WASHINGTON (AP) — A new study says climate change has tripled the frequency of atmospheric wave events linked to extreme summer weather in the last 75 years. And the research indicates that may explain why long-range computer forecasts keep underestimating the surge in killer heat waves, droughts and floods. Monday’s study says that in the 1950s, Earth averaged about one extreme weather-inducing planetary wave event a summer. But now it’s getting about three each summer. Planetary waves are connected to 2021’s deadly and unprecedented Pacific Northwest heat wave and wildfires, the 2010 Russian heatwave and Pakistan flooding and the 2003 killer European heatwave. Reporting by Seth Borenstein, Associated Press Banner image: Survivors wade through water in their village Khairpur Nathan Shah, Pakistan, on Nov. 2, 2010, which is surrounded by floodwaters. (AP Photo/Shakil Adil, File)This article was originally published on Mongabay