Wednesday, January 29, 2014

New paper finds Australian tropical cyclones are currently at 'unprecedented' lowest levels in 550-1,500 years

A paper published today in Nature finds "Australian tropical cyclone activity [is currently] lower than at any time over the past 550–1,500 years" and "we show, on the basis of a new tropical cyclone activity index (CAI), that the present low levels of storm activity on the mid west and northeast coasts of Australia are unprecedented over the past 550 to 1,500 years."

"Other studies project a decrease in the frequency of tropical cyclones towards the end of the twenty-first century in the southwest Pacific, southern Indian and Australian regions. Our results, although based on a limited record, suggest that this may be occurring much earlier than expected."


The paper adds to many other peer-reviewed publications finding global warming decreases storm activity, and that climate models predict decreased storm activity in the future, opposite to the claims of climate alarmists. 


Nature 505, 7485 (2014). doi:10.1038/nature12882

Authors: Jordahna Haig, Jonathan Nott & Gert-Jan Reichart

The assessment of changes in tropical cyclone activity within the context of anthropogenically influenced climate change has been limited by the short temporal resolution of the instrumental tropical cyclone record (less than 50 years). Furthermore, controversy exists regarding the robustness of the observational record, especially before 1990. Here we show, on the basis of a new tropical cyclone activity index (CAI), that the present low levels of storm activity on the mid west and northeast coasts of Australia are unprecedented over the past 550 to 1,500 years. The CAI allows for a direct comparison between the modern instrumental record and long-term palaeotempest (prehistoric tropical cyclone) records derived from the 18O/16O ratio of seasonally accreting carbonate layers of actively growing stalagmites. Our results reveal a repeated multicentennial cycle of tropical cyclone activity, the most recent of which commenced around ad 1700. The present cycle includes a sharp decrease in activity after 1960 in Western Australia. This is in contrast to the increasing frequency and destructiveness of Northern Hemisphere tropical cyclones since 1970 in the Atlantic Ocean and the western North Pacific Ocean. Other studies project a decrease in the frequency of tropical cyclones towards the end of the twenty-first century in the southwest Pacific, southern Indian and Australian regions. Our results, although based on a limited record, suggest that this may be occurring much earlier than expected.

1 comment:

  1. http://www.theaustralian.com.au/news/health-science/twister-decline-linked-to-warming/story-e6frg8y6-1226813535725

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