Final answer:
The contemporary climate change is influenced by natural factors such as volcanic eruptions and variations in the sun's intensity but cannot be fully explained by these alone. The rapid warming seen since the Industrial Revolution is largely due to human activities, despite historical climate changes being influenced by natural phenomena like solar activity and volcanic eruptions.
Step-by-step explanation:
Natural Influences on Climate Change
The climate change we are experiencing is influenced by various natural factors, including volcanic eruptions and changes in the sun's intensity. Volcanic eruptions can launch aerosols into the atmosphere, potentially cooling the planet by reflecting sunlight away. Solar intensity, characterized by the 11-year solar cycle, affects Earth's climate, but its role in recent warming is minimal as variations are quite small. Historical records and ice core data show that climate variations like the Medieval Climate Anomaly and the Little Ice Age can be attributed to natural climate drivers such as solar activity and volcanic eruptions. Nonetheless, these natural influences do not account for the rapid rise in global temperatures and the associated increase in atmospheric carbon dioxide levels seen since the Industrial Revolution.
Solar activity's impact on climate includes the changes to the chemistry and temperature structure of the upper atmosphere, potentially affecting ozone levels and altering circulation patterns. However, climate change data and models are clear that the warming observed over the past 50 years is not caused by solar variability. Long-term climatic shifts, such as ice ages, are influenced by changes in Earth's orbit and axis tilt, known as Milankovitch cycles, but these occur over tens of thousands of years and do not explain the contemporary rapid warming.