Earth is the only planet in the solar system that is capable of supporting advanced life. Its unique combination of liquid water, a rich oxygen and nitrogen-based atmosphere, and dynamic weather patterns provide the basic elements for a diverse distribution of plant and animal life. The atmosphere acts like a blanket, evening out temperature extremes and keeping warmth in. Without this "greenhouse effect", Earth would be about 60°F cooler on average. Over the last few decades, scientists have measured a gradual increase in Earth's temperature. Human activity is causing this rapid change by increasing the amount of carbon dioxide and other greenhouse gases in the atmosphere.