In 2007 the United States Supreme Court ruled that Carbon dioxide is a pollutant and so the EPA (Environmental Protection Agency) has the right to regulate CO2 emissions from new cars. Any burning of fossil fuels like gasoline releases long-hidden carbon dioxide, a powerful greenhouse gas. This extra gas is too much for the natural carbon cycle to remove from the atmosphere, so it remains there capturing the sun's heat and causing global warming.
Certainly our normal understanding of pollution has very little to do with global warming. However you might argue that the
extra carbon dioxide being put into the atmosphere since the Industrial Revolution is disrupting the natural carbon cycle and so is a pollutant. (One definition of pollutant is "A substance or energy introduced into the environment that has undesired effects, or adversely affects the usefulness of a resource.")
Global warming, or climate change, is being caused by the
enhanced greenhouse effect. This is caused by the
extra carbon dioxide from the burning of fossil fuels (coal, oil and natural gas). It is also caused by methane belched from the many cows that are being raised just to feed red meat to the huge population of the world.
These greenhouse gases are the pollution that is directly causing global warming.