Scientists say a record-smashing March heat wave in the U.S. Southwest shows climate change is already driving more dangerous weather extremes. World Weather Attribution said Friday that the heat would have been virtually impossible without human-caused warming. Experts say extremes now hit more often, in odd seasons, and in unusual places. NOAA data shows a much larger share of the country sees extreme conditions than decades ago. An analysis by The Associated Press finds the U.S. breaks far more heat records than in past decades. One former FEMA official said disasters now fall outside old planning models and noted insurers pulling back.