Instead of positing all of this "he said she said" crap let's look at some facts and do a little analysis.
According to a Seattle times article from 2004 the U.S. burned 8.93 million barrels of gasoline a day in 2003. At 42 gallons per barrel this amounted to 375,060,000 gallons a day. Now, multiply that times 365 days and the total comes to 136,896,900,000 gallons a year.
Ok, so we burn around 137 billion gallons of fuel a year in the United States alone.
Now, let's say assuming historical use trends that we use this number to average the past 30 years. This is imprecise, but given that oil usage hasn't changed much since the 1970's it's not completely unrealistic either. Our final number should come out to, roughly, the equivalent of the past 35 years of use.
137 billion times thirty years equals 4,106,907,000,000 gallons!
The bottom line? Even while cutting corners it's pretty obvious that the United States has burned 4.1 trillion gallons of gasoline or more in recent history. To put this in perspective that comes out to 4/5ths the volume of the Great Salt Lake. Throw in the rest of the world and a lot more has been burned.
The details beyond this I'm not qualified to cover, but seeing as we know that matter can't be created or destroyed it's safe to say when gas burns the vast majority goes into the atmosphere.
Bottom line is, true or false, there's reason to believe our actions *could* have consequences.
Sources:
http://www.eia.doe.gov/emeu/aer/eh/frame.html
http://seattletimes.nwsource.com/html/opinion/2001918066_gascomment30.html
http://www.deq.utah.gov/Issues/GSL_WQSC/docs/related_fact_sheets/GSLcharacteristics.pdf