Earth will eventually lose its oxygen because the sun gets brighter over time

As the Sun ages, it grows roughly 2% to 3% brighter every billion years, a process that will eventually destabilize Earth's climate. In approximately 1.1 billion years, this increased solar heat will trigger a runaway greenhouse effect, causing water to evaporate and trap even more heat. This process breaks down carbon dioxide, effectively starving the plants that produce our oxygen.