Deforestation is the process of cutting down trees or forest for the purpose of farming, lumbering mining, industrial, grazing and residential without immediate replanting of trees to replace the cut ones.
Climate is the long-term manifestations of weather and other atmospheric conditions in a given geographical area.
Air pollution is the contamination of the atmosphere with noxious gases such as fumes, smoke, dust particles, nuclear waste and so on.
Desert encroachment is the transformation of a habitable land into a desert. It is the incursion or advancement of desert to a place that is not originally a desert.