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 NSF, he uses dendrochronology--or tree-ring dating--to get a snapshot of climate change over time. Stahle can also determine things like the socioeconomic impact of droughts. In 1998, he made news with his discovery that drought could have contributed to the disappearance of colonists in Jamestown. He also found that 1587 was the driest year in 800 years. Stahle runs the Tree-ring Lab at the University of Arkansas and what he and fellow tree-ring researchers are learning is 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.
This is an episode from Science Nation, NSF's online magazine that's all about science for the people.
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