Volcanoes are areas on or beneath the surface of the Earth where magma (molten rock) is stored, containing trapped gases such as carbon dioxide and sulfur dioxide. When magma is ready to erupt, it breaks through the surface, providing a conduit for releasing gasses that cool the Earth’s atmosphere.
While there are natural volcanic eruptions on this planet, human activities have increased the amount of volcanic activity worldwide. The main reason for this is the creation of new islands formed by volcanic activity.