The Earth's glaciers and polar ice caps may seem like indestructible mountains of ice, but they are slowly melting from global warming. Climate change is also causing sea levels to rise, increasing the risk of floods in some coastal areas.

Human activity has an impact on global temperatures. Cars and large factories burn fossil fuels, which raise the level of carbon dioxide in the atmosphere. Decomposing waste in landfills and increased livestock rearing add to the amount of methane in the air. In fact, almost 30% of the methane in the air may be from animals like cows passing gas! To cap it all off, deforestation means there are fewer green plants to help keep the atmosphere in balance.