This document discusses global warming and its causes and effects. It states that global warming is caused by both natural phenomena like methane gas releases as well as human activities such as burning fossil fuels. Some of the documented effects of global warming include rising sea levels which threaten coastal communities, melting glaciers and permafrost, more frequent and severe storms, widespread species extinction by 2050, disappearance of coral reefs, spread of diseases, economic consequences, more wildfires, and increased air pollution and smog.