The notion that human activities might be warming the planet started coming into focus in the 1960s and ’70s, before a scientific consensus emerged in the 1980s and ’90s. But the rough outlines of the science surrounding humanity’s greatest contemporary threat has a surprising, little-known history that dates back roughly two centuries. This brief animation from BBC Ideas traces our modern understanding of the greenhouse effect through the work of three pioneering scientists, beginning with the US scientist and women’s rights activist Eunice Foote, whose 1856 work on the heat-trapping effects of CO₂ was buried for decades before being rediscovered in 2010.