A tonne of carbon dioxide is the strangest commodity ever traded. Nobody wants it, its value is the value of its absence, and the whole market rests on two things no one can see: the tonne itself, and the world in which it was emitted. Since 1997 we have built, broken, and rebuilt markets for that tonne — Kyoto's flexible mechanisms, Europe's emissions trading system and the €5 billion tax carousel that looted it, California's cap-and-trade and its forest offsets, the UN's scheme to pay tropical forests to stand, and a voluntary offset market that touched two billion dollars a year and then lost most of it when journalists and scientists found that most of what it sold did not exist. The Price of a Tonne walks that history with dates and sources: the Chinese refrigerant plants paid more to destroy their waste gas than to make their product; the phantom rainforest credits Disney, Shell and Gucci bought; the hundred-year wildfire insurance fund that burned through in a decade; the World Bank carbon pioneer indicted over cookstove data; the satellites now trying to weigh the world's forests from orbit; and the carbon border charge that went live on Europe's imports in January 2026. Then it asks the forester's question underneath all of it: you can price a tonne at a smokestack — but can you price a standing tree? Compiled by a physician who once weighed Douglas-firs for the Forest Service growth model that still projects every forest-carbon baseline in California, and who is now building software for the carbon-offset market. Thirteen episodes. ▶ Full series playlist: youtube.com/playlist?list=PLd_CyLzigkvo 🔔 Subscribe: youtube.com/@LetsRethinkHistory?sub_confirmation=1 🎙 Also available as an audio podcast — search "ReThink History: The Price of a Tonne" on Apple Podcasts or Spotify. 👍 Like and Subscribe — it really helps the channel reach others. #PriceOfATonne #CarbonMarkets #CarbonOffsets #ClimatePolicy #Forestry #EconomicHistory #ReThinkHistory