When humans first set foot on the moon in 1969, the people of that decade thought the world had changed forever. Little did they know the world had already laid down the precise marker of a far greater global change four years earlier, signalling our planet had entered an entirely new geological epoch, the Anthropocene. That new epoch began between October and December 1965 according to new research published today in Scientific Reports by members of the Australasian Antarctic Expedition 2013-2014. The researchers were able to mark this profound change so precisely because of a radiocarbon “golden spike” found in the heartwood of a strange and singular tree, a Sitka Spruce found on Campbell Island, a World Heritage site in the middle of the Southern Ocean. The spruce is locally referred to as ‘the loneliest tree in the world’ with the next closest tree over 200km away on the Auckland Islands. The radioactive carbon spike was created by the culmination of mostly Northern Hemisphere atmospheric thermonuclear bomb tests in the 1950s and 1960s. The signal was fixed in the wood of the Campbell Island Sitka spruce by photosynthesis. “We were incredibly excited to find this signal in the Southern Hemisphere [...]