What happened during the Pleistocene to cause global cooling?low solar activityfossil fuel consumptionbreakup of Pangaeaa shift in earth’s orbit

The Pleistocene epoch, also known as the Ice Age, was characterized by global cooling and the expansion of ice sheets across the Earth. This was primarily caused by a shift in the Earth's orbit, known as Milankovitch cycles.

Here's a step-by-step explanation:

1. Milankovitch cycles: These are long-term variations in the orbit of the Earth which result in changes in climate over periods of tens to hundreds of thousands of years. The cycles are related to changes in the Earth's orbit around the sun, the tilt of the Earth's axis, and the precession, or 'wobble', of the Earth's axis.

2. Changes in the Earth's orbit: The Earth's orbit around the sun is not a perfect circle, but an ellipse. The shape of this ellipse changes over time, in a cycle that takes around 100,000 years. When the ellipse is more elongated, the Earth is further from the sun and receives less solar energy, leading to cooler temperatures.

3. Changes in the Earth's tilt: The Earth's axis is tilted relative to its orbit around the sun. This tilt changes over a cycle of around 41,000 years. When the tilt is smaller, the difference between summer and winter temperatures is less extreme, leading to cooler summers and milder winters.

4. Changes in the Earth's precession: The Earth's axis also 'wobbles' in a cycle of around 26,000 years. This wobble changes the timing of the seasons, which can lead to cooler temperatures.

These factors combined to cause the global cooling during the Pleistocene epoch. It's important to note that other factors, such as volcanic activity and changes in greenhouse gas concentrations, also played a role in the Earth's climate during this time. However, the breakup of Pangaea, low solar activity, and fossil fuel consumption are not considered primary causes of the global cooling during the Pleistocene.