What are the main factors that contribute to climate change? Your response should contain at least 3 paragraphs. Paragraphs are separated with the markdown divider: ***. Highlight at least 2 sections in your answer with markdown, i.e. *highlighted section*. In your response, the word "greenhouse" should appear at least 3 times. At the end of your response, please explicitly add a postscript starting with "P.S.".

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