Climate: Last northern summer was the warmest in more than 2,000 years, tree rings show The Associated PressAncient trees unlock an alarming new insight into our warming world CNNSummer 2023 Was the Northern Hemisphere’s Hottest in 2000 Years, Study Finds The New York TimesHottest summer in 2,000 years: Summer 2023 shattered records USA TODAYSummer of 2023 was the hottest in 2,000 years in some parts of the world, researchers say CBS News