Understand weather, climate, and the greenhouse effect. Weather depends on air temperature, humidity, clouds, wind, and air pressure. Learn about the water cycle, forms precipitation, meteorologist, weather forecasters, climate, climatologists, climate zones, latitudes, altitude, the greenhouse effect, climate change, carbon dioxide emissions, methane, clouds' effect on temperature, oceans and heat, currents, effects of higher ocean temperatures, melting sea ice, and the effects of global warming on ecosystems. Detailed graphics, diagrams, video, and multiple-choice reviews reinforce important concepts.