Answer:
There is a term "atmospheric circulation". It is when the air throughout the globe moves around. When the sun heats air near the equator more, and less at the poles. So the equator is warmer. The warm air near the equator moves either towards the south or the north, toward the poles. The warm air also rises up, and the cold air sinks. This is convection, but at a global scale. THis is also the cause of wind.