An Inuit hunter shot a strange polar bear in Hudson Bay. Its paws were not white, but brown. Upon further analysis, it was found that the animal also had larger than normal paws, and the shape of its head resembled that of a grizzly bear. Climate change is one of the greatest challenges facing humanity. But how and when did it begin? What is the history of its discovery? Why is science so emphatic about it? What impact is it having on the biosphere? The renowned science popularizer Angel Leon, author of History of Invasive Species, proposes an exciting journey to get to know those who solved the complex puzzle of the main events that shape the climate of our planet. With a pleasant and accessible style, he takes us into the anfractuous interactions between glaciers, volcanoes or the Sun itself, following the thread of how science studied their effects, to end up understanding that a single species, Homo sapiens, had been able to influence the climate of an entire planet.