In the years 43 and 42 before this era there was a sudden and severe cooling throughout the northern hemisphere. Tree rings from Scandinavia, stalactites from caves in northeastern China or ice trapped in the White Mountains of California recorded the climate anomaly. Temperatures in the northern hemisphere dropped by 7º in some areas. A study now points to an eruption of a volcano in Alaska. It was so intense and lasting that the authors of the work relate it to the end of the Roman Republic or Cleopatra's Egypt.
