Projected increase in El Niño-driven tropical cyclone frequency in the Pacific

• Published in: Nature climate change Vol. 7; no. 2; pp. 123 - 127
• Main Authors: Chand, Savin S., Tory, Kevin J., Ye, Hua, Walsh, Kevin J. E.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 01.02.2017
• Subjects: Climate change; Cyclones; El Nino; Environmental conditions; Greenhouse effect; La Nina; Marine; Ocean basins; Simulation; Southern Oscillation; Tropical cyclones; Wind shear; Australia; ISE, USA, Hawaii; ISEW, Pacific, Vanuatu; I, Central Pacific, Pacific Ocean Is; Marshall Islands; ISEW, Pacific, Fiji; IN, North Pacific
• ISSN: 1758-678X; 1758-6798
• DOI: 10.1038/nclimate3181

The El Niño/Southern Oscillation (ENSO) drives substantial variability in tropical cyclone (TC) activity around the world. However, it remains uncertain how the projected future changes in ENSO under greenhouse warming will affect TC activity, apart from an expectation that the overall frequency of TCs is likely to decrease for most ocean basins. Here we show robust changes in ENSO-driven variability in TC occurrence by the late twenty-first century. In particular, we show that TCs become more frequent (∼20-40%) during future-climate El Niño events compared with present-climate El Niño events--and less frequent during future-climate La Niña events--around a group of small island nations (for example, Fiji, Vanuatu, Marshall Islands and Hawaii) in the Pacific. We examine TCs across 20 models from the Coupled Model Intercomparison Project phase 5 database, forced under historical and greenhouse warming conditions. The 12 most realistic models identified show a strong consensus on El Niño-driven changes in future-climate large-scale environmental conditions that modulate development of TCs over the off-equatorial western Pacific and the central North Pacific regions. These results have important implications for climate change and adaptation pathways for the vulnerable Pacific island nations.