Nafeez,

Does the current understanding of El-Nino/La Nina Southern Oscillation  
include an explanation of the waxing and waning of the strength of the  
phenomenon. Or to put it more succinctly has the waxing and waning  
been successfully modelled?

Regards,

Brian Orr

On 11 Jan 2011, at 16:45, Nafeez Ahmed wrote:

> Dear Alastair,
>
> It's pretty clear that there is no direct evidence that the current  
> flash floods in Australia is a consequence of global warming.  
> However, there is some plausible and tentative evidence of a link.
>
> Certainly, the consensus is that the current floods are due to La  
> Nina. However, a recent NASA study last year published in  
> Geophysical Research Letters concluded that the El-Nino/La Nina  
> Southern Oscillation (ENSO is growing stronger over the last two  
> decades. This particular paper focuses on a 'relatively new' kind of  
> El-Nino. Also, I'm not aware of any other papers on this subject.  
> While this paper certainly suggests the scale of these floods may  
> well be linked to the partial strengthening of ENSO , it cannot yet  
> be scientifically proved, and the jury is still out on the exact way  
> in which climate change may affect ENSO, though the authors of this  
> paper have said that climate change may be a cause of this  
> strengthening.
>
> http://www.jpl.nasa.gov/news/news.cfm?release=2010-277&cid=release_2010-277&msource=nino20100825&tr=y&auid=6878202
>
> http://www.agu.org/pubs/crossref/2010/2010GL044007.shtml
>
> Here's what the co-author of the study told America.gov:
>
> “The shift of action from the eastern to the central Pacific is  
> plausibly the result of global warming, based on an analysis of sea  
> surface temperature data records that are admittedly limited in  
> terms of their length [30 years] and models that are admittedly  
> imperfect,” he added. “But the two pieces of evidence together are  
> pointing in the same direction.”
>
> Many climate models predict that such events will become much more  
> frequent under projected global warming scenarios, McPhaden said.
>
> Read more: http://www.america.gov/st/energy-english/2010/September/20100917080213lcnirellep0.4197199.html&distid=ucs#ixzz1AkHQivo7
>
> So it looks plausible that events like what has happened in  
> Australia are a consequence of climate change - but we should very  
> cautious about drawing any firm conclusions, as the evidence at the  
> moment is ultimately inconclusive.
>
> Best
> nafeez
>
>
> -- 
> Dr. Nafeez Mosaddeq Ahmed M.A. D.Phil (Sussex)
>
> Executive Director
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