Life-cycle greenhouse gas emissions of energy sources refer to the amount of greenhouse gases (GHGs) released into the atmosphere when a type of energy is created. A greenhouse gas is a gas that traps heat in the atmosphere and makes the Earth warmer. Burning different types of fuel, like gasoline, diesel, coal, and natural gas, releases GHGs into the atmosphere. GHGs come from different places in the life cycle of energy sources: when the fuel is produced, when it is burned, and when it is disposed of. The amount of GHGs released from each type of energy source can be different. For example, burning natural gas for electricity can release fewer GHGs than burning coal or oil. It is important to reduce GHG emissions from energy production so we can help slow down climate change.