What were the conditions of the eath at the start of the big yawn?

At the start of the Big Yawn, roughly 2.5 billion years ago, Earth was characterized by a harsh and inhospitable environment. The atmosphere was primarily composed of carbon dioxide, with little to no free oxygen, and the planet was dominated by volcanic activity. Oceans were present but lacked the complex life forms seen today, and the surface temperatures were high, leading to a predominantly molten landscape. This period marked the transition into the Great Oxidation Event, which dramatically changed Earth's atmosphere and paved the way for the evolution of aerobic life.