Uncertainty over typhoons’ link to climate change

Three typhoons churn through Asia in a week, a heatwave bakes the northern hemisphere and a drought slashes grain crop estimates in Australia.  Signs that scientists' worst fears about global warming are unfolding before our eyes, or is it just too early to tell?
While scientists say evidence that a build-up of gases such as carbon dioxide will likely bring more frequent and severe typhoons, heatwaves and drought in the future, there is uncertainty about whether the effects have already started to appear.
Lack of detailed historical data about the intensity of storms make it difficult for scientists to judge just how quickly weather patterns are changing.
"Usually we don’t associate a particular event to global change, simply because these extreme weather phenomena are occuring essentially year after year," said Liu Shaw-chen, director of Taiwan’s Research Centre for Environmental Changes at the government think-tank, Academia Sinica.