A greenhouse is a structure that allows people to regulate climatic conditions, such as temperature and humidity. Greenhouses can be constructed of a variety of materials, like wood and polyethylene plastic, and can range in size from small sheds to industrial-sized buildings and enormous glasshouses. The word greenhouse can be used interchangeably with the terms glasshouse and hothouse, depending on the buildings material and heating system. The smallest example is a miniature greenhouse known as a cold frame, typically used at home, whereas large commercial greenhouses are high tech production facilities for vegetables, flowers or fruits. Greenhouses are filled with equipment including screening installations, heating, cooling, and lighting, and may be controlled by a computer to optimize conditions for plant growth. Heating or electricity is one of the most considerable costs in the operation of greenhouses across the globe, especially in colder climates.

The greenhouse effect is a natural process that occurs when gases in Earths atmosphere trap the Suns heat, similar to the way a greenhouse traps heat. Greenhouse gases consist of carbon dioxide, methane, ozone, nitrous oxide, chlorofluorocarbons, and water vapor. Water vapor, which reacts to temperature changes and is the most abundant greenhouse gas, is responsible for about two-thirds of the greenhouse effect. However, human activities, such as burning fossil fuels, have increased the concentration of carbon dioxide in the atmosphere, which traps extra heat near Earths surface and causes temperatures to rise.