Contemporary climate change includes both global warming and its impacts on Earth’s weather patterns. There have been previous periods of climate change, but the current rise in global average temperature is more rapid and is primarily caused by humans.[2][3] Burning fossil fuels adds greenhouse gases to the atmosphere, most importantly carbon dioxide (CO2) and methane. Smaller contributions come from agriculture, industrial processes, and forest loss.[4] Greenhouse gases warm the air by absorbing heat radiated by the Earth, trapping the heat near the surface. Greenhouse gas emissions amplify this effect, causing the Earth to take in more energy from sunlight than it can radiate back into space.