Without the natural greenhouse effect it would be 33 C colder than it is now. The water cycle is the system by which water in its varying forms cycles through the ground, through the atmosphere and at the Earth s surface. It plays a major, complex role in the Earth s climate. Water vapour in the atmosphere, on the other hand, is a powerful greenhouse gas. There is no universally accepted definition of drought.
Farmers define it differently than city dwellers and water engineers.
Any extended periods of dry weather that lasts longer than expected, or than normal, and leads to measurable losses like crop damage and water supply shortages are considered droughts. Droughts often creep up on us slowly but end with incredible abruptness. Since oceans cover so much of the Earth s surface, it is not surprising that they influence climate greatly. Water loses and gains heat more slowly than air. Because of this, oceans provide a moderating effect on the climate of coastal areas.