Some oil companies plan to get rid of some of the pollution they produce by pumping it into rocks deep inside the Earth, where they say it will stay for thousands of years. Other people ,though, aren’t so sure this is advisable; environmental groups say that putting this pollution back into the Earth is a bad idea.
When oil burns, it doesn’ t just produce heat: it also produces carbon dioxide. Carbon dioxide is a natural part of the air, but because people burn so much oil, there’ s too much carbon dioxide in the air. This extra carbon dioxide is pollution; some scientific studies show that carbon dioxide is one of the" greenhouse gases" that is causing the Earth’ s temperature to rise.
Environmentalists say that the oil companies’ plans may not work. The oil companies say they are making sure that the gas will never escape, but environmentalists wonder how the oil companies can be so sure that the gas won’ t seep into the air. They also point out that there’ s no way to check to make sure the gas isn’ t leaking. In addition, the environmentalists point out that the pumping costs money--for research and for equipment--that the oil companies should be spending on preventing pollution, rather than on just moving it someplace else.
Another problem, say some people who are concerned about the Earth, is that if the oil companies find a cheap way to get rid of their pollution, they won’ t look for new kinds of energy. These environmentalists say that energy companies should be researching ways to use hydrogen, wind power, and solar power instead of finding better ways to use oil. They argue that continuing to use oil means that we will still need to buy oil from other countries instead of producing our own cheap, clean energy.
Environmentalists also say that burying pollution just pushes the problem into the future, rather than really solving it. They say that if the oil companies pump carbon dioxide into the rocks inside the Earth, it will be there for thousands of years, and that no one knows if this plan--even if it works--might turn into a pollution problem for all of us in the future.
The oil companies insist that their plan is safe, and that putting the gas inside the Earth is a reasonable way to deal with it. They point out that there is a lot of room in the Earth for this extra gas, and that putting carbon dioxide inside the Earth means that the gas won’t be in the air, and if it’ s not in the air, it won’ t make the Earth warmer.
According to the passage, oil results in air pollution because（）
A. it burns very easily and has a very awful smell
B. it produces too much heat that warm up the temperature
C. it emits too much carbon dioxide into the air when burning
D. it is called the" greenhouse gas"