As global warming proceeds, it is feared there will be an increase in typhoon occurrence. Giant Clams, found widely on coral reefs, have a lifespan of more than a hundred years and the largest shell among bivalves. The annual and daily rings built up on the shells during their lifetimes are drawing attention as detailed indicators of climate change in tropical areas. I would like to introduce recent efforts at searching for traces of past typhoons through daily growth ring and chemical analyses of Giant Clam shells found on Okinotori Island.