The cause of the occurrence of drought?
1. by nature.
1.1 the world temperature changes.
1.2 climate change.
1.3 changes of sea level.
1.4 natural disasters such as earthquakes.
2. by the actions of human beings.
2.1 destruction of the ozone layer
2.2 impact of greenhouse deflation.
2.3 the development industry.
2.4 deforestation