Question

Why did the ice sheets of 18,000 years ago, which covered much of North America, melt? Question 13 options: The ozone layer temporarily disappeared The Milankovitch orbital cycles shifted into a pattern that favored warmer summers and melting ice over thousands of years Large volcanic eruptions melted the ice The sunspot cycle amplified and the increased solar energy melted the ice Natural increases in carbon dioxide, methane, and CFCs caused an earlier version of "global warming"

Answer 1

The melting of the ice sheets from 18,000 years ago was primarily due to Milankovitch orbital cycles that changed how solar energy was distributed, leading to warmer summers and the gradual retreat of ice over thousands of years.

Step-by-step explanation:

The ice sheets from 18,000 years ago melted primarily due to shifts in earth's orbit, known as Milankovitch cycles. These cycles are long-term changes in the tilt and shape of Earth's orbit caused by gravitational interactions with other celestial bodies, leading to variations in the distribution of solar energy across the planet.

These changes favored warmer summers, which over thousands of years contributed to the melting of the ice. Additionally, other natural factors such as volcanic activity, changes in solar activity, and alterations in atmospheric gas concentrations can influence global temperatures and ice sheet dynamics. However, the primary driver for the melting of the ice sheets from the last ice age was the shift in orbital patterns.