There can be many caused to the change of Earths temperature but one would be the use of fossil fuels. This is because when burned it releases Greenhouse gasses which are trapped in the atmosphere and causes heat. Which eventually leads to Global Warming. (Hopes this helps! )
Desert and Rainforest, I believe this could the right answer
Hinduism, it is a religion and most consider it a way of life and is one of the oldest religions is history.