Final answer:
Long-term swings between hothouse and icehouse conditions are driven by natural factors such as Milankovitch cycles, changes in solar activity, and volcanic eruptions. These factors influence Earth's climate by altering the amount of solar radiation it receives or by reflecting sunlight back into space, leading to significant periods of glaciation and changes in global temperatures over millions of years.
Step-by-step explanation:
The causes of long-term swings between hothouse and icehouse conditions on Earth, which occur over millions of years, can be attributed to various natural factors. One primary driver is Milankovitch cycles, which involve changes in Earth’s orbit and tilt due to the gravitational effects of other planets, influencing the distribution of solar energy received by Earth.
Another factor is changes in solar activity, like the low solar activity phase during the Little Ice Age, which leads to variations in solar radiation affecting Earth’s climate. Lastly, volcanic eruptions can release large amounts of sulfate particles into the atmosphere, reflecting sunlight back into space and causing cooling, as seen in periods of glaciation and ice sheet expansion.
These factors do not lead to rapid increases in global temperature or sustained increases in carbon dioxide, but they contribute to the natural climate variability over geologic time, manifesting in significant chilling events such as the Little Ice Age and massive ice ages that have periodically occurred throughout Earth's history.