More extreme swings of the South Pacific convergence zone due to greenhouse warming

Cai, Wenju and Lengaigne, Matthieu and Borlace, Simon and Collins, Matthew and Cowan, Tim and McPhaden, Michael J. and Timmermann, Axel and Power, Scott and Brown, Josephine and Menkes, Christophe and Ngari, Arona and Vincent, Emmanuel M. and Widlansky, Matthew J. (2012) More extreme swings of the South Pacific convergence zone due to greenhouse warming. Nature, 488 (7411). pp. 365-369. ISSN 0028-0836


The South Pacific convergence zone (SPCZ) is the Southern Hemispheres most expansive and persistent rain band, extending from the equatorial western Pacific Ocean southeastward towards French Polynesia. Owing to its strong rainfall gradient, a small displacement in the position of the SPCZ causes drastic changes to hydroclimatic conditions and the frequency of extreme weather events-such as droughts, floods and tropical cyclones-experienced by vulnerable island countries in the region. The SPCZ position varies from its climatological mean location with the El Niño/Southern Oscillation (ENSO), moving a few degrees northward during moderate El Niño events and southward during La Niña events. During strong El Niño events, however, the SPCZ undergoes an extreme swing-by up to ten degrees of latitude toward the Equator-and collapses to a more zonally oriented structure with commensurately severe weather impacts. Understanding changes in the characteristics of the SPCZ in a changing climate is therefore of broad scientific and socioeconomic interest. Here we present climate modelling evidence for a near doubling in the occurrences of zonal SPCZ events between the periods 1891g-1990 and 1991g-2090 in response to greenhouse warming, even in the absence of a consensus on how ENSO will change. We estimate the increase in zonal SPCZ events from an aggregation of the climate models in the Coupled Model Intercomparison Project phases 3 and 5 (CMIP3 and CMIP5) multi-model database that are able to simulate such events. The change is caused by a projected enhanced equatorial warming in the Pacific and may lead to more frequent occurrences of extreme events across the Pacific island nations most affected by zonal SPCZ events.

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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Faculty/School / Institute/Centre: No Faculty
Faculty/School / Institute/Centre: No Faculty
Date Deposited: 06 Jan 2022 00:40
Last Modified: 16 Feb 2022 05:19
Uncontrolled Keywords: General; Environmental Health and Pollution Control; METEOROLOGICAL ASPECTS OF POLLUTION; Air-sea interaction; Air-sea interaction;
Fields of Research (2008): 04 Earth Sciences > 0401 Atmospheric Sciences > 040104 Climate Change Processes
Fields of Research (2020): 37 EARTH SCIENCES > 3702 Climate change science > 370201 Climate change processes
Socio-Economic Objectives (2008): D Environment > 96 Environment > 9603 Climate and Climate Change > 960309 Effects of Climate Change and Variability on the South Pacific (excl. Australia and New Zealand) (excl. Social Impacts)
Socio-Economic Objectives (2020): 19 ENVIRONMENTAL POLICY, CLIMATE CHANGE AND NATURAL HAZARDS > 1905 Understanding climate change > 190506 Effects of climate change on the South Pacific (excl. Australia and New Zealand) (excl. social impacts)
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