<P> According to U.S. Scientist Jerry Mahlman and USA Today: Mahlman, who crafted the IPCC language used to define levels of scientific certainty, says the new report will lay the blame at the feet of fossil fuels with "virtual certainty," meaning 99% sure . That's a significant jump from "likely," or 66% sure, in the group's last report in 2001, Mahlman says . His role in this year's effort involved spending two months reviewing the more than 1,600 pages of research that went into the new assessment . </P> <P> Combustion of fossil fuels generates sulfuric, carbonic, and nitric acids, which fall to Earth as acid rain, impacting both natural areas and the built environment . Monuments and sculptures made from marble and limestone are particularly vulnerable, as the acids dissolve calcium carbonate . </P> <P> Fossil fuels also contain radioactive materials, mainly uranium and thorium, which are released into the atmosphere . In 2000, about 12,000 tonnes of thorium and 5,000 tonnes of uranium were released worldwide from burning coal . It is estimated that during 1982, US coal burning released 155 times as much radioactivity into the atmosphere as the Three Mile Island accident . </P> <P> Burning coal also generates large amounts of bottom ash and fly ash . These materials are used in a wide variety of applications, utilizing, for example, about 40% of the US production . </P>

Where does c in fossil fuels come from