place in Tonga and Fiji when it started, but those areas are now cooling while the north Equatorial Pacific, especially Kiribati, is warming dramatically.

 

Record temperatures there this year won’t make much difference for coral bleaching, since it has been estimated by field coral experts that 99.9% of the corals are already dead, in the most remote and least polluted part of the ocean.

 

From: healthy-planet-...@googlegroups.com <healthy-planet-...@googlegroups.com> on behalf of Jan Umsonst <j.o.u...@gmail.com>
Date: Wednesday, April 15, 2026 at 12:56
To: healthy-planet-...@googlegroups.com <healthy-planet-...@googlegroups.com>
Subject: Re: [HPAC] Hansen's latest on El Niño

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[John Dixon]

Hansen says it well. 

From another perspective the distribution provides a reminder of the diversity of current knowledge 

Best

John

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