With Tree Rings On Their Fingers

There's a lot of apparently confident talk about how current temperatures compare with those in the past, including claims of 2023 being the “hottest year ever“ or at least in the last 125,000. But how do we actually know, and how much do we actually know, about historic and prehistoric temperatures? In this Climate Discussion Nexus “Backgrounder“ video John Robson examines the uses, and abuses, of various temperature proxies. To support the Climate Discussion Nexus, subscribe to our YouTube channel (), our Rumble channel (), our newsletter (at ) and our podcast on Spotify ( and Google (), like us on Facebook (), follow us on Twitter () and Gettr () and Instagram (), and make a monthly or one-time pledge at You can also now buy CDN merchandise at