Yale Environment 360: For the past three decades, Europe has been experiencing its warmest summers since the days of the Roman Empire, according to a study published in the Environmental Research Letters Journal. The study, compiled by 40 academics, concluded that average summer temperatures have been 1.3 degrees Celsius hotter than they were 2,000 years ago. Heat waves also occur more often and last longer. The temperature figures were calculated by analyzing the tree ring analysis of three pine species found in Austria,...