He walks through the Milankovitch cycles step by step, explaining how perihelion distance varies and how three orbital forces can either cancel each other out or amplify together. Around 14,500 to 15,000 years ago, these forces aligned in a way that triggered warming, pulling Earth out of the most extreme ice age on record. This is not speculation, this is orbital mechanics translating into climate forcing. The evidence shows the planet began to warm slowly, driven by predictable celestial geometry, not random fluctuation. What happened next, as that warming accelerated, is where the story gets more complicated and the data more striking.