The document discusses global warming, climate change, and the greenhouse effect. It explains that greenhouse gases like carbon dioxide and methane trap heat in the lower atmosphere, causing global warming and climate change over time. While some effects may appear positive, like longer growing seasons, global warming is largely caused by human emissions and will have severe consequences like rising sea levels and ecosystem damage if left unaddressed. Some ways to reduce global warming include using less energy and driving less. While most scientists agree that human activity is causing climate change, there are dissenting opinions.