The greenhouse effect is the process by which greenhouse gases like water vapor, carbon dioxide, and methane in the atmosphere trap heat from the sun, warming the planet's surface above what it would be without an atmosphere. The existence of the greenhouse effect has been known since the early 19th century, and it is now understood that rising greenhouse gas levels from human activities like burning fossil fuels are enhancing the greenhouse effect and causing global climate change. Some effects of climate change include rising sea levels, changes to agricultural growing seasons, and threats to plants and animals unable to adapt to the changes. Reducing greenhouse gas emissions through individual actions like using energy efficient products and driving less can help address the problem.