If the earth is too warm, plants and animals may die. It can also change the places and times that rain falls, the amount of rain that falls, and all of our other weather patterns. The temperature will be too high and the rain patterns change. The rise in temperature is called global warming . Acid Rain Air pollution also causes acid rain .
Rainwater picks up particles and gases when it falls through the air.
If the air is polluted, the rainwater becomes polluted, too. Polluted rain is called acid rain . Some acids are helpful. We have acid in our stomachs to break down and digest food. We use vinegar, an acid, to pickle cucumbers.