Every day, the ocean absorbs about 22 million tons of carbon dioxide, which is about the weight of 15 million hybrid automobiles. Just as you can't see the carbon dioxide that comes out of your own body each time you exhale, you can't see the gas as it dissolves into the seas. Space isn't an issue, considering that the oceans cover 72 percent of the planet, but there is a problem brewing beneath the waves. Carbon dioxide in the air helps insulate our planet and keep it warm. But there can be too much of a good thing: In the last 200 years, humans have added a lot of extra carbon dioxide to the atmosphere by burning fossil fuels like wood, coal and petroleum to produce energy. Two hundred years' worth of extra carbon dioxide in the atmosphere has bulked up our carbon dioxide blanket ? and average temperatures around the world are now rising. It's being referred to as global warming.