cyclones double in 30 years

NEWS During cyclone Meena last year, waves smashed up 13 metre high cliffs in Mangaia, southern most of the Cook Islands, took out two houses at the top and ran a further 50 metres inland. “Just imagine a couple of those hitting here,” warns coastal protection developer Don Dorrell on the first day of a climate change workshop on Rarotonga. Meena was one of five cyclones that struck Cook Islands last year, all of them high intensity events. “You have to remember that none of these cyclones actually hit us,” says Dorrell. All five were near misses. Severe cyclones have more than doubled in number in the last 30 years, according to figures quoted by Dorrell. Atmospheric scientist Kerry Emanual published an extensive study of 4,800 hurricanes over the last 30 years of satellite tracking. “His findings are as damning as they are scary,” says Dorrell. Category four and five cyclones are the most damaging. These have risen from 17 between 1970 and 1974 to 37 extreme cyclones between 2000 and 2004. “There’s only one problem with this graph is that it stops in 2004,” says Dorrell, “so that it doesn’t include the likes of Katrina and the four or five that went through us here in the Cook Islands.” Many Rarotonga residents remember Cyclone Sally in 1987 that did hit but was only a category one cyclone. Category one cyclones have actually decreased from 43 at the start of the 1970’s to 29 at the start of the 2000’s, while category two and three remain stable at around 40 events. If this trend continues, the number of extreme cyclones will double again within 15 years, and double again in less than a decade after that. At the same time, sea levels across the Pacific will rise, delegates at the World Wildlife Fund climate change workshop were told today. By 2020, sea level will be nine centimetres higher than they were in 1990. “Up in the northern group of the Cook Islands, most of the islands are one metre or one and a half metres above sea level,” says Maara Vaiimene from the Meterological Office. “The sea can also cause coastal flooding with people living near the coast.” Coastal flooding is expected to worsen well before 2060, when sea level rise will be as much as 28 centimetres. “Here in Rarotonga because we are quite a high place in the coastal areas we don’t worry about the impacts of sea level rise.” Like the northern Cooks, most of the region’s islands are low atolls. Future sea level rises come on top of an estimated 10 to 25 centimetres rise already in the last century between 1906 and 2006. Rates of climate change impacts are about to increase rapidly, replacing decades of slow change, according to WWF officials. “Over the last 200 years the amount of carbon dioxide in the atmosphere has increased by about a third. Over the next 30 years the carbon dioxide is going to increase by 60 per cent,” says WWF’s Jyotishma Rajan. “So we should be worried.” Presenting the sea level rise figures, Rajan quoted from figures put together by Ian Fry, International Environment Issues Adviser to the government of Tuvalu, an all-atoll nation which has taken a lead role in raising awareness of impacts on low lying islands. Climate change sceptics have previously dismissed effects of global warming saying global temperatures have risen by less than one degree. Rajan confirms the percentage. “Since 1860 global temperatures have risen by an average of 0.8 degrees. But remember that when you go to the doctor a rise of just one percent means that you are quite ill.” But averages do not provide the full picture of weather extremes. “The world has never experienced a year as hot as 2005. It was the hottest year on record,” says Rajan. “By 2100 temperatures will be 1.6 degrees to 5 degrees hotter than they are now.” Already, at less than one percent increase, “scientists are saying and I find this fact quite alarming that the average storm is lasting 60 percent longer and the wind speeds 15 percent higher.” Dorrell told participants that this year has already seen the world’s most powerful cyclone off Australia and that weather scientists are considering if there is a need to add a new category. photo: Geoff Mackley www.rambocam.com