CNN —The West’s recent heat-driven megadroughts are unprecedented in at least 500 years, new research shows. “Hot drought” — when extreme drought and heat occur simultaneously — has increased in severity and frequency over the last century due to human-caused climate change, according to a study published Wednesday in the journal Science Advances. While the previous study measured the length and width of the tree rings to gauge drought conditions, King’s research analyzed the density of the rings to measure how temperatures changed over time. “More dense rings mean warmer temperatures, and less dense rings mean cooler temperatures, typically,” King explained. “Water security and wildfire will become bigger problems until climate change is stopped,” said Overpeck, who was not involved with the study but has done research on hot droughts.

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Persons: ”, Karen King, ” King, King, Jonathan Overpeck, Overpeck Organizations: CNN, University of Tennessee, University of Michigan’s School for Environment, Sustainability Locations: Knoxville, Pacific Northwest, Utah , Arizona, Colorado