Global warming refers to the rising average temperature of the Earth due to increased greenhouse gas emissions. The greenhouse effect occurs when heat from the sun is trapped in the atmosphere by greenhouse gases like carbon dioxide, causing the planet to warm up. The main causes of global warming include the burning of fossil fuels for energy and transportation, which releases greenhouse gases into the atmosphere, as well as deforestation and decomposition in landfills. Results of global warming include melting glaciers and rising sea levels which flood coastal areas, destruction of forests by acid rain and increased wildfires, and threats to plants, animals, and humans.