This document discusses greenhouse gases and global climate change. It defines greenhouse gases as gases that cause the greenhouse effect and trap heat in the lower atmosphere. It then defines global climate change as identifiable changes in Earth's climate that last for decades or longer, and are usually caused by either natural processes or human activities that release greenhouse gases. The document goes on to explain that current climate changes happening include warming oceans and atmospheres and melting ice, and that these changes are extremely likely to be caused by human-caused greenhouse gases according to the IPCC. The effects of continued climate change will include more extreme weather, sea level rise, damage to ecosystems and increased species extinctions.