The greenhouse effect makes the earth able to have people living on it, if there gets to be too many gases, the earth can get unusually warmer, and many plants, animals, and people will die. They would die because there would be less food this would happen because the plants would not be able to take the heat. This would cause us to have less food to eat, but it would also limit the food that animals have. With less food, gradually, people, plants, and animals would all die of hunger.