For example, aside from solar magnetic activity, the Sun affects the Earth's climate in several other ways, including ultraviolet warming of the upper stratosphere, the nucleation of aerosols, and cloud formation. The climate is also subject to the rate of water vapor exchange between the atmosphere and Earth's surface, which requires taking into account ocean currents, wind, and geography.
La atmósfera contiene unas 750 gigatoneladas (Gt, 109 toneladas) de CO2, mientras que las emisiones anuales totales del ser humano son aproximadamente 5.5 Gt, añadiendo así cerca de 0.7% del total cada año.