Transcript: The Sun is the source of all the Earth’s energy, and life could not exist without the Sun. In addition, there’s growing evidence that long term variations in the Sun’s output profoundly affect the Earth’s climate. For example, in the period from 1645 to 1715 sunspots were at a generic minimum called the Maunder Minimum. And in Europe an ice age was experienced with cold temperatures, and this is confirmed by tree rings from the time. From 1540 to the present day there have been many droughts in Africa. Statistical analysis shows that they correlate very well with sunspot minima. Thus, on a period of the solar cycle there’s evidence that the Sun affects the Earth’s climate. In addition, there is less secure evidence that variation in the Sun’s output affects the Earth’s climate on a timescale of hundreds or thousands of years. Earth, for example, experiences mini ice ages every several thousand years. This evidence is less good because evidence of the Sun’s output is indirect over those timescales, as is evidence of the Earth’s temperature.