Gergis, JLFowler, Anthony2012-03-092009Climatic Change 92:343-387 20090165-0009https://hdl.handle.net/2292/13602Reconstructions of past climate are important for providing a historical context for evaluating the nature of 20th century climate change. Here, a number of percentile-based palaeoclimate reconstructions were used to isolate signals of both phases of El Niño-Southern Oscillation (ENSO). A total of 92 (82) El Niño (La Niña) events were reconstructed since A.D. 1525. Signi cantly, we introduce the most comprehensive La Niña event record compiled to date. This annual record of ENSO events can now be used for independent veri cation of climate model simulations, reconstructions of ENSO indices and as a chronological control for archaeologists/social scientists interested in human responses to past climate events. Although extreme ENSO events are seen throughout the 478-year ENSO reconstruction, approximately 43% of extreme and 28% of all protracted ENSO events (i.e. both El Niño and La Niña phase) occur in the 20th century. The post-1940 period alone accounts for 30% of extreme ENSO years observed since A.D. 1525. These results suggest that ENSO may operate diff erently under natural (pre-industrial) and anthropogenic background states. As evidence of stresses on water supply, agriculture and natural ecosystems caused by climate change strengthens, studies into how ENSO will operate under global warming should be a global research priority.Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. Details obtained from http://www.sherpa.ac.uk/romeo/issn/0165-0009/https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htmJournal Article10.1007/s10584-008-9476-zCopyright: Springer Science + Business Media B.Vhttp://purl.org/eprint/accessRights/RestrictedAccess