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How Tree Rings Reveal Climate Secrets (Infographic)

Chart shows variability of El Niño since the year 1300.
We're headed for a drought worse than any seen in the past 1,000 years, according to a study of tree ring evidence. (Image credit: By Karl Tate, Infographics Artist)

Scientists can determine a lot about past climates by taking core samples from trees that have lived for hundreds or thousands of years. The study of a tree’s rings is called dendrochronology. 


The width of tree rings indicates the climate while the tree was growing. One ring represents one year. Thinner rings represent years when growth was stunted by lack of water.