Final answer:
The period known as the inter-glacial period began about 12,000 years ago following the rapid warming of Earth after the Pleistocene maximum.
Step-by-step explanation:
The time period that marks the end of rapid warming on Earth after the Pleistocene maximum, about 12,000 years before the present, is called the inter-glacial period. This period follows the last ice age and signifies a phase when Earth experienced warmer temperatures, leading to the melting of large ice sheets that had covered much of the Northern Hemisphere. The transition to the inter-glacial period is a significant event in Earth's climate history, as it marked the end of the last glaciation and the beginning of a warmer climate phase that continues to the present day.