Extreme La Niña events expected to increase *N&V*
Embargoed until:
26-Jan-2015 11:00 US Eastern time | 16:00 London time
27-Jan-2015 01:00 Japanese time | 03:00 Australian Eastern time
DOI: 10.1038/nclimate2492
DOI: 10.1038/nclimate2509
Extreme La Niña events, which impact on both sides of the Pacific Ocean are
predicted to occur almost twice as often, reports a paper published online this week
in Nature Climate Change. The atmospheric circulation associated with La Niña
generates extreme weather in many parts of the world, including droughts in the
southwestern United States, floods in the western Pacific and increased landfalling
west Pacific cyclones and Atlantic hurricanes.
El Niño and La Niña events are opposite phases of the natural climate
phenomenon, the El Niño/Southern Oscillation. Extreme La Niña events occur
when cold sea surface temperatures in the central Pacific Ocean contrast with the
warming land areas of Maritime Southeast Asia in the west and create a strong
temperature gradient.
Wenju Cai and colleagues report that increased land warming relative to the ocean
and an increased frequency of extreme El Niño events, are setting the scene for
these events every 13 years compared with a past frequency of one every 23 years.
They use a collection of global climate models, selected for their ability to simulate
extreme La Niña events, to investigate how the frequency of those events will
change with global warming. The authors find that extreme La Niña events will
increase in frequency and that approximately 75% of this increase will occur
immediately following an extreme El Niño event. The implication of this is that
weather patterns will switch between extremes of wet and dry.
In an accompanying News and Views, Antonietta Capotondi notes that “events
associated with devastating impacts on the world climate and economies will
become more frequent, but they may shortly follow other devastating effects of
somewhat opposite sign.” She concludes that “the possibility of more frequent
devastating La Niña events must be seriously considered as we prepare to face the
consequences of global warming”
CONTACT
Wenju Cai (CSIRO Oceans and Atmosphere Flagship, Aspendale, Australia)
Tel: +61 3 9239 4419; E-mail: wenju.cai@csiro.au
Antonietta Capotondi (NOAA Earth System Research Laboratory, Boulder, CO,
USA) N&V author
Tel: +1 303 497-6105; E-mail: antonietta.capotondi@noaa.gov
Please link to the scientific paper in online versions of your report (the URL will
go live after the embargo ends):
http://nature.com/articles/doi:10.1038/nclimate2492
http://nature.com/articles/doi:10.1038/nclimate2509