The global climate system is driven by energy, almost all of which comes from the Sun. In this chapter, variations in the Sun-Earth relationship, which create spatial and temporal variations in the receipt of solar radiation over Earth's surface, are examined. Imbalances in energy inputs and outputs lead to massive transfers of energy in both the atmosphere and oceans. These factors control the nature of climate and lead to very distinctive climates in different regions of the world. To understand New Zealand's climate, it is necessary to first take a global view of the climate system of Earth.