Ninety years of observational data has revealed summer climates in regions across the globe are changing and mostly warming, U.S. researchers say. Those are the results of a study reported by Irina Mahlstein, an environmental scientist at the University of Colorado Boulder, which reveals location-by-location temperature changes rather than global averages. \"It is the first time that we show on a local scale that there are significant changes in summer temperatures,\" Mahlstein said. \"This result shows us that we are experiencing a new summer climate regime in some regions.\" By detecting temperatures outside the expected norm, the study could yield valuable insights into changes in ecosystems on a regional scale, she said. To identify potential temperature changes, the researchers analyzed climate observations recorded from 1920 to 2010 from around the globe. Their analysis found some changes began to appear as early as the 1960s, and the observed changes were more prevalent in tropical areas. Temperature extremes became more frequent in the later time periods, Mahlstein said. \"You see how the extreme events of the past have become a normal event.\"