Washington -- California's drought will be one of the extreme weather events that the American Meteorological Society will examine later this year to determine whether the cause is natural variability or human-caused climate change, a federal official said Tuesday. Scientists have not yet linked the California drought directly to climate change, Thomas Karl, head of the National Oceanic and Atmospheric Administration's National Climatic Data Center, said Tuesday in announcing the latest study. "I'M SURE THERE'S A WAY, but we haven't done it yet," he said.