The document discusses global warming and its effects. It notes that global warming is caused by increasing greenhouse gases from human activities like burning fossil fuels. This causes the average temperature of the earth to rise and leads to problems like rising sea levels, more extreme weather, and species extinction. The document also discusses how sea level rise occurs from thermal expansion of oceans and melting of land-based ice sheets and glaciers. It outlines some of the impacts of rising sea levels like coastal erosion and increased flooding.