We have been warned that our planet will change in unimaginable ways if we don't act soon, and new research shows that almost 50 percent of people aged 15-84 have already experienced significant changes. Seeing what lies ahead, climatologists have tried to show us, how climate change will intensify so that today's youth will be in the coming years bear the burden of climate impacts. Yet people around the world are already witnessing extreme and deadly weather events driven by rising temperatures that once seemed unimaginable. So how much climate change have humans experienced in their lifetimes? And who has weathered the biggest warming yet? These are the questions that Andrew King, a climate scientist who studies extreme events at the University of Melbourne in Australia, and his colleagues set out to answer in a new study. (CLARE WATSON)