Fewer cyclones with climate change, but They are getting Stronger - but why? - 7th Apr 2011

At this week's Greenhouse 2011 conference in Cairns, a swell of researchers agreed on one conclusion.

Quoting Tom Knutson, co-chairman of the World Meteorological Organisation's expert team on climate impacts on tropical cyclones, The Australian reports: Also at the conference was meteorologist Kevin Walsh of the University of Melbourne, who told Sydney Morning Herald that his climate models predicted a 20 per cent drop in the number of cyclones affecting Australia by 2100, but an increase of about five per cent in the strength of cyclones.

The big question, posed by Matthew Collins at Exeter University, UK, was: why? "We can't give a lucid answer at this time," replied Knutson - which he admitted, was a concern. One clue, however, came from the modelling.

Knutson said that removing carbon dioxide from the models wiped off around half of the cyclone's predicted intensity. Speculating, Steve Sherwood at the University of New South Wales, Sydney, Australia says that since CO₂ absorbs heat, more CO₂ in the atmosphere could affect where, and with what intensity, water vapour is being heated over the ocean.

As for what would make cyclones happen less often: "That's something I would like to figure out," says Sherwood: Source