In 2112, Earth’s air ceased to be breathable in a runaway atmospheric event which later came to be known as the shift. After centuries of ignoring their impact on their atmosphere, Humankind found themselves too late to stop a series of chemical reactions that had begun. Temperatures rose rapidly until the oceans began to boil. This heating of the crust released numerous toxic gases into the atmosphere. Though Humanity was faced with extinction, they survived. They built up.