Final answer:
The Roman and Han Empires were impacted by the end of the Roman Climate Optimum, surge in El Niño events, and reduced temperatures after a volcanic eruption.
Step-by-step explanation:
The climatic events that impacted both the Roman and Han Empires include:
- The end of the Roman Climate Optimum in the second century
- A surge in El Niño events in the fourth century
- Reduced temperatures after a massive volcanic eruption in the sixth century
These events had significant effects on agriculture, resulting in famine, economic instability, and weakened empires.