Science Nation: Lord Of The Tree Rings

David Stahle travels to ancient forests around the world, collecting tree rings to learn more about major climate and historical events dating back hundreds and thousands of years. With help from the National Science Foundation, he uses dendrochronology, or tree-ring dating, to get a snapshot of climate change over time. Stahle runs the Tree-ring Lab at the University of Arkansas, where he and fellow tree-ring researchers are learning that a trend of global warming began in the 1800s and continues today, brought about by changes in tropical sea surface temperatures of no more than a few tenths of a degree Celsius. Today Stahle is working with hydrologists and government planners in California and throughout Mexico to plan for drought and climate change events.

(Source: DCMP)