First: America is about 50 km thick. And no that is not around our waists. And 3937 km across, again not at our waists. We are about 2,700 km "tall." Now, you should all remember that density is mass divided by volume and that volume is base times height times width and that density times volume will equal the mass. Rock has an average density of 3.0x10^12 kg/ km^3 This means that if we mathy multiply everything that America, if we assume a box of uniform density and ignor continental shelves and oceany stuff and peopley stuff, weighs approximately 1.59 x 10^21 kg (about 7.23 x 10^20 lbs--alot!)
Second: According to the Brittanica 2005 Almanac this planet has something like 735 million cars. Now if we make the ridiculous assumption that each vehicle has a 20 gallon tank filled with octane that needs filling if you are lucky every two weeks or about 26 times per year. And if we remember from our chemistry classes that octane is an 8 carbon chain that when combusted will form 8 carbon dioxides. We need a few unit converters like 1 Gallon is equal to 3.785 litres and that there are 6.023 x 10 with 23 zeros after it husbands of Eve (atoms) per small fury rodent (mole) and that there are 22.4 litres per said rodent. If we again remember that CO2 is made up of two oxygen and a carbon and that a whole lot of them weigh about 44 grams/ rodent and knowing that there are 1000 g/kg This means that by driving our cars we are pumping 1.425 x 10^12 kg per year into the atmosphere.
Conclusion: Assuming that we could turn every rock into gasoline, oh wouldn't the oil companies love that, we will have turned our entire country into atmospheric pollutants in just over 1.1 Billion years. We MUST stop this calamity. If you are a true patriot, for the love of our country PLEASE stop burning fossil fuels. We only have 1.1 Billion years left! Remember what we do today will affect our grandchildren 50 million generations hence! So I implore you, act now, ride the bus, carpool, do what ever you can to reduce global warming Incidently, if we assume a linear relationship between carbon concentrations and temperature our planet's average temperature should be something like 3.1 gajillion degrees Fahrenheit. That's not even considering other resources drains such as breathing, population doubling, etc. Things really are looking grim so please act now!