Greenhouses are increasingly important in the food supply of high latitude countries. Greenhouses protect crops from too much heat or cold,shield plants from dust storms and blizzards, and help to keep out pests. Light and temperature control allows greenhouses to turn inarable land into arable land. Greenhouses can feed starving nations where crops can't survive in the harsh deserts and Arctic wastes. Hydroponics can be used in greenhouses as well to make the most use of the interior space.