Letters to Nature

Nature 413, 508-512 (4 October 2001) | doi:10.1038/35097055; Received 20 February 2001; Accepted 21 August 2001

High frequency of 'super-cyclones' along the Great Barrier Reef over the past 5,000 years

Jonathan Nott1 & Matthew Hayne2

  1. School of Tropical Environment Studies and Geography, James Cook University, PO Box 6811, Cairns, Queensland, 4870, Australia
  2. Australian Geological Survey Organisation, GPO Box 378, Canberra, Australian Capital Territory, 2601 Australia

Correspondence to: Jonathan Nott1 Correspondence and requests for material should be addressed to J.N. (e-mail: Email: Jonathan.Nott@jcu.edu.au).

Understanding long-term variability in the occurrence of tropical cyclones that are of extreme intensity is important for determining their role in ecological disturbances1, 2, 3, 4, 5, for predicting present and future community vulnerability and economic loss6 and for assessing whether changes in the variability of such cyclones are induced by climate change7. Our ability to accurately make these assessments has been limited by the short (less than 100 years) instrumented record of cyclone intensity. Here we determine the intensity of prehistoric tropical cyclones over the past 5,000 years from ridges of detrital coral and shell deposited above highest tide and terraces that have been eroded into coarse-grained alluvial fan deposits. These features occur along 1,500 km of the Great Barrier Reef and also the Gulf of Carpentaria, Australia. We infer that the deposits were formed by storms with recurrence intervals of two to three centuries8, 9, 10, 11, and we show that the cyclones responsible must have been of extreme intensity (central pressures less than 920 hPa). Our estimate of the frequency of such 'super-cyclones' is an order of magnitude higher than that previously estimated (which was once every several millennia12, 13, 14), and is sufficiently high to suggest that the character of rainforests and coral reef communities were probably shaped by these events.