Global warming is caused by carbon dioxide emissions from human activities like driving cars and burning fossil fuels for energy. This carbon dioxide traps heat in the atmosphere in the same way that glass traps heat in a greenhouse, causing average temperatures on Earth to rise. As the planet warms, ice caps and glaciers are melting, which causes sea levels to rise and could flood coastal areas. Many plants and animals are also affected by the changing climate. The rate of warming has increased over the past 150 years due to humanity's growing use of fossil fuels. Reducing fossil fuel use would help slow the pace of global warming.