Tree ring expert Kevin Anchukaitis, of the tree ring lab at the Lamont-Doherty Earth Observatory, part of Columbia University's Earth Institute, talks about the information available in tree rings. And Colin Chartres, the director general of the International Water Management Institute, talks to Lynne Peeples about water issues. Plus, we test your knowledge of some recent science in the news, specifically the November issue of Scientific American magazine. Web sites related to this episode include;