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.