Hi Luis,

there is in fact no clear consensus about the future change in the overall frequency of El Nino or La Nina events.  The simulations of the 21st century carried out under the Coupled Model Intercomparison Project (CMIP) contain the best computer climate models in the world but do not show agreement between different models.  Neither do they agree on any future change in the duration of events. 

However, what they do show is that the very strongest events will become more frequent and that the teleconnections to ENSO will likely become stronger in future.  I recommend this review paper which summarizes the current situation:

http://www.nature.com/nclimate/journal/v5/n9/full/nclimate2743.html

Best regards

Adam

Studies show increases in frequency, duration, and impact severity resulting from these events. A study in Nature Climate Change (2014) quantifies it as doubling in impacts. These are mostly from shifts in sea surface temperature and its expansion that causes serious changes in rainfall patterns and moisture regimes. The impacts on ecosystems and socioeconomic systems could be substantial.

Due to rise in temperature following climate change the El nino event will become more frequent leading to drought in Asia, Africa and Australia and floods in North Africa.

 Continuation from #Arvind Singh's answer... i would say and vice versa for the la nina  phenomenon as one is just the opposite of the other.

And perhaps this would be good research in particular if you specialize on its impact on a certain region for example the above average rains in the greater horn of Africa  during  Nov-Feb is linked to climate change and the ENSOs.

In my opinion, it's worth the trouble to explore all possibilities.

I found this paper interesting and include it as one approach that considers natural phenomena that impact both global climate and ENSO, though by how much appears uncertain.

Luis Eduardo Antunes Vieira and Ligia Alves da Silva, Geomagnetic modulation of clouds effects in the Southern Hemisphere Magnetic Anomaly through lower atmosphere cosmic ray effects, GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L14802, doi:10.1029/2006GL026389, 2006

http://mtc-m16.sid.inpe.br/attachment.cgi/sid.inpe.br/mtc-m16@80/2006/08.02.16.40/doc/grl21625.pdf

Hi Luis,

there is in fact no clear consensus about the future change in the overall frequency of El Nino or La Nina events.  The simulations of the 21st century carried out under the Coupled Model Intercomparison Project (CMIP) contain the best computer climate models in the world but do not show agreement between different models.  Neither do they agree on any future change in the duration of events. 

However, what they do show is that the very strongest events will become more frequent and that the teleconnections to ENSO will likely become stronger in future.  I recommend this review paper which summarizes the current situation:

http://www.nature.com/nclimate/journal/v5/n9/full/nclimate2743.html

Best regards

Adam

What is “climate change?”

In nature, what has been the impact of climate change on the frequency, duration and severity of El Niño and La Niña events?

What is a "teleconnection?"

Last night came across this subject in Climate Change in Prehistory W. J. Burroughs, Cambridge, 2005), covering the Holocene up to about 2500 before the present. Chapter 2 is an over view of the past 100,0000 years, and section 2.7 is an overview of the Holocene, with emphasis on climate variability, including ENSO.

The author cites Rodbell et al. 1999,and Sandweiss, Maasch, &Anderson, 2001 stating that ENSO was largely absent during the early Holocene. He cites Kavoutas et al. 2002 regarding linkage between ENSO and global climate mentioning 1.2 deg C as sufficient to cause southward shift of ITCZ and persistent ENSO.

The author cites Andean ice core date (Thompson, 1998), as evidence of 'return' of ENSO about 5500 years BP. There is discussion of the CASTINE Project. (Mayewski, Maine.edu).

The author cautions against a top-down (deductive) approach to regional climate study (including ENSO) presumably because he has discovered inconsistencies in results based on over-generalization based on global theories.

http://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter14_FINAL.pdf

page 1220 ef

"The realism of the representation of El Niño-Southern Oscillation (ENSO) in climate models is increasing and models simulate ongoing ENSO variability in the future. Therefore there is high confidence that ENSO very likely remains as the dominant mode of interannual variability in the future and due to increased moisture availability, the associated precipitation variability on regional scales likely intensifies"